diff options
Diffstat (limited to 'arch/x86/include/asm/nospec-branch.h')
| -rw-r--r-- | arch/x86/include/asm/nospec-branch.h | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h index 08ed5a2e46a5..a6526c5be5ca 100644 --- a/arch/x86/include/asm/nospec-branch.h +++ b/arch/x86/include/asm/nospec-branch.h @@ -308,24 +308,26 @@ * CFLAGS.ZF. * Note: Only the memory operand variant of VERW clears the CPU buffers. */ -.macro __CLEAR_CPU_BUFFERS feature #ifdef CONFIG_X86_64 - ALTERNATIVE "", "verw x86_verw_sel(%rip)", \feature +#define VERW verw x86_verw_sel(%rip) #else - /* - * In 32bit mode, the memory operand must be a %cs reference. The data - * segments may not be usable (vm86 mode), and the stack segment may not - * be flat (ESPFIX32). - */ - ALTERNATIVE "", "verw %cs:x86_verw_sel", \feature +/* + * In 32bit mode, the memory operand must be a %cs reference. The data segments + * may not be usable (vm86 mode), and the stack segment may not be flat (ESPFIX32). + */ +#define VERW verw %cs:x86_verw_sel #endif -.endm -#define CLEAR_CPU_BUFFERS \ - __CLEAR_CPU_BUFFERS X86_FEATURE_CLEAR_CPU_BUF +/* + * Provide a stringified VERW macro for simple usage, and a non-stringified + * VERW macro for use in more elaborate sequences, e.g. to encode a conditional + * VERW within an ALTERNATIVE. + */ +#define __CLEAR_CPU_BUFFERS __stringify(VERW) -#define VM_CLEAR_CPU_BUFFERS \ - __CLEAR_CPU_BUFFERS X86_FEATURE_CLEAR_CPU_BUF_VM +/* If necessary, emit VERW on exit-to-userspace to clear CPU buffers. */ +#define CLEAR_CPU_BUFFERS \ + ALTERNATIVE "", __CLEAR_CPU_BUFFERS, X86_FEATURE_CLEAR_CPU_BUF #ifdef CONFIG_X86_64 .macro CLEAR_BRANCH_HISTORY @@ -580,8 +582,6 @@ DECLARE_STATIC_KEY_FALSE(cpu_buf_idle_clear); DECLARE_STATIC_KEY_FALSE(switch_mm_cond_l1d_flush); -DECLARE_STATIC_KEY_FALSE(cpu_buf_vm_clear); - extern u16 x86_verw_sel; #include <asm/segment.h> |