| Message ID | 1485533738-30062-1-git-send-email-mark.rutland@arm.com |
|---|---|
| State | Accepted |
| Commit | 49f6cba617fef4bc097a291e0dfd028cc7073c52 |
| Headers | show |
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> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/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> _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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);
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(-) -- 1.9.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel