LoongArch changes for v6.9

1, Add objtool support for LoongArch;
 2, Add ORC stack unwinder support for LoongArch;
 3, Add kernel livepatching support for LoongArch;
 4, Select ARCH_HAS_CURRENT_STACK_POINTER in Kconfig;
 5, Select HAVE_ARCH_USERFAULTFD_MINOR in Kconfig;
 6, Some bug fixes and other small changes.
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Merge tag 'loongarch-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson

Pull LoongArch updates from Huacai Chen:

 - Add objtool support for LoongArch

 - Add ORC stack unwinder support for LoongArch

 - Add kernel livepatching support for LoongArch

 - Select ARCH_HAS_CURRENT_STACK_POINTER in Kconfig

 - Select HAVE_ARCH_USERFAULTFD_MINOR in Kconfig

 - Some bug fixes and other small changes

* tag 'loongarch-6.9' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson:
  LoongArch/crypto: Clean up useless assignment operations
  LoongArch: Define the __io_aw() hook as mmiowb()
  LoongArch: Remove superfluous flush_dcache_page() definition
  LoongArch: Move {dmw,tlb}_virt_to_page() definition to page.h
  LoongArch: Change __my_cpu_offset definition to avoid mis-optimization
  LoongArch: Select HAVE_ARCH_USERFAULTFD_MINOR in Kconfig
  LoongArch: Select ARCH_HAS_CURRENT_STACK_POINTER in Kconfig
  LoongArch: Add kernel livepatching support
  LoongArch: Add ORC stack unwinder support
  objtool: Check local label in read_unwind_hints()
  objtool: Check local label in add_dead_ends()
  objtool/LoongArch: Enable orc to be built
  objtool/x86: Separate arch-specific and generic parts
  objtool/LoongArch: Implement instruction decoder
  objtool/LoongArch: Enable objtool to be built

arch/loongarch/Kconfig

@@ -15,6 +15,7 @@ config LOONGARCH
 	select ARCH_ENABLE_THP_MIGRATION if TRANSPARENT_HUGEPAGE
 	select ARCH_HAS_ACPI_TABLE_UPGRADE	if ACPI
 	select ARCH_HAS_CPU_FINALIZE_INIT
+	select ARCH_HAS_CURRENT_STACK_POINTER
 	select ARCH_HAS_FORTIFY_SOURCE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS
@@ -104,6 +105,7 @@ config LOONGARCH
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
+	select HAVE_ARCH_USERFAULTFD_MINOR if USERFAULTFD
 	select HAVE_ASM_MODVERSIONS
 	select HAVE_CONTEXT_TRACKING_USER
 	select HAVE_C_RECORDMCOUNT
@@ -133,20 +135,24 @@ config LOONGARCH
 	select HAVE_KPROBES
 	select HAVE_KPROBES_ON_FTRACE
 	select HAVE_KRETPROBES
+	select HAVE_LIVEPATCH
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_NMI
+	select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS
 	select HAVE_PCI
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
 	select HAVE_PREEMPT_DYNAMIC_KEY
 	select HAVE_REGS_AND_STACK_ACCESS_API
+	select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC
 	select HAVE_RETHOOK
 	select HAVE_RSEQ
 	select HAVE_RUST
 	select HAVE_SAMPLE_FTRACE_DIRECT
 	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
 	select HAVE_SETUP_PER_CPU_AREA if NUMA
+	select HAVE_STACK_VALIDATION if HAVE_OBJTOOL
 	select HAVE_STACKPROTECTOR
 	select HAVE_SYSCALL_TRACEPOINTS
 	select HAVE_TIF_NOHZ
@@ -624,6 +630,8 @@ config RANDOMIZE_BASE_MAX_OFFSET
 
 	  This is limited by the size of the lower address memory, 256MB.
 
+source "kernel/livepatch/Kconfig"
+
 endmenu
 
 config ARCH_SELECT_MEMORY_MODEL

arch/loongarch/Kconfig.debug

@@ -26,4 +26,15 @@ config UNWINDER_PROLOGUE
 	  Some of the addresses it reports may be incorrect (but better than the
 	  Guess unwinder).
 
+config UNWINDER_ORC
+	bool "ORC unwinder"
+	select OBJTOOL
+	help
+	  This option enables the ORC (Oops Rewind Capability) unwinder for
+	  unwinding kernel stack traces.  It uses a custom data format which is
+	  a simplified version of the DWARF Call Frame Information standard.
+
+	  Enabling this option will increase the kernel's runtime memory usage
+	  by roughly 2-4MB, depending on your kernel config.
+
 endchoice

arch/loongarch/Makefile

@@ -26,6 +26,18 @@ endif
 32bit-emul		= elf32loongarch
 64bit-emul		= elf64loongarch
 
+ifdef CONFIG_UNWINDER_ORC
+orc_hash_h := arch/$(SRCARCH)/include/generated/asm/orc_hash.h
+orc_hash_sh := $(srctree)/scripts/orc_hash.sh
+targets += $(orc_hash_h)
+quiet_cmd_orc_hash = GEN     $@
+      cmd_orc_hash = mkdir -p $(dir $@); \
+		     $(CONFIG_SHELL) $(orc_hash_sh) < $< > $@
+$(orc_hash_h): $(srctree)/arch/loongarch/include/asm/orc_types.h $(orc_hash_sh) FORCE
+	$(call if_changed,orc_hash)
+archprepare: $(orc_hash_h)
+endif
+
 ifdef CONFIG_DYNAMIC_FTRACE
 KBUILD_CPPFLAGS += -DCC_USING_PATCHABLE_FUNCTION_ENTRY
 CC_FLAGS_FTRACE := -fpatchable-function-entry=2
@@ -72,8 +84,6 @@ KBUILD_CFLAGS_KERNEL		+= $(call cc-option,-mdirect-extern-access)
 KBUILD_CFLAGS_KERNEL		+= $(call cc-option,-fdirect-access-external-data)
 KBUILD_AFLAGS_MODULE		+= $(call cc-option,-fno-direct-access-external-data)
 KBUILD_CFLAGS_MODULE		+= $(call cc-option,-fno-direct-access-external-data)
-KBUILD_AFLAGS_MODULE		+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
-KBUILD_CFLAGS_MODULE		+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
 else
 cflags-y			+= $(call cc-option,-mno-explicit-relocs)
 KBUILD_AFLAGS_KERNEL		+= -Wa,-mla-global-with-pcrel
@@ -82,6 +92,15 @@ KBUILD_AFLAGS_MODULE		+= -Wa,-mla-global-with-abs
 KBUILD_CFLAGS_MODULE		+= -fplt -Wa,-mla-global-with-abs,-mla-local-with-abs
 endif
 
+KBUILD_AFLAGS			+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
+KBUILD_CFLAGS			+= $(call cc-option,-mno-relax) $(call cc-option,-Wa$(comma)-mno-relax)
+KBUILD_AFLAGS			+= $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
+KBUILD_CFLAGS			+= $(call cc-option,-mthin-add-sub) $(call cc-option,-Wa$(comma)-mthin-add-sub)
+
+ifdef CONFIG_OBJTOOL
+KBUILD_CFLAGS			+= -fno-jump-tables
+endif
+
 KBUILD_RUSTFLAGS			+= --target=$(objtree)/scripts/target.json
 KBUILD_RUSTFLAGS_MODULE		+= -Crelocation-model=pic
 

arch/loongarch/crypto/crc32-loongarch.c

@@ -44,7 +44,6 @@ static u32 crc32_loongarch_hw(u32 crc_, const u8 *p, unsigned int len)
 
 		CRC32(crc, value, w);
 		p += sizeof(u32);
-		len -= sizeof(u32);
 	}
 
 	if (len & sizeof(u16)) {
@@ -80,7 +79,6 @@ static u32 crc32c_loongarch_hw(u32 crc_, const u8 *p, unsigned int len)
 
 		CRC32C(crc, value, w);
 		p += sizeof(u32);
-		len -= sizeof(u32);
 	}
 
 	if (len & sizeof(u16)) {

arch/loongarch/include/asm/Kbuild

@@ -1,9 +1,12 @@
 # SPDX-License-Identifier: GPL-2.0
+generated-y += orc_hash.h
+
 generic-y += dma-contiguous.h
 generic-y += mcs_spinlock.h
 generic-y += parport.h
 generic-y += early_ioremap.h
 generic-y += qrwlock.h
+generic-y += qspinlock.h
 generic-y += rwsem.h
 generic-y += segment.h
 generic-y += user.h

arch/loongarch/include/asm/bug.h

@@ -44,6 +44,7 @@
 do {								\
 	instrumentation_begin();				\
 	__BUG_FLAGS(BUGFLAG_WARNING|(flags));			\
+	annotate_reachable();					\
 	instrumentation_end();					\
 } while (0)
 

arch/loongarch/include/asm/cacheflush.h

@@ -37,8 +37,6 @@ void local_flush_icache_range(unsigned long start, unsigned long end);
 #define flush_icache_range	local_flush_icache_range
 #define flush_icache_user_range	local_flush_icache_range
 
-#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 0
-
 #define flush_cache_all()				do { } while (0)
 #define flush_cache_mm(mm)				do { } while (0)
 #define flush_cache_dup_mm(mm)				do { } while (0)
@@ -47,7 +45,6 @@ void local_flush_icache_range(unsigned long start, unsigned long end);
 #define flush_cache_vmap(start, end)			do { } while (0)
 #define flush_cache_vunmap(start, end)			do { } while (0)
 #define flush_icache_user_page(vma, page, addr, len)	do { } while (0)
-#define flush_dcache_page(page)				do { } while (0)
 #define flush_dcache_mmap_lock(mapping)			do { } while (0)
 #define flush_dcache_mmap_unlock(mapping)		do { } while (0)
 

arch/loongarch/include/asm/exception.h

@@ -6,6 +6,8 @@
 #include <asm/ptrace.h>
 #include <linux/kprobes.h>
 
+extern void *exception_table[];
+
 void show_registers(struct pt_regs *regs);
 
 asmlinkage void cache_parity_error(void);

arch/loongarch/include/asm/io.h

@@ -71,6 +71,8 @@ extern void __memcpy_fromio(void *to, const volatile void __iomem *from, size_t
 #define memcpy_fromio(a, c, l) __memcpy_fromio((a), (c), (l))
 #define memcpy_toio(c, a, l)   __memcpy_toio((c), (a), (l))
 
+#define __io_aw() mmiowb()
+
 #include <asm-generic/io.h>
 
 #define ARCH_HAS_VALID_PHYS_ADDR_RANGE

arch/loongarch/include/asm/module.h

@@ -6,6 +6,7 @@
 #define _ASM_MODULE_H
 
 #include <asm/inst.h>
+#include <asm/orc_types.h>
 #include <asm-generic/module.h>
 
 #define RELA_STACK_DEPTH 16
@@ -21,6 +22,12 @@ struct mod_arch_specific {
 	struct mod_section plt;
 	struct mod_section plt_idx;
 
+#ifdef CONFIG_UNWINDER_ORC
+	unsigned int num_orcs;
+	int *orc_unwind_ip;
+	struct orc_entry *orc_unwind;
+#endif
+
 	/* For CONFIG_DYNAMIC_FTRACE */
 	struct plt_entry *ftrace_trampolines;
 };

arch/loongarch/include/asm/orc_header.h

@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#ifndef _ORC_HEADER_H
+#define _ORC_HEADER_H
+
+#include <linux/types.h>
+#include <linux/compiler.h>
+#include <asm/orc_hash.h>
+
+/*
+ * The header is currently a 20-byte hash of the ORC entry definition; see
+ * scripts/orc_hash.sh.
+ */
+#define ORC_HEADER					\
+	__used __section(".orc_header") __aligned(4)	\
+	static const u8 orc_header[] = { ORC_HASH }
+
+#endif /* _ORC_HEADER_H */

arch/loongarch/include/asm/orc_lookup.h

@@ -0,0 +1,31 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ORC_LOOKUP_H
+#define _ORC_LOOKUP_H
+
+/*
+ * This is a lookup table for speeding up access to the .orc_unwind table.
+ * Given an input address offset, the corresponding lookup table entry
+ * specifies a subset of the .orc_unwind table to search.
+ *
+ * Each block represents the end of the previous range and the start of the
+ * next range.  An extra block is added to give the last range an end.
+ *
+ * The block size should be a power of 2 to avoid a costly 'div' instruction.
+ *
+ * A block size of 256 was chosen because it roughly doubles unwinder
+ * performance while only adding ~5% to the ORC data footprint.
+ */
+#define LOOKUP_BLOCK_ORDER	8
+#define LOOKUP_BLOCK_SIZE	(1 << LOOKUP_BLOCK_ORDER)
+
+#ifndef LINKER_SCRIPT
+
+extern unsigned int orc_lookup[];
+extern unsigned int orc_lookup_end[];
+
+#define LOOKUP_START_IP		(unsigned long)_stext
+#define LOOKUP_STOP_IP		(unsigned long)_etext
+
+#endif /* LINKER_SCRIPT */
+
+#endif /* _ORC_LOOKUP_H */

arch/loongarch/include/asm/orc_types.h

@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ORC_TYPES_H
+#define _ORC_TYPES_H
+
+#include <linux/types.h>
+
+/*
+ * The ORC_REG_* registers are base registers which are used to find other
+ * registers on the stack.
+ *
+ * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
+ * address of the previous frame: the caller's SP before it called the current
+ * function.
+ *
+ * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
+ * the current frame.
+ *
+ * The most commonly used base registers are SP and FP -- which the previous SP
+ * is usually based on -- and PREV_SP and UNDEFINED -- which the previous FP is
+ * usually based on.
+ *
+ * The rest of the base registers are needed for special cases like entry code
+ * and GCC realigned stacks.
+ */
+#define ORC_REG_UNDEFINED		0
+#define ORC_REG_PREV_SP			1
+#define ORC_REG_SP			2
+#define ORC_REG_FP			3
+#define ORC_REG_MAX			4
+
+#define ORC_TYPE_UNDEFINED		0
+#define ORC_TYPE_END_OF_STACK		1
+#define ORC_TYPE_CALL			2
+#define ORC_TYPE_REGS			3
+#define ORC_TYPE_REGS_PARTIAL		4
+
+#ifndef __ASSEMBLY__
+/*
+ * This struct is more or less a vastly simplified version of the DWARF Call
+ * Frame Information standard.  It contains only the necessary parts of DWARF
+ * CFI, simplified for ease of access by the in-kernel unwinder.  It tells the
+ * unwinder how to find the previous SP and FP (and sometimes entry regs) on
+ * the stack for a given code address.  Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+	s16		sp_offset;
+	s16		fp_offset;
+	s16		ra_offset;
+	unsigned int	sp_reg:4;
+	unsigned int	fp_reg:4;
+	unsigned int	ra_reg:4;
+	unsigned int	type:3;
+	unsigned int	signal:1;
+};
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_TYPES_H */

arch/loongarch/include/asm/page.h

@@ -75,6 +75,9 @@ typedef struct { unsigned long pgprot; } pgprot_t;
 #define pfn_to_kaddr(pfn)	__va((pfn) << PAGE_SHIFT)
 #define sym_to_pfn(x)		__phys_to_pfn(__pa_symbol(x))
 
