From 6b51311c976593fb7311322b1647a912cd456ec4 Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Fri, 3 Apr 2015 14:25:28 +0200 Subject: [PATCH] x86/asm/entry/64: Use a define for an invalid segment selector ... instead of a naked number, for better readability. Signed-off-by: Borislav Petkov Cc: Alexei Starovoitov Cc: Andy Lutomirski Cc: Denys Vlasenko Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Steven Rostedt Cc: Will Drewry Link: http://lkml.kernel.org/r/1428054130-25847-1-git-send-email-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/include/asm/segment.h | 2 ++ arch/x86/kernel/cpu/common.c | 2 +- 2 files changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h index d394899e055c..5a9856eb12ba 100644 --- a/arch/x86/include/asm/segment.h +++ b/arch/x86/include/asm/segment.h @@ -39,6 +39,8 @@ /* ... GDT has it cleared */ #define SEGMENT_GDT 0x0 +#define GDT_ENTRY_INVALID_SEG 0 + #ifdef CONFIG_X86_32 /* * The layout of the per-CPU GDT under Linux: diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index d56d30714d43..3f70538012e2 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1184,7 +1184,7 @@ void syscall_init(void) wrmsrl_safe(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target); #else wrmsrl(MSR_CSTAR, ignore_sysret); - wrmsrl_safe(MSR_IA32_SYSENTER_CS, 0ULL); + wrmsrl_safe(MSR_IA32_SYSENTER_CS, (u64)GDT_ENTRY_INVALID_SEG); wrmsrl_safe(MSR_IA32_SYSENTER_ESP, 0ULL); wrmsrl_safe(MSR_IA32_SYSENTER_EIP, 0ULL); #endif -- 2.34.1