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authorH.J. Lu <hjl.tools@gmail.com>2015-07-12 14:38:58 -0700
committerH.J. Lu <hjl.tools@gmail.com>2015-08-03 14:32:47 -0700
commit08094d48c130d3ae6182296ef3c9561ca1066b39 (patch)
treecdfba5498d2451b4066ea469e74591eaf556fe9d
parent723a5bd465082390bd9369d4f95ec11b32cf47dd (diff)
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Align stack to 16 bytes when calling __setcontext
Don't use pop to restore %rdi so that stack is aligned to 16 bytes
when calling __setcontext.

	[BZ #18661]
	* sysdeps/unix/sysv/linux/x86_64/__start_context.S
	(__start_context): Don't use pop to restore %rdi so that stack
	is aligned to 16 bytes when calling __setcontext.
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/__start_context.S4
1 files changed, 2 insertions, 2 deletions
diff --git a/sysdeps/unix/sysv/linux/x86_64/__start_context.S b/sysdeps/unix/sysv/linux/x86_64/__start_context.S
index 52a5afa9a6..96366e0536 100644
--- a/sysdeps/unix/sysv/linux/x86_64/__start_context.S
+++ b/sysdeps/unix/sysv/linux/x86_64/__start_context.S
@@ -31,8 +31,8 @@ ENTRY(__start_context)
 	   on the stack pointer for the next context.  */
 	movq	%rbx, %rsp
 
-	popq	%rdi			/* This is the next context.  */
-	cfi_adjust_cfa_offset(-8)
+	/* Don't use pop here so that stack is aligned to 16 bytes.  */
+	movq	(%rsp), %rdi		/* This is the next context.  */
 	testq	%rdi, %rdi
 	je	2f			/* If it is zero exit.  */