Messages in this thread Patch in this message | | | From | Josh Poimboeuf <> | Subject | [PATCH 1/2] x86/boot/64: use 'push' instead of 'call' in start_cpu() | Date | Tue, 13 Dec 2016 21:25:35 -0600 |
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start_cpu() pushes a text address on the stack so that stack traces from idle tasks will show start_cpu() at the end. But it uses a call instruction to do that, which is rather obtuse. Use a straightforward push instead.
Suggested-by: Borislav Petkov <bp@alien8.de> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- arch/x86/kernel/head_64.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 90de288..1facaf4 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -298,7 +298,7 @@ ENTRY(start_cpu) * REX.W + FF /5 JMP m16:64 Jump far, absolute indirect, * address given in m16:64. */ - call 1f # put return address on stack for unwinder + pushq $1f # put return address on stack for unwinder 1: xorq %rbp, %rbp # clear frame pointer movq initial_code(%rip), %rax pushq $__KERNEL_CS # set correct cs -- 2.7.4
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