Messages in this thread | | | Subject | Re: [PATCH V15 01/11] acpi: apei: read ack upon ghes record consumption | From | "Baicar, Tyler" <> | Date | Wed, 19 Apr 2017 14:31:13 -0600 |
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On 4/19/2017 12:31 PM, Borislav Petkov wrote: > On Tue, Apr 18, 2017 at 05:05:13PM -0600, 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. >> >> Add support for parsing of GHESv2 sub-tables as well. >> >> Signed-off-by: Tyler Baicar <tbaicar@codeaurora.org> >> CC: Jonathan (Zhixiong) Zhang <zjzhang@codeaurora.org> >> Reviewed-by: James Morse <james.morse@arm.com> >> --- >> drivers/acpi/apei/ghes.c | 55 +++++++++++++++++++++++++++++++++++++++++++++--- >> drivers/acpi/apei/hest.c | 7 ++++-- >> include/acpi/ghes.h | 5 ++++- >> 3 files changed, 61 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c >> index 79b3c9c..6d87ab7 100644 >> --- a/drivers/acpi/apei/ghes.c >> +++ b/drivers/acpi/apei/ghes.c >> @@ -46,6 +46,7 @@ >> #include <linux/nmi.h> >> #include <linux/sched/clock.h> >> >> +#include <acpi/actbl1.h> >> #include <acpi/ghes.h> >> #include <acpi/apei.h> >> #include <asm/tlbflush.h> >> @@ -80,6 +81,10 @@ >> ((struct acpi_hest_generic_status *) \ >> ((struct ghes_estatus_node *)(estatus_node) + 1)) >> >> +#define IS_HEST_TYPE_GENERIC_V2(ghes) \ >> + ((struct acpi_hest_header *)ghes->generic)->type == \ > This is a nasty hack: casting the ghes->generic pointer to a pointer of its > first member which is a acpi_hest_header. > > Why isn't this a nice inline function with proper dereferencing: > > static inline bool is_hest_type_generic_v2(struct ghes *ghes) > { > return ghes->generic->header.type == ACPI_HEST_TYPE_GENERIC_ERROR_V2; > } > > ? I'll change it to this. > Also, please integrate scripts/checkpatch.pl in your patch creation > workflow. Some of the warnings/errors *actually* make sense. > >> /* >> * This driver isn't really modular, however for the time being, >> * continuing to use module_param is the easiest way to remain >> @@ -240,6 +245,17 @@ static int ghes_estatus_pool_expand(unsigned long len) >> return 0; >> } >> >> +static int map_gen_v2(struct ghes *ghes) >> +{ >> + return apei_map_generic_address(&ghes->generic_v2->read_ack_register); >> +} >> + >> +static void unmap_gen_v2(struct ghes *ghes) >> +{ >> + apei_unmap_generic_address(&ghes->generic_v2->read_ack_register); >> + return; >> +} > Like this one, for example: > > WARNING: void function return statements are not generally useful > #89: FILE: drivers/acpi/apei/ghes.c:257: > + return; > +} Will remove the return. > >> + >> static struct ghes *ghes_new(struct acpi_hest_generic *generic) >> { >> struct ghes *ghes; >> @@ -249,10 +265,17 @@ 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 (IS_HEST_TYPE_GENERIC_V2(ghes)) { >> + rc = map_gen_v2(ghes); >> + if (rc) >> + goto err_free; >> + } >> + >> rc = apei_map_generic_address(&generic->error_status_address); >> if (rc) >> - goto err_free; >> + goto err_unmap_read_ack_addr; >> error_block_length = generic->error_block_length; >> if (error_block_length > GHES_ESTATUS_MAX_SIZE) { >> pr_warning(FW_WARN GHES_PFX >> @@ -264,13 +287,16 @@ static struct ghes *ghes_new(struct acpi_hest_generic *generic) >> ghes->estatus = kmalloc(error_block_length, GFP_KERNEL); >> if (!ghes->estatus) { >> rc = -ENOMEM; >> - goto err_unmap; >> + goto err_unmap_status_addr; >> } >> >> return ghes; >> >> -err_unmap: >> +err_unmap_status_addr: >> apei_unmap_generic_address(&generic->error_status_address); >> +err_unmap_read_ack_addr: >> + if (IS_HEST_TYPE_GENERIC_V2(ghes)) >> + unmap_gen_v2(ghes); >> err_free: >> kfree(ghes); >> return ERR_PTR(rc); >> @@ -280,6 +306,8 @@ static void ghes_fini(struct ghes *ghes) >> { >> kfree(ghes->estatus); >> apei_unmap_generic_address(&ghes->generic->error_status_address); >> + if (IS_HEST_TYPE_GENERIC_V2(ghes)) >> + unmap_gen_v2(ghes); >> } >> >> static inline int ghes_severity(int severity) >> @@ -649,6 +677,21 @@ static void ghes_estatus_cache_add( >> rcu_read_unlock(); >> } >> >> +static int ghes_ack_error(struct acpi_hest_generic_v2 *generic_v2) > If you name this function parameter to something shorter, say gv2, for > example... Will do. > >> +{ >> + int rc; >> + u64 val = 0; >> + >> + rc = apei_read(&val, &generic_v2->read_ack_register); >> + if (rc) >> + return rc; >> + >> + val &= generic_v2->read_ack_preserve << generic_v2->read_ack_register.bit_offset; >> + val |= generic_v2->read_ack_write << generic_v2->read_ack_register.bit_offset; > ... you can align those two nicely while remaining within the 80 cols width: > > val &= gv2->read_ack_preserve << gv2->read_ack_register.bit_offset; > val |= gv2->read_ack_write << gv2->read_ack_register.bit_offset; > > and make them readable at a quick glance. Will do. >> + >> + return apei_write(val, &generic_v2->read_ack_register); >> +} >> + >> static int ghes_proc(struct ghes *ghes) >> { >> int rc; >> @@ -661,6 +704,12 @@ static int ghes_proc(struct ghes *ghes) >> ghes_estatus_cache_add(ghes->generic, ghes->estatus); >> } >> ghes_do_proc(ghes, ghes->estatus); > This needs a comment why v2 needs to ACK the error. The commit message > is not necessarily something we'll find quickly in the future. Will do.
Thanks, Tyler
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