4.4-stable review patch. If anyone has any objections, please let me know.
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From: Waiman Long longman@redhat.com
commit 1df37383a8aeabb9b418698f0bcdffea01f4b1b2 upstream.
It doesn't make sense to have an indirect call thunk with esp/rsp as retpoline code won't work correctly with the stack pointer register. Removing it will help compiler writers to catch error in case such a thunk call is emitted incorrectly.
Fixes: 76b043848fd2 ("x86/retpoline: Add initial retpoline support") Suggested-by: Jeff Law law@redhat.com Signed-off-by: Waiman Long longman@redhat.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Acked-by: David Woodhouse dwmw@amazon.co.uk Cc: Tom Lendacky thomas.lendacky@amd.com Cc: Kees Cook keescook@google.com Cc: Andi Kleen ak@linux.intel.com Cc: Tim Chen tim.c.chen@linux.intel.com Cc: Peter Zijlstra peterz@infradead.org Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Jiri Kosina jikos@kernel.org Cc: Andy Lutomirski luto@amacapital.net Cc: Dave Hansen dave.hansen@intel.com Cc: Josh Poimboeuf jpoimboe@redhat.com Cc: Arjan van de Ven arjan@linux.intel.com Cc: Greg Kroah-Hartman gregkh@linux-foundation.org Cc: Paul Turner pjt@google.com Link: https://lkml.kernel.org/r/1516658974-27852-1-git-send-email-longman@redhat.c... Signed-off-by: David Woodhouse dwmw@amazon.co.uk [jwang: cherry pick to 4.4] Signed-off-by: Jack Wang jinpu.wang@profitbricks.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/include/asm/asm-prototypes.h | 1 - arch/x86/lib/retpoline.S | 1 - 2 files changed, 2 deletions(-)
--- a/arch/x86/include/asm/asm-prototypes.h +++ b/arch/x86/include/asm/asm-prototypes.h @@ -37,5 +37,4 @@ INDIRECT_THUNK(dx) INDIRECT_THUNK(si) INDIRECT_THUNK(di) INDIRECT_THUNK(bp) -INDIRECT_THUNK(sp) #endif /* CONFIG_RETPOLINE */ --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -36,7 +36,6 @@ GENERATE_THUNK(_ASM_DX) GENERATE_THUNK(_ASM_SI) GENERATE_THUNK(_ASM_DI) GENERATE_THUNK(_ASM_BP) -GENERATE_THUNK(_ASM_SP) #ifdef CONFIG_64BIT GENERATE_THUNK(r8) GENERATE_THUNK(r9)