On Thu, Jul 25, 2024 at 04:57:09PM +0100, Dave Martin wrote: > On Fri, May 03, 2024 at 02:01:33PM +0100, Joey Gouly wrote: > > If a memory fault occurs that is due to an overlay/pkey fault, report that to > > userspace with a SEGV_PKUERR. > > > > Signed-off-by: Joey Gouly <joey.gouly@xxxxxxx> > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > > Cc: Will Deacon <will@xxxxxxxxxx> > > --- > > arch/arm64/include/asm/traps.h | 1 + > > arch/arm64/kernel/traps.c | 12 ++++++-- > > arch/arm64/mm/fault.c | 56 ++++++++++++++++++++++++++++++++-- > > 3 files changed, 64 insertions(+), 5 deletions(-) > > > > diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h > > index eefe766d6161..f6f6f2cb7f10 100644 > > --- a/arch/arm64/include/asm/traps.h > > +++ b/arch/arm64/include/asm/traps.h > > @@ -25,6 +25,7 @@ try_emulate_armv8_deprecated(struct pt_regs *regs, u32 insn) > > void force_signal_inject(int signal, int code, unsigned long address, unsigned long err); > > void arm64_notify_segfault(unsigned long addr); > > void arm64_force_sig_fault(int signo, int code, unsigned long far, const char *str); > > +void arm64_force_sig_fault_pkey(int signo, int code, unsigned long far, const char *str, int pkey); > > void arm64_force_sig_mceerr(int code, unsigned long far, short lsb, const char *str); > > void arm64_force_sig_ptrace_errno_trap(int errno, unsigned long far, const char *str); > > > > diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c > > index 215e6d7f2df8..1bac6c84d3f5 100644 > > --- a/arch/arm64/kernel/traps.c > > +++ b/arch/arm64/kernel/traps.c > > @@ -263,16 +263,24 @@ static void arm64_show_signal(int signo, const char *str) > > __show_regs(regs); > > } > > > > -void arm64_force_sig_fault(int signo, int code, unsigned long far, > > - const char *str) > > +void arm64_force_sig_fault_pkey(int signo, int code, unsigned long far, > > + const char *str, int pkey) > > { > > arm64_show_signal(signo, str); > > if (signo == SIGKILL) > > force_sig(SIGKILL); > > + else if (code == SEGV_PKUERR) > > + force_sig_pkuerr((void __user *)far, pkey); > > Is signo definitely SIGSEGV here? It looks to me like we can get in > here for SIGBUS, SIGTRAP etc. > > si_codes are not unique between different signo here, so I'm wondering > whether this should this be: > > else if (signo == SIGSEGV && code == SEGV_PKUERR) > > ...? > > > > else > > force_sig_fault(signo, code, (void __user *)far); > > } > > > > +void arm64_force_sig_fault(int signo, int code, unsigned long far, > > + const char *str) > > +{ > > + arm64_force_sig_fault_pkey(signo, code, far, str, 0); > > Is there a reason not to follow the same convention as elsewhere, where > -1 is passed for "no pkey"? > > If we think this should never be called with signo == SIGSEGV && > code == SEGV_PKUERR and no valid pkey but if it's messy to prove, then > maybe a WARN_ON_ONCE() would be worth it here? > Anshuman suggested to separate them out, which I did like below, I think that addresses your comments too? diff --git arch/arm64/kernel/traps.c arch/arm64/kernel/traps.c index 215e6d7f2df8..49bac9ae04c0 100644 --- arch/arm64/kernel/traps.c +++ arch/arm64/kernel/traps.c @@ -273,6 +273,13 @@ void arm64_force_sig_fault(int signo, int code, unsigned long far, force_sig_fault(signo, code, (void __user *)far); } +void arm64_force_sig_fault_pkey(int signo, int code, unsigned long far, + const char *str, int pkey) +{ + arm64_show_signal(signo, str); + force_sig_pkuerr((void __user *)far, pkey); +} + void arm64_force_sig_mceerr(int code, unsigned long far, short lsb, const char *str) { diff --git arch/arm64/mm/fault.c arch/arm64/mm/fault.c index 451ba7cbd5ad..1ddd46b97f88 100644 --- arch/arm64/mm/fault.c +++ arch/arm64/mm/fault.c - arm64_force_sig_fault(SIGSEGV, si_code, far, inf->name); + if (si_code == SEGV_PKUERR) + arm64_force_sig_fault_pkey(SIGSEGV, si_code, far, inf->name, pkey); + else + arm64_force_sig_fault(SIGSEGV, si_code, far, inf->name); Thanks, Joey