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authorJames Morse <james.morse@arm.com>2019-01-29 21:48:45 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2019-02-08 01:10:45 +0300
commitee2eb3d4ee175c2fb5c7f67e84f5fe40a8147d92 (patch)
treeafce734b48c7e0b83ff6d7950c24e372e4b6ade1 /drivers/acpi/apei
parent5cc6c68287ae4be22c40b41cf6844746cddebbcc (diff)
downloadlinux-ee2eb3d4ee175c2fb5c7f67e84f5fe40a8147d92.tar.xz
ACPI / APEI: Generalise the estatus queue's notify code
Refactor the estatus queue's pool notification routine from NOTIFY_NMI's handlers. This will allow another notification method to use the estatus queue without duplicating this code. Add rcu_read_lock()/rcu_read_unlock() around the list list_for_each_entry_rcu() walker. These aren't strictly necessary as the whole nmi_enter/nmi_exit() window is a spooky RCU read-side critical section. in_nmi_queue_one_entry() is separate from the rcu-list walker for a later caller that doesn't need to walk a list. Signed-off-by: James Morse <james.morse@arm.com> Reviewed-by: Punit Agrawal <punit.agrawal@arm.com> Tested-by: Tyler Baicar <tbaicar@codeaurora.org> [ rjw: Drop unnecessary err variable in two places ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/apei')
-rw-r--r--drivers/acpi/apei/ghes.c63
1 files changed, 41 insertions, 22 deletions
diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index af3c10f47f20..babd2d53f319 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -912,37 +912,56 @@ static void __process_error(struct ghes *ghes)
#endif
}
-static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
+static int ghes_in_nmi_queue_one_entry(struct ghes *ghes)
{
u64 buf_paddr;
- struct ghes *ghes;
- int sev, ret = NMI_DONE;
+ int sev;
- if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
- return ret;
+ if (ghes_read_estatus(ghes, &buf_paddr)) {
+ ghes_clear_estatus(ghes, buf_paddr);
+ return -ENOENT;
+ }
- list_for_each_entry_rcu(ghes, &ghes_nmi, list) {
- if (ghes_read_estatus(ghes, &buf_paddr)) {
- ghes_clear_estatus(ghes, buf_paddr);
- continue;
- } else {
- ret = NMI_HANDLED;
- }
+ sev = ghes_severity(ghes->estatus->error_severity);
+ if (sev >= GHES_SEV_PANIC) {
+ ghes_print_queued_estatus();
+ __ghes_panic(ghes, buf_paddr);
+ }
- sev = ghes_severity(ghes->estatus->error_severity);
- if (sev >= GHES_SEV_PANIC) {
- ghes_print_queued_estatus();
- __ghes_panic(ghes, buf_paddr);
- }
+ __process_error(ghes);
+ ghes_clear_estatus(ghes, buf_paddr);
- __process_error(ghes);
- ghes_clear_estatus(ghes, buf_paddr);
+ return 0;
+}
+
+static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list)
+{
+ int ret = -ENOENT;
+ struct ghes *ghes;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ghes, rcu_list, list) {
+ if (!ghes_in_nmi_queue_one_entry(ghes))
+ ret = 0;
}
+ rcu_read_unlock();
-#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
- if (ret == NMI_HANDLED)
+ if (IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) && !ret)
irq_work_queue(&ghes_proc_irq_work);
-#endif
+
+ return ret;
+}
+
+static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
+{
+ int ret = NMI_DONE;
+
+ if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
+ return ret;
+
+ if (!ghes_in_nmi_spool_from_list(&ghes_nmi))
+ ret = NMI_HANDLED;
+
atomic_dec(&ghes_in_nmi);
return ret;
}