Commit 7f43c201 authored by Marc Zyngier's avatar Marc Zyngier
Browse files

arm64: Make the Meltdown mitigation state available 



Our Meltdown mitigation state isn't exposed outside of cpufeature.c,
contrary to the rest of the Spectre mitigation state. As we are going
to use it in KVM, expose a arm64_get_meltdown_state() helper which
returns the same possible values as arm64_get_spectre_v?_state().

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent 09162bc3

arch/arm64/include/asm/spectre.h

+2 −0
Original line number Diff line number Diff line
@@ -29,4 +29,6 @@ bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope); 
void spectre_v4_enable_mitigation(const struct arm64_cpu_capabilities *__unused);

void spectre_v4_enable_task_mitigation(struct task_struct *tsk);



enum mitigation_state arm64_get_meltdown_state(void);



#endif	/* __ASM_SPECTRE_H */

arch/arm64/kernel/cpufeature.c

+17 −3
Original line number Diff line number Diff line
@@ -2846,14 +2846,28 @@ static int __init enable_mrs_emulation(void) 


core_initcall(enable_mrs_emulation);



enum mitigation_state arm64_get_meltdown_state(void)

{

	if (__meltdown_safe)

		return SPECTRE_UNAFFECTED;



	if (arm64_kernel_unmapped_at_el0())

		return SPECTRE_MITIGATED;



	return SPECTRE_VULNERABLE;

}



ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr,

			  char *buf)

{

	if (__meltdown_safe)

	switch (arm64_get_meltdown_state()) {

	case SPECTRE_UNAFFECTED:

		return sprintf(buf, "Not affected\n");



	if (arm64_kernel_unmapped_at_el0())

	case SPECTRE_MITIGATED:

		return sprintf(buf, "Mitigation: PTI\n");



	default:

		return sprintf(buf, "Vulnerable\n");

	}

}

CRA Git | Maintained and supported by SUSTech CRA and CCSE