+struct page *dmw_virt_to_page(unsigned long kaddr);
+struct page *tlb_virt_to_page(unsigned long kaddr);
+
 #define virt_to_pfn(kaddr)	PFN_DOWN(PHYSADDR(kaddr))
 
 #define virt_to_page(kaddr)								\

arch/loongarch/include/asm/percpu.h

@@ -29,7 +29,12 @@ static inline void set_my_cpu_offset(unsigned long off)
 	__my_cpu_offset = off;
 	csr_write64(off, PERCPU_BASE_KS);
 }
-#define __my_cpu_offset __my_cpu_offset
+
+#define __my_cpu_offset					\
+({							\
+	__asm__ __volatile__("":"+r"(__my_cpu_offset));	\
+	__my_cpu_offset;				\
+})
 
 #define PERCPU_OP(op, asm_op, c_op)					\
 static __always_inline unsigned long __percpu_##op(void *ptr,		\

arch/loongarch/include/asm/pgtable.h

@@ -363,9 +363,6 @@ static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *pt
 extern pgd_t swapper_pg_dir[];
 extern pgd_t invalid_pg_dir[];
 
-struct page *dmw_virt_to_page(unsigned long kaddr);
-struct page *tlb_virt_to_page(unsigned long kaddr);
-
 /*
  * The following only work if pte_present() is true.
  * Undefined behaviour if not..

arch/loongarch/include/asm/qspinlock.h

@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_QSPINLOCK_H
-#define _ASM_QSPINLOCK_H
-
-#include <asm-generic/qspinlock_types.h>
-
-#define queued_spin_unlock queued_spin_unlock
-
-static inline void queued_spin_unlock(struct qspinlock *lock)
-{
-	compiletime_assert_atomic_type(lock->locked);
-	c_sync();
-	WRITE_ONCE(lock->locked, 0);
-}
-
-#include <asm-generic/qspinlock.h>
-
-#endif /* _ASM_QSPINLOCK_H */

arch/loongarch/include/asm/stackframe.h

@@ -13,6 +13,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/loongarch.h>
 #include <asm/thread_info.h>
+#include <asm/unwind_hints.h>
 
 /* Make the addition of cfi info a little easier. */
 	.macro cfi_rel_offset reg offset=0 docfi=0
@@ -162,6 +163,7 @@
 	li.w	t0, CSR_CRMD_WE
 	csrxchg	t0, t0, LOONGARCH_CSR_CRMD
 #endif
+	UNWIND_HINT_REGS
 	.endm
 
 	.macro	SAVE_ALL docfi=0
@@ -219,6 +221,7 @@
 
 	.macro	RESTORE_SP_AND_RET docfi=0
 	cfi_ld	sp, PT_R3, \docfi
+	UNWIND_HINT_FUNC
 	ertn
 	.endm
 

arch/loongarch/include/asm/thread_info.h

@@ -86,6 +86,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
 #define TIF_LASX_CTX_LIVE	18	/* LASX context must be preserved */
 #define TIF_USEDLBT		19	/* LBT was used by this task this quantum (SMP) */
 #define TIF_LBT_CTX_LIVE	20	/* LBT context must be preserved */
+#define TIF_PATCH_PENDING	21	/* pending live patching update */
 
 #define _TIF_SIGPENDING		(1<<TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1<<TIF_NEED_RESCHED)
@@ -105,6 +106,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
 #define _TIF_LASX_CTX_LIVE	(1<<TIF_LASX_CTX_LIVE)
 #define _TIF_USEDLBT		(1<<TIF_USEDLBT)
 #define _TIF_LBT_CTX_LIVE	(1<<TIF_LBT_CTX_LIVE)
+#define _TIF_PATCH_PENDING	(1<<TIF_PATCH_PENDING)
 
 #endif /* __KERNEL__ */
 #endif /* _ASM_THREAD_INFO_H */

arch/loongarch/include/asm/unwind.h

@@ -16,6 +16,7 @@
 enum unwinder_type {
 	UNWINDER_GUESS,
 	UNWINDER_PROLOGUE,
+	UNWINDER_ORC,
 };
 
 struct unwind_state {
@@ -24,7 +25,7 @@ struct unwind_state {
 	struct task_struct *task;
 	bool first, error, reset;
 	int graph_idx;
-	unsigned long sp, pc, ra;
+	unsigned long sp, fp, pc, ra;
 };
 
 bool default_next_frame(struct unwind_state *state);
@@ -61,14 +62,17 @@ static __always_inline void __unwind_start(struct unwind_state *state,
 		state->sp = regs->regs[3];
 		state->pc = regs->csr_era;
 		state->ra = regs->regs[1];
+		state->fp = regs->regs[22];
 	} else if (task && task != current) {
 		state->sp = thread_saved_fp(task);
 		state->pc = thread_saved_ra(task);
 		state->ra = 0;
+		state->fp = 0;
 	} else {
 		state->sp = (unsigned long)__builtin_frame_address(0);
 		state->pc = (unsigned long)__builtin_return_address(0);
 		state->ra = 0;
+		state->fp = 0;
 	}
 	state->task = task;
 	get_stack_info(state->sp, state->task, &state->stack_info);
@@ -77,6 +81,18 @@ static __always_inline void __unwind_start(struct unwind_state *state,
 
 static __always_inline unsigned long __unwind_get_return_address(struct unwind_state *state)
 {
-	return unwind_done(state) ? 0 : state->pc;
+	if (unwind_done(state))
+		return 0;
+
+	return __kernel_text_address(state->pc) ? state->pc : 0;
 }
+
+#ifdef CONFIG_UNWINDER_ORC
+void unwind_init(void);
+void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size);
+#else
+static inline void unwind_init(void) {}
+static inline void unwind_module_init(struct module *mod, void *orc_ip, size_t orc_ip_size, void *orc, size_t orc_size) {}
+#endif
+
 #endif /* _ASM_UNWIND_H */

arch/loongarch/include/asm/unwind_hints.h

@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_LOONGARCH_UNWIND_HINTS_H
+#define _ASM_LOONGARCH_UNWIND_HINTS_H
+
+#include <linux/objtool.h>
+#include <asm/orc_types.h>
+
+#ifdef __ASSEMBLY__
+
+.macro UNWIND_HINT_UNDEFINED
+	UNWIND_HINT type=UNWIND_HINT_TYPE_UNDEFINED
+.endm
+
+.macro UNWIND_HINT_END_OF_STACK
+	UNWIND_HINT type=UNWIND_HINT_TYPE_END_OF_STACK
+.endm
+
+.macro UNWIND_HINT_REGS
+	UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_REGS
+.endm
+
+.macro UNWIND_HINT_FUNC
+	UNWIND_HINT sp_reg=ORC_REG_SP type=UNWIND_HINT_TYPE_CALL
+.endm
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ASM_LOONGARCH_UNWIND_HINTS_H */

arch/loongarch/kernel/Makefile

@@ -3,6 +3,8 @@
 # Makefile for the Linux/LoongArch kernel.
 #
 
+OBJECT_FILES_NON_STANDARD_head.o := y
+
 extra-y		:= vmlinux.lds
 
 obj-y		+= head.o cpu-probe.o cacheinfo.o env.o setup.o entry.o genex.o \
@@ -21,6 +23,7 @@ obj-$(CONFIG_ARCH_STRICT_ALIGN)	+= unaligned.o
 
 CFLAGS_module.o		+= $(call cc-option,-Wno-override-init,)
 CFLAGS_syscall.o	+= $(call cc-option,-Wno-override-init,)
+CFLAGS_traps.o		+= $(call cc-option,-Wno-override-init,)
 CFLAGS_perf_event.o	+= $(call cc-option,-Wno-override-init,)
 
 ifdef CONFIG_FUNCTION_TRACER
@@ -62,6 +65,7 @@ obj-$(CONFIG_CRASH_DUMP)	+= crash_dump.o
 
 obj-$(CONFIG_UNWINDER_GUESS)	+= unwind_guess.o
 obj-$(CONFIG_UNWINDER_PROLOGUE) += unwind_prologue.o
+obj-$(CONFIG_UNWINDER_ORC)	+= unwind_orc.o
 
 obj-$(CONFIG_PERF_EVENTS)	+= perf_event.o perf_regs.o
 obj-$(CONFIG_HAVE_HW_BREAKPOINT)	+= hw_breakpoint.o

arch/loongarch/kernel/entry.S

@@ -14,11 +14,13 @@
 #include <asm/regdef.h>
 #include <asm/stackframe.h>
 #include <asm/thread_info.h>
+#include <asm/unwind_hints.h>
 
 	.text
 	.cfi_sections	.debug_frame
 	.align	5
 SYM_CODE_START(handle_syscall)
+	UNWIND_HINT_UNDEFINED
 	csrrd		t0, PERCPU_BASE_KS
 	la.pcrel	t1, kernelsp
 	add.d		t1, t1, t0
@@ -57,6 +59,7 @@ SYM_CODE_START(handle_syscall)
 	cfi_st		fp, PT_R22
 
 	SAVE_STATIC
+	UNWIND_HINT_REGS
 
 #ifdef CONFIG_KGDB
 	li.w		t1, CSR_CRMD_WE
@@ -75,6 +78,7 @@ SYM_CODE_END(handle_syscall)
 _ASM_NOKPROBE(handle_syscall)
 
 SYM_CODE_START(ret_from_fork)
+	UNWIND_HINT_REGS
 	bl		schedule_tail		# a0 = struct task_struct *prev
 	move		a0, sp
 	bl 		syscall_exit_to_user_mode
@@ -84,6 +88,7 @@ SYM_CODE_START(ret_from_fork)
 SYM_CODE_END(ret_from_fork)
 
 SYM_CODE_START(ret_from_kernel_thread)
+	UNWIND_HINT_REGS
 	bl		schedule_tail		# a0 = struct task_struct *prev
 	move		a0, s1
 	jirl		ra, s0, 0

arch/loongarch/kernel/fpu.S

@@ -15,6 +15,7 @@
 #include <asm/fpregdef.h>
 #include <asm/loongarch.h>
 #include <asm/regdef.h>
+#include <asm/unwind_hints.h>
 
 #define FPU_REG_WIDTH		8
 #define LSX_REG_WIDTH		16
@@ -526,3 +527,9 @@ SYM_FUNC_END(_restore_lasx_context)
 .L_fpu_fault:
 	li.w	a0, -EFAULT				# failure
 	jr	ra
+
+#ifdef CONFIG_CPU_HAS_LBT
+STACK_FRAME_NON_STANDARD _restore_fp
+STACK_FRAME_NON_STANDARD _restore_lsx
+STACK_FRAME_NON_STANDARD _restore_lasx
+#endif

arch/loongarch/kernel/genex.S

@@ -32,6 +32,7 @@ SYM_FUNC_START(__arch_cpu_idle)
 SYM_FUNC_END(__arch_cpu_idle)
 
 SYM_CODE_START(handle_vint)
+	UNWIND_HINT_UNDEFINED
 	BACKUP_T0T1
 	SAVE_ALL
 	la_abs	t1, __arch_cpu_idle
@@ -49,6 +50,7 @@ SYM_CODE_START(handle_vint)
 SYM_CODE_END(handle_vint)
 
 SYM_CODE_START(except_vec_cex)
+	UNWIND_HINT_UNDEFINED
 	b	cache_parity_error
 SYM_CODE_END(except_vec_cex)
 
@@ -67,6 +69,7 @@ SYM_CODE_END(except_vec_cex)
 	.macro	BUILD_HANDLER exception handler prep
 	.align	5
 	SYM_CODE_START(handle_\exception)
+	UNWIND_HINT_UNDEFINED
 	666:
 	BACKUP_T0T1
 	SAVE_ALL
@@ -77,7 +80,9 @@ SYM_CODE_END(except_vec_cex)
 	668:
 	RESTORE_ALL_AND_RET
 	SYM_CODE_END(handle_\exception)
+	.pushsection	".data", "aw", %progbits
 	SYM_DATA(unwind_hint_\exception, .word 668b - 666b)
+	.popsection
 	.endm
 
 	BUILD_HANDLER ade ade badv
@@ -94,6 +99,7 @@ SYM_CODE_END(except_vec_cex)
 	BUILD_HANDLER reserved reserved none	/* others */
 
 SYM_CODE_START(handle_sys)
+	UNWIND_HINT_UNDEFINED
 	la_abs	t0, handle_syscall
 	jr	t0
 SYM_CODE_END(handle_sys)

arch/loongarch/kernel/lbt.S

@@ -11,6 +11,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/errno.h>
 #include <asm/regdef.h>
+#include <asm/unwind_hints.h>
 
 #define SCR_REG_WIDTH 8
 
@@ -153,3 +154,5 @@ SYM_FUNC_END(_restore_ftop_context)
 .L_lbt_fault:
 	li.w		a0, -EFAULT		# failure
 	jr		ra
+
+STACK_FRAME_NON_STANDARD _restore_ftop_context

arch/loongarch/kernel/mcount_dyn.S

@@ -73,6 +73,7 @@ SYM_FUNC_START(ftrace_stub)
 SYM_FUNC_END(ftrace_stub)
 
 SYM_CODE_START(ftrace_common)
+	UNWIND_HINT_UNDEFINED
 	PTR_ADDI	a0, ra, -8	/* arg0: ip */
 	move		a1, t0		/* arg1: parent_ip */
 	la.pcrel	t1, function_trace_op
@@ -113,12 +114,14 @@ ftrace_common_return:
 SYM_CODE_END(ftrace_common)
 
