| Message ID | 1519308057-4953-10-git-send-email-will.deacon@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Feb 22, 2018 at 02:00:57PM +0000, Will Deacon wrote: > Using arm64_force_sig_info means that printing messages about unhandled > signals is dealt with for us, so use that in preference to force_sig_info > and remove any homebrew printing code. > > Signed-off-by: Will Deacon <will.deacon@arm.com> > --- > arch/arm64/kernel/debug-monitors.c | 3 ++- > arch/arm64/kernel/ptrace.c | 2 +- > arch/arm64/kernel/traps.c | 9 ++------- > 3 files changed, 5 insertions(+), 9 deletions(-) > > diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c > index 53781f5687c5..06ca574495af 100644 > --- a/arch/arm64/kernel/debug-monitors.c > +++ b/arch/arm64/kernel/debug-monitors.c > @@ -33,6 +33,7 @@ > #include <asm/daifflags.h> > #include <asm/debug-monitors.h> > #include <asm/system_misc.h> > +#include <asm/traps.h> > > /* Determine debug architecture. */ > u8 debug_monitors_arch(void) > @@ -223,7 +224,7 @@ static void send_user_sigtrap(int si_code) > if (interrupts_enabled(regs)) > local_irq_enable(); > > - force_sig_info(SIGTRAP, &info, current); > + arm64_force_sig_info(&info, "User debug trap", current); > } > > static int single_step_handler(unsigned long addr, unsigned int esr, > diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c > index 6618036ae6d4..dd359ee02e2b 100644 > --- a/arch/arm64/kernel/ptrace.c > +++ b/arch/arm64/kernel/ptrace.c > @@ -209,7 +209,7 @@ static void ptrace_hbptriggered(struct perf_event *bp, > force_sig_ptrace_errno_trap(si_errno, (void __user *)bkpt->trigger); > } > #endif > - force_sig_info(SIGTRAP, &info, current); > + arm64_force_sig_info(&info, "Hardware breakpoint trap (ptrace)", current); > } > > /* > diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c > index 4231488a5a9f..cb5ad77524f3 100644 > --- a/arch/arm64/kernel/traps.c > +++ b/arch/arm64/kernel/traps.c > @@ -633,11 +633,6 @@ asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr) > { > siginfo_t info; > void __user *pc = (void __user *)instruction_pointer(regs); > - console_verbose(); > - > - pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n", > - smp_processor_id(), esr, esr_get_class_string(esr)); > - __show_regs(regs); Here we dump the CPU so that a developer can figure out which microarchitecture the exception was taken on (e.g. to allow them to decode an IMP DEF SError). We added that in commit: 8051f4d16ef1d037 ("arm64: report CPU number in bad_mode") However, in arm64_force_sig_info() we don't dump the CPU, and I guess that may be preemptible in cases other than bad_el0_sync(). Are we happy to lose this? Thanks, Mark.
On Thu, Feb 22, 2018 at 03:48:21PM +0000, Mark Rutland wrote: > On Thu, Feb 22, 2018 at 02:00:57PM +0000, Will Deacon wrote: > > Using arm64_force_sig_info means that printing messages about unhandled > > signals is dealt with for us, so use that in preference to force_sig_info > > and remove any homebrew printing code. > > > > Signed-off-by: Will Deacon <will.deacon@arm.com> > > --- > > arch/arm64/kernel/debug-monitors.c | 3 ++- > > arch/arm64/kernel/ptrace.c | 2 +- > > arch/arm64/kernel/traps.c | 9 ++------- > > 3 files changed, 5 insertions(+), 9 deletions(-) [...] > > diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c > > index 4231488a5a9f..cb5ad77524f3 100644 > > --- a/arch/arm64/kernel/traps.c > > +++ b/arch/arm64/kernel/traps.c > > @@ -633,11 +633,6 @@ asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr) > > { > > siginfo_t info; > > void __user *pc = (void __user *)instruction_pointer(regs); > > - console_verbose(); > > - > > - pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n", > > - smp_processor_id(), esr, esr_get_class_string(esr)); > > - __show_regs(regs); > > Here we dump the CPU so that a developer can figure out which > microarchitecture the exception was taken on (e.g. to allow them to > decode an IMP DEF SError). We added that in commit: > > 8051f4d16ef1d037 ("arm64: report CPU number in bad_mode") > > However, in arm64_force_sig_info() we don't dump the CPU, and I guess > that may be preemptible in cases other than bad_el0_sync(). __show_regs prints the CPU number already. If we're preemptible, then it could be inaccurate. Will
