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[PATCH v15 24/25] x86/uaccess: Add stack frame output operand in get_user inline asm

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From: Chris J Arges <chris.j.arges@canonical.com>

Numerous 'call without frame pointer save/setup' warnings are introduced by
stacktool because of functions using the get_user macro. Bad stack traces could
occur due to lack of or misplacement of stack frame setup code.

This patch forces a stack frame to be created before the inline asm code if
CONFIG_FRAME_POINTER is enabled by listing the stack pointer as an output
operand for the get_user inline assembly statement.

Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
 arch/x86/include/asm/uaccess.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 660458a..2584134 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -176,10 +176,11 @@ __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 ({									\
 	int __ret_gu;							\
 	register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX);		\
+	register void *__sp asm(_ASM_SP);				\
 	__chk_user_ptr(ptr);						\
 	might_fault();							\
-	asm volatile("call __get_user_%P3"				\
-		     : "=a" (__ret_gu), "=r" (__val_gu)			\
+	asm volatile("call __get_user_%P4"				\
+		     : "=a" (__ret_gu), "=r" (__val_gu), "+r" (__sp)	\
 		     : "0" (ptr), "i" (sizeof(*(ptr))));		\
 	(x) = (__force __typeof__(*(ptr))) __val_gu;			\
 	__builtin_expect(__ret_gu, 0);					\
-- 
2.4.3

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[PATCH v15 00/25] Compile-time stack metadata validation Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 10/25] x86/paravirt: Add stack frame dependency to PVOP inline asm calls Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 12/25] x86/amd: Set ELF function type for vide() Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 17/25] x86/asm/crypto: Move jump_table to .rodata section Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 25/25] x86/stacktool: Ignore head_$(BITS) files. Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 05/25] x86/asm: Add C versions of frame pointer macros Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 21/25] x86/asm: Create stack frames in rwsem functions Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 22/25] x86/asm/efi: Create a stack frame in efi_call() Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 24/25] x86/uaccess: Add stack frame output operand in get_user inline asm Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 08/25] x86/stacktool: Add ignore macros Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100
  [PATCH v15 02/25] tools: Make list.h self-sufficient Josh Poimboeuf <jpoimboe@redhat.com> - 2015-12-18 13:50 +0100

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