 SYM_CODE_START(ftrace_caller)
+	UNWIND_HINT_UNDEFINED
 	ftrace_regs_entry allregs=0
 	b		ftrace_common
 SYM_CODE_END(ftrace_caller)
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS
 SYM_CODE_START(ftrace_regs_caller)
+	UNWIND_HINT_UNDEFINED
 	ftrace_regs_entry allregs=1
 	b		ftrace_common
 SYM_CODE_END(ftrace_regs_caller)
@@ -126,6 +129,7 @@ SYM_CODE_END(ftrace_regs_caller)
 
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 SYM_CODE_START(ftrace_graph_caller)
+	UNWIND_HINT_UNDEFINED
 	PTR_L		a0, sp, PT_ERA
 	PTR_ADDI	a0, a0, -8	/* arg0: self_addr */
 	PTR_ADDI	a1, sp, PT_R1	/* arg1: parent */
@@ -134,6 +138,7 @@ SYM_CODE_START(ftrace_graph_caller)
 SYM_CODE_END(ftrace_graph_caller)
 
 SYM_CODE_START(return_to_handler)
+	UNWIND_HINT_UNDEFINED
 	/* Save return value regs */
 	PTR_ADDI	sp, sp, -FGRET_REGS_SIZE
 	PTR_S		a0, sp, FGRET_REGS_A0
@@ -155,6 +160,7 @@ SYM_CODE_END(return_to_handler)
 
 #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 SYM_CODE_START(ftrace_stub_direct_tramp)
+	UNWIND_HINT_UNDEFINED
 	jr		t0
 SYM_CODE_END(ftrace_stub_direct_tramp)
 #endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */

arch/loongarch/kernel/module.c

@@ -20,6 +20,7 @@
 #include <linux/kernel.h>
 #include <asm/alternative.h>
 #include <asm/inst.h>
+#include <asm/unwind.h>
 
 static int rela_stack_push(s64 stack_value, s64 *rela_stack, size_t *rela_stack_top)
 {
@@ -515,15 +516,28 @@ static void module_init_ftrace_plt(const Elf_Ehdr *hdr,
 int module_finalize(const Elf_Ehdr *hdr,
 		    const Elf_Shdr *sechdrs, struct module *mod)
 {
-	const Elf_Shdr *s, *se;
 	const char *secstrs = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
+	const Elf_Shdr *s, *alt = NULL, *orc = NULL, *orc_ip = NULL, *ftrace = NULL;
 
-	for (s = sechdrs, se = sechdrs + hdr->e_shnum; s < se; s++) {
+	for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
 		if (!strcmp(".altinstructions", secstrs + s->sh_name))
-			apply_alternatives((void *)s->sh_addr, (void *)s->sh_addr + s->sh_size);
+			alt = s;
+		if (!strcmp(".orc_unwind", secstrs + s->sh_name))
+			orc = s;
+		if (!strcmp(".orc_unwind_ip", secstrs + s->sh_name))
+			orc_ip = s;
 		if (!strcmp(".ftrace_trampoline", secstrs + s->sh_name))
-			module_init_ftrace_plt(hdr, s, mod);
+			ftrace = s;
 	}
 
+	if (alt)
+		apply_alternatives((void *)alt->sh_addr, (void *)alt->sh_addr + alt->sh_size);
+
+	if (orc && orc_ip)
+		unwind_module_init(mod, (void *)orc_ip->sh_addr, orc_ip->sh_size, (void *)orc->sh_addr, orc->sh_size);
+
+	if (ftrace)
+		module_init_ftrace_plt(hdr, ftrace, mod);
+
 	return 0;
 }

arch/loongarch/kernel/relocate_kernel.S

@@ -15,6 +15,7 @@
 #include <asm/addrspace.h>
 
 SYM_CODE_START(relocate_new_kernel)
+	UNWIND_HINT_UNDEFINED
 	/*
 	 * a0: EFI boot flag for the new kernel
 	 * a1: Command line pointer for the new kernel
@@ -90,6 +91,7 @@ SYM_CODE_END(relocate_new_kernel)
  * then start at the entry point from LOONGARCH_IOCSR_MBUF0.
  */
 SYM_CODE_START(kexec_smp_wait)
+	UNWIND_HINT_UNDEFINED
 1:	li.w		t0, 0x100			/* wait for init loop */
 2:	addi.w		t0, t0, -1			/* limit mailbox access */
 	bnez		t0, 2b
@@ -106,6 +108,5 @@ SYM_CODE_END(kexec_smp_wait)
 
 relocate_new_kernel_end:
 
-SYM_DATA_START(relocate_new_kernel_size)
+	.section ".data"
-	PTR		relocate_new_kernel_end - relocate_new_kernel
+SYM_DATA(relocate_new_kernel_size, .long relocate_new_kernel_end - relocate_new_kernel)
-SYM_DATA_END(relocate_new_kernel_size)

arch/loongarch/kernel/rethook_trampoline.S

@@ -76,6 +76,7 @@
 	.endm
 
 SYM_CODE_START(arch_rethook_trampoline)
+	UNWIND_HINT_UNDEFINED
 	addi.d	sp, sp, -PT_SIZE
 	save_all_base_regs
 

arch/loongarch/kernel/setup.c

@@ -47,6 +47,7 @@
 #include <asm/sections.h>
 #include <asm/setup.h>
 #include <asm/time.h>
+#include <asm/unwind.h>
 
 #define SMBIOS_BIOSSIZE_OFFSET		0x09
 #define SMBIOS_BIOSEXTERN_OFFSET	0x13
@@ -587,6 +588,7 @@ static void __init prefill_possible_map(void)
 void __init setup_arch(char **cmdline_p)
 {
 	cpu_probe();
+	unwind_init();
 
 	init_environ();
 	efi_init();

arch/loongarch/kernel/stacktrace.c

@@ -29,6 +29,7 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
 			regs->csr_era = thread_saved_ra(task);
 		}
 		regs->regs[1] = 0;
+		regs->regs[22] = 0;
 	}
 
 	for (unwind_start(&state, task, regs);
@@ -39,6 +40,46 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
 	}
 }
 
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+			     void *cookie, struct task_struct *task)
+{
+	unsigned long addr;
+	struct pt_regs dummyregs;
+	struct pt_regs *regs = &dummyregs;
+	struct unwind_state state;
+
+	if (task == current) {
+		regs->regs[3] = (unsigned long)__builtin_frame_address(0);
+		regs->csr_era = (unsigned long)__builtin_return_address(0);
+	} else {
+		regs->regs[3] = thread_saved_fp(task);
+		regs->csr_era = thread_saved_ra(task);
+	}
+	regs->regs[1] = 0;
+	regs->regs[22] = 0;
+
+	for (unwind_start(&state, task, regs);
+	     !unwind_done(&state) && !unwind_error(&state); unwind_next_frame(&state)) {
+		addr = unwind_get_return_address(&state);
+
+		/*
+		 * A NULL or invalid return address probably means there's some
+		 * generated code which __kernel_text_address() doesn't know about.
+		 */
+		if (!addr)
+			return -EINVAL;
+
+		if (!consume_entry(cookie, addr))
+			return -EINVAL;
+	}
+
+	/* Check for stack corruption */
+	if (unwind_error(&state))
+		return -EINVAL;
+
+	return 0;
+}
+
 static int
 copy_stack_frame(unsigned long fp, struct stack_frame *frame)
 {

arch/loongarch/kernel/traps.c

@@ -53,6 +53,32 @@
 
 #include "access-helper.h"
 
+void *exception_table[EXCCODE_INT_START] = {
+	[0 ... EXCCODE_INT_START - 1] = handle_reserved,
+
+	[EXCCODE_TLBI]		= handle_tlb_load,
+	[EXCCODE_TLBL]		= handle_tlb_load,
+	[EXCCODE_TLBS]		= handle_tlb_store,
+	[EXCCODE_TLBM]		= handle_tlb_modify,
+	[EXCCODE_TLBNR]		= handle_tlb_protect,
+	[EXCCODE_TLBNX]		= handle_tlb_protect,
+	[EXCCODE_TLBPE]		= handle_tlb_protect,
+	[EXCCODE_ADE]		= handle_ade,
+	[EXCCODE_ALE]		= handle_ale,
+	[EXCCODE_BCE]		= handle_bce,
+	[EXCCODE_SYS]		= handle_sys,
+	[EXCCODE_BP]		= handle_bp,
+	[EXCCODE_INE]		= handle_ri,
+	[EXCCODE_IPE]		= handle_ri,
+	[EXCCODE_FPDIS]		= handle_fpu,
+	[EXCCODE_LSXDIS]	= handle_lsx,
+	[EXCCODE_LASXDIS]	= handle_lasx,
+	[EXCCODE_FPE]		= handle_fpe,
+	[EXCCODE_WATCH]		= handle_watch,
+	[EXCCODE_BTDIS]		= handle_lbt,
+};
+EXPORT_SYMBOL_GPL(exception_table);
+
 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
 			   const char *loglvl, bool user)
 {
@@ -1150,19 +1176,9 @@ void __init trap_init(void)
 	for (i = EXCCODE_INT_START; i <= EXCCODE_INT_END; i++)
 		set_handler(i * VECSIZE, handle_vint, VECSIZE);
 
-	set_handler(EXCCODE_ADE * VECSIZE, handle_ade, VECSIZE);
+	/* Set exception vector handler */
-	set_handler(EXCCODE_ALE * VECSIZE, handle_ale, VECSIZE);
+	for (i = EXCCODE_ADE; i <= EXCCODE_BTDIS; i++)
-	set_handler(EXCCODE_BCE * VECSIZE, handle_bce, VECSIZE);
+		set_handler(i * VECSIZE, exception_table[i], VECSIZE);
-	set_handler(EXCCODE_SYS * VECSIZE, handle_sys, VECSIZE);
-	set_handler(EXCCODE_BP * VECSIZE, handle_bp, VECSIZE);
-	set_handler(EXCCODE_INE * VECSIZE, handle_ri, VECSIZE);
-	set_handler(EXCCODE_IPE * VECSIZE, handle_ri, VECSIZE);
-	set_handler(EXCCODE_FPDIS * VECSIZE, handle_fpu, VECSIZE);
-	set_handler(EXCCODE_LSXDIS * VECSIZE, handle_lsx, VECSIZE);
-	set_handler(EXCCODE_LASXDIS * VECSIZE, handle_lasx, VECSIZE);
-	set_handler(EXCCODE_FPE * VECSIZE, handle_fpe, VECSIZE);
-	set_handler(EXCCODE_BTDIS * VECSIZE, handle_lbt, VECSIZE);
-	set_handler(EXCCODE_WATCH * VECSIZE, handle_watch, VECSIZE);
 
 	cache_error_setup();
 

