[PATCH v6 01/18] ACPI / APEI: Move the estatus queue code up, and under its own ifdef

James Morse
2018-09-21T22:17:49Z

To support asynchronous NMI-like notifications on arm64 we need to use
the estatus-queue. These patches refactor it to allow multiple APEI
notification types to use it.

First we move the estatus-queue code higher in the file so that any
notify_foo() handler can make use of it.

This patch moves code around ... and makes the following trivial change:
Freshen the dated comment above ghes_estatus_llist. printk() is no
longer the issue, its the helpers like memory_failure_queue() that
still aren't nmi safe.

Signed-off-by: James Morse <james.morse@arm.com>
Reviewed-by: Punit Agrawal <punit.agrawal@arm.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Tested-by: Tyler Baicar <tbaicar@codeaurora.org>
---
drivers/acpi/apei/ghes.c | 265 ++++++++++++++++++++-------------------
1 file changed, 137 insertions(+), 128 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 02c6fd9caff7..f5732e6b5be8 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -545,6 +545,16 @@ static int ghes_print_estatus(const char *pfx,
return 0;
}

+static void __ghes_panic(struct ghes *ghes)
+{
+ __ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);
+
+ /* reboot to log the error! */
+ if (!panic_timeout)
+ panic_timeout = ghes_panic_timeout;
+ panic("Fatal hardware error!");
+}
+
/*
* GHES error status reporting throttle, to report more kinds of
* errors, instead of just most frequently occurred errors.
@@ -672,6 +682,133 @@ static void ghes_estatus_cache_add(
rcu_read_unlock();
}

+#ifdef CONFIG_HAVE_ACPI_APEI_NMI
+/*
+ * Handlers for CPER records may not be NMI safe. For example,
+ * memory_failure_queue() takes spinlocks and calls schedule_work_on().
+ * In any NMI-like handler, memory from ghes_estatus_pool is used to save
+ * estatus, and added to the ghes_estatus_llist. irq_work_queue() causes
+ * ghes_proc_in_irq() to run in IRQ context where each estatus in
+ * ghes_estatus_llist is processed. Each NMI-like error source must grow
+ * the ghes_estatus_pool to ensure memory is available.
+ *
+ * Memory from the ghes_estatus_pool is also used with the ghes_estatus_cache
+ * to suppress frequent messages.
+ */
+static struct llist_head ghes_estatus_llist;
+static struct irq_work ghes_proc_irq_work;
+
+static void ghes_print_queued_estatus(void)
+{
+ struct llist_node *llnode;
+ struct ghes_estatus_node *estatus_node;
+ struct acpi_hest_generic *generic;
+ struct acpi_hest_generic_status *estatus;
+
+ llnode = llist_del_all(&ghes_estatus_llist);
+ /*
+ * Because the time order of estatus in list is reversed,
+ * revert it back to proper order.
+ */
+ llnode = llist_reverse_order(llnode);
+ while (llnode) {
+ estatus_node = llist_entry(llnode, struct ghes_estatus_node,
+ llnode);
+ estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
+ generic = estatus_node->generic;
+ ghes_print_estatus(NULL, generic, estatus);
+ llnode = llnode->next;
+ }
+}
+
+/* Save estatus for further processing in IRQ context */
+static void __process_error(struct ghes *ghes)
+{
+#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
+ u32 len, node_len;
+ struct ghes_estatus_node *estatus_node;
+ struct acpi_hest_generic_status *estatus;
+
+ if (ghes_estatus_cached(ghes->estatus))
+ return;
+
+ len = cper_estatus_len(ghes->estatus);
+ node_len = GHES_ESTATUS_NODE_LEN(len);
+
+ estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool, node_len);
+ if (!estatus_node)
+ return;
+
+ estatus_node->ghes = ghes;
+ estatus_node->generic = ghes->generic;
+ estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
+ memcpy(estatus, ghes->estatus, len);
+ llist_add(&estatus_node->llnode, &ghes_estatus_llist);
+#endif
+}
+
+static unsigned long ghes_esource_prealloc_size(
+ const struct acpi_hest_generic *generic)
+{
+ unsigned long block_length, prealloc_records, prealloc_size;
+
+ block_length = min_t(unsigned long, generic->error_block_length,
+ GHES_ESTATUS_MAX_SIZE);
+ prealloc_records = max_t(unsigned long,
+ generic->records_to_preallocate, 1);
+ prealloc_size = min_t(unsigned long, block_length * prealloc_records,
+ GHES_ESOURCE_PREALLOC_MAX_SIZE);
+
+ return prealloc_size;
+}
+
+static void ghes_estatus_pool_shrink(unsigned long len)
+{
+ ghes_estatus_pool_size_request -= PAGE_ALIGN(len);
+}
+
+static void ghes_proc_in_irq(struct irq_work *irq_work)
+{
+ struct llist_node *llnode, *next;
+ struct ghes_estatus_node *estatus_node;
+ struct acpi_hest_generic *generic;
+ struct acpi_hest_generic_status *estatus;
+ u32 len, node_len;
+
+ llnode = llist_del_all(&ghes_estatus_llist);
+ /*
+ * Because the time order of estatus in list is reversed,
+ * revert it back to proper order.
+ */
+ llnode = llist_reverse_order(llnode);
+ while (llnode) {
+ next = llnode->next;
+ estatus_node = llist_entry(llnode, struct ghes_estatus_node,
+ llnode);
+ estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
+ len = cper_estatus_len(estatus);
+ node_len = GHES_ESTATUS_NODE_LEN(len);
+ ghes_do_proc(estatus_node->ghes, estatus);
+ if (!ghes_estatus_cached(estatus)) {
+ generic = estatus_node->generic;
+ if (ghes_print_estatus(NULL, generic, estatus))
+ ghes_estatus_cache_add(generic, estatus);
+ }
+ gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node,
+ node_len);
+ llnode = next;
+ }
+}
+
+static void ghes_nmi_init_cxt(void)
+{
+ init_irq_work(&ghes_proc_irq_work, ghes_proc_in_irq);
+}
+
+#else
+static inline void ghes_nmi_init_cxt(void) { }
+#endif /* CONFIG_HAVE_ACPI_APEI_NMI */
+
static int ghes_ack_error(struct acpi_hest_generic_v2 *gv2)
{
int rc;
@@ -687,16 +824,6 @@ static int ghes_ack_error(struct acpi_hest_generic_v2 *gv2)
return apei_write(val, &gv2->read_ack_register);
}