On Thu, Feb 22, 2018 at 04:58:05PM +0000, Will Deacon wrote: > On Thu, Feb 22, 2018 at 03:48:21PM +0000, Mark Rutland wrote: > > On Thu, Feb 22, 2018 at 02:00:57PM +0000, Will Deacon wrote: > > > Using arm64_force_sig_info means that printing messages about unhandled > > > signals is dealt with for us, so use that in preference to force_sig_info > > > and remove any homebrew printing code. > > > > > > Signed-off-by: Will Deacon <will.deacon@arm.com> > > > --- > > > arch/arm64/kernel/debug-monitors.c | 3 ++- > > > arch/arm64/kernel/ptrace.c | 2 +- > > > arch/arm64/kernel/traps.c | 9 ++------- > > > 3 files changed, 5 insertions(+), 9 deletions(-) > > [...] > > > > diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c > > > index 4231488a5a9f..cb5ad77524f3 100644 > > > --- a/arch/arm64/kernel/traps.c > > > +++ b/arch/arm64/kernel/traps.c > > > @@ -633,11 +633,6 @@ asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr) > > > { > > > siginfo_t info; > > > void __user *pc = (void __user *)instruction_pointer(regs); > > > - console_verbose(); > > > - > > > - pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n", > > > - smp_processor_id(), esr, esr_get_class_string(esr)); > > > - __show_regs(regs); > > > > Here we dump the CPU so that a developer can figure out which > > microarchitecture the exception was taken on (e.g. to allow them to > > decode an IMP DEF SError). We added that in commit: > > > > 8051f4d16ef1d037 ("arm64: report CPU number in bad_mode") > > > > However, in arm64_force_sig_info() we don't dump the CPU, and I guess > > that may be preemptible in cases other than bad_el0_sync(). > > __show_regs prints the CPU number already. If we're preemptible, then it > could be inaccurate. Ah, that'll do. :) Mark.
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index 53781f5687c5..06ca574495af 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -33,6 +33,7 @@ #include <asm/daifflags.h> #include <asm/debug-monitors.h> #include <asm/system_misc.h> +#include <asm/traps.h> /* Determine debug architecture. */ u8 debug_monitors_arch(void) @@ -223,7 +224,7 @@ static void send_user_sigtrap(int si_code) if (interrupts_enabled(regs)) local_irq_enable(); - force_sig_info(SIGTRAP, &info, current); + arm64_force_sig_info(&info, "User debug trap", current); } static int single_step_handler(unsigned long addr, unsigned int esr, diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 6618036ae6d4..dd359ee02e2b 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -209,7 +209,7 @@ static void ptrace_hbptriggered(struct perf_event *bp, force_sig_ptrace_errno_trap(si_errno, (void __user *)bkpt->trigger); } #endif - force_sig_info(SIGTRAP, &info, current); + arm64_force_sig_info(&info, "Hardware breakpoint trap (ptrace)", current); } /* diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 4231488a5a9f..cb5ad77524f3 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -633,11 +633,6 @@ asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr) { siginfo_t info; void __user *pc = (void __user *)instruction_pointer(regs); - console_verbose(); - - pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n", - smp_processor_id(), esr, esr_get_class_string(esr)); - __show_regs(regs); info.si_signo = SIGILL; info.si_errno = 0; @@ -645,9 +640,9 @@ asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr) info.si_addr = pc; current->thread.fault_address = 0; - current->thread.fault_code = 0; + current->thread.fault_code = esr; - force_sig_info(info.si_signo, &info, current); + arm64_force_sig_info(&info, "Bad EL0 synchronous exception", current); } #ifdef CONFIG_VMAP_STACK
Using arm64_force_sig_info means that printing messages about unhandled signals is dealt with for us, so use that in preference to force_sig_info and remove any homebrew printing code. Signed-off-by: Will Deacon <will.deacon@arm.com> --- arch/arm64/kernel/debug-monitors.c | 3 ++- arch/arm64/kernel/ptrace.c | 2 +- arch/arm64/kernel/traps.c | 9 ++------- 3 files changed, 5 insertions(+), 9 deletions(-)