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Diffstat (limited to 'arch/arm64/kernel/proton-pack.c')
-rw-r--r--arch/arm64/kernel/proton-pack.c26
1 files changed, 7 insertions, 19 deletions
diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c
index bfce41c2a53b..fca9cc6f5581 100644
--- a/arch/arm64/kernel/proton-pack.c
+++ b/arch/arm64/kernel/proton-pack.c
@@ -521,10 +521,13 @@ bool has_spectre_v4(const struct arm64_cpu_capabilities *cap, int scope)
return state != SPECTRE_UNAFFECTED;
}
-static int ssbs_emulation_handler(struct pt_regs *regs, u32 instr)
+bool try_emulate_el1_ssbs(struct pt_regs *regs, u32 instr)
{
- if (user_mode(regs))
- return 1;
+ const u32 instr_mask = ~(1U << PSTATE_Imm_shift);
+ const u32 instr_val = 0xd500401f | PSTATE_SSBS;
+
+ if ((instr & instr_mask) != instr_val)
+ return false;
if (instr & BIT(PSTATE_Imm_shift))
regs->pstate |= PSR_SSBS_BIT;
@@ -532,19 +535,11 @@ static int ssbs_emulation_handler(struct pt_regs *regs, u32 instr)
regs->pstate &= ~PSR_SSBS_BIT;
arm64_skip_faulting_instruction(regs, 4);
- return 0;
+ return true;
}
-static struct undef_hook ssbs_emulation_hook = {
- .instr_mask = ~(1U << PSTATE_Imm_shift),
- .instr_val = 0xd500401f | PSTATE_SSBS,
- .fn = ssbs_emulation_handler,
-};
-
static enum mitigation_state spectre_v4_enable_hw_mitigation(void)
{
- static bool undef_hook_registered = false;
- static DEFINE_RAW_SPINLOCK(hook_lock);
enum mitigation_state state;
/*
@@ -555,13 +550,6 @@ static enum mitigation_state spectre_v4_enable_hw_mitigation(void)
if (state != SPECTRE_MITIGATED || !this_cpu_has_cap(ARM64_SSBS))
return state;
- raw_spin_lock(&hook_lock);
- if (!undef_hook_registered) {
- register_undef_hook(&ssbs_emulation_hook);
- undef_hook_registered = true;
- }
- raw_spin_unlock(&hook_lock);
-
if (spectre_v4_mitigations_off()) {
sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_DSSBS);
set_pstate_ssbs(1);