Commit e3e3bab1 authored by Waiman Long's avatar Waiman Long Committed by Ingo Molnar
Browse files

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: default avatarPeter Zijlstra <peterz@infradead.org>
Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarRafael 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
parent ea41bb51

arch/x86/include/asm/spec-ctrl.h

+11 −0
Original line number Diff line number Diff line
@@ -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