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.mo...@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

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