[PATCH v6 10/18] ACPI / APEI: preparatory split of ghes->estatus

James Morse
2018-09-21T22:18:28Z

The NMI-like notifications scribble over ghes->estatus, before
copying it somewhere else. If this interrupts the ghes_probe() code
calling ghes_proc() on each struct ghes, the data is corrupted.

We want the NMI-like notifications to use a queued estatus entry
from the beginning. To that end, break up any use of "ghes->estatus"
so that all functions take the estatus as an argument.

This patch is just moving code around, no change in behaviour.

Signed-off-by: James Morse <james.morse@arm.com>
---
drivers/acpi/apei/ghes.c | 82 ++++++++++++++++++++++------------------
1 file changed, 45 insertions(+), 37 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index adf7fd402813..586689cbc0fd 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -298,7 +298,9 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
}
}

-static int ghes_read_estatus(struct ghes *ghes, int silent, int fixmap_idx)
+static int ghes_read_estatus(struct ghes *ghes,
+ struct acpi_hest_generic_status *estatus,
+ int silent, int fixmap_idx)
{
struct acpi_hest_generic *g = ghes->generic;
u64 buf_paddr;
@@ -316,26 +318,26 @@ static int ghes_read_estatus(struct ghes *ghes, int silent, int fixmap_idx)
if (!buf_paddr)
return -ENOENT;

- ghes_copy_tofrom_phys(ghes->estatus, buf_paddr,
- sizeof(*ghes->estatus), 1, fixmap_idx);
- if (!ghes->estatus->block_status)
+ ghes_copy_tofrom_phys(estatus, buf_paddr,
+ sizeof(*estatus), 1, fixmap_idx);
+ if (!estatus->block_status)
return -ENOENT;

ghes->buffer_paddr = buf_paddr;
ghes->flags |= GHES_TO_CLEAR;

rc = -EIO;
- len = cper_estatus_len(ghes->estatus);
- if (len < sizeof(*ghes->estatus))
+ len = cper_estatus_len(estatus);
+ if (len < sizeof(*estatus))
goto err_read_block;
if (len > ghes->generic->error_block_length)
goto err_read_block;
- if (cper_estatus_check_header(ghes->estatus))
+ if (cper_estatus_check_header(estatus))
goto err_read_block;
- ghes_copy_tofrom_phys(ghes->estatus + 1,
- buf_paddr + sizeof(*ghes->estatus),
- len - sizeof(*ghes->estatus), 1, fixmap_idx);
- if (cper_estatus_check(ghes->estatus))
+ ghes_copy_tofrom_phys(estatus + 1,
+ buf_paddr + sizeof(*estatus),
+ len - sizeof(*estatus), 1, fixmap_idx);
+ if (cper_estatus_check(estatus))
goto err_read_block;
rc = 0;

@@ -346,13 +348,15 @@ static int ghes_read_estatus(struct ghes *ghes, int silent, int fixmap_idx)
return rc;
}

-static void ghes_clear_estatus(struct ghes *ghes, int fixmap_idx)
+static void ghes_clear_estatus(struct ghes *ghes,
+ struct acpi_hest_generic_status *estatus,
+ int fixmap_idx)
{
- ghes->estatus->block_status = 0;
+ estatus->block_status = 0;
if (!(ghes->flags & GHES_TO_CLEAR))
return;
- ghes_copy_tofrom_phys(ghes->estatus, ghes->buffer_paddr,
- sizeof(ghes->estatus->block_status), 0, fixmap_idx);
+ ghes_copy_tofrom_phys(estatus, ghes->buffer_paddr,
+ sizeof(estatus->block_status), 0, fixmap_idx);
ghes->flags &= ~GHES_TO_CLEAR;
}

@@ -518,9 +522,10 @@ static int ghes_print_estatus(const char *pfx,
return 0;
}

-static void __ghes_panic(struct ghes *ghes)
+static void __ghes_panic(struct ghes *ghes,
+ struct acpi_hest_generic_status *estatus)
{
- __ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);
+ __ghes_print_estatus(KERN_EMERG, ghes->generic, estatus);

