Messages in this thread Patch in this message | | | Date | Sat, 07 Oct 2023 17:10:59 -0000 | From | "tip-bot2 for Waiman Long" <> | Subject | [tip: sched/core] x86/speculation: Add __update_spec_ctrl() helper |
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The following commit has been merged into the sched/core branch of tip:
Commit-ID: e3e3bab1844d448a239cd57ebf618839e26b4157 Gitweb: https://git.kernel.org/tip/e3e3bab1844d448a239cd57ebf618839e26b4157 Author: Waiman Long <longman@redhat.com> AuthorDate: Thu, 27 Jul 2023 14:45:57 -04:00 Committer: Ingo Molnar <mingo@kernel.org> CommitterDate: Sat, 07 Oct 2023 11:33:28 +02:00
x86/speculation: Add __update_spec_ctrl() helper
Add a new __update_spec_ctrl() helper which is a variant of update_spec_ctrl() that can be used in a noinstr function.
Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Waiman Long <longman@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lore.kernel.org/r/20230727184600.26768-2-longman@redhat.com --- arch/x86/include/asm/spec-ctrl.h | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/arch/x86/include/asm/spec-ctrl.h b/arch/x86/include/asm/spec-ctrl.h index cb0386f..c648502 100644 --- a/arch/x86/include/asm/spec-ctrl.h +++ b/arch/x86/include/asm/spec-ctrl.h @@ -4,6 +4,7 @@ #include <linux/thread_info.h> #include <asm/nospec-branch.h> +#include <asm/msr.h> /* * On VMENTER we must preserve whatever view of the SPEC_CTRL MSR @@ -76,6 +77,16 @@ static inline u64 ssbd_tif_to_amd_ls_cfg(u64 tifn) return (tifn & _TIF_SSBD) ? x86_amd_ls_cfg_ssbd_mask : 0ULL; } +/* + * This can be used in noinstr functions & should only be called in bare + * metal context. + */ +static __always_inline void __update_spec_ctrl(u64 val) +{ + __this_cpu_write(x86_spec_ctrl_current, val); + native_wrmsrl(MSR_IA32_SPEC_CTRL, val); +} + #ifdef CONFIG_SMP extern void speculative_store_bypass_ht_init(void); #else
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