Messages in this thread | | | Subject | Re: [PATCH V6 04/10] arm64: exception: handle Synchronous External Abort | From | "Baicar, Tyler" <> | Date | Fri, 6 Jan 2017 09:58:54 -0700 |
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Hi Will,
On 1/4/2017 6:54 AM, Will Deacon wrote: > On Wed, Dec 07, 2016 at 02:48:17PM -0700, Tyler Baicar wrote: >> SEA exceptions are often caused by an uncorrected hardware >> error, and are handled when data abort and instruction abort >> exception classes have specific values for their Fault Status >> Code. >> When SEA occurs, before killing the process, go through >> the handlers registered in the notification list. >> Update fault_info[] with specific SEA faults so that the >> new SEA handler is used. >> >> Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org> >> Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org> >> Signed-off-by: Naveen Kaje <nkaje@codeaurora.org> >> --- >> arch/arm64/include/asm/system_misc.h | 13 ++++++++ >> arch/arm64/mm/fault.c | 58 +++++++++++++++++++++++++++++------- >> 2 files changed, 61 insertions(+), 10 deletions(-) >> >> diff --git a/arch/arm64/include/asm/system_misc.h b/arch/arm64/include/asm/system_misc.h >> index 57f110b..9040e1d 100644 >> --- a/arch/arm64/include/asm/system_misc.h >> +++ b/arch/arm64/include/asm/system_misc.h >> @@ -64,4 +64,17 @@ extern void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); >> >> #endif /* __ASSEMBLY__ */ >> >> +/* >> + * The functions below are used to register and unregister callbacks >> + * that are to be invoked when a Synchronous External Abort (SEA) >> + * occurs. An SEA is raised by certain fault status codes that have >> + * either data or instruction abort as the exception class, and >> + * callbacks may be registered to parse or handle such hardware errors. >> + * >> + * Registered callbacks are run in an interrupt/atomic context. They >> + * are not allowed to block or sleep. >> + */ >> +int register_synchronous_ext_abort_notifier(struct notifier_block *nb); >> +void unregister_synchronous_ext_abort_notifier(struct notifier_block *nb); > I think that we may as well use the "SEA" acronym consistently in code, > expanding it only for strings and comments, so these can be renamed to > {register,unregister}_sea_notifier. That said, what is the use of having a > notifier chain here as well as in the ghes code? If the ghes code is the > only place to register a notifier, we may as well start simple and call that > code directly, like we call handle_mm_fault directly for data aborts. I originally used the acronym and got feedback to expand it, but I'll revert back to just using the acronym. Using a notifier here is consistent with the SCI error type in the GHES code which is also only registered in the GHES code. I can remove the notifier for SEA if you think making the call directly is better here. >> static const struct fault_info { >> int (*fn)(unsigned long addr, unsigned int esr, struct pt_regs *regs); >> int sig; >> @@ -502,22 +540,22 @@ static const struct fault_info { >> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 1 permission fault" }, >> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 2 permission fault" }, >> { do_page_fault, SIGSEGV, SEGV_ACCERR, "level 3 permission fault" }, >> - { do_bad, SIGBUS, 0, "synchronous external abort" }, >> + { do_synch_ext_abort, SIGBUS, 0, "synchronous external abort" }, > Again, just stick with do_sea for the function name... > >> { do_bad, SIGBUS, 0, "unknown 17" }, >> { do_bad, SIGBUS, 0, "unknown 18" }, >> { do_bad, SIGBUS, 0, "unknown 19" }, >> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous abort (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous parity error" }, >> + { do_synch_ext_abort, SIGBUS, 0, "level 0 SEA (trans tbl walk)" }, > ... but there's no need to abbreviate "translation table walk" here. Long > strings that run over 80 chars are fine. Similarly for "SEA". I will expand this in the next patchset. >> + { do_synch_ext_abort, SIGBUS, 0, "level 1 SEA (trans tbl walk)" }, >> + { do_synch_ext_abort, SIGBUS, 0, "level 2 SEA (trans tbl walk)" }, >> + { do_synch_ext_abort, SIGBUS, 0, "level 3 SEA (trans tbl walk)" }, >> + { do_synch_ext_abort, SIGBUS, 0, "synchronous parity or ECC err" }, >> { do_bad, SIGBUS, 0, "unknown 25" }, >> { do_bad, SIGBUS, 0, "unknown 26" }, >> { do_bad, SIGBUS, 0, "unknown 27" }, >> - { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, >> - { do_bad, SIGBUS, 0, "synchronous parity error (translation table walk)" }, >> + { do_synch_ext_abort, SIGBUS, 0, "level 0 synch parity error" }, >> + { do_synch_ext_abort, SIGBUS, 0, "level 1 synch parity error" }, >> + { do_synch_ext_abort, SIGBUS, 0, "level 2 synch parity error" }, >> + { do_synch_ext_abort, SIGBUS, 0, "level 3 synch parity error" }, > Please keep mention of "translation table walk", since we have exception > levels too and it's confusing just saying "level n". I will add them back in the next patchset.
Thanks, Tyler > Will
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