/* reboot to log the error! */
if (!panic_timeout)
@@ -695,16 +700,17 @@ static void ghes_print_queued_estatus(void)
}

/* Save estatus for further processing in IRQ context */
-static void __process_error(struct ghes *ghes)
+static void __process_error(struct ghes *ghes,
+ struct acpi_hest_generic_status *ghes_estatus)
{
u32 len, node_len;
struct ghes_estatus_node *estatus_node;
struct acpi_hest_generic_status *estatus;

- if (ghes_estatus_cached(ghes->estatus))
+ if (ghes_estatus_cached(ghes_estatus))
return;

- len = cper_estatus_len(ghes->estatus);
+ len = cper_estatus_len(ghes_estatus);
node_len = GHES_ESTATUS_NODE_LEN(len);

estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool, node_len);
@@ -714,35 +720,37 @@ static void __process_error(struct ghes *ghes)
estatus_node->ghes = ghes;
estatus_node->generic = ghes->generic;
estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
- memcpy(estatus, ghes->estatus, len);
+ memcpy(estatus, ghes_estatus, len);
llist_add(&estatus_node->llnode, &ghes_estatus_llist);
}

static int _in_nmi_notify_one(struct ghes *ghes, int fixmap_idx)
{
int sev;
+ struct acpi_hest_generic_status *estatus = ghes->estatus;

- if (ghes_read_estatus(ghes, 1, fixmap_idx)) {
- ghes_clear_estatus(ghes, fixmap_idx);
+ if (ghes_read_estatus(ghes, estatus, 1, fixmap_idx)) {
+ ghes_clear_estatus(ghes, estatus, fixmap_idx);
return -ENOENT;
}

- sev = ghes_severity(ghes->estatus->error_severity);
+ sev = ghes_severity(estatus->error_severity);
if (sev >= GHES_SEV_PANIC) {
ghes_print_queued_estatus();
- __ghes_panic(ghes);
+ __ghes_panic(ghes, estatus);
}

if (!(ghes->flags & GHES_TO_CLEAR))
return 0;

- __process_error(ghes);
- ghes_clear_estatus(ghes, fixmap_idx);
+ __process_error(ghes, estatus);
+ ghes_clear_estatus(ghes, estatus, fixmap_idx);

return 0;
}

-static int ghes_estatus_queue_notified(struct list_head *rcu_list, int fixmap_idx)
+static int ghes_estatus_queue_notified(struct list_head *rcu_list,
+ int fixmap_idx)
{
int ret = -ENOENT;
struct ghes *ghes;
@@ -853,23 +861,23 @@ static int ghes_ack_error(struct acpi_hest_generic_v2 *gv2)
static int ghes_proc(struct ghes *ghes)
{
int rc;
+ struct acpi_hest_generic_status *estatus = ghes->estatus;

- rc = ghes_read_estatus(ghes, 0, FIX_APEI_GHES_IRQ);
+ rc = ghes_read_estatus(ghes, estatus, 0, FIX_APEI_GHES_IRQ);
if (rc)
goto out;

- if (ghes_severity(ghes->estatus->error_severity) >= GHES_SEV_PANIC) {
- __ghes_panic(ghes);
- }
+ if (ghes_severity(estatus->error_severity) >= GHES_SEV_PANIC)
+ __ghes_panic(ghes, estatus);

- if (!ghes_estatus_cached(ghes->estatus)) {
- if (ghes_print_estatus(NULL, ghes->generic, ghes->estatus))
- ghes_estatus_cache_add(ghes->generic, ghes->estatus);
+ if (!ghes_estatus_cached(estatus)) {
+ if (ghes_print_estatus(NULL, ghes->generic, estatus))
+ ghes_estatus_cache_add(ghes->generic, estatus);
}
- ghes_do_proc(ghes, ghes->estatus);
+ ghes_do_proc(ghes, estatus);

out:
- ghes_clear_estatus(ghes, FIX_APEI_GHES_IRQ);
+ ghes_clear_estatus(ghes, estatus, FIX_APEI_GHES_IRQ);

if (rc == -ENOENT)
return rc;
--
2.19.0