diff options
Diffstat (limited to 'arch/x86/include/asm/entry-common.h')
| -rw-r--r-- | arch/x86/include/asm/entry-common.h | 28 |
1 files changed, 17 insertions, 11 deletions
diff --git a/arch/x86/include/asm/entry-common.h b/arch/x86/include/asm/entry-common.h index 7e523bb3d2d3..77d20555e04d 100644 --- a/arch/x86/include/asm/entry-common.h +++ b/arch/x86/include/asm/entry-common.h @@ -8,6 +8,7 @@ #include <asm/nospec-branch.h> #include <asm/io_bitmap.h> #include <asm/fpu/api.h> +#include <asm/fred.h> /* Check that the stack and regs on entry from user mode are sane. */ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) @@ -44,8 +45,7 @@ static __always_inline void arch_enter_from_user_mode(struct pt_regs *regs) } #define arch_enter_from_user_mode arch_enter_from_user_mode -static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, - unsigned long ti_work) +static inline void arch_exit_work(unsigned long ti_work) { if (ti_work & _TIF_USER_RETURN_NOTIFY) fire_user_return_notifiers(); @@ -56,6 +56,15 @@ static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, fpregs_assert_state_consistent(); if (unlikely(ti_work & _TIF_NEED_FPU_LOAD)) switch_fpu_return(); +} + +static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, + unsigned long ti_work) +{ + if (IS_ENABLED(CONFIG_X86_DEBUG_FPU) || unlikely(ti_work)) + arch_exit_work(ti_work); + + fred_update_rsp0(); #ifdef CONFIG_COMPAT /* @@ -73,19 +82,16 @@ static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, #endif /* - * Ultimately, this value will get limited by KSTACK_OFFSET_MAX(), - * but not enough for x86 stack utilization comfort. To keep - * reasonable stack head room, reduce the maximum offset to 8 bits. - * - * The actual entropy will be further reduced by the compiler when - * applying stack alignment constraints (see cc_stack_align4/8 in + * This value will get limited by KSTACK_OFFSET_MAX(), which is 10 + * bits. The actual entropy will be further reduced by the compiler + * when applying stack alignment constraints (see cc_stack_align4/8 in * arch/x86/Makefile), which will remove the 3 (x86_64) or 2 (ia32) * low bits from any entropy chosen here. * - * Therefore, final stack offset entropy will be 5 (x86_64) or - * 6 (ia32) bits. + * Therefore, final stack offset entropy will be 7 (x86_64) or + * 8 (ia32) bits. */ - choose_random_kstack_offset(rdtsc() & 0xFF); + choose_random_kstack_offset(rdtsc()); } #define arch_exit_to_user_mode_prepare arch_exit_to_user_mode_prepare |