From af02933d59bd1621a48d8b0b331cca9e530ba14b Mon Sep 17 00:00:00 2001 From: James Morse Date: Fri, 1 May 2020 17:45:43 +0100 Subject: arm64: acpi: Make apei_claim_sea() synchronise with APEI's irq work [ Upstream commit 8fcc4ae6faf8b455eeef00bc9ae70744e3b0f462 ] APEI is unable to do all of its error handling work in nmi-context, so it defers non-fatal work onto the irq_work queue. arch_irq_work_raise() sends an IPI to the calling cpu, but this is not guaranteed to be taken before returning to user-space. Unless the exception interrupted a context with irqs-masked, irq_work_run() can run immediately. Otherwise return -EINPROGRESS to indicate ghes_notify_sea() found some work to do, but it hasn't finished yet. With this apei_claim_sea() returning '0' means this external-abort was also notification of a firmware-first RAS error, and that APEI has processed the CPER records. Signed-off-by: James Morse Tested-by: Tyler Baicar Acked-by: Catalin Marinas Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- arch/arm64/mm/fault.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'arch/arm64/mm') diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index d26e6cd28953..2a7339aeb1ad 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -654,11 +654,13 @@ static int do_sea(unsigned long addr, unsigned int esr, struct pt_regs *regs) inf = esr_to_fault_info(esr); - /* - * Return value ignored as we rely on signal merging. - * Future patches will make this more robust. - */ - apei_claim_sea(regs); + if (user_mode(regs) && apei_claim_sea(regs) == 0) { + /* + * APEI claimed this as a firmware-first notification. + * Some processing deferred to task_work before ret_to_user(). + */ + return 0; + } if (esr & ESR_ELx_FnV) siaddr = NULL; -- cgit v1.2.3