arch/loongarch/kernel/unwind_orc.c

@@ -0,0 +1,528 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/objtool.h>
+#include <linux/module.h>
+#include <linux/sort.h>
+#include <asm/exception.h>
+#include <asm/orc_header.h>
+#include <asm/orc_lookup.h>
+#include <asm/orc_types.h>
+#include <asm/ptrace.h>
+#include <asm/setup.h>
+#include <asm/stacktrace.h>
+#include <asm/tlb.h>
+#include <asm/unwind.h>
+
+ORC_HEADER;
+
+#define orc_warn(fmt, ...) \
+	printk_deferred_once(KERN_WARNING "WARNING: " fmt, ##__VA_ARGS__)
+
+extern int __start_orc_unwind_ip[];
+extern int __stop_orc_unwind_ip[];
+extern struct orc_entry __start_orc_unwind[];
+extern struct orc_entry __stop_orc_unwind[];
+
+static bool orc_init __ro_after_init;
+static unsigned int lookup_num_blocks __ro_after_init;
+
+/* Fake frame pointer entry -- used as a fallback for generated code */
+static struct orc_entry orc_fp_entry = {
+	.sp_reg		= ORC_REG_FP,
+	.sp_offset	= 16,
+	.fp_reg		= ORC_REG_PREV_SP,
+	.fp_offset	= -16,
+	.ra_reg		= ORC_REG_PREV_SP,
+	.ra_offset	= -8,
+	.type		= ORC_TYPE_CALL
+};
+
+/*
+ * If we crash with IP==0, the last successfully executed instruction
+ * was probably an indirect function call with a NULL function pointer,
+ * and we don't have unwind information for NULL.
+ * This hardcoded ORC entry for IP==0 allows us to unwind from a NULL function
+ * pointer into its parent and then continue normally from there.
+ */
+static struct orc_entry orc_null_entry = {
+	.sp_reg		= ORC_REG_SP,
+	.sp_offset	= sizeof(long),
+	.fp_reg		= ORC_REG_UNDEFINED,
+	.type		= ORC_TYPE_CALL
+};
+
+static inline unsigned long orc_ip(const int *ip)
+{
+	return (unsigned long)ip + *ip;
+}
+
+static struct orc_entry *__orc_find(int *ip_table, struct orc_entry *u_table,
+				    unsigned int num_entries, unsigned long ip)
+{
+	int *first = ip_table;
+	int *mid = first, *found = first;
+	int *last = ip_table + num_entries - 1;
+
+	if (!num_entries)
+		return NULL;
+
+	/*
+	 * Do a binary range search to find the rightmost duplicate of a given
+	 * starting address.  Some entries are section terminators which are
+	 * "weak" entries for ensuring there are no gaps.  They should be
+	 * ignored when they conflict with a real entry.
+	 */
+	while (first <= last) {
+		mid = first + ((last - first) / 2);
+
+		if (orc_ip(mid) <= ip) {
+			found = mid;
+			first = mid + 1;
+		} else
+			last = mid - 1;
+	}
+
+	return u_table + (found - ip_table);
+}
+
+#ifdef CONFIG_MODULES
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+	struct module *mod;
+
+	mod = __module_address(ip);
+	if (!mod || !mod->arch.orc_unwind || !mod->arch.orc_unwind_ip)
+		return NULL;
+
+	return __orc_find(mod->arch.orc_unwind_ip, mod->arch.orc_unwind, mod->arch.num_orcs, ip);
+}
+#else
+static struct orc_entry *orc_module_find(unsigned long ip)
+{
+	return NULL;
+}
+#endif
+
+#ifdef CONFIG_DYNAMIC_FTRACE
+static struct orc_entry *orc_find(unsigned long ip);
+
+/*
+ * Ftrace dynamic trampolines do not have orc entries of their own.
+ * But they are copies of the ftrace entries that are static and
+ * defined in ftrace_*.S, which do have orc entries.
+ *
+ * If the unwinder comes across a ftrace trampoline, then find the
+ * ftrace function that was used to create it, and use that ftrace
+ * function's orc entry, as the placement of the return code in
+ * the stack will be identical.
+ */
+static struct orc_entry *orc_ftrace_find(unsigned long ip)
+{
+	struct ftrace_ops *ops;
+	unsigned long tramp_addr, offset;
+
+	ops = ftrace_ops_trampoline(ip);
+	if (!ops)
+		return NULL;
+
+	/* Set tramp_addr to the start of the code copied by the trampoline */
+	if (ops->flags & FTRACE_OPS_FL_SAVE_REGS)
+		tramp_addr = (unsigned long)ftrace_regs_caller;
+	else
+		tramp_addr = (unsigned long)ftrace_caller;
+
+	/* Now place tramp_addr to the location within the trampoline ip is at */
+	offset = ip - ops->trampoline;
+	tramp_addr += offset;
+
+	/* Prevent unlikely recursion */
+	if (ip == tramp_addr)
+		return NULL;
+
+	return orc_find(tramp_addr);
+}
+#else
+static struct orc_entry *orc_ftrace_find(unsigned long ip)
+{
+	return NULL;
+}
+#endif
+
+static struct orc_entry *orc_find(unsigned long ip)
+{
+	static struct orc_entry *orc;
+
+	if (ip == 0)
+		return &orc_null_entry;
+
+	/* For non-init vmlinux addresses, use the fast lookup table: */
+	if (ip >= LOOKUP_START_IP && ip < LOOKUP_STOP_IP) {
+		unsigned int idx, start, stop;
+
+		idx = (ip - LOOKUP_START_IP) / LOOKUP_BLOCK_SIZE;
+
+		if (unlikely((idx >= lookup_num_blocks-1))) {
+			orc_warn("WARNING: bad lookup idx: idx=%u num=%u ip=%pB\n",
+				 idx, lookup_num_blocks, (void *)ip);
+			return NULL;
+		}
+
+		start = orc_lookup[idx];
+		stop = orc_lookup[idx + 1] + 1;
+
+		if (unlikely((__start_orc_unwind + start >= __stop_orc_unwind) ||
+			     (__start_orc_unwind + stop > __stop_orc_unwind))) {
+			orc_warn("WARNING: bad lookup value: idx=%u num=%u start=%u stop=%u ip=%pB\n",
+				 idx, lookup_num_blocks, start, stop, (void *)ip);
+			return NULL;
+		}
+
+		return __orc_find(__start_orc_unwind_ip + start,
+				  __start_orc_unwind + start, stop - start, ip);
+	}
+
+	/* vmlinux .init slow lookup: */
+	if (is_kernel_inittext(ip))
+		return __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+				  __stop_orc_unwind_ip - __start_orc_unwind_ip, ip);
+
+	/* Module lookup: */
+	orc = orc_module_find(ip);
+	if (orc)
+		return orc;
+
+	return orc_ftrace_find(ip);
+}
+
+#ifdef CONFIG_MODULES
+
+static DEFINE_MUTEX(sort_mutex);
+static int *cur_orc_ip_table = __start_orc_unwind_ip;
+static struct orc_entry *cur_orc_table = __start_orc_unwind;
+
+static void orc_sort_swap(void *_a, void *_b, int size)
+{
+	int delta = _b - _a;
+	int *a = _a, *b = _b, tmp;
+	struct orc_entry *orc_a, *orc_b;
+
+	/* Swap the .orc_unwind_ip entries: */
+	tmp = *a;
+	*a = *b + delta;
+	*b = tmp - delta;
+
+	/* Swap the corresponding .orc_unwind entries: */
+	orc_a = cur_orc_table + (a - cur_orc_ip_table);
+	orc_b = cur_orc_table + (b - cur_orc_ip_table);
+	swap(*orc_a, *orc_b);
+}
+
+static int orc_sort_cmp(const void *_a, const void *_b)
+{
+	const int *a = _a, *b = _b;
+	unsigned long a_val = orc_ip(a);
+	unsigned long b_val = orc_ip(b);
+	struct orc_entry *orc_a;
+
+	if (a_val > b_val)
+		return 1;
+	if (a_val < b_val)
+		return -1;
+
+	/*
+	 * The "weak" section terminator entries need to always be first
+	 * to ensure the lookup code skips them in favor of real entries.
+	 * These terminator entries exist to handle any gaps created by
+	 * whitelisted .o files which didn't get objtool generation.
+	 */
+	orc_a = cur_orc_table + (a - cur_orc_ip_table);
+
+	return orc_a->type == ORC_TYPE_UNDEFINED ? -1 : 1;
+}
+
+void unwind_module_init(struct module *mod, void *_orc_ip, size_t orc_ip_size,
+			void *_orc, size_t orc_size)
+{
+	int *orc_ip = _orc_ip;
+	struct orc_entry *orc = _orc;
+	unsigned int num_entries = orc_ip_size / sizeof(int);
+
+	WARN_ON_ONCE(orc_ip_size % sizeof(int) != 0 ||
+		     orc_size % sizeof(*orc) != 0 ||
+		     num_entries != orc_size / sizeof(*orc));
+
+	/*
+	 * The 'cur_orc_*' globals allow the orc_sort_swap() callback to
+	 * associate an .orc_unwind_ip table entry with its corresponding
+	 * .orc_unwind entry so they can both be swapped.
+	 */
+	mutex_lock(&sort_mutex);
+	cur_orc_ip_table = orc_ip;
+	cur_orc_table = orc;
+	sort(orc_ip, num_entries, sizeof(int), orc_sort_cmp, orc_sort_swap);
+	mutex_unlock(&sort_mutex);
+
+	mod->arch.orc_unwind_ip = orc_ip;
+	mod->arch.orc_unwind = orc;
+	mod->arch.num_orcs = num_entries;
+}
+#endif
+
+void __init unwind_init(void)
+{
+	int i;
+	size_t orc_size = (void *)__stop_orc_unwind - (void *)__start_orc_unwind;
+	size_t orc_ip_size = (void *)__stop_orc_unwind_ip - (void *)__start_orc_unwind_ip;
+	size_t num_entries = orc_ip_size / sizeof(int);
+	struct orc_entry *orc;
+
+	if (!num_entries || orc_ip_size % sizeof(int) != 0 ||
+	    orc_size % sizeof(struct orc_entry) != 0 ||
+	    num_entries != orc_size / sizeof(struct orc_entry)) {
+		orc_warn("WARNING: Bad or missing .orc_unwind table.  Disabling unwinder.\n");
+		return;
+	}
+
+	/*
+	 * Note, the orc_unwind and orc_unwind_ip tables were already
+	 * sorted at build time via the 'sorttable' tool.
+	 * It's ready for binary search straight away, no need to sort it.
+	 */
+
+	/* Initialize the fast lookup table: */
+	lookup_num_blocks = orc_lookup_end - orc_lookup;
+	for (i = 0; i < lookup_num_blocks-1; i++) {
+		orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind,
+				 num_entries, LOOKUP_START_IP + (LOOKUP_BLOCK_SIZE * i));
+		if (!orc) {
+			orc_warn("WARNING: Corrupt .orc_unwind table.  Disabling unwinder.\n");
+			return;
+		}
+
+		orc_lookup[i] = orc - __start_orc_unwind;
+	}
+
+	/* Initialize the ending block: */
+	orc = __orc_find(__start_orc_unwind_ip, __start_orc_unwind, num_entries, LOOKUP_STOP_IP);
+	if (!orc) {
+		orc_warn("WARNING: Corrupt .orc_unwind table.  Disabling unwinder.\n");
+		return;
+	}
+	orc_lookup[lookup_num_blocks-1] = orc - __start_orc_unwind;
+
+	orc_init = true;
+}
+
+static inline bool on_stack(struct stack_info *info, unsigned long addr, size_t len)
+{
+	unsigned long begin = info->begin;
+	unsigned long end   = info->end;
+
+	return (info->type != STACK_TYPE_UNKNOWN &&
+		addr >= begin && addr < end && addr + len > begin && addr + len <= end);
+}
+
+static bool stack_access_ok(struct unwind_state *state, unsigned long addr, size_t len)
+{
+	struct stack_info *info = &state->stack_info;
+
+	if (on_stack(info, addr, len))
+		return true;
+
+	return !get_stack_info(addr, state->task, info) && on_stack(info, addr, len);
+}
+
+unsigned long unwind_get_return_address(struct unwind_state *state)
+{
+	return __unwind_get_return_address(state);
+}
+EXPORT_SYMBOL_GPL(unwind_get_return_address);
+
+void unwind_start(struct unwind_state *state, struct task_struct *task,
+		    struct pt_regs *regs)
+{
+	__unwind_start(state, task, regs);
+	state->type = UNWINDER_ORC;
+	if (!unwind_done(state) && !__kernel_text_address(state->pc))
+		unwind_next_frame(state);
+}
+EXPORT_SYMBOL_GPL(unwind_start);
+
+static bool is_entry_func(unsigned long addr)
+{
+	extern u32 kernel_entry;
+	extern u32 kernel_entry_end;
+
+	return addr >= (unsigned long)&kernel_entry && addr < (unsigned long)&kernel_entry_end;
+}
+
+static inline unsigned long bt_address(unsigned long ra)
+{
+	extern unsigned long eentry;
+
+	if (__kernel_text_address(ra))
+		return ra;
+
+	if (__module_text_address(ra))
+		return ra;
+
+	if (ra >= eentry && ra < eentry +  EXCCODE_INT_END * VECSIZE) {
+		unsigned long func;
+		unsigned long type = (ra - eentry) / VECSIZE;
+		unsigned long offset = (ra - eentry) % VECSIZE;
+
+		switch (type) {
+		case 0 ... EXCCODE_INT_START - 1:
+			func = (unsigned long)exception_table[type];
+			break;
+		case EXCCODE_INT_START ... EXCCODE_INT_END:
+			func = (unsigned long)handle_vint;
+			break;
+		default:
+			func = (unsigned long)handle_reserved;
+			break;
+		}
+
+		return func + offset;
+	}
+
+	return ra;
+}
+
+bool unwind_next_frame(struct unwind_state *state)
+{
+	unsigned long *p, pc;
+	struct pt_regs *regs;
+	struct orc_entry *orc;
+	struct stack_info *info = &state->stack_info;
+
+	if (unwind_done(state))
+		return false;
+
+	/* Don't let modules unload while we're reading their ORC data. */
+	preempt_disable();
+
+	if (is_entry_func(state->pc))
+		goto end;
+
+	orc = orc_find(state->pc);
+	if (!orc) {
+		/*
+		 * As a fallback, try to assume this code uses a frame pointer.
+		 * This is useful for generated code, like BPF, which ORC
+		 * doesn't know about.  This is just a guess, so the rest of
+		 * the unwind is no longer considered reliable.
+		 */
+		orc = &orc_fp_entry;
+		state->error = true;
+	} else {
+		if (orc->type == ORC_TYPE_UNDEFINED)
+			goto err;
+
+		if (orc->type == ORC_TYPE_END_OF_STACK)
+			goto end;
+	}
+
+	switch (orc->sp_reg) {
+	case ORC_REG_SP:
+		if (info->type == STACK_TYPE_IRQ && state->sp == info->end)
+			orc->type = ORC_TYPE_REGS;
+		else
+			state->sp = state->sp + orc->sp_offset;
+		break;
+	case ORC_REG_FP:
+		state->sp = state->fp;
+		break;
+	default:
+		orc_warn("unknown SP base reg %d at %pB\n", orc->sp_reg, (void *)state->pc);
+		goto err;
+	}
+
+	switch (orc->fp_reg) {
+	case ORC_REG_PREV_SP:
+		p = (unsigned long *)(state->sp + orc->fp_offset);
+		if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long)))
+			goto err;
+
+		state->fp = *p;
+		break;
+	case ORC_REG_UNDEFINED:
+		/* Nothing. */
+		break;
+	default:
+		orc_warn("unknown FP base reg %d at %pB\n", orc->fp_reg, (void *)state->pc);
+		goto err;
+	}
+
+	switch (orc->type) {
+	case ORC_TYPE_CALL:
+		if (orc->ra_reg == ORC_REG_PREV_SP) {
+			p = (unsigned long *)(state->sp + orc->ra_offset);
+			if (!stack_access_ok(state, (unsigned long)p, sizeof(unsigned long)))
+				goto err;
+
+			pc = unwind_graph_addr(state, *p, state->sp);
+			pc -= LOONGARCH_INSN_SIZE;
+		} else if (orc->ra_reg == ORC_REG_UNDEFINED) {
+			if (!state->ra || state->ra == state->pc)
+				goto err;
+
+			pc = unwind_graph_addr(state, state->ra, state->sp);
+			pc -=  LOONGARCH_INSN_SIZE;
+			state->ra = 0;
+		} else {
+			orc_warn("unknown ra base reg %d at %pB\n", orc->ra_reg, (void *)state->pc);
+			goto err;
+		}
+		break;
+	case ORC_TYPE_REGS:
+		if (info->type == STACK_TYPE_IRQ && state->sp == info->end)
+			regs = (struct pt_regs *)info->next_sp;
+		else
+			regs = (struct pt_regs *)state->sp;
+
+		if (!stack_access_ok(state, (unsigned long)regs, sizeof(*regs)))
+			goto err;
+
+		if ((info->end == (unsigned long)regs + sizeof(*regs)) &&
+		    !regs->regs[3] && !regs->regs[1])
+			goto end;
+
+		if (user_mode(regs))
+			goto end;
+
+		pc = regs->csr_era;
+		if (!__kernel_text_address(pc))
+			goto err;
+
+		state->sp = regs->regs[3];
+		state->ra = regs->regs[1];
+		state->fp = regs->regs[22];
+		get_stack_info(state->sp, state->task, info);
+
+		break;
+	default:
+		orc_warn("unknown .orc_unwind entry type %d at %pB\n", orc->type, (void *)state->pc);
+		goto err;
+	}
+
+	state->pc = bt_address(pc);
+	if (!state->pc) {
+		pr_err("cannot find unwind pc at %pK\n", (void *)pc);
+		goto err;
+	}
+
+	if (!__kernel_text_address(state->pc))
+		goto err;
+
+	preempt_enable();
+	return true;
+
+err:
+	state->error = true;
+
+end:
+	preempt_enable();
+	state->stack_info.type = STACK_TYPE_UNKNOWN;
+	return false;
+}
+EXPORT_SYMBOL_GPL(unwind_next_frame);

arch/loongarch/kernel/vmlinux.lds.S

@@ -2,6 +2,7 @@
 #include <linux/sizes.h>
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
+#include <asm/orc_lookup.h>
 
