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Commit 4b59bdb5 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/bugs: Remove x86_spec_ctrl_set() 



x86_spec_ctrl_set() is only used in bugs.c and the extra mask checks there
provide no real value as both call sites can just write x86_spec_ctrl_base
to MSR_SPEC_CTRL. x86_spec_ctrl_base is valid and does not need any extra
masking or checking.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent fa8ac498

arch/x86/include/asm/nospec-branch.h

+0 −2
Original line number Diff line number Diff line
@@ -217,8 +217,6 @@ enum spectre_v2_mitigation { 
	SPECTRE_V2_IBRS,

};



extern void x86_spec_ctrl_set(u64);



/* The Speculative Store Bypass disable variants */

enum ssb_mitigation {

	SPEC_STORE_BYPASS_NONE,

arch/x86/kernel/cpu/bugs.c

+2 −11
Original line number Diff line number Diff line
@@ -133,15 +133,6 @@ static const char *spectre_v2_strings[] = { 
static enum spectre_v2_mitigation spectre_v2_enabled __ro_after_init =

	SPECTRE_V2_NONE;



void x86_spec_ctrl_set(u64 val)

{

	if (val & x86_spec_ctrl_mask)

		WARN_ONCE(1, "SPEC_CTRL MSR value 0x%16llx is unknown.\n", val);

	else

		wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base | val);

}

EXPORT_SYMBOL_GPL(x86_spec_ctrl_set);



void

x86_virt_spec_ctrl(u64 guest_spec_ctrl, u64 guest_virt_spec_ctrl, bool setguest)

{
@@ -503,7 +494,7 @@ static enum ssb_mitigation __init __ssb_select_mitigation(void) 
		case X86_VENDOR_INTEL:

			x86_spec_ctrl_base |= SPEC_CTRL_SSBD;

			x86_spec_ctrl_mask &= ~SPEC_CTRL_SSBD;

			x86_spec_ctrl_set(SPEC_CTRL_SSBD);

			wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);

			break;

		case X86_VENDOR_AMD:

			x86_amd_ssb_disable();
@@ -615,7 +606,7 @@ int arch_prctl_spec_ctrl_get(struct task_struct *task, unsigned long which) 
void x86_spec_ctrl_setup_ap(void)

{

	if (boot_cpu_has(X86_FEATURE_MSR_SPEC_CTRL))

		x86_spec_ctrl_set(x86_spec_ctrl_base & ~x86_spec_ctrl_mask);

		wrmsrl(MSR_IA32_SPEC_CTRL, x86_spec_ctrl_base);



	if (ssb_mode == SPEC_STORE_BYPASS_DISABLE)

		x86_amd_ssb_disable();