Hello Punit, On 10/12/2016 11:46 AM, Punit Agrawal wrote:
Hi Tyler, A couple of hopefully not bike shedding comments below. Tyler Baicar <tbaicar@xxxxxxxxxxxxxx> writes: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: Jonathan (Zhixiong) Zhang <zjzhang@xxxxxxxxxxxxxx> Signed-off-by: Tyler Baicar <tbaicar@xxxxxxxxxxxxxx> Signed-off-by: Naveen Kaje <nkaje@xxxxxxxxxxxxxx> --- 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..90daf4a 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 sea_register_handler_chain(struct notifier_block *nb); +void sea_unregister_handler_chain(struct notifier_block *nb); + #endif /* __ASM_SYSTEM_MISC_H */ diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 05d2bd7..81cb7ad 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -39,6 +39,22 @@ #include <asm/pgtable.h> #include <asm/tlbflush.h>+/*+ * GHES SEA handler code may register a notifier call here to + * handle HW error record passed from platform. + */ +static ATOMIC_NOTIFIER_HEAD(sea_handler_chain); + +int sea_register_handler_chain(struct notifier_block *nb) +{ + return atomic_notifier_chain_register(&sea_handler_chain, nb); +} + +void sea_unregister_handler_chain(struct notifier_block *nb) +{ + atomic_notifier_chain_unregister(&sea_handler_chain, nb); +} +What do you think of naming the above functions as [un]register_synchonous_ext_abort_notifier? For an API, I find "sea" doesn't quite convey the message. One more comment below.
Yes, those names seem easier to understand.
I'll expand sea here as well. This should make it easier to understand without knowing the code.static const char *fault_name(unsigned int esr);#ifdef CONFIG_KPROBES@@ -480,6 +496,28 @@ static int do_bad(unsigned long addr, unsigned int esr, struct pt_regs *regs) return 1; }+/*+ * This abort handler deals with Synchronous External Abort. + * It calls notifiers, and then returns "fault". + */ +static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) +{ + struct siginfo info; + + atomic_notifier_call_chain(&sea_handler_chain, 0, NULL); + + pr_err("Synchronous External Abort: %s (0x%08x) at 0x%016lx\n", + fault_name(esr), esr, addr); + + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = 0; + info.si_addr = (void __user *)addr; + arm64_notify_die("", regs, &info, esr); + + return 0; +} + 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_sea, SIGBUS, 0, "synchronous external abort" }, { 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_sea, SIGBUS, 0, "level 0 SEA (trans tbl walk)" }, + { do_sea, SIGBUS, 0, "level 1 SEA (trans tbl walk)" }, + { do_sea, SIGBUS, 0, "level 2 SEA (trans tbl walk)" }, + { do_sea, SIGBUS, 0, "level 3 SEA (trans tbl walk)" },^^^ The comment about naming applies here as well. Thanks, Punit
Thanks, Tyler
[...]
-- Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project. -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
