Hi James, Sorry for reply late, and thanks for your comments. On 2017/4/1 0:20, James Morse wrote: > Hi Xie XiuQi, > > On 30/03/17 11:31, Xie XiuQi wrote: >> ARM APEI extension proposal added SEI (asynchronous SError interrupt) >> notification type for ARMv8. >> >> Add a new GHES error source handling function for SEI. In firmware >> first mode, if an error source's notification type is SEI. Then GHES >> could parse and report the detail error information. > > The APEI additions are unsafe until patch 4 as SEA can interrupt SEI and > deadlock while trying to take the same set of locks. This patch needs to be > after that interaction is fixed/prevented, or we should prevent it by adding a > depends-on-not to the Kconfig to prevent SEI and SEA being registered at the > same time. (as a short term fix). Will fix later. > > (more comments on this on that later patch) > > >> diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c >> index e52be6a..53710a2 100644 >> --- a/arch/arm64/kernel/traps.c >> +++ b/arch/arm64/kernel/traps.c > >> @@ -625,6 +627,14 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) > > bad_mode() is called in other scenarios too, for example executing an undefined > instruction at EL1. You split the SError path out of the vectors in patch 7, I > think we should do that here. > > >> handler[reason], smp_processor_id(), esr, >> esr_get_class_string(esr)); >> >> + /* >> + * In firmware first mode, we could assume firmware will only generate one >> + * of cper records at a time. There is no risk for one cpu to parse ghes table. >> + */ > > I don't follow this comment, is this saying SError can't interrupt SError? We > already get this guarantee as the CPU masks SError when it takes an exception. > > Firmware can generate multiple CPER records for a single 'event'. The CPER > records are the 'Data' in ACPI:Table 18-343 Generic Error Data Entry, and there > are 'zero or more' of these with a 'Generic Error Status Block' header that > describes the overall event. (Table 18-342). > > I don't think we need this comment. Thanks for your explanation, OK, I'll remove this comment. > > >> + if (IS_ENABLED(CONFIG_ACPI_APEI_SEI) && ESR_ELx_EC(esr) == ESR_ELx_EC_SERROR) { >> + ghes_notify_sei(); >> + } > >> die("Oops - bad mode", regs, 0); >> local_irq_disable(); >> panic("bad mode"); > > Thanks, > > James > > > . > -- Thanks, Xie XiuQi