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ACPI / APEI: Move locking to the notification helper

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ghes_copy_tofrom_phys() takes different locks depending on in_nmi().
This doesn't work if there are multiple NMI-like notifications, that
can interrupt each other.

Now that NOTIFY_SEA is always called in the same context, move the
lock-taking to the notification helper. The helper will always know
which lock to take. This avoids ghes_copy_tofrom_phys() taking a guess
based on in_nmi().

This splits NOTIFY_NMI and NOTIFY_SEA to use different locks. All
the other notifications use ghes_proc(), and are called in process
or IRQ context. Move the spin_lock_irqsave() around their ghes_proc()
calls.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
James Morse 2019-01-29 18:48:51 +00:00 committed by Rafael J. Wysocki
parent d44f1b8dd7
commit 3b880cbe4d
1 changed files with 25 additions and 9 deletions
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34
drivers/acpi/apei/ghes.c
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@ -114,11 +114,10 @@ static DEFINE_MUTEX(ghes_list_mutex);
* handler, but general ioremap can not be used in atomic context, so
* the fixmap is used instead.
*
* These 2 spinlocks are used to prevent the fixmap entries from being used
* This spinlock is used to prevent the fixmap entry from being used
* simultaneously.
*/
static DEFINE_RAW_SPINLOCK(ghes_ioremap_lock_nmi);
static DEFINE_SPINLOCK(ghes_ioremap_lock_irq);
static DEFINE_SPINLOCK(ghes_notify_lock_irq);
static struct gen_pool *ghes_estatus_pool;
static unsigned long ghes_estatus_pool_size_request;
@ -287,7 +286,6 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
int from_phys)
{
void __iomem *vaddr;
unsigned long flags = 0;
int in_nmi = in_nmi();
u64 offset;
u32 trunk;
@ -295,10 +293,8 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
while (len > 0) {
offset = paddr - (paddr & PAGE_MASK);
if (in_nmi) {
raw_spin_lock(&ghes_ioremap_lock_nmi);
vaddr = ghes_ioremap_pfn_nmi(paddr >> PAGE_SHIFT);
} else {
spin_lock_irqsave(&ghes_ioremap_lock_irq, flags);
vaddr = ghes_ioremap_pfn_irq(paddr >> PAGE_SHIFT);
}
trunk = PAGE_SIZE - offset;
@ -312,10 +308,8 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
buffer += trunk;
if (in_nmi) {
ghes_iounmap_nmi();
raw_spin_unlock(&ghes_ioremap_lock_nmi);
} else {
ghes_iounmap_irq();
spin_unlock_irqrestore(&ghes_ioremap_lock_irq, flags);
}
}
}
@ -729,8 +723,11 @@ static void ghes_add_timer(struct ghes *ghes)
static void ghes_poll_func(struct timer_list *t)
{
struct ghes *ghes = from_timer(ghes, t, timer);
unsigned long flags;
spin_lock_irqsave(&ghes_notify_lock_irq, flags);
ghes_proc(ghes);
spin_unlock_irqrestore(&ghes_notify_lock_irq, flags);
if (!(ghes->flags & GHES_EXITING))
ghes_add_timer(ghes);
}
@ -738,9 +735,12 @@ static void ghes_poll_func(struct timer_list *t)
static irqreturn_t ghes_irq_func(int irq, void *data)
{
struct ghes *ghes = data;
unsigned long flags;
int rc;
spin_lock_irqsave(&ghes_notify_lock_irq, flags);
rc = ghes_proc(ghes);
spin_unlock_irqrestore(&ghes_notify_lock_irq, flags);
if (rc)
return IRQ_NONE;
@ -751,14 +751,17 @@ static int ghes_notify_hed(struct notifier_block *this, unsigned long event,
void *data)
{
struct ghes *ghes;
unsigned long flags;
int ret = NOTIFY_DONE;
spin_lock_irqsave(&ghes_notify_lock_irq, flags);
rcu_read_lock();
list_for_each_entry_rcu(ghes, &ghes_hed, list) {
if (!ghes_proc(ghes))
ret = NOTIFY_OK;
}
rcu_read_unlock();
spin_unlock_irqrestore(&ghes_notify_lock_irq, flags);
return ret;
}
@ -912,7 +915,14 @@ static LIST_HEAD(ghes_sea);
*/
int ghes_notify_sea(void)
{
return ghes_in_nmi_spool_from_list(&ghes_sea);
static DEFINE_RAW_SPINLOCK(ghes_notify_lock_sea);
int rv;
raw_spin_lock(&ghes_notify_lock_sea);
rv = ghes_in_nmi_spool_from_list(&ghes_sea);
raw_spin_unlock(&ghes_notify_lock_sea);
return rv;
}
static void ghes_sea_add(struct ghes *ghes)
@ -945,13 +955,16 @@ static LIST_HEAD(ghes_nmi);
static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
{
static DEFINE_RAW_SPINLOCK(ghes_notify_lock_nmi);
int ret = NMI_DONE;
if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
return ret;
raw_spin_lock(&ghes_notify_lock_nmi);
if (!ghes_in_nmi_spool_from_list(&ghes_nmi))
ret = NMI_HANDLED;
raw_spin_unlock(&ghes_notify_lock_nmi);
atomic_dec(&ghes_in_nmi);
return ret;
@ -993,6 +1006,7 @@ static int ghes_probe(struct platform_device *ghes_dev)
{
struct acpi_hest_generic *generic;
struct ghes *ghes = NULL;
unsigned long flags;
int rc = -EINVAL;
@ -1095,7 +1109,9 @@ static int ghes_probe(struct platform_device *ghes_dev)
ghes_edac_register(ghes, &ghes_dev->dev);
/* Handle any pending errors right away */
spin_lock_irqsave(&ghes_notify_lock_irq, flags);
ghes_proc(ghes);
spin_unlock_irqrestore(&ghes_notify_lock_irq, flags);
return 0;