6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Waiman Long <longman@xxxxxxxxxx> [ Upstream commit e3e3bab1844d448a239cd57ebf618839e26b4157 ] 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@xxxxxxxxxxxxx> Signed-off-by: Waiman Long <longman@xxxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20230727184600.26768-2-longman@xxxxxxxxxx Stable-dep-of: c157d351460b ("intel_idle: Handle older CPUs, which stop the TSC in deeper C states, correctly") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 cb0386fc4dc3b..c648502e45357 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 -- 2.39.5
