ACPI / APEI: Pass ghes and estatus separately to avoid a later copy

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.

All the NMI-like notifications should use a queued estatus entry
from the beginning, instead of the ghes version, then copying it.
To do this, break up any use of "ghes->estatus" so that all
functions take the estatus as an argument.

This patch just moves these ghes->estatus dereferences into separate
arguments, no change in behaviour. struct ghes becomes unused in
ghes_clear_estatus() as it only wanted ghes->estatus, which we now
pass directly. This is removed.

Signed-off-by: James Morse <james.morse@arm.com>
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 9a24641..54746a7 100644 (file)
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -293,9 +293,9 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
        }
 }
 
-static int ghes_read_estatus(struct ghes *ghes, u64 *buf_paddr,
-                            enum fixed_addresses fixmap_idx)
-
+static int ghes_read_estatus(struct ghes *ghes,
+                            struct acpi_hest_generic_status *estatus,
+                            u64 *buf_paddr, enum fixed_addresses fixmap_idx)
 {
        struct acpi_hest_generic *g = ghes->generic;
        u32 len;
@@ -312,25 +312,25 @@ static int ghes_read_estatus(struct ghes *ghes, u64 *buf_paddr,
        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) {
                *buf_paddr = 0;
                return -ENOENT;
        }
 
        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;
 
@@ -342,16 +342,17 @@ err_read_block:
        return rc;
 }
 
-static void ghes_clear_estatus(struct ghes *ghes, u64 buf_paddr,
-                              enum fixed_addresses fixmap_idx)
+static void ghes_clear_estatus(struct ghes *ghes,
+                              struct acpi_hest_generic_status *estatus,
+                              u64 buf_paddr, enum fixed_addresses fixmap_idx)
 {
-       ghes->estatus->block_status = 0;
+       estatus->block_status = 0;
 
        if (!buf_paddr)
                return;
 
-       ghes_copy_tofrom_phys(ghes->estatus, buf_paddr,
-                             sizeof(ghes->estatus->block_status), 0,
+       ghes_copy_tofrom_phys(estatus, buf_paddr,
+                             sizeof(estatus->block_status), 0,
                              fixmap_idx);
 
        /*
@@ -651,12 +652,13 @@ static void ghes_estatus_cache_add(
        rcu_read_unlock();
 }
 
-static void __ghes_panic(struct ghes *ghes, u64 buf_paddr,
-                        enum fixed_addresses fixmap_idx)
+static void __ghes_panic(struct ghes *ghes,
+                        struct acpi_hest_generic_status *estatus,
+                        u64 buf_paddr, enum fixed_addresses fixmap_idx)
 {
-       __ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);
+       __ghes_print_estatus(KERN_EMERG, ghes->generic, estatus);
 
-       ghes_clear_estatus(ghes, buf_paddr, fixmap_idx);
+       ghes_clear_estatus(ghes, estatus, buf_paddr, fixmap_idx);
 
        /* reboot to log the error! */
        if (!panic_timeout)
@@ -666,25 +668,25 @@ static void __ghes_panic(struct ghes *ghes, u64 buf_paddr,
 
 static int ghes_proc(struct ghes *ghes)
 {
+       struct acpi_hest_generic_status *estatus = ghes->estatus;
        u64 buf_paddr;
        int rc;
 
-       rc = ghes_read_estatus(ghes, &buf_paddr, FIX_APEI_GHES_IRQ);
+       rc = ghes_read_estatus(ghes, estatus, &buf_paddr, FIX_APEI_GHES_IRQ);
        if (rc)
                goto out;
 
-       if (ghes_severity(ghes->estatus->error_severity) >= GHES_SEV_PANIC) {
-               __ghes_panic(ghes, buf_paddr, FIX_APEI_GHES_IRQ);
-       }
+       if (ghes_severity(estatus->error_severity) >= GHES_SEV_PANIC)
+               __ghes_panic(ghes, estatus, buf_paddr, FIX_APEI_GHES_IRQ);
 
-       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, buf_paddr, FIX_APEI_GHES_IRQ);
+       ghes_clear_estatus(ghes, estatus, buf_paddr, FIX_APEI_GHES_IRQ);
 
        return rc;
 }
@@ -825,17 +827,20 @@ 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 *src_estatus)
 {
-#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
        u32 len, node_len;
        struct ghes_estatus_node *estatus_node;
        struct acpi_hest_generic_status *estatus;
 
-       if (ghes_estatus_cached(ghes->estatus))
+       if (!IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG))
                return;
 
-       len = cper_estatus_len(ghes->estatus);
+       if (ghes_estatus_cached(src_estatus))
+               return;
+
+       len = cper_estatus_len(src_estatus);
        node_len = GHES_ESTATUS_NODE_LEN(len);
 
        estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool, node_len);
@@ -845,30 +850,31 @@ 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, src_estatus, len);
        llist_add(&estatus_node->llnode, &ghes_estatus_llist);
-#endif
 }
 
 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, &buf_paddr, fixmap_idx)) {
-               ghes_clear_estatus(ghes, buf_paddr, fixmap_idx);
+       if (ghes_read_estatus(ghes, estatus, &buf_paddr, fixmap_idx)) {
+               ghes_clear_estatus(ghes, estatus, buf_paddr, 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, buf_paddr, fixmap_idx);
+               __ghes_panic(ghes, estatus, buf_paddr, fixmap_idx);
+
        }
 
-       __process_error(ghes);
-       ghes_clear_estatus(ghes, buf_paddr, fixmap_idx);
+       __process_error(ghes, estatus);
+       ghes_clear_estatus(ghes, estatus, buf_paddr, fixmap_idx);
 
        return 0;
 }