 #define PAGE_SIZE _PAGE_SIZE
 #define RO_EXCEPTION_TABLE_ALIGN	4
@@ -122,6 +123,8 @@ SECTIONS
 	}
 #endif
 
+	ORC_UNWIND_TABLE
+
 	.sdata : {
 		*(.sdata)
 	}

arch/loongarch/kvm/switch.S

@@ -8,7 +8,7 @@
 #include <asm/asmmacro.h>
 #include <asm/loongarch.h>
 #include <asm/regdef.h>
-#include <asm/stackframe.h>
+#include <asm/unwind_hints.h>
 
 #define HGPR_OFFSET(x)		(PT_R0 + 8*x)
 #define GGPR_OFFSET(x)		(KVM_ARCH_GGPR + 8*x)
@@ -112,6 +112,7 @@
 	.text
 	.cfi_sections	.debug_frame
 SYM_CODE_START(kvm_exc_entry)
+	UNWIND_HINT_UNDEFINED
 	csrwr	a2,   KVM_TEMP_KS
 	csrrd	a2,   KVM_VCPU_KS
 	addi.d	a2,   a2, KVM_VCPU_ARCH
@@ -273,3 +274,9 @@ SYM_FUNC_END(kvm_restore_lasx)
 	.section ".rodata"
 SYM_DATA(kvm_exception_size, .quad kvm_exc_entry_end - kvm_exc_entry)
 SYM_DATA(kvm_enter_guest_size, .quad kvm_enter_guest_end - kvm_enter_guest)
+
+#ifdef CONFIG_CPU_HAS_LBT
+STACK_FRAME_NON_STANDARD kvm_restore_fpu
+STACK_FRAME_NON_STANDARD kvm_restore_lsx
+STACK_FRAME_NON_STANDARD kvm_restore_lasx
+#endif

arch/loongarch/lib/clear_user.S

@@ -10,6 +10,7 @@
 #include <asm/asm-extable.h>
 #include <asm/cpu.h>
 #include <asm/regdef.h>
+#include <asm/unwind_hints.h>
 
 SYM_FUNC_START(__clear_user)
 	/*
@@ -204,3 +205,5 @@ SYM_FUNC_START(__clear_user_fast)
 	_asm_extable 28b, .Lsmall_fixup
 	_asm_extable 29b, .Lexit
 SYM_FUNC_END(__clear_user_fast)
+
+STACK_FRAME_NON_STANDARD __clear_user_fast

arch/loongarch/lib/copy_user.S

@@ -10,6 +10,7 @@
 #include <asm/asm-extable.h>
 #include <asm/cpu.h>
 #include <asm/regdef.h>
+#include <asm/unwind_hints.h>
 
 SYM_FUNC_START(__copy_user)
 	/*
@@ -278,3 +279,5 @@ SYM_FUNC_START(__copy_user_fast)
 	_asm_extable 58b, .Lexit
 	_asm_extable 59b, .Lexit
 SYM_FUNC_END(__copy_user_fast)
+
+STACK_FRAME_NON_STANDARD __copy_user_fast

arch/loongarch/lib/memcpy.S

@@ -9,6 +9,7 @@
 #include <asm/asmmacro.h>
 #include <asm/cpu.h>
 #include <asm/regdef.h>
+#include <asm/unwind_hints.h>
 
 .section .noinstr.text, "ax"
 
@@ -197,3 +198,5 @@ SYM_FUNC_START(__memcpy_fast)
 	jr	ra
 SYM_FUNC_END(__memcpy_fast)
 _ASM_NOKPROBE(__memcpy_fast)
+
+STACK_FRAME_NON_STANDARD __memcpy_small

arch/loongarch/lib/memset.S

@@ -9,6 +9,7 @@
 #include <asm/asmmacro.h>
 #include <asm/cpu.h>
 #include <asm/regdef.h>
+#include <asm/unwind_hints.h>
 
 .macro fill_to_64 r0
 	bstrins.d \r0, \r0, 15, 8
@@ -166,3 +167,5 @@ SYM_FUNC_START(__memset_fast)
 	jr	ra
 SYM_FUNC_END(__memset_fast)
 _ASM_NOKPROBE(__memset_fast)
+
+STACK_FRAME_NON_STANDARD __memset_fast

arch/loongarch/mm/tlb.c

@@ -9,8 +9,9 @@
 #include <linux/hugetlb.h>
 #include <linux/export.h>
 
-#include <asm/cpu.h>
 #include <asm/bootinfo.h>
+#include <asm/cpu.h>
+#include <asm/exception.h>
 #include <asm/mmu_context.h>
 #include <asm/pgtable.h>
 #include <asm/tlb.h>
@@ -266,24 +267,20 @@ static void setup_tlb_handler(int cpu)
 	setup_ptwalker();
 	local_flush_tlb_all();
 
+	if (cpu_has_ptw) {
+		exception_table[EXCCODE_TLBI] = handle_tlb_load_ptw;
+		exception_table[EXCCODE_TLBL] = handle_tlb_load_ptw;
+		exception_table[EXCCODE_TLBS] = handle_tlb_store_ptw;
+		exception_table[EXCCODE_TLBM] = handle_tlb_modify_ptw;
+	}
+
 	/* The tlb handlers are generated only once */
 	if (cpu == 0) {
 		memcpy((void *)tlbrentry, handle_tlb_refill, 0x80);
 		local_flush_icache_range(tlbrentry, tlbrentry + 0x80);
-		if (!cpu_has_ptw) {
+
-			set_handler(EXCCODE_TLBI * VECSIZE, handle_tlb_load, VECSIZE);
+		for (int i = EXCCODE_TLBL; i <= EXCCODE_TLBPE; i++)
-			set_handler(EXCCODE_TLBL * VECSIZE, handle_tlb_load, VECSIZE);
+			set_handler(i * VECSIZE, exception_table[i], VECSIZE);
-			set_handler(EXCCODE_TLBS * VECSIZE, handle_tlb_store, VECSIZE);
-			set_handler(EXCCODE_TLBM * VECSIZE, handle_tlb_modify, VECSIZE);
-		} else {
-			set_handler(EXCCODE_TLBI * VECSIZE, handle_tlb_load_ptw, VECSIZE);
-			set_handler(EXCCODE_TLBL * VECSIZE, handle_tlb_load_ptw, VECSIZE);
-			set_handler(EXCCODE_TLBS * VECSIZE, handle_tlb_store_ptw, VECSIZE);
-			set_handler(EXCCODE_TLBM * VECSIZE, handle_tlb_modify_ptw, VECSIZE);
-		}
-		set_handler(EXCCODE_TLBNR * VECSIZE, handle_tlb_protect, VECSIZE);
-		set_handler(EXCCODE_TLBNX * VECSIZE, handle_tlb_protect, VECSIZE);
-		set_handler(EXCCODE_TLBPE * VECSIZE, handle_tlb_protect, VECSIZE);
 	} else {
 		int vec_sz __maybe_unused;
 		void *addr __maybe_unused;

arch/loongarch/mm/tlbex.S

@@ -18,6 +18,7 @@
 
 	.macro tlb_do_page_fault, write
 	SYM_CODE_START(tlb_do_page_fault_\write)
+	UNWIND_HINT_UNDEFINED
 	SAVE_ALL
 	csrrd		a2, LOONGARCH_CSR_BADV
 	move		a0, sp
@@ -32,6 +33,7 @@
 	tlb_do_page_fault 1
 
 SYM_CODE_START(handle_tlb_protect)
+	UNWIND_HINT_UNDEFINED
 	BACKUP_T0T1
 	SAVE_ALL
 	move		a0, sp
@@ -44,6 +46,7 @@ SYM_CODE_START(handle_tlb_protect)
 SYM_CODE_END(handle_tlb_protect)
 
 SYM_CODE_START(handle_tlb_load)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, EXCEPTION_KS0
 	csrwr		t1, EXCEPTION_KS1
 	csrwr		ra, EXCEPTION_KS2
@@ -190,6 +193,7 @@ nopage_tlb_load:
 SYM_CODE_END(handle_tlb_load)
 
 SYM_CODE_START(handle_tlb_load_ptw)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, LOONGARCH_CSR_KS0
 	csrwr		t1, LOONGARCH_CSR_KS1
 	la_abs		t0, tlb_do_page_fault_0
@@ -197,6 +201,7 @@ SYM_CODE_START(handle_tlb_load_ptw)
 SYM_CODE_END(handle_tlb_load_ptw)
 
 SYM_CODE_START(handle_tlb_store)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, EXCEPTION_KS0
 	csrwr		t1, EXCEPTION_KS1
 	csrwr		ra, EXCEPTION_KS2
@@ -346,6 +351,7 @@ nopage_tlb_store:
 SYM_CODE_END(handle_tlb_store)
 
 SYM_CODE_START(handle_tlb_store_ptw)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, LOONGARCH_CSR_KS0
 	csrwr		t1, LOONGARCH_CSR_KS1
 	la_abs		t0, tlb_do_page_fault_1
@@ -353,6 +359,7 @@ SYM_CODE_START(handle_tlb_store_ptw)
 SYM_CODE_END(handle_tlb_store_ptw)
 
 SYM_CODE_START(handle_tlb_modify)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, EXCEPTION_KS0
 	csrwr		t1, EXCEPTION_KS1
 	csrwr		ra, EXCEPTION_KS2
@@ -500,6 +507,7 @@ nopage_tlb_modify:
 SYM_CODE_END(handle_tlb_modify)
 
 SYM_CODE_START(handle_tlb_modify_ptw)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, LOONGARCH_CSR_KS0
 	csrwr		t1, LOONGARCH_CSR_KS1
 	la_abs		t0, tlb_do_page_fault_1
@@ -507,6 +515,7 @@ SYM_CODE_START(handle_tlb_modify_ptw)
 SYM_CODE_END(handle_tlb_modify_ptw)
 
 SYM_CODE_START(handle_tlb_refill)
+	UNWIND_HINT_UNDEFINED
 	csrwr		t0, LOONGARCH_CSR_TLBRSAVE
 	csrrd		t0, LOONGARCH_CSR_PGD
 	lddir		t0, t0, 3

arch/loongarch/vdso/Makefile

@@ -4,6 +4,7 @@
 KASAN_SANITIZE := n
 UBSAN_SANITIZE := n
 KCOV_INSTRUMENT := n
+OBJECT_FILES_NON_STANDARD := y
 
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile

include/linux/compiler.h

@@ -116,6 +116,14 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
  */
 #define __stringify_label(n) #n
 
+#define __annotate_reachable(c) ({					\
+	asm volatile(__stringify_label(c) ":\n\t"			\
+			".pushsection .discard.reachable\n\t"		\
+			".long " __stringify_label(c) "b - .\n\t"	\
+			".popsection\n\t");				\
+})
+#define annotate_reachable() __annotate_reachable(__COUNTER__)
+
 #define __annotate_unreachable(c) ({					\
 	asm volatile(__stringify_label(c) ":\n\t"			\
 		     ".pushsection .discard.unreachable\n\t"		\
@@ -128,6 +136,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
 #define __annotate_jump_table __section(".rodata..c_jump_table")
 
 #else /* !CONFIG_OBJTOOL */
+#define annotate_reachable()
 #define annotate_unreachable()
 #define __annotate_jump_table
 #endif /* CONFIG_OBJTOOL */

scripts/Makefile

@@ -33,9 +33,12 @@ HOSTLDLIBS_sign-file = $(shell $(HOSTPKG_CONFIG) --libs libcrypto 2> /dev/null |
 
 ifdef CONFIG_UNWINDER_ORC
 ifeq ($(ARCH),x86_64)
-ARCH := x86
+SRCARCH := x86
 endif
-HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/x86/include
+ifeq ($(ARCH),loongarch)
+SRCARCH := loongarch
+endif
+HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/$(SRCARCH)/include
 HOSTCFLAGS_sorttable.o += -DUNWINDER_ORC_ENABLED
 endif
 

