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arm64: entry: Allow handling of undefined instructions from EL1

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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>
This commit is contained in:
Will Deacon 2018-08-07 13:43:06 +01:00 committed by Catalin Marinas
parent 2d1b2a91d5
commit 0bf0f444b2
2 changed files with 8 additions and 5 deletions
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2
arch/arm64/kernel/entry.S
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@ -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

11
arch/arm64/kernel/traps.c
View File

@ -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)