ACPI / APEI: Only use queued estatus entry during in_nmi_queue_one_entry()

Each struct ghes has an worst-case sized buffer for storing the
estatus. If an error is being processed by ghes_proc() in process
context this buffer will be in use. If the error source then triggers
an NMI-like notification, the same buffer will be used by
in_nmi_queue_one_entry() to stage the estatus data, before
__process_error() copys it into a queued estatus entry.

Merge __process_error()s work into in_nmi_queue_one_entry() so that
the queued estatus entry is used from the beginning. Use the new
ghes_peek_estatus() to know how much memory to allocate from
the ghes_estatus_pool before reading the records.

Reported-by: Borislav Petkov <bp@suse.de>
Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Change since v6:
 * Added a comment explaining the 'ack-error, then goto no_work'.
 * Added missing esatus-clearing, which is necessary after reading the GAS,
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 4c1d8e5e9ada01b323c2ae2500f632acaca792a3..eb5bf2ced1fbaa6c67c2d98579136a5ba5d50bff 100644 (file)
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -862,57 +862,67 @@ static void ghes_print_queued_estatus(void)
        }
 }
 
-/* Save estatus for further processing in IRQ context */
-static void __process_error(struct ghes *ghes,
-                           struct acpi_hest_generic_status *src_estatus)
+static int ghes_in_nmi_queue_one_entry(struct ghes *ghes,
+                                      enum fixed_addresses fixmap_idx)
 {
-       u32 len, node_len;
+       struct acpi_hest_generic_status *estatus, tmp_header;
        struct ghes_estatus_node *estatus_node;
-       struct acpi_hest_generic_status *estatus;
+       u32 len, node_len;
+       u64 buf_paddr;
+       int sev, rc;
 
        if (!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG))
-               return;
+               return -EOPNOTSUPP;
 
-       if (ghes_estatus_cached(src_estatus))
-               return;
+       rc = __ghes_peek_estatus(ghes, &tmp_header, &buf_paddr, fixmap_idx);
+       if (rc) {
+               ghes_clear_estatus(ghes, &tmp_header, buf_paddr, fixmap_idx);
+               return rc;
+       }
 
-       len = cper_estatus_len(src_estatus);
-       node_len = GHES_ESTATUS_NODE_LEN(len);
+       rc = __ghes_check_estatus(ghes, &tmp_header);
+       if (rc) {
+               ghes_clear_estatus(ghes, &tmp_header, buf_paddr, fixmap_idx);
+               return rc;
+       }
 
+       len = cper_estatus_len(&tmp_header);
+       node_len = GHES_ESTATUS_NODE_LEN(len);
        estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool, node_len);
        if (!estatus_node)
-               return;
+               return -ENOMEM;
 
        estatus_node->ghes = ghes;
        estatus_node->generic = ghes->generic;
        estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
-       memcpy(estatus, src_estatus, len);
-       llist_add(&estatus_node->llnode, &ghes_estatus_llist);
-}
 
-static int ghes_in_nmi_queue_one_entry(struct ghes *ghes,
-                                      enum fixed_addresses fixmap_idx)
-{
-       struct acpi_hest_generic_status *estatus = ghes->estatus;
-       u64 buf_paddr;
-       int sev;
-
-       if (ghes_read_estatus(ghes, estatus, &buf_paddr, fixmap_idx)) {
+       if (__ghes_read_estatus(estatus, buf_paddr, fixmap_idx, len)) {
                ghes_clear_estatus(ghes, estatus, buf_paddr, fixmap_idx);
-               return -ENOENT;
+               rc = -ENOENT;
+               goto no_work;
        }
 
        sev = ghes_severity(estatus->error_severity);
        if (sev >= GHES_SEV_PANIC) {
                ghes_print_queued_estatus();
                __ghes_panic(ghes, estatus, buf_paddr, fixmap_idx);
-
        }
 
-       __process_error(ghes, estatus);
-       ghes_clear_estatus(ghes, estatus, buf_paddr, fixmap_idx);
+       ghes_clear_estatus(ghes, &tmp_header, buf_paddr, fixmap_idx);
 
-       return 0;
+       /* This error has been reported before, don't process it again. */
+       if (ghes_estatus_cached(estatus))
+               goto no_work;
+
+       llist_add(&estatus_node->llnode, &ghes_estatus_llist);
+
+       return rc;
+
+no_work:
+       gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node,
+                     node_len);
+
+       return rc;
 }
 
 static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list,