diff options
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 3 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 23 | ||||
| -rw-r--r-- | arch/arm64/kernel/traps.c | 3 |
3 files changed, 10 insertions, 19 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index f73f11b55042..03d1c9d7af82 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -832,7 +832,8 @@ static inline bool system_supports_tlb_range(void) cpus_have_const_cap(ARM64_HAS_TLB_RANGE); } -extern int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); +int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); +bool try_emulate_mrs(struct pt_regs *regs, u32 isn); static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange) { diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index b3f37e2209ad..9592e75b07cd 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -3435,35 +3435,22 @@ int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt) return rc; } -static int emulate_mrs(struct pt_regs *regs, u32 insn) +bool try_emulate_mrs(struct pt_regs *regs, u32 insn) { u32 sys_reg, rt; + if (compat_user_mode(regs) || !aarch64_insn_is_mrs(insn)) + return false; + /* * sys_reg values are defined as used in mrs/msr instruction. * shift the imm value to get the encoding. */ sys_reg = (u32)aarch64_insn_decode_immediate(AARCH64_INSN_IMM_16, insn) << 5; rt = aarch64_insn_decode_register(AARCH64_INSN_REGTYPE_RT, insn); - return do_emulate_mrs(regs, sys_reg, rt); + return do_emulate_mrs(regs, sys_reg, rt) == 0; } -static struct undef_hook mrs_hook = { - .instr_mask = 0xffff0000, - .instr_val = 0xd5380000, - .pstate_mask = PSR_AA32_MODE_MASK, - .pstate_val = PSR_MODE_EL0t, - .fn = emulate_mrs, -}; - -static int __init enable_mrs_emulation(void) -{ - register_undef_hook(&mrs_hook); - return 0; -} - -core_initcall(enable_mrs_emulation); - enum mitigation_state arm64_get_meltdown_state(void) { if (__meltdown_safe) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 4d51afd010e1..96eaf1aaec12 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -499,6 +499,9 @@ void do_el0_undef(struct pt_regs *regs, unsigned long esr) if (user_insn_read(regs, &insn)) goto out_err; + if (try_emulate_mrs(regs, insn)) + return; + if (call_undef_hook(regs, insn) == 0) return; |