tools/arch/loongarch/include/asm/inst.h

@@ -0,0 +1,161 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_INST_H
+#define _ASM_INST_H
+
+#include <linux/bitops.h>
+
+#define LOONGARCH_INSN_NOP		0x03400000
+
+enum reg0i15_op {
+	break_op	= 0x54,
+};
+
+enum reg0i26_op {
+	b_op		= 0x14,
+	bl_op		= 0x15,
+};
+
+enum reg1i21_op {
+	beqz_op		= 0x10,
+	bnez_op		= 0x11,
+	bceqz_op	= 0x12, /* bits[9:8] = 0x00 */
+	bcnez_op	= 0x12, /* bits[9:8] = 0x01 */
+};
+
+enum reg2_op {
+	ertn_op		= 0x1920e,
+};
+
+enum reg2i12_op {
+	addid_op	= 0x0b,
+	andi_op		= 0x0d,
+	ldd_op		= 0xa3,
+	std_op		= 0xa7,
+};
+
+enum reg2i14_op {
+	ldptrd_op	= 0x26,
+	stptrd_op	= 0x27,
+};
+
+enum reg2i16_op {
+	jirl_op		= 0x13,
+	beq_op		= 0x16,
+	bne_op		= 0x17,
+	blt_op		= 0x18,
+	bge_op		= 0x19,
+	bltu_op		= 0x1a,
+	bgeu_op		= 0x1b,
+};
+
+struct reg0i15_format {
+	unsigned int immediate : 15;
+	unsigned int opcode : 17;
+};
+
+struct reg0i26_format {
+	unsigned int immediate_h : 10;
+	unsigned int immediate_l : 16;
+	unsigned int opcode : 6;
+};
+
+struct reg1i21_format {
+	unsigned int immediate_h  : 5;
+	unsigned int rj : 5;
+	unsigned int immediate_l : 16;
+	unsigned int opcode : 6;
+};
+
+struct reg2_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int opcode : 22;
+};
+
+struct reg2i12_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 12;
+	unsigned int opcode : 10;
+};
+
+struct reg2i14_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 14;
+	unsigned int opcode : 8;
+};
+
+struct reg2i16_format {
+	unsigned int rd : 5;
+	unsigned int rj : 5;
+	unsigned int immediate : 16;
+	unsigned int opcode : 6;
+};
+
+union loongarch_instruction {
+	unsigned int word;
+	struct reg0i15_format	reg0i15_format;
+	struct reg0i26_format	reg0i26_format;
+	struct reg1i21_format	reg1i21_format;
+	struct reg2_format	reg2_format;
+	struct reg2i12_format	reg2i12_format;
+	struct reg2i14_format	reg2i14_format;
+	struct reg2i16_format	reg2i16_format;
+};
+
+#define LOONGARCH_INSN_SIZE	sizeof(union loongarch_instruction)
+
+enum loongarch_gpr {
+	LOONGARCH_GPR_ZERO = 0,
+	LOONGARCH_GPR_RA = 1,
+	LOONGARCH_GPR_TP = 2,
+	LOONGARCH_GPR_SP = 3,
+	LOONGARCH_GPR_A0 = 4,	/* Reused as V0 for return value */
+	LOONGARCH_GPR_A1,	/* Reused as V1 for return value */
+	LOONGARCH_GPR_A2,
+	LOONGARCH_GPR_A3,
+	LOONGARCH_GPR_A4,
+	LOONGARCH_GPR_A5,
+	LOONGARCH_GPR_A6,
+	LOONGARCH_GPR_A7,
+	LOONGARCH_GPR_T0 = 12,
+	LOONGARCH_GPR_T1,
+	LOONGARCH_GPR_T2,
+	LOONGARCH_GPR_T3,
+	LOONGARCH_GPR_T4,
+	LOONGARCH_GPR_T5,
+	LOONGARCH_GPR_T6,
+	LOONGARCH_GPR_T7,
+	LOONGARCH_GPR_T8,
+	LOONGARCH_GPR_FP = 22,
+	LOONGARCH_GPR_S0 = 23,
+	LOONGARCH_GPR_S1,
+	LOONGARCH_GPR_S2,
+	LOONGARCH_GPR_S3,
+	LOONGARCH_GPR_S4,
+	LOONGARCH_GPR_S5,
+	LOONGARCH_GPR_S6,
+	LOONGARCH_GPR_S7,
+	LOONGARCH_GPR_S8,
+	LOONGARCH_GPR_MAX
+};
+
+#define DEF_EMIT_REG2I16_FORMAT(NAME, OP)				\
+static inline void emit_##NAME(union loongarch_instruction *insn,	\
+			       enum loongarch_gpr rj,			\
+			       enum loongarch_gpr rd,			\
+			       int offset)				\
+{									\
+	insn->reg2i16_format.opcode = OP;				\
+	insn->reg2i16_format.immediate = offset;			\
+	insn->reg2i16_format.rj = rj;					\
+	insn->reg2i16_format.rd = rd;					\
+}
+
+DEF_EMIT_REG2I16_FORMAT(jirl, jirl_op)
+
+#endif /* _ASM_INST_H */

tools/arch/loongarch/include/asm/orc_types.h

@@ -0,0 +1,58 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _ORC_TYPES_H
+#define _ORC_TYPES_H
+
+#include <linux/types.h>
+
+/*
+ * The ORC_REG_* registers are base registers which are used to find other
+ * registers on the stack.
+ *
+ * ORC_REG_PREV_SP, also known as DWARF Call Frame Address (CFA), is the
+ * address of the previous frame: the caller's SP before it called the current
+ * function.
+ *
+ * ORC_REG_UNDEFINED means the corresponding register's value didn't change in
+ * the current frame.
+ *
+ * The most commonly used base registers are SP and FP -- which the previous SP
+ * is usually based on -- and PREV_SP and UNDEFINED -- which the previous FP is
+ * usually based on.
+ *
+ * The rest of the base registers are needed for special cases like entry code
+ * and GCC realigned stacks.
+ */
+#define ORC_REG_UNDEFINED		0
+#define ORC_REG_PREV_SP			1
+#define ORC_REG_SP			2
+#define ORC_REG_FP			3
+#define ORC_REG_MAX			4
+
+#define ORC_TYPE_UNDEFINED		0
+#define ORC_TYPE_END_OF_STACK		1
+#define ORC_TYPE_CALL			2
+#define ORC_TYPE_REGS			3
+#define ORC_TYPE_REGS_PARTIAL		4
+
+#ifndef __ASSEMBLY__
+/*
+ * This struct is more or less a vastly simplified version of the DWARF Call
+ * Frame Information standard.  It contains only the necessary parts of DWARF
+ * CFI, simplified for ease of access by the in-kernel unwinder.  It tells the
+ * unwinder how to find the previous SP and FP (and sometimes entry regs) on
+ * the stack for a given code address.  Each instance of the struct corresponds
+ * to one or more code locations.
+ */
+struct orc_entry {
+	s16		sp_offset;
+	s16		fp_offset;
+	s16		ra_offset;
+	unsigned int	sp_reg:4;
+	unsigned int	fp_reg:4;
+	unsigned int	ra_reg:4;
+	unsigned int	type:3;
+	unsigned int	signal:1;
+};
+#endif /* __ASSEMBLY__ */
+
+#endif /* _ORC_TYPES_H */

tools/include/linux/bitops.h

@@ -87,4 +87,15 @@ static inline __u32 rol32(__u32 word, unsigned int shift)
 	return (word << shift) | (word >> ((-shift) & 31));
 }
 
+/**
+ * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
+ * @value: value to sign extend
+ * @index: 0 based bit index (0<=index<64) to sign bit
+ */
+static __always_inline __s64 sign_extend64(__u64 value, int index)
+{
+	__u8 shift = 63 - index;
+	return (__s64)(value << shift) >> shift;
+}
+
 #endif

tools/objtool/Makefile

@@ -57,6 +57,10 @@ ifeq ($(SRCARCH),x86)
 	BUILD_ORC := y
 endif
 
+ifeq ($(SRCARCH),loongarch)
+	BUILD_ORC := y
+endif
+
 export BUILD_ORC
 export srctree OUTPUT CFLAGS SRCARCH AWK
 include $(srctree)/tools/build/Makefile.include

tools/objtool/arch/loongarch/Build

@@ -0,0 +1,3 @@
+objtool-y += decode.o
+objtool-y += special.o
+objtool-y += orc.o

tools/objtool/arch/loongarch/decode.c

@@ -0,0 +1,356 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <string.h>
+#include <objtool/check.h>
+#include <objtool/warn.h>
+#include <asm/inst.h>
+#include <asm/orc_types.h>
+#include <linux/objtool_types.h>
+
+#ifndef EM_LOONGARCH
+#define EM_LOONGARCH	258
+#endif
+
+int arch_ftrace_match(char *name)
+{
+	return !strcmp(name, "_mcount");
+}
+
+unsigned long arch_jump_destination(struct instruction *insn)
+{
+	return insn->offset + (insn->immediate << 2);
+}
+
+unsigned long arch_dest_reloc_offset(int addend)
+{
+	return addend;
+}
+
+bool arch_pc_relative_reloc(struct reloc *reloc)
+{
+	return false;
+}
+
+bool arch_callee_saved_reg(unsigned char reg)
+{
+	switch (reg) {
+	case CFI_RA:
+	case CFI_FP:
+	case CFI_S0 ... CFI_S8:
+		return true;
+	default:
+		return false;
+	}
+}
+
+int arch_decode_hint_reg(u8 sp_reg, int *base)
+{
+	switch (sp_reg) {
+	case ORC_REG_UNDEFINED:
+		*base = CFI_UNDEFINED;
+		break;
+	case ORC_REG_SP:
+		*base = CFI_SP;
+		break;
+	case ORC_REG_FP:
+		*base = CFI_FP;
+		break;
+	default:
+		return -1;
+	}
+
+	return 0;
+}
+
+static bool is_loongarch(const struct elf *elf)
+{
+	if (elf->ehdr.e_machine == EM_LOONGARCH)
+		return true;
+
+	WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
+	return false;
+}
+
+#define ADD_OP(op) \
+	if (!(op = calloc(1, sizeof(*op)))) \
+		return -1; \
+	else for (*ops_list = op, ops_list = &op->next; op; op = NULL)
+
+static bool decode_insn_reg0i26_fomat(union loongarch_instruction inst,
+				      struct instruction *insn)
+{
+	switch (inst.reg0i26_format.opcode) {
+	case b_op:
+		insn->type = INSN_JUMP_UNCONDITIONAL;
+		insn->immediate = sign_extend64(inst.reg0i26_format.immediate_h << 16 |
+						inst.reg0i26_format.immediate_l, 25);
+		break;
+	case bl_op:
+		insn->type = INSN_CALL;
+		insn->immediate = sign_extend64(inst.reg0i26_format.immediate_h << 16 |
+						inst.reg0i26_format.immediate_l, 25);
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool decode_insn_reg1i21_fomat(union loongarch_instruction inst,
+				      struct instruction *insn)
+{
+	switch (inst.reg1i21_format.opcode) {
+	case beqz_op:
+	case bnez_op:
+	case bceqz_op:
+		insn->type = INSN_JUMP_CONDITIONAL;
+		insn->immediate = sign_extend64(inst.reg1i21_format.immediate_h << 16 |
+						inst.reg1i21_format.immediate_l, 20);
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool decode_insn_reg2i12_fomat(union loongarch_instruction inst,
+				      struct instruction *insn,
+				      struct stack_op **ops_list,
+				      struct stack_op *op)
+{
+	switch (inst.reg2i12_format.opcode) {
+	case addid_op:
+		if ((inst.reg2i12_format.rd == CFI_SP) || (inst.reg2i12_format.rj == CFI_SP)) {
+			/* addi.d sp,sp,si12 or addi.d fp,sp,si12 */
+			insn->immediate = sign_extend64(inst.reg2i12_format.immediate, 11);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_ADD;
+				op->src.reg = inst.reg2i12_format.rj;
+				op->src.offset = insn->immediate;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = inst.reg2i12_format.rd;
+			}
+		}
+		break;
+	case ldd_op:
+		if (inst.reg2i12_format.rj == CFI_SP) {
+			/* ld.d rd,sp,si12 */
+			insn->immediate = sign_extend64(inst.reg2i12_format.immediate, 11);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG_INDIRECT;
+				op->src.reg = CFI_SP;
+				op->src.offset = insn->immediate;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = inst.reg2i12_format.rd;
+			}
+		}
+		break;
+	case std_op:
+		if (inst.reg2i12_format.rj == CFI_SP) {
+			/* st.d rd,sp,si12 */
+			insn->immediate = sign_extend64(inst.reg2i12_format.immediate, 11);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = inst.reg2i12_format.rd;
+				op->dest.type = OP_DEST_REG_INDIRECT;
+				op->dest.reg = CFI_SP;
+				op->dest.offset = insn->immediate;
+			}
+		}
+		break;
+	case andi_op:
+		if (inst.reg2i12_format.rd == 0 &&
+		    inst.reg2i12_format.rj == 0 &&
+		    inst.reg2i12_format.immediate == 0)
+			/* andi r0,r0,0 */
+			insn->type = INSN_NOP;
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool decode_insn_reg2i14_fomat(union loongarch_instruction inst,
+				      struct instruction *insn,
+				      struct stack_op **ops_list,
+				      struct stack_op *op)
+{
+	switch (inst.reg2i14_format.opcode) {
+	case ldptrd_op:
+		if (inst.reg2i14_format.rj == CFI_SP) {
+			/* ldptr.d rd,sp,si14 */
+			insn->immediate = sign_extend64(inst.reg2i14_format.immediate, 13);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG_INDIRECT;
+				op->src.reg = CFI_SP;
+				op->src.offset = insn->immediate;
+				op->dest.type = OP_DEST_REG;
+				op->dest.reg = inst.reg2i14_format.rd;
+			}
+		}
+		break;
+	case stptrd_op:
+		if (inst.reg2i14_format.rj == CFI_SP) {
+			/* stptr.d ra,sp,0 */
+			if (inst.reg2i14_format.rd == LOONGARCH_GPR_RA &&
+			    inst.reg2i14_format.immediate == 0)
+				break;
+
+			/* stptr.d rd,sp,si14 */
+			insn->immediate = sign_extend64(inst.reg2i14_format.immediate, 13);
+			ADD_OP(op) {
+				op->src.type = OP_SRC_REG;
+				op->src.reg = inst.reg2i14_format.rd;
+				op->dest.type = OP_DEST_REG_INDIRECT;
+				op->dest.reg = CFI_SP;
+				op->dest.offset = insn->immediate;
+			}
+		}
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static bool decode_insn_reg2i16_fomat(union loongarch_instruction inst,
+				      struct instruction *insn)
+{
+	switch (inst.reg2i16_format.opcode) {
+	case jirl_op:
+		if (inst.reg2i16_format.rd == 0 &&
+		    inst.reg2i16_format.rj == CFI_RA &&
+		    inst.reg2i16_format.immediate == 0) {
+			/* jirl r0,ra,0 */
+			insn->type = INSN_RETURN;
+		} else if (inst.reg2i16_format.rd == CFI_RA) {
+			/* jirl ra,rj,offs16 */
+			insn->type = INSN_CALL_DYNAMIC;
+		} else if (inst.reg2i16_format.rd == CFI_A0 &&
+			   inst.reg2i16_format.immediate == 0) {
+			/*
+			 * jirl a0,t0,0
+			 * this is a special case in loongarch_suspend_enter,
+			 * just treat it as a call instruction.
+			 */
+			insn->type = INSN_CALL_DYNAMIC;
+		} else if (inst.reg2i16_format.rd == 0 &&
+			   inst.reg2i16_format.immediate == 0) {
+			/* jirl r0,rj,0 */
+			insn->type = INSN_JUMP_DYNAMIC;
+		} else if (inst.reg2i16_format.rd == 0 &&
+			   inst.reg2i16_format.immediate != 0) {
+			/*
+			 * jirl r0,t0,12
+			 * this is a rare case in JUMP_VIRT_ADDR,
+			 * just ignore it due to it is harmless for tracing.
+			 */
+			break;
+		} else {
+			/* jirl rd,rj,offs16 */
+			insn->type = INSN_JUMP_UNCONDITIONAL;
+			insn->immediate = sign_extend64(inst.reg2i16_format.immediate, 15);
+		}
+		break;
+	case beq_op:
+	case bne_op:
+	case blt_op:
+	case bge_op:
+	case bltu_op:
+	case bgeu_op:
+		insn->type = INSN_JUMP_CONDITIONAL;
+		insn->immediate = sign_extend64(inst.reg2i16_format.immediate, 15);
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+int arch_decode_instruction(struct objtool_file *file, const struct section *sec,
+			    unsigned long offset, unsigned int maxlen,
+			    struct instruction *insn)
+{
+	struct stack_op **ops_list = &insn->stack_ops;
+	const struct elf *elf = file->elf;
+	struct stack_op *op = NULL;
+	union loongarch_instruction inst;
+
+	if (!is_loongarch(elf))
+		return -1;
+
+	if (maxlen < LOONGARCH_INSN_SIZE)
+		return 0;
+
+	insn->len = LOONGARCH_INSN_SIZE;
+	insn->type = INSN_OTHER;
+	insn->immediate = 0;
+
+	inst = *(union loongarch_instruction *)(sec->data->d_buf + offset);
+
+	if (decode_insn_reg0i26_fomat(inst, insn))
+		return 0;
+	if (decode_insn_reg1i21_fomat(inst, insn))
+		return 0;
+	if (decode_insn_reg2i12_fomat(inst, insn, ops_list, op))
+		return 0;
+	if (decode_insn_reg2i14_fomat(inst, insn, ops_list, op))
+		return 0;
+	if (decode_insn_reg2i16_fomat(inst, insn))
+		return 0;
+
+	if (inst.word == 0)
+		insn->type = INSN_NOP;
+	else if (inst.reg0i15_format.opcode == break_op) {
+		/* break */
+		insn->type = INSN_BUG;
+	} else if (inst.reg2_format.opcode == ertn_op) {
+		/* ertn */
+		insn->type = INSN_RETURN;
+	}
+
+	return 0;
+}
+
+const char *arch_nop_insn(int len)
+{
+	static u32 nop;
+
+	if (len != LOONGARCH_INSN_SIZE)
+		WARN("invalid NOP size: %d\n", len);
+
+	nop = LOONGARCH_INSN_NOP;
+
+	return (const char *)&nop;
+}
+
+const char *arch_ret_insn(int len)
+{
+	static u32 ret;
+
+	if (len != LOONGARCH_INSN_SIZE)
+		WARN("invalid RET size: %d\n", len);
+
+	emit_jirl((union loongarch_instruction *)&ret, LOONGARCH_GPR_RA, LOONGARCH_GPR_ZERO, 0);
+
+	return (const char *)&ret;
+}
+
+void arch_initial_func_cfi_state(struct cfi_init_state *state)
+{
+	int i;
+
+	for (i = 0; i < CFI_NUM_REGS; i++) {
+		state->regs[i].base = CFI_UNDEFINED;
+		state->regs[i].offset = 0;
+	}
+
+	/* initial CFA (call frame address) */
+	state->cfa.base = CFI_SP;
+	state->cfa.offset = 0;
+}

