ARM development updates for 5.6-rc1:

- decompressor updates
 - prevention of out-of-bounds access while stacktracing
 - fix a section mismatch warning with free_memmap()
 - make kexec depend on MMU to avoid some build errors
 - remove swapops stubs
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Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM updates from Russell King:

 - decompressor updates

 - prevention of out-of-bounds access while stacktracing

 - fix a section mismatch warning with free_memmap()

 - make kexec depend on MMU to avoid some build errors

 - remove swapops stubs

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8954/1: NOMMU: remove stubs for swapops
  ARM: 8952/1: Disable kmemleak on XIP kernels
  ARM: 8951/1: Fix Kexec compilation issue.
  ARM: 8949/1: mm: mark free_memmap as __init
  ARM: 8948/1: Prevent OOB access in stacktrace
  ARM: 8945/1: decompressor: use CONFIG option instead of cc-option
  ARM: 8942/1: Revert "8857/1: efi: enable CP15 DMB instructions before cleaning the cache"
  ARM: 8941/1: decompressor: enable CP15 barrier instructions in v7 cache setup code

arch/arm/Kconfig

@@ -74,7 +74,7 @@ config ARM
 	select HAVE_CONTEXT_TRACKING
 	select HAVE_COPY_THREAD_TLS
 	select HAVE_C_RECORDMCOUNT
-	select HAVE_DEBUG_KMEMLEAK
+	select HAVE_DEBUG_KMEMLEAK if !XIP_KERNEL
 	select HAVE_DMA_CONTIGUOUS if MMU
 	select HAVE_DYNAMIC_FTRACE if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS if HAVE_DYNAMIC_FTRACE
@@ -1905,7 +1905,7 @@ config XIP_DEFLATED_DATA
 config KEXEC
 	bool "Kexec system call (EXPERIMENTAL)"
 	depends on (!SMP || PM_SLEEP_SMP)
-	depends on !CPU_V7M
+	depends on MMU
 	select KEXEC_CORE
 	help
 	  kexec is a system call that implements the ability to shutdown your

arch/arm/boot/compressed/Makefile

@@ -110,12 +110,12 @@ endif
 
 # -fstack-protector-strong triggers protection checks in this code,
 # but it is being used too early to link to meaningful stack_chk logic.
-nossp_flags := $(call cc-option, -fno-stack-protector)
-CFLAGS_atags_to_fdt.o := $(nossp_flags)
-CFLAGS_fdt.o := $(nossp_flags)
-CFLAGS_fdt_ro.o := $(nossp_flags)
-CFLAGS_fdt_rw.o := $(nossp_flags)
-CFLAGS_fdt_wip.o := $(nossp_flags)
+nossp-flags-$(CONFIG_CC_HAS_STACKPROTECTOR_NONE) := -fno-stack-protector
+CFLAGS_atags_to_fdt.o := $(nossp-flags-y)
+CFLAGS_fdt.o := $(nossp-flags-y)
+CFLAGS_fdt_ro.o := $(nossp-flags-y)
+CFLAGS_fdt_rw.o := $(nossp-flags-y)
+CFLAGS_fdt_wip.o := $(nossp-flags-y)
 
 ccflags-y := -fpic $(call cc-option,-mno-single-pic-base,) -fno-builtin -I$(obj)
 asflags-y := -DZIMAGE

arch/arm/boot/compressed/head.S

@@ -140,6 +140,17 @@
 #endif
 		.endm
 
+		.macro	enable_cp15_barriers, reg
+		mrc	p15, 0, \reg, c1, c0, 0	@ read SCTLR
+		tst	\reg, #(1 << 5)		@ CP15BEN bit set?
+		bne	.L_\@
+		orr	\reg, \reg, #(1 << 5)	@ CP15 barrier instructions
+		mcr	p15, 0, \reg, c1, c0, 0	@ write SCTLR
+ ARM(		.inst   0xf57ff06f		@ v7+ isb	)
+ THUMB(		isb						)
+.L_\@:
+		.endm
+
 		.section ".start", "ax"
 /*
  * sort out different calling conventions
@@ -820,6 +831,7 @@ __armv4_mmu_cache_on:
 		mov	pc, r12
 
