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| author |   Will Deacon <will.deacon@arm.com> | 2018-08-07 13:43:06 +0100 |
|---|---|---|
| committer |   Catalin Marinas <catalin.marinas@arm.com> | 2018-09-14 17:46:17 +0100 |
| commit | 0bf0f444b2c49241b2b39aa3cf210d7c95ef6c34 (patch) | |
| tree | 19c947d9efc758b44a4e23cf7b6984669a761324 | |
| parent | arm64: ssbd: Drop #ifdefs for PR_SPEC_STORE_BYPASS (diff) | |
| download | linux-dev-0bf0f444b2c49241b2b39aa3cf210d7c95ef6c34.tar.xz linux-dev-0bf0f444b2c49241b2b39aa3cf210d7c95ef6c34.zip | |
arm64: entry: Allow handling of undefined instructions from EL1
Rather than panic() when taking an undefined instruction exception from
EL1, allow a hook to be registered in case we want to emulate the
instruction, like we will for the SSBS PSTATE manipulation instructions.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
| -rw-r--r-- | arch/arm64/kernel/entry.S | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/traps.c | 11 |
2 files changed, 8 insertions, 5 deletions
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 09dbea221a27..8556876c9109 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -589,7 +589,7 @@ el1_undef: inherit_daif pstate=x23, tmp=x2 mov x0, sp bl do_undefinstr - ASM_BUG() + kernel_exit 1 el1_dbg: /* * Debug exception handling diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 039e9ff379cc..b9da093e0341 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -310,10 +310,12 @@ static int call_undef_hook(struct pt_regs *regs) int (*fn)(struct pt_regs *regs, u32 instr) = NULL; void __user *pc = (void __user *)instruction_pointer(regs); - if (!user_mode(regs)) - return 1; - - if (compat_thumb_mode(regs)) { + if (!user_mode(regs)) { + __le32 instr_le; + if (probe_kernel_address((__force __le32 *)pc, instr_le)) + goto exit; + instr = le32_to_cpu(instr_le); + } else if (compat_thumb_mode(regs)) { /* 16-bit Thumb instruction */ __le16 instr_le; if (get_user(instr_le, (__le16 __user *)pc)) @@ -407,6 +409,7 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs) return; force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc); + BUG_ON(!user_mode(regs)); } void cpu_enable_cache_maint_trap(const struct arm64_cpu_capabilities *__unused) |