tools/objtool/arch/loongarch/include/arch/cfi_regs.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_CFI_REGS_H
+#define _OBJTOOL_ARCH_CFI_REGS_H
+
+#define CFI_RA		1
+#define CFI_SP		3
+#define CFI_A0		4
+#define CFI_FP		22
+#define CFI_S0		23
+#define CFI_S1		24
+#define CFI_S2		25
+#define CFI_S3		26
+#define CFI_S4		27
+#define CFI_S5		28
+#define CFI_S6		29
+#define CFI_S7		30
+#define CFI_S8		31
+#define CFI_NUM_REGS	32
+
+#define CFI_BP		CFI_FP
+
+#endif /* _OBJTOOL_ARCH_CFI_REGS_H */

tools/objtool/arch/loongarch/include/arch/elf.h

@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_ELF_H
+#define _OBJTOOL_ARCH_ELF_H
+
+/*
+ * See the following link for more info about ELF Relocation types:
+ * https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html#_relocations
+ */
+#ifndef R_LARCH_NONE
+#define R_LARCH_NONE		0
+#endif
+#ifndef R_LARCH_32
+#define R_LARCH_32		1
+#endif
+#ifndef R_LARCH_64
+#define R_LARCH_64		2
+#endif
+#ifndef R_LARCH_32_PCREL
+#define R_LARCH_32_PCREL	99
+#endif
+
+#define R_NONE			R_LARCH_NONE
+#define R_ABS32			R_LARCH_32
+#define R_ABS64			R_LARCH_64
+#define R_DATA32		R_LARCH_32_PCREL
+#define R_DATA64		R_LARCH_32_PCREL
+#define R_TEXT32		R_LARCH_32_PCREL
+#define R_TEXT64		R_LARCH_32_PCREL
+
+#endif /* _OBJTOOL_ARCH_ELF_H */

tools/objtool/arch/loongarch/include/arch/special.h

@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ARCH_SPECIAL_H
+#define _OBJTOOL_ARCH_SPECIAL_H
+
+/*
+ * See more info about struct exception_table_entry
+ * in arch/loongarch/include/asm/extable.h
+ */
+#define EX_ENTRY_SIZE		12
+#define EX_ORIG_OFFSET		0
+#define EX_NEW_OFFSET		4
+
+/*
+ * See more info about struct jump_entry
+ * in include/linux/jump_label.h
+ */
+#define JUMP_ENTRY_SIZE		16
+#define JUMP_ORIG_OFFSET	0
+#define JUMP_NEW_OFFSET		4
+#define JUMP_KEY_OFFSET		8
+
+/*
+ * See more info about struct alt_instr
+ * in arch/loongarch/include/asm/alternative.h
+ */
+#define ALT_ENTRY_SIZE		12
+#define ALT_ORIG_OFFSET		0
+#define ALT_NEW_OFFSET		4
+#define ALT_FEATURE_OFFSET	8
+#define ALT_ORIG_LEN_OFFSET	10
+#define ALT_NEW_LEN_OFFSET	11
+
+#endif /* _OBJTOOL_ARCH_SPECIAL_H */

tools/objtool/arch/loongarch/orc.c

@@ -0,0 +1,171 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/objtool_types.h>
+#include <asm/orc_types.h>
+
+#include <objtool/check.h>
+#include <objtool/orc.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
+{
+	struct cfi_reg *fp = &cfi->regs[CFI_FP];
+	struct cfi_reg *ra = &cfi->regs[CFI_RA];
+
+	memset(orc, 0, sizeof(*orc));
+
+	if (!cfi) {
+		/*
+		 * This is usually either unreachable nops/traps (which don't
+		 * trigger unreachable instruction warnings), or
+		 * STACK_FRAME_NON_STANDARD functions.
+		 */
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	}
+
+	switch (cfi->type) {
+	case UNWIND_HINT_TYPE_UNDEFINED:
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	case UNWIND_HINT_TYPE_END_OF_STACK:
+		orc->type = ORC_TYPE_END_OF_STACK;
+		return 0;
+	case UNWIND_HINT_TYPE_CALL:
+		orc->type = ORC_TYPE_CALL;
+		break;
+	case UNWIND_HINT_TYPE_REGS:
+		orc->type = ORC_TYPE_REGS;
+		break;
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
+		orc->type = ORC_TYPE_REGS_PARTIAL;
+		break;
+	default:
+		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
+		return -1;
+	}
+
+	orc->signal = cfi->signal;
+
+	switch (cfi->cfa.base) {
+	case CFI_SP:
+		orc->sp_reg = ORC_REG_SP;
+		break;
+	case CFI_FP:
+		orc->sp_reg = ORC_REG_FP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
+		return -1;
+	}
+
+	switch (fp->base) {
+	case CFI_UNDEFINED:
+		orc->fp_reg = ORC_REG_UNDEFINED;
+		orc->fp_offset = 0;
+		break;
+	case CFI_CFA:
+		orc->fp_reg = ORC_REG_PREV_SP;
+		orc->fp_offset = fp->offset;
+		break;
+	case CFI_FP:
+		orc->fp_reg = ORC_REG_FP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown FP base reg %d", fp->base);
+		return -1;
+	}
+
+	switch (ra->base) {
+	case CFI_UNDEFINED:
+		orc->ra_reg = ORC_REG_UNDEFINED;
+		orc->ra_offset = 0;
+		break;
+	case CFI_CFA:
+		orc->ra_reg = ORC_REG_PREV_SP;
+		orc->ra_offset = ra->offset;
+		break;
+	case CFI_FP:
+		orc->ra_reg = ORC_REG_FP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown RA base reg %d", ra->base);
+		return -1;
+	}
+
+	orc->sp_offset = cfi->cfa.offset;
+
+	return 0;
+}
+
+int write_orc_entry(struct elf *elf, struct section *orc_sec,
+		    struct section *ip_sec, unsigned int idx,
+		    struct section *insn_sec, unsigned long insn_off,
+		    struct orc_entry *o)
+{
+	struct orc_entry *orc;
+
+	/* populate ORC data */
+	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
+	memcpy(orc, o, sizeof(*orc));
+
+	/* populate reloc for ip */
+	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
+				     insn_sec, insn_off))
+		return -1;
+
+	return 0;
+}
+
+static const char *reg_name(unsigned int reg)
+{
+	switch (reg) {
+	case ORC_REG_SP:
+		return "sp";
+	case ORC_REG_FP:
+		return "fp";
+	case ORC_REG_PREV_SP:
+		return "prevsp";
+	default:
+		return "?";
+	}
+}
+
+static const char *orc_type_name(unsigned int type)
+{
+	switch (type) {
+	case UNWIND_HINT_TYPE_CALL:
+		return "call";
+	case UNWIND_HINT_TYPE_REGS:
+		return "regs";
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
+		return "regs (partial)";
+	default:
+		return "?";
+	}
+}
+
+static void print_reg(unsigned int reg, int offset)
+{
+	if (reg == ORC_REG_UNDEFINED)
+		printf(" (und) ");
+	else
+		printf("%s + %3d", reg_name(reg), offset);
+
+}
+
+void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i)
+{
+	printf("type:%s", orc_type_name(orc[i].type));
+
+	printf(" sp:");
+	print_reg(orc[i].sp_reg, orc[i].sp_offset);
+
+	printf(" fp:");
+	print_reg(orc[i].fp_reg, orc[i].fp_offset);
+
+	printf(" ra:");
+	print_reg(orc[i].ra_reg, orc[i].ra_offset);
+
+	printf(" signal:%d\n", orc[i].signal);
+}

tools/objtool/arch/loongarch/special.c

@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <objtool/special.h>
+
+bool arch_support_alt_relocation(struct special_alt *special_alt,
+				 struct instruction *insn,
+				 struct reloc *reloc)
+{
+	return false;
+}
+
+struct reloc *arch_find_switch_table(struct objtool_file *file,
+				     struct instruction *insn)
+{
+	return NULL;
+}

tools/objtool/arch/x86/Build

@@ -1,5 +1,6 @@
 objtool-y += special.o
 objtool-y += decode.o
+objtool-y += orc.o
 
 inat_tables_script = ../arch/x86/tools/gen-insn-attr-x86.awk
 inat_tables_maps = ../arch/x86/lib/x86-opcode-map.txt

tools/objtool/arch/x86/orc.c

@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+#include <linux/objtool_types.h>
+#include <asm/orc_types.h>
+
+#include <objtool/check.h>
+#include <objtool/orc.h>
+#include <objtool/warn.h>
+#include <objtool/endianness.h>
+
+int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn)
+{
+	struct cfi_reg *bp = &cfi->regs[CFI_BP];
+
+	memset(orc, 0, sizeof(*orc));
+
+	if (!cfi) {
+		/*
+		 * This is usually either unreachable nops/traps (which don't
+		 * trigger unreachable instruction warnings), or
+		 * STACK_FRAME_NON_STANDARD functions.
+		 */
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	}
+
+	switch (cfi->type) {
+	case UNWIND_HINT_TYPE_UNDEFINED:
+		orc->type = ORC_TYPE_UNDEFINED;
+		return 0;
+	case UNWIND_HINT_TYPE_END_OF_STACK:
+		orc->type = ORC_TYPE_END_OF_STACK;
+		return 0;
+	case UNWIND_HINT_TYPE_CALL:
+		orc->type = ORC_TYPE_CALL;
+		break;
+	case UNWIND_HINT_TYPE_REGS:
+		orc->type = ORC_TYPE_REGS;
+		break;
+	case UNWIND_HINT_TYPE_REGS_PARTIAL:
+		orc->type = ORC_TYPE_REGS_PARTIAL;
+		break;
+	default:
+		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
+		return -1;
+	}
+
+	orc->signal = cfi->signal;
+
+	switch (cfi->cfa.base) {
+	case CFI_SP:
+		orc->sp_reg = ORC_REG_SP;
+		break;
+	case CFI_SP_INDIRECT:
+		orc->sp_reg = ORC_REG_SP_INDIRECT;
+		break;
+	case CFI_BP:
+		orc->sp_reg = ORC_REG_BP;
+		break;
+	case CFI_BP_INDIRECT:
+		orc->sp_reg = ORC_REG_BP_INDIRECT;
+		break;
+	case CFI_R10:
+		orc->sp_reg = ORC_REG_R10;
+		break;
+	case CFI_R13:
+		orc->sp_reg = ORC_REG_R13;
+		break;
+	case CFI_DI:
+		orc->sp_reg = ORC_REG_DI;
+		break;
+	case CFI_DX:
+		orc->sp_reg = ORC_REG_DX;
+		break;
+	default:
+		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
+		return -1;
+	}
+
+	switch (bp->base) {
+	case CFI_UNDEFINED:
+		orc->bp_reg = ORC_REG_UNDEFINED;
+		break;
+	case CFI_CFA:
+		orc->bp_reg = ORC_REG_PREV_SP;
+		break;
+	case CFI_BP:
+		orc->bp_reg = ORC_REG_BP;
+		break;
+	default:
+		WARN_INSN(insn, "unknown BP base reg %d", bp->base);
+		return -1;
+	}
+
+	orc->sp_offset = cfi->cfa.offset;
+	orc->bp_offset = bp->offset;
+
+	return 0;
+}
+
+int write_orc_entry(struct elf *elf, struct section *orc_sec,
+		    struct section *ip_sec, unsigned int idx,
+		    struct section *insn_sec, unsigned long insn_off,
+		    struct orc_entry *o)
+{
+	struct orc_entry *orc;
+
+	/* populate ORC data */
+	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
+	memcpy(orc, o, sizeof(*orc));
+	orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
+	orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
+
+	/* populate reloc for ip */
+	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
+				     insn_sec, insn_off))
+		return -1;
+
+	return 0;
+}
+
+static const char *reg_name(unsigned int reg)
+{
+	switch (reg) {
+	case ORC_REG_PREV_SP:
+		return "prevsp";
+	case ORC_REG_DX:
+		return "dx";
+	case ORC_REG_DI:
+		return "di";
+	case ORC_REG_BP:
+		return "bp";
+	case ORC_REG_SP:
+		return "sp";
+	case ORC_REG_R10:
+		return "r10";
+	case ORC_REG_R13:
+		return "r13";
+	case ORC_REG_BP_INDIRECT:
+		return "bp(ind)";
+	case ORC_REG_SP_INDIRECT:
+		return "sp(ind)";
+	default:
+		return "?";
+	}
+}
+
+static const char *orc_type_name(unsigned int type)
+{
+	switch (type) {
+	case ORC_TYPE_UNDEFINED:
+		return "(und)";
+	case ORC_TYPE_END_OF_STACK:
+		return "end";
+	case ORC_TYPE_CALL:
+		return "call";
+	case ORC_TYPE_REGS:
+		return "regs";
+	case ORC_TYPE_REGS_PARTIAL:
+		return "regs (partial)";
+	default:
+		return "?";
+	}
+}
+
+static void print_reg(unsigned int reg, int offset)
+{
+	if (reg == ORC_REG_BP_INDIRECT)
+		printf("(bp%+d)", offset);
+	else if (reg == ORC_REG_SP_INDIRECT)
+		printf("(sp)%+d", offset);
+	else if (reg == ORC_REG_UNDEFINED)
+		printf("(und)");
+	else
+		printf("%s%+d", reg_name(reg), offset);
+}
+
+void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i)
+{
+	printf("type:%s", orc_type_name(orc[i].type));
+
+	printf(" sp:");
+	print_reg(orc[i].sp_reg, bswap_if_needed(dummy_elf, orc[i].sp_offset));
+
+	printf(" bp:");
+	print_reg(orc[i].bp_reg, bswap_if_needed(dummy_elf, orc[i].bp_offset));
+
+	printf(" signal:%d\n", orc[i].signal);
+}

