Messages in this thread Patch in this message | | | Subject | Re: [PATCH V4 01/10] acpi: apei: read ack upon ghes record consumption | From | "Baicar, Tyler" <> | Date | Mon, 24 Oct 2016 14:28:09 -0600 |
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On 10/24/2016 2:51 AM, Suzuki K Poulose wrote: > On 21/10/16 18:30, Tyler Baicar wrote: >> A RAS (Reliability, Availability, Serviceability) controller >> may be a separate processor running in parallel with OS >> execution, and may generate error records for consumption by >> the OS. If the RAS controller produces multiple error records, >> then they may be overwritten before the OS has consumed them. >> >> The Generic Hardware Error Source (GHES) v2 structure >> introduces the capability for the OS to acknowledge the >> consumption of the error record generated by the RAS >> controller. A RAS controller supporting GHESv2 shall wait for >> the acknowledgment before writing a new error record, thus >> eliminating the race condition. >> >> Signed-off-by: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org> >> Signed-off-by: Richard Ruigrok <rruigrok@codeaurora.org> >> Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org> >> Signed-off-by: Naveen Kaje <nkaje@codeaurora.org> >> --- >> drivers/acpi/apei/ghes.c | 42 >> ++++++++++++++++++++++++++++++++++++++++++ >> drivers/acpi/apei/hest.c | 7 +++++-- >> include/acpi/ghes.h | 5 ++++- >> 3 files changed, 51 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c >> index 60746ef..7d020b0 100644 >> --- a/drivers/acpi/apei/ghes.c >> +++ b/drivers/acpi/apei/ghes.c >> @@ -45,6 +45,7 @@ >> #include <linux/aer.h> >> #include <linux/nmi.h> >> >> +#include <acpi/actbl1.h> >> #include <acpi/ghes.h> >> #include <acpi/apei.h> >> #include <asm/tlbflush.h> >> @@ -79,6 +80,10 @@ >> ((struct acpi_hest_generic_status *) \ >> ((struct ghes_estatus_node *)(estatus_node) + 1)) >> >> +#define HEST_TYPE_GENERIC_V2(ghes) \ >> + ((struct acpi_hest_header *)ghes->generic)->type == \ >> + ACPI_HEST_TYPE_GENERIC_ERROR_V2 >> + >> /* >> * This driver isn't really modular, however for the time being, >> * continuing to use module_param is the easiest way to remain >> @@ -248,7 +253,15 @@ static struct ghes *ghes_new(struct >> acpi_hest_generic *generic) >> ghes = kzalloc(sizeof(*ghes), GFP_KERNEL); >> if (!ghes) >> return ERR_PTR(-ENOMEM); >> + >> ghes->generic = generic; >> + if (HEST_TYPE_GENERIC_V2(ghes)) { >> + rc = apei_map_generic_address( >> + &ghes->generic_v2->read_ack_register); >> + if (rc) >> + goto err_unmap; > > I think should be goto err_free, see more below. > >> + } >> + >> rc = apei_map_generic_address(&generic->error_status_address); >> if (rc) >> goto err_free; >> @@ -270,6 +283,9 @@ static struct ghes *ghes_new(struct >> acpi_hest_generic *generic) >> >> err_unmap: >> apei_unmap_generic_address(&generic->error_status_address); >> + if (HEST_TYPE_GENERIC_V2(ghes)) >> + apei_unmap_generic_address( >> + &ghes->generic_v2->read_ack_register); > > We might end up trying to unmap (error_status_address) which is not > mapped > if we hit the error in mapping read_ack_register. The > read_ack_register unmap > hunk should be moved below to err_free. > This needs to be changed, I'll add a separate label for unmapping read_ack_register and error_status_address for the case that the read_ack_register map succeeds but the error_status_address map fails.
err_unmap_status_addr: apei_unmap_generic_address(&generic->error_status_address); err_unmap_read_ack_addr: if (HEST_TYPE_GENERIC_V2(ghes)) apei_unmap_generic_address( &ghes->generic_v2->read_ack_register); err_free: kfree(ghes); return ERR_PTR(rc);
If mapping read_ack_register fails, goto err_free. If mapping read_ack_register is successful but mapping error_status_address fails, goto err_unmap_read_ack_addr. And if both mappings succeed but the kmalloc fails, then goto err_unmap_status_addr.
> >> err_free: >> kfree(ghes); >> return ERR_PTR(rc); >> @@ -279,6 +295,9 @@ static void ghes_fini(struct ghes *ghes) >> { >> kfree(ghes->estatus); >> apei_unmap_generic_address(&ghes->generic->error_status_address); >> + if (HEST_TYPE_GENERIC_V2(ghes)) >> + apei_unmap_generic_address( >> + &ghes->generic_v2->read_ack_register); >> } >> >> static inline int ghes_severity(int severity) >> @@ -648,6 +667,23 @@ static void ghes_estatus_cache_add( >> rcu_read_unlock(); >> } >> > >> +static int ghes_do_read_ack(struct acpi_hest_generic_v2 *generic_v2) > > nit: We are actually writing something to the read_ack_register. The > names > read_ack_register (which may be as per standard) and more importantly the > function name (ghes_do_read_ack) sounds a bit misleading. It is called "Read Ack Register" in the spec (ACPI 6.1 table 18-344), but I agree the function name can be improved. Maybe ghes_acknowledge_error or ghes_ack_error.
Thanks, Tyler > > Rest looks fine to me. > > Suzuki >
-- 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.
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