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ACPI / APEI: Generalise the estatus queue's notify code

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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>
This commit is contained in:
James Morse 2019-01-29 18:48:45 +00:00 committed by Rafael J. Wysocki
parent 5cc6c68287
commit ee2eb3d4ee
1 changed files with 42 additions and 23 deletions
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65
drivers/acpi/apei/ghes.c
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@ -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;
int sev;
if (ghes_read_estatus(ghes, &buf_paddr)) {
ghes_clear_estatus(ghes, buf_paddr);
return -ENOENT;
}
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);
return 0;
}
static int ghes_in_nmi_spool_from_list(struct list_head *rcu_list)
{
int ret = -ENOENT;
struct ghes *ghes;
int sev, ret = NMI_DONE;
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();
if (IS_ENABLED(CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG) && !ret)
irq_work_queue(&ghes_proc_irq_work);
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;
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;
}
if (!ghes_in_nmi_spool_from_list(&ghes_nmi))
ret = NMI_HANDLED;
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);
}
#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
if (ret == NMI_HANDLED)
irq_work_queue(&ghes_proc_irq_work);
#endif
atomic_dec(&ghes_in_nmi);
return ret;
}