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| author | Will Deacon <will@kernel.org> | 2020-09-18 11:54:33 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-09-29 16:08:16 +0100 |
| commit | c28762070ca651fe7a981b8f31d972c9b7d2c386 (patch) | |
| tree | 907e7cdfc0461b55880ac1ecccc54e460797f219 /arch/arm64/kernel/cpufeature.c | |
| parent | 9e78b659b4539ee20fd0c415cf8c231cea59e9c0 (diff) | |
| download | linux-stable-c28762070ca651fe7a981b8f31d972c9b7d2c386.tar.gz linux-stable-c28762070ca651fe7a981b8f31d972c9b7d2c386.tar.bz2 linux-stable-c28762070ca651fe7a981b8f31d972c9b7d2c386.zip | |
arm64: Rewrite Spectre-v4 mitigation code
Rewrite the Spectre-v4 mitigation handling code to follow the same
approach as that taken by Spectre-v2.
For now, report to KVM that the system is vulnerable (by forcing
'ssbd_state' to ARM64_SSBD_UNKNOWN), as this will be cleared up in
subsequent steps.
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/kernel/cpufeature.c')
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 41 |
1 files changed, 0 insertions, 41 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 033e6c952705..a4debb63ebfb 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1583,46 +1583,6 @@ static void cpu_has_fwb(const struct arm64_cpu_capabilities *__unused) WARN_ON(val & (7 << 27 | 7 << 21)); } -static int ssbs_emulation_handler(struct pt_regs *regs, u32 instr) -{ - if (user_mode(regs)) - return 1; - - if (instr & BIT(PSTATE_Imm_shift)) - regs->pstate |= PSR_SSBS_BIT; - else - regs->pstate &= ~PSR_SSBS_BIT; - - arm64_skip_faulting_instruction(regs, 4); - return 0; -} - -static struct undef_hook ssbs_emulation_hook = { - .instr_mask = ~(1U << PSTATE_Imm_shift), - .instr_val = 0xd500401f | PSTATE_SSBS, - .fn = ssbs_emulation_handler, -}; - -static void cpu_enable_ssbs(const struct arm64_cpu_capabilities *__unused) -{ - static bool undef_hook_registered = false; - static DEFINE_RAW_SPINLOCK(hook_lock); - - 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 (arm64_get_ssbd_state() == ARM64_SSBD_FORCE_DISABLE) { - sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_DSSBS); - arm64_set_ssbd_mitigation(false); - } else { - arm64_set_ssbd_mitigation(true); - } -} - #ifdef CONFIG_ARM64_PAN static void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused) { @@ -1983,7 +1943,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .field_pos = ID_AA64PFR1_SSBS_SHIFT, .sign = FTR_UNSIGNED, .min_field_value = ID_AA64PFR1_SSBS_PSTATE_ONLY, - .cpu_enable = cpu_enable_ssbs, }, #ifdef CONFIG_ARM64_CNP { |