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@xxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
---
Changes since v7:
* Moved the locks into the function that uses them to make it clearer this
is only use in_nmi().
Changes since v6:
* Tinkered with the commit message
* Lock definitions have moved due to the #ifdefs
---
drivers/acpi/apei/ghes.c | 34 +++++++++++++++++++++++++---------
1 file changed, 25 insertions(+), 9 deletions(-)
diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index ab794ab29554..c6bc73281d6a 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -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;
}
@@ -913,7 +916,14 @@ 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)
@@ -946,14 +956,17 @@ 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 err, ret = NMI_DONE;
if (!atomic_add_unless(&ghes_in_nmi, 1, 1))
return ret;
+ raw_spin_lock(&ghes_notify_lock_nmi);
err = ghes_in_nmi_spool_from_list(&ghes_nmi);
if (!err)
ret = NMI_HANDLED;
+ raw_spin_unlock(&ghes_notify_lock_nmi);
atomic_dec(&ghes_in_nmi);
return ret;
@@ -995,6 +1008,7 @@ static int ghes_probe(struct platform_device *ghes_dev)
{
struct acpi_hest_generic *generic;
struct ghes *ghes = NULL;
+ unsigned long flags;
int rc = -EINVAL;
@@ -1097,7 +1111,9 @@ 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;
--
2.20.1
