powerpc fixes for 6.5 #4

- Reinstate support for little endian ELFv1 binaries, which it turns out still
    exist in the wild.
 
  - Revert a change which used asm goto for WARN_ON/__WARN_FLAGS, as it lead to
    dead code generation and seemed to trigger compiler bugs in some edge cases.
 
  - Fix a deadlock in the pseries VAS code, between live migration and the
    driver's mmap handler.
 
  - Disable KCOV instrumentation in the powerpc KASAN code.
 
 Thanks to: Andrew Donnellan, Benjamin Gray, Christophe Leroy, Haren Myneni,
 Russell Currey, Uwe Kleine-König.
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Merge tag 'powerpc-6.5-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:

 - Reinstate support for little endian ELFv1 binaries, which it turns
   out still exist in the wild.

 - Revert a change which used asm goto for WARN_ON/__WARN_FLAGS, as it
   lead to dead code generation and seemed to trigger compiler bugs in
   some edge cases.

 - Fix a deadlock in the pseries VAS code, between live migration and
   the driver's mmap handler.

 - Disable KCOV instrumentation in the powerpc KASAN code.

Thanks to Andrew Donnellan, Benjamin Gray, Christophe Leroy, Haren
Myneni, Russell Currey, and Uwe Kleine-König.

* tag 'powerpc-6.5-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  Revert "powerpc/64s: Remove support for ELFv1 little endian userspace"
  powerpc/kasan: Disable KCOV in KASAN code
  powerpc/512x: lpbfifo: Convert to platform remove callback returning void
  powerpc/crypto: Add gitignore for generated P10 AES/GCM .S files
  Revert "powerpc/bug: Provide better flexibility to WARN_ON/__WARN_FLAGS() with asm goto"
  powerpc/pseries/vas: Hold mmap_mutex after mmap lock during window close

arch/powerpc/crypto/.gitignore

@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
+aesp10-ppc.S
+ghashp10-ppc.S

arch/powerpc/include/asm/bug.h

@@ -4,14 +4,13 @@
 #ifdef __KERNEL__
 
 #include <asm/asm-compat.h>
-#include <asm/extable.h>
 
 #ifdef CONFIG_BUG
 
 #ifdef __ASSEMBLY__
 #include <asm/asm-offsets.h>
 #ifdef CONFIG_DEBUG_BUGVERBOSE
-.macro __EMIT_BUG_ENTRY addr,file,line,flags
+.macro EMIT_BUG_ENTRY addr,file,line,flags
 	 .section __bug_table,"aw"
 5001:	 .4byte \addr - .
 	 .4byte 5002f - .
@@ -23,7 +22,7 @@
 	 .previous
 .endm
 #else
-.macro __EMIT_BUG_ENTRY addr,file,line,flags
+.macro EMIT_BUG_ENTRY addr,file,line,flags
 	 .section __bug_table,"aw"
 5001:	 .4byte \addr - .
 	 .short \flags
@@ -32,18 +31,6 @@
 .endm
 #endif /* verbose */
 
-.macro EMIT_WARN_ENTRY addr,file,line,flags
-	EX_TABLE(\addr,\addr+4)
-	__EMIT_BUG_ENTRY \addr,\file,\line,\flags
-.endm
-
-.macro EMIT_BUG_ENTRY addr,file,line,flags
-	.if \flags & 1 /* BUGFLAG_WARNING */
-	.err /* Use EMIT_WARN_ENTRY for warnings */
-	.endif
-	__EMIT_BUG_ENTRY \addr,\file,\line,\flags
-.endm
-
 #else /* !__ASSEMBLY__ */
 /* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and
    sizeof(struct bug_entry), respectively */
@@ -73,16 +60,6 @@
 		  "i" (sizeof(struct bug_entry)),	\
 		  ##__VA_ARGS__)
 
