* [PATCH] arm64: handle sys and undef traps consistently
@ 2017-01-27 16:15 Mark Rutland
2017-01-27 16:35 ` Catalin Marinas
2017-01-27 16:41 ` Suzuki K Poulose
0 siblings, 2 replies; 3+ messages in thread
From: Mark Rutland @ 2017-01-27 16:15 UTC (permalink / raw)
To: linux-arm-kernel
If an EL0 instruction in the SYS class triggers an exception, do_sysintr
looks for a sys64_hook matching the instruction, and if none is found,
injects a SIGILL. This mirrors what we do for undefined instruction
encodings in do_undefinstr, where we look for an undef_hook matching the
instruction, and if none is found, inject a SIGILL.
Over time, new SYS instruction encodings may be allocated. Prior to
allocation, exceptions resulting from these would be handled by
do_undefinstr, whereas after allocation these may be handled by
do_sysintr.
To ensure that we have consistent behaviour if and when this happens, it
would be beneficial to have do_sysinstr fall back to do_undefinstr.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Suzuki Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
---
arch/arm64/kernel/traps.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 8187229..7c3fc06 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -531,7 +531,12 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
return;
}
- force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
+ /*
+ * New SYS instructions may previously have been undefined at EL0. Fall
+ * back to our usual undefined instruction handler so that we handle
+ * these consistently.
+ */
+ do_undefinstr(regs);
}
long compat_arm_syscall(struct pt_regs *regs);
--
1.9.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* [PATCH] arm64: handle sys and undef traps consistently
2017-01-27 16:15 [PATCH] arm64: handle sys and undef traps consistently Mark Rutland
@ 2017-01-27 16:35 ` Catalin Marinas
2017-01-27 16:41 ` Suzuki K Poulose
1 sibling, 0 replies; 3+ messages in thread
From: Catalin Marinas @ 2017-01-27 16:35 UTC (permalink / raw)
To: linux-arm-kernel
On Fri, Jan 27, 2017 at 04:15:38PM +0000, Mark Rutland wrote:
> If an EL0 instruction in the SYS class triggers an exception, do_sysintr
> looks for a sys64_hook matching the instruction, and if none is found,
> injects a SIGILL. This mirrors what we do for undefined instruction
> encodings in do_undefinstr, where we look for an undef_hook matching the
> instruction, and if none is found, inject a SIGILL.
>
> Over time, new SYS instruction encodings may be allocated. Prior to
> allocation, exceptions resulting from these would be handled by
> do_undefinstr, whereas after allocation these may be handled by
> do_sysintr.
>
> To ensure that we have consistent behaviour if and when this happens, it
> would be beneficial to have do_sysinstr fall back to do_undefinstr.
>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Suzuki Poulose <suzuki.poulose@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] arm64: handle sys and undef traps consistently
2017-01-27 16:15 [PATCH] arm64: handle sys and undef traps consistently Mark Rutland
2017-01-27 16:35 ` Catalin Marinas
@ 2017-01-27 16:41 ` Suzuki K Poulose
1 sibling, 0 replies; 3+ messages in thread
From: Suzuki K Poulose @ 2017-01-27 16:41 UTC (permalink / raw)
To: linux-arm-kernel
On 27/01/17 16:15, Mark Rutland wrote:
> If an EL0 instruction in the SYS class triggers an exception, do_sysintr
> looks for a sys64_hook matching the instruction, and if none is found,
> injects a SIGILL. This mirrors what we do for undefined instruction
> encodings in do_undefinstr, where we look for an undef_hook matching the
> instruction, and if none is found, inject a SIGILL.
>
> Over time, new SYS instruction encodings may be allocated. Prior to
> allocation, exceptions resulting from these would be handled by
> do_undefinstr, whereas after allocation these may be handled by
> do_sysintr.
>
> To ensure that we have consistent behaviour if and when this happens, it
> would be beneficial to have do_sysinstr fall back to do_undefinstr.
>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Suzuki Poulose <suzuki.poulose@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> ---
> arch/arm64/kernel/traps.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> index 8187229..7c3fc06 100644
> --- a/arch/arm64/kernel/traps.c
> +++ b/arch/arm64/kernel/traps.c
> @@ -531,7 +531,12 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
> return;
> }
>
> - force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
> + /*
> + * New SYS instructions may previously have been undefined at EL0. Fall
> + * back to our usual undefined instruction handler so that we handle
> + * these consistently.
> + */
> + do_undefinstr(regs);
> }
>
> long compat_arm_syscall(struct pt_regs *regs);
>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-01-27 16:15 [PATCH] arm64: handle sys and undef traps consistently Mark Rutland
2017-01-27 16:35 ` Catalin Marinas
2017-01-27 16:41 ` Suzuki K Poulose
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