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ACPI / APEI: Don't allow ghes_ack_error() to mask earlier errors

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During ghes_proc() we use ghes_ack_error() to tell an external agent
we are done with these records and it can re-use the memory.

rc may hold an error returned by ghes_read_estatus(), ENOENT causes
us to skip ghes_ack_error() (as there is nothing to ack), but rc may
also by EIO, which gets supressed.

ghes_clear_estatus() is where we mark the records as processed for
non GHESv2 error sources, and already spots the ENOENT case as
buf_paddr is set to 0 by ghes_read_estatus().

Move the ghes_ack_error() call in here to avoid extra logic with
the return code in ghes_proc().

This enables GHESv2 acking for NMI-like error sources. This is safe
as the buffer is pre-mapped by map_gen_v2() before the GHES is added
to any NMI handler lists.

This same pre-mapping step means we can't receive an error from
apei_read()/write() here as apei_check_gar() succeeded when it
was mapped, and the mapping was cached, so the address can't be
rejected at runtime. Remove the error-returns as this is now
called from a function with no return.

Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
James Morse 2019-01-29 18:48:46 +00:00 committed by Rafael J. Wysocki
parent ee2eb3d4ee
commit 06ddeadc8d
1 changed files with 22 additions and 25 deletions
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47
drivers/acpi/apei/ghes.c
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@ -197,6 +197,21 @@ static void unmap_gen_v2(struct ghes *ghes)
apei_unmap_generic_address(&ghes->generic_v2->read_ack_register);
}
static void ghes_ack_error(struct acpi_hest_generic_v2 *gv2)
{
int rc;
u64 val = 0;
rc = apei_read(&val, &gv2->read_ack_register);
if (rc)
return;
val &= gv2->read_ack_preserve << gv2->read_ack_register.bit_offset;
val |= gv2->read_ack_write << gv2->read_ack_register.bit_offset;
apei_write(val, &gv2->read_ack_register);
}
static struct ghes *ghes_new(struct acpi_hest_generic *generic)
{
struct ghes *ghes;
@ -361,6 +376,13 @@ static void ghes_clear_estatus(struct ghes *ghes, u64 buf_paddr)
ghes_copy_tofrom_phys(ghes->estatus, buf_paddr,
sizeof(ghes->estatus->block_status), 0);
/*
* GHESv2 type HEST entries introduce support for error acknowledgment,
* so only acknowledge the error if this support is present.
*/
if (is_hest_type_generic_v2(ghes))
ghes_ack_error(ghes->generic_v2);
}
static void ghes_handle_memory_failure(struct acpi_hest_generic_data *gdata, int sev)
@ -652,21 +674,6 @@ static void ghes_estatus_cache_add(
rcu_read_unlock();
}
static int ghes_ack_error(struct acpi_hest_generic_v2 *gv2)
{
int rc;
u64 val = 0;
rc = apei_read(&val, &gv2->read_ack_register);
if (rc)
return rc;
val &= gv2->read_ack_preserve << gv2->read_ack_register.bit_offset;
val |= gv2->read_ack_write << gv2->read_ack_register.bit_offset;
return apei_write(val, &gv2->read_ack_register);
}
static void __ghes_panic(struct ghes *ghes, u64 buf_paddr)
{
__ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);
@ -701,16 +708,6 @@ static int ghes_proc(struct ghes *ghes)
out:
ghes_clear_estatus(ghes, buf_paddr);
if (rc == -ENOENT)
return rc;
/*
* GHESv2 type HEST entries introduce support for error acknowledgment,
* so only acknowledge the error if this support is present.
*/
if (is_hest_type_generic_v2(ghes))
return ghes_ack_error(ghes->generic_v2);
return rc;
}