-#define WARN_ENTRY(insn, flags, label, ...)		\
-	asm_volatile_goto(				\
-		"1:	" insn "\n"			\
-		EX_TABLE(1b, %l[label])			\
-		_EMIT_BUG_ENTRY				\
-		: : "i" (__FILE__), "i" (__LINE__),	\
-		  "i" (flags),				\
-		  "i" (sizeof(struct bug_entry)),	\
-		  ##__VA_ARGS__ : : label)
-
 /*
  * BUG_ON() and WARN_ON() do their best to cooperate with compile-time
  * optimisations. However depending on the complexity of the condition
@@ -95,16 +72,7 @@
 } while (0)
 #define HAVE_ARCH_BUG
 
-#define __WARN_FLAGS(flags) do {				\
-	__label__ __label_warn_on;				\
-								\
-	WARN_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags), __label_warn_on); \
-	barrier_before_unreachable();				\
-	__builtin_unreachable();				\
-								\
-__label_warn_on:						\
-	break;							\
-} while (0)
+#define __WARN_FLAGS(flags) BUG_ENTRY("twi 31, 0, 0", BUGFLAG_WARNING | (flags))
 
 #ifdef CONFIG_PPC64
 #define BUG_ON(x) do {						\
@@ -117,25 +85,15 @@ __label_warn_on:						\
 } while (0)
 
 #define WARN_ON(x) ({						\
-	bool __ret_warn_on = false;				\
-	do {							\
-		if (__builtin_constant_p((x))) {		\
-			if (!(x)) 				\
-				break; 				\
+	int __ret_warn_on = !!(x);				\
+	if (__builtin_constant_p(__ret_warn_on)) {		\
+		if (__ret_warn_on)				\
 			__WARN();				\
-			__ret_warn_on = true;			\
-		} else {					\
-			__label__ __label_warn_on;		\
-								\
-			WARN_ENTRY(PPC_TLNEI " %4, 0",		\
-				   BUGFLAG_WARNING | BUGFLAG_TAINT(TAINT_WARN),	\
-				   __label_warn_on,		\
-				   "r" ((__force long)(x)));	\
-			break;					\
-__label_warn_on:						\
-			__ret_warn_on = true;			\
-		}						\
-	} while (0);						\
+	} else {						\
+		BUG_ENTRY(PPC_TLNEI " %4, 0",			\
+			  BUGFLAG_WARNING | BUGFLAG_TAINT(TAINT_WARN),	\
+			  "r" (__ret_warn_on));	\
+	}							\
 	unlikely(__ret_warn_on);				\
 })
 
@@ -148,14 +106,13 @@ __label_warn_on:						\
 #ifdef __ASSEMBLY__
 .macro EMIT_BUG_ENTRY addr,file,line,flags
 .endm
-.macro EMIT_WARN_ENTRY addr,file,line,flags
-.endm
 #else /* !__ASSEMBLY__ */
 #define _EMIT_BUG_ENTRY
-#define _EMIT_WARN_ENTRY
 #endif
 #endif /* CONFIG_BUG */
 
+#define EMIT_WARN_ENTRY EMIT_BUG_ENTRY
+
 #include <asm-generic/bug.h>
 
 #ifndef __ASSEMBLY__

arch/powerpc/include/asm/elf.h

@@ -12,14 +12,8 @@
 
 /*
  * This is used to ensure we don't load something for the wrong architecture.
- * 64le only supports ELFv2 64-bit binaries (64be supports v1 and v2).
  */
-#if defined(CONFIG_PPC64) && defined(CONFIG_CPU_LITTLE_ENDIAN)
-#define elf_check_arch(x) (((x)->e_machine == ELF_ARCH) && \
-			   (((x)->e_flags & 0x3) == 0x2))
-#else
 #define elf_check_arch(x) ((x)->e_machine == ELF_ARCH)
-#endif
 #define compat_elf_check_arch(x)	((x)->e_machine == EM_PPC)
 
 #define CORE_DUMP_USE_REGSET

arch/powerpc/include/asm/thread_info.h

@@ -183,13 +183,9 @@ static inline bool test_thread_local_flags(unsigned int flags)
 #define clear_tsk_compat_task(tsk) do { } while (0)
 #endif
 
