From df729fb05ae2db52f7de150439392a88ee9d9b4f Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin (Intel)" Date: Wed, 11 Jan 2023 23:20:30 -0800 Subject: [PATCH] x86/gsseg: Make asm_load_gs_index() take an u16 Let GCC know that only the low 16 bits of load_gs_index() argument actually matter. It might allow it to create slightly better code. However, do not propagate this into the prototypes of functions that end up being paravirtualized, to avoid unnecessary changes. Signed-off-by: H. Peter Anvin (Intel) Signed-off-by: Xin Li Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20230112072032.35626-4-xin3.li@intel.com --- arch/x86/entry/entry_64.S | 2 +- arch/x86/include/asm/special_insns.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 15739a2c0983..7ecd2aeeeffc 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -782,7 +782,7 @@ _ASM_NOKPROBE(common_interrupt_return) /* * Reload gs selector with exception handling - * edi: new selector + * di: new selector * * Is in entry.text as it shouldn't be instrumented. */ diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index 35f709f619fb..a71d0e8d4684 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -120,7 +120,7 @@ static inline void native_wbinvd(void) asm volatile("wbinvd": : :"memory"); } -extern asmlinkage void asm_load_gs_index(unsigned int selector); +extern asmlinkage void asm_load_gs_index(u16 selector); static inline void native_load_gs_index(unsigned int selector) {