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author | James Morse <james.morse@arm.com> | 2019-01-29 19:48:51 +0100 |
---|---|---|
committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2019-02-07 23:10:45 +0100 |
commit | 3b880cbe4df5dd78a2b2279dbe16db9d193412ca (patch) | |
tree | 936e9ff81c2627217f03733ec9f7c8ee93b6568e /drivers/acpi | |
parent | arm64: KVM/mm: Move SEA handling behind a single 'claim' interface (diff) | |
download | linux-3b880cbe4df5dd78a2b2279dbe16db9d193412ca.tar.xz linux-3b880cbe4df5dd78a2b2279dbe16db9d193412ca.zip |
ACPI / APEI: Move locking to the notification helper
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>
Diffstat (limited to 'drivers/acpi')
-rw-r--r-- | drivers/acpi/apei/ghes.c | 34 |
1 files changed, 25 insertions, 9 deletions
diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index 679ab0f93ee8..c7dbdb915e7e 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; } @@ -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; |