-#ifdef CONFIG_PPC64
-#ifdef CONFIG_CPU_BIG_ENDIAN
+#if defined(CONFIG_PPC64)
 #define is_elf2_task() (test_thread_flag(TIF_ELF2ABI))
 #else
-#define is_elf2_task() (1)
-#endif
-#else
 #define is_elf2_task() (0)
 #endif
 

arch/powerpc/kernel/traps.c

@@ -1508,13 +1508,8 @@ static void do_program_check(struct pt_regs *regs)
 
 		if (!(regs->msr & MSR_PR) &&  /* not user-mode */
 		    report_bug(bugaddr, regs) == BUG_TRAP_TYPE_WARN) {
-			const struct exception_table_entry *entry;
-
-			entry = search_exception_tables(bugaddr);
-			if (entry) {
-				regs_set_return_ip(regs, extable_fixup(entry) + regs->nip - bugaddr);
-				return;
-			}
+			regs_add_return_ip(regs, 4);
+			return;
 		}
 
 		if (cpu_has_feature(CPU_FTR_DEXCR_NPHIE) && user_mode(regs)) {

arch/powerpc/mm/kasan/Makefile

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
 KASAN_SANITIZE := n
+KCOV_INSTRUMENT := n
 
 obj-$(CONFIG_PPC32)		+= init_32.o
 obj-$(CONFIG_PPC_8xx)		+= 8xx.o

arch/powerpc/platforms/512x/mpc512x_lpbfifo.c

@@ -477,7 +477,7 @@ static int mpc512x_lpbfifo_probe(struct platform_device *pdev)
 	return ret;
 }
 
-static int mpc512x_lpbfifo_remove(struct platform_device *pdev)
+static void mpc512x_lpbfifo_remove(struct platform_device *pdev)
 {
 	unsigned long flags;
 	struct dma_device *dma_dev = lpbfifo.chan->device;
@@ -494,8 +494,6 @@ static int mpc512x_lpbfifo_remove(struct platform_device *pdev)
 	free_irq(lpbfifo.irq, &pdev->dev);
 	irq_dispose_mapping(lpbfifo.irq);
 	dma_release_channel(lpbfifo.chan);
-
-	return 0;
 }
 
 static const struct of_device_id mpc512x_lpbfifo_match[] = {
@@ -506,7 +504,7 @@ MODULE_DEVICE_TABLE(of, mpc512x_lpbfifo_match);
 
 static struct platform_driver mpc512x_lpbfifo_driver = {
 	.probe = mpc512x_lpbfifo_probe,
-	.remove = mpc512x_lpbfifo_remove,
+	.remove_new = mpc512x_lpbfifo_remove,
 	.driver = {
 		.name = DRV_NAME,
 		.of_match_table = mpc512x_lpbfifo_match,

arch/powerpc/platforms/pseries/vas.c

@@ -744,6 +744,12 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds,
 		}
 
 		task_ref = &win->vas_win.task_ref;
+		/*
+		 * VAS mmap (coproc_mmap()) and its fault handler
+		 * (vas_mmap_fault()) are called after holding mmap lock.
+		 * So hold mmap mutex after mmap_lock to avoid deadlock.
+		 */
+		mmap_write_lock(task_ref->mm);
 		mutex_lock(&task_ref->mmap_mutex);
 		vma = task_ref->vma;
 		/*
@@ -752,7 +758,6 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds,
 		 */
 		win->vas_win.status |= flag;
 
-		mmap_write_lock(task_ref->mm);
 		/*
 		 * vma is set in the original mapping. But this mapping
 		 * is done with mmap() after the window is opened with ioctl.
@@ -762,8 +767,8 @@ static int reconfig_close_windows(struct vas_caps *vcap, int excess_creds,
 		if (vma)
 			zap_vma_pages(vma);
 
-		mmap_write_unlock(task_ref->mm);
 		mutex_unlock(&task_ref->mmap_mutex);
+		mmap_write_unlock(task_ref->mm);
 		/*
 		 * Close VAS window in the hypervisor, but do not
 		 * free vas_window struct since it may be reused