 __armv7_mmu_cache_on:
+		enable_cp15_barriers	r11
 		mov	r12, lr
 #ifdef CONFIG_MMU
 		mrc	p15, 0, r11, c0, c1, 4	@ read ID_MMFR0
@@ -1209,6 +1221,7 @@ __armv6_mmu_cache_flush:
 		mov	pc, lr
 
 __armv7_mmu_cache_flush:
+		enable_cp15_barriers	r10
 		tst	r4, #1
 		bne	iflush
 		mrc	p15, 0, r10, c0, c1, 5	@ read ID_MMFR1
@@ -1447,21 +1460,7 @@ ENTRY(efi_stub_entry)
 
 		@ Preserve return value of efi_entry() in r4
 		mov	r4, r0
-
-		@ our cache maintenance code relies on CP15 barrier instructions
-		@ but since we arrived here with the MMU and caches configured
-		@ by UEFI, we must check that the CP15BEN bit is set in SCTLR.
-		@ Note that this bit is RAO/WI on v6 and earlier, so the ISB in
-		@ the enable path will be executed on v7+ only.
-		mrc	p15, 0, r1, c1, c0, 0	@ read SCTLR
-		tst	r1, #(1 << 5)		@ CP15BEN bit set?
-		bne	0f
-		orr	r1, r1, #(1 << 5)	@ CP15 barrier instructions
-		mcr	p15, 0, r1, c1, c0, 0	@ write SCTLR
- ARM(		.inst	0xf57ff06f		@ v7+ isb	)
- THUMB(		isb						)
-
-0:		bl	cache_clean_flush
+		bl	cache_clean_flush
 		bl	cache_off
 
 		@ Set parameters for booting zImage according to boot protocol

arch/arm/include/asm/pgtable-nommu.h

@@ -42,12 +42,6 @@
 
 #define swapper_pg_dir ((pgd_t *) 0)
 
-#define __swp_type(x)		(0)
-#define __swp_offset(x)		(0)
-#define __swp_entry(typ,off)	((swp_entry_t) { ((typ) | ((off) << 7)) })
-#define __pte_to_swp_entry(pte)	((swp_entry_t) { pte_val(pte) })
-#define __swp_entry_to_pte(x)	((pte_t) { (x).val })
-
 
 typedef pte_t *pte_addr_t;
 

arch/arm/kernel/stacktrace.c

@@ -92,6 +92,8 @@ static int save_trace(struct stackframe *frame, void *d)
 		return 0;
 
 	regs = (struct pt_regs *)frame->sp;
+	if ((unsigned long)&regs[1] > ALIGN(frame->sp, THREAD_SIZE))
+		return 0;
 
 	trace->entries[trace->nr_entries++] = regs->ARM_pc;
 

arch/arm/kernel/traps.c

@@ -64,14 +64,16 @@ static void dump_mem(const char *, const char *, unsigned long, unsigned long);
 
 void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
 {
+	unsigned long end = frame + 4 + sizeof(struct pt_regs);
+
 #ifdef CONFIG_KALLSYMS
 	printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
 #else
 	printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
 #endif
 
-	if (in_entry_text(from))
-		dump_mem("", "Exception stack", frame + 4, frame + 4 + sizeof(struct pt_regs));
+	if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE))
+		dump_mem("", "Exception stack", frame + 4, end);
 }
 
 void dump_backtrace_stm(u32 *stack, u32 instruction)

arch/arm/mm/init.c

@@ -324,7 +324,7 @@ static inline void poison_init_mem(void *s, size_t count)
 		*p++ = 0xe7fddef0;
 }
 
-static inline void
+static inline void __init
 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
 {
 	struct page *start_pg, *end_pg;