tools/objtool/check.c

@@ -20,6 +20,7 @@
 #include <linux/hashtable.h>
 #include <linux/kernel.h>
 #include <linux/static_call_types.h>
+#include <linux/string.h>
 
 struct alternative {
 	struct alternative *next;
@@ -584,7 +585,7 @@ static int add_dead_ends(struct objtool_file *file)
 	struct section *rsec;
 	struct reloc *reloc;
 	struct instruction *insn;
-	s64 addend;
+	unsigned long offset;
 
 	/*
 	 * Check for manually annotated dead ends.
@@ -594,27 +595,28 @@ static int add_dead_ends(struct objtool_file *file)
 		goto reachable;
 
 	for_each_reloc(rsec, reloc) {
-
+		if (reloc->sym->type == STT_SECTION) {
-		if (reloc->sym->type != STT_SECTION) {
+			offset = reloc_addend(reloc);
+		} else if (reloc->sym->local_label) {
+			offset = reloc->sym->offset;
+		} else {
 			WARN("unexpected relocation symbol type in %s", rsec->name);
 			return -1;
 		}
 
-		addend = reloc_addend(reloc);
+		insn = find_insn(file, reloc->sym->sec, offset);
-
-		insn = find_insn(file, reloc->sym->sec, addend);
 		if (insn)
 			insn = prev_insn_same_sec(file, insn);
-		else if (addend == reloc->sym->sec->sh.sh_size) {
+		else if (offset == reloc->sym->sec->sh.sh_size) {
 			insn = find_last_insn(file, reloc->sym->sec);
 			if (!insn) {
 				WARN("can't find unreachable insn at %s+0x%" PRIx64,
-				     reloc->sym->sec->name, addend);
+				     reloc->sym->sec->name, offset);
 				return -1;
 			}
 		} else {
 			WARN("can't find unreachable insn at %s+0x%" PRIx64,
-			     reloc->sym->sec->name, addend);
+			     reloc->sym->sec->name, offset);
 			return -1;
 		}
 
@@ -633,27 +635,28 @@ reachable:
 		return 0;
 
 	for_each_reloc(rsec, reloc) {
-
+		if (reloc->sym->type == STT_SECTION) {
-		if (reloc->sym->type != STT_SECTION) {
+			offset = reloc_addend(reloc);
+		} else if (reloc->sym->local_label) {
+			offset = reloc->sym->offset;
+		} else {
 			WARN("unexpected relocation symbol type in %s", rsec->name);
 			return -1;
 		}
 
-		addend = reloc_addend(reloc);
+		insn = find_insn(file, reloc->sym->sec, offset);
-
-		insn = find_insn(file, reloc->sym->sec, addend);
 		if (insn)
 			insn = prev_insn_same_sec(file, insn);
-		else if (addend == reloc->sym->sec->sh.sh_size) {
+		else if (offset == reloc->sym->sec->sh.sh_size) {
 			insn = find_last_insn(file, reloc->sym->sec);
 			if (!insn) {
 				WARN("can't find reachable insn at %s+0x%" PRIx64,
-				     reloc->sym->sec->name, addend);
+				     reloc->sym->sec->name, offset);
 				return -1;
 			}
 		} else {
 			WARN("can't find reachable insn at %s+0x%" PRIx64,
-			     reloc->sym->sec->name, addend);
+			     reloc->sym->sec->name, offset);
 			return -1;
 		}
 
@@ -2224,6 +2227,7 @@ static int read_unwind_hints(struct objtool_file *file)
 	struct unwind_hint *hint;
 	struct instruction *insn;
 	struct reloc *reloc;
+	unsigned long offset;
 	int i;
 
 	sec = find_section_by_name(file->elf, ".discard.unwind_hints");
@@ -2251,7 +2255,16 @@ static int read_unwind_hints(struct objtool_file *file)
 			return -1;
 		}
 
-		insn = find_insn(file, reloc->sym->sec, reloc_addend(reloc));
+		if (reloc->sym->type == STT_SECTION) {
+			offset = reloc_addend(reloc);
+		} else if (reloc->sym->local_label) {
+			offset = reloc->sym->offset;
+		} else {
+			WARN("unexpected relocation symbol type in %s", sec->rsec->name);
+			return -1;
+		}
+
+		insn = find_insn(file, reloc->sym->sec, offset);
 		if (!insn) {
 			WARN("can't find insn for unwind_hints[%d]", i);
 			return -1;
@@ -2522,6 +2535,9 @@ static int classify_symbols(struct objtool_file *file)
 	struct symbol *func;
 
 	for_each_sym(file, func) {
+		if (func->type == STT_NOTYPE && strstarts(func->name, ".L"))
+			func->local_label = true;
+
 		if (func->bind != STB_GLOBAL)
 			continue;
 

tools/objtool/include/objtool/elf.h

@@ -67,6 +67,7 @@ struct symbol {
 	u8 profiling_func    : 1;
 	u8 warned	     : 1;
 	u8 embedded_insn     : 1;
+	u8 local_label       : 1;
 	struct list_head pv_target;
 	struct reloc *relocs;
 };

tools/objtool/include/objtool/orc.h

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef _OBJTOOL_ORC_H
+#define _OBJTOOL_ORC_H
+
+#include <objtool/check.h>
+
+int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi, struct instruction *insn);
+void orc_print_dump(struct elf *dummy_elf, struct orc_entry *orc, int i);
+int write_orc_entry(struct elf *elf, struct section *orc_sec,
+		    struct section *ip_sec, unsigned int idx,
+		    struct section *insn_sec, unsigned long insn_off,
+		    struct orc_entry *o);
+
+#endif /* _OBJTOOL_ORC_H */

tools/objtool/orc_dump.c

@@ -6,65 +6,10 @@
 #include <unistd.h>
 #include <asm/orc_types.h>
 #include <objtool/objtool.h>
+#include <objtool/orc.h>
 #include <objtool/warn.h>
 #include <objtool/endianness.h>
 
-static const char *reg_name(unsigned int reg)
-{
-	switch (reg) {
-	case ORC_REG_PREV_SP:
-		return "prevsp";
-	case ORC_REG_DX:
-		return "dx";
-	case ORC_REG_DI:
-		return "di";
-	case ORC_REG_BP:
-		return "bp";
-	case ORC_REG_SP:
-		return "sp";
-	case ORC_REG_R10:
-		return "r10";
-	case ORC_REG_R13:
-		return "r13";
-	case ORC_REG_BP_INDIRECT:
-		return "bp(ind)";
-	case ORC_REG_SP_INDIRECT:
-		return "sp(ind)";
-	default:
-		return "?";
-	}
-}
-
-static const char *orc_type_name(unsigned int type)
-{
-	switch (type) {
-	case ORC_TYPE_UNDEFINED:
-		return "(und)";
-	case ORC_TYPE_END_OF_STACK:
-		return "end";
-	case ORC_TYPE_CALL:
-		return "call";
-	case ORC_TYPE_REGS:
-		return "regs";
-	case ORC_TYPE_REGS_PARTIAL:
-		return "regs (partial)";
-	default:
-		return "?";
-	}
-}
-
-static void print_reg(unsigned int reg, int offset)
-{
-	if (reg == ORC_REG_BP_INDIRECT)
-		printf("(bp%+d)", offset);
-	else if (reg == ORC_REG_SP_INDIRECT)
-		printf("(sp)%+d", offset);
-	else if (reg == ORC_REG_UNDEFINED)
-		printf("(und)");
-	else
-		printf("%s%+d", reg_name(reg), offset);
-}
-
 int orc_dump(const char *_objname)
 {
 	int fd, nr_entries, i, *orc_ip = NULL, orc_size = 0;
@@ -205,17 +150,7 @@ int orc_dump(const char *_objname)
 			printf("%llx:", (unsigned long long)(orc_ip_addr + (i * sizeof(int)) + orc_ip[i]));
 		}
 
-		printf("type:%s", orc_type_name(orc[i].type));
+		orc_print_dump(&dummy_elf, orc, i);
-
-		printf(" sp:");
-
-		print_reg(orc[i].sp_reg, bswap_if_needed(&dummy_elf, orc[i].sp_offset));
-
-		printf(" bp:");
-
-		print_reg(orc[i].bp_reg, bswap_if_needed(&dummy_elf, orc[i].bp_offset));
-
-		printf(" signal:%d\n", orc[i].signal);
 	}
 
 	elf_end(elf);

tools/objtool/orc_gen.c

@@ -10,121 +10,10 @@
 #include <asm/orc_types.h>
 
 #include <objtool/check.h>
+#include <objtool/orc.h>
 #include <objtool/warn.h>
 #include <objtool/endianness.h>
 
-static int init_orc_entry(struct orc_entry *orc, struct cfi_state *cfi,
-			  struct instruction *insn)
-{
-	struct cfi_reg *bp = &cfi->regs[CFI_BP];
-
-	memset(orc, 0, sizeof(*orc));
-
-	if (!cfi) {
-		/*
-		 * This is usually either unreachable nops/traps (which don't
-		 * trigger unreachable instruction warnings), or
-		 * STACK_FRAME_NON_STANDARD functions.
-		 */
-		orc->type = ORC_TYPE_UNDEFINED;
-		return 0;
-	}
-
-	switch (cfi->type) {
-	case UNWIND_HINT_TYPE_UNDEFINED:
-		orc->type = ORC_TYPE_UNDEFINED;
-		return 0;
-	case UNWIND_HINT_TYPE_END_OF_STACK:
-		orc->type = ORC_TYPE_END_OF_STACK;
-		return 0;
-	case UNWIND_HINT_TYPE_CALL:
-		orc->type = ORC_TYPE_CALL;
-		break;
-	case UNWIND_HINT_TYPE_REGS:
-		orc->type = ORC_TYPE_REGS;
-		break;
-	case UNWIND_HINT_TYPE_REGS_PARTIAL:
-		orc->type = ORC_TYPE_REGS_PARTIAL;
-		break;
-	default:
-		WARN_INSN(insn, "unknown unwind hint type %d", cfi->type);
-		return -1;
-	}
-
-	orc->signal = cfi->signal;
-
-	switch (cfi->cfa.base) {
-	case CFI_SP:
-		orc->sp_reg = ORC_REG_SP;
-		break;
-	case CFI_SP_INDIRECT:
-		orc->sp_reg = ORC_REG_SP_INDIRECT;
-		break;
-	case CFI_BP:
-		orc->sp_reg = ORC_REG_BP;
-		break;
-	case CFI_BP_INDIRECT:
-		orc->sp_reg = ORC_REG_BP_INDIRECT;
-		break;
-	case CFI_R10:
-		orc->sp_reg = ORC_REG_R10;
-		break;
-	case CFI_R13:
-		orc->sp_reg = ORC_REG_R13;
-		break;
-	case CFI_DI:
-		orc->sp_reg = ORC_REG_DI;
-		break;
-	case CFI_DX:
-		orc->sp_reg = ORC_REG_DX;
-		break;
-	default:
-		WARN_INSN(insn, "unknown CFA base reg %d", cfi->cfa.base);
-		return -1;
-	}
-
-	switch (bp->base) {
-	case CFI_UNDEFINED:
-		orc->bp_reg = ORC_REG_UNDEFINED;
-		break;
-	case CFI_CFA:
-		orc->bp_reg = ORC_REG_PREV_SP;
-		break;
-	case CFI_BP:
-		orc->bp_reg = ORC_REG_BP;
-		break;
-	default:
-		WARN_INSN(insn, "unknown BP base reg %d", bp->base);
-		return -1;
-	}
-
-	orc->sp_offset = cfi->cfa.offset;
-	orc->bp_offset = bp->offset;
-
-	return 0;
-}
-
-static int write_orc_entry(struct elf *elf, struct section *orc_sec,
-			   struct section *ip_sec, unsigned int idx,
-			   struct section *insn_sec, unsigned long insn_off,
-			   struct orc_entry *o)
-{
-	struct orc_entry *orc;
-
-	/* populate ORC data */
-	orc = (struct orc_entry *)orc_sec->data->d_buf + idx;
-	memcpy(orc, o, sizeof(*orc));
-	orc->sp_offset = bswap_if_needed(elf, orc->sp_offset);
-	orc->bp_offset = bswap_if_needed(elf, orc->bp_offset);
-
-	/* populate reloc for ip */
-	if (!elf_init_reloc_text_sym(elf, ip_sec, idx * sizeof(int), idx,
-				     insn_sec, insn_off))
-		return -1;
-
-	return 0;
-}
-
 struct orc_list_entry {
 	struct list_head list;
 	struct orc_entry orc;