-static void __ghes_panic(struct ghes *ghes)
-{
- __ghes_print_estatus(KERN_EMERG, ghes->generic, ghes->estatus);
-
- /* reboot to log the error! */
- if (!panic_timeout)
- panic_timeout = ghes_panic_timeout;
- panic("Fatal hardware error!");
-}
-
static int ghes_proc(struct ghes *ghes)
{
int rc;
@@ -828,17 +955,6 @@ static inline void ghes_sea_remove(struct ghes *ghes) { }
#endif /* CONFIG_ACPI_APEI_SEA */

#ifdef CONFIG_HAVE_ACPI_APEI_NMI
-/*
- * printk is not safe in NMI context. So in NMI handler, we allocate
- * required memory from lock-less memory allocator
- * (ghes_estatus_pool), save estatus into it, put them into lock-less
- * list (ghes_estatus_llist), then delay printk into IRQ context via
- * irq_work (ghes_proc_irq_work). ghes_estatus_size_request record
- * required pool size by all NMI error source.
- */
-static struct llist_head ghes_estatus_llist;
-static struct irq_work ghes_proc_irq_work;
-
/*
* NMI may be triggered on any CPU, so ghes_in_nmi is used for
* having only one concurrent reader.
@@ -847,88 +963,6 @@ static atomic_t ghes_in_nmi = ATOMIC_INIT(0);

static LIST_HEAD(ghes_nmi);

-static void ghes_proc_in_irq(struct irq_work *irq_work)
-{
- struct llist_node *llnode, *next;
- struct ghes_estatus_node *estatus_node;
- struct acpi_hest_generic *generic;
- struct acpi_hest_generic_status *estatus;
- u32 len, node_len;
-
- llnode = llist_del_all(&ghes_estatus_llist);
- /*
- * Because the time order of estatus in list is reversed,
- * revert it back to proper order.
- */
- llnode = llist_reverse_order(llnode);
- while (llnode) {
- next = llnode->next;
- estatus_node = llist_entry(llnode, struct ghes_estatus_node,
- llnode);
- estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
- len = cper_estatus_len(estatus);
- node_len = GHES_ESTATUS_NODE_LEN(len);
- ghes_do_proc(estatus_node->ghes, estatus);
- if (!ghes_estatus_cached(estatus)) {
- generic = estatus_node->generic;
- if (ghes_print_estatus(NULL, generic, estatus))
- ghes_estatus_cache_add(generic, estatus);
- }
- gen_pool_free(ghes_estatus_pool, (unsigned long)estatus_node,
- node_len);
- llnode = next;
- }
-}
-
-static void ghes_print_queued_estatus(void)
-{
- struct llist_node *llnode;
- struct ghes_estatus_node *estatus_node;
- struct acpi_hest_generic *generic;
- struct acpi_hest_generic_status *estatus;
-
- llnode = llist_del_all(&ghes_estatus_llist);
- /*
- * Because the time order of estatus in list is reversed,
- * revert it back to proper order.
- */
- llnode = llist_reverse_order(llnode);
- while (llnode) {
- estatus_node = llist_entry(llnode, struct ghes_estatus_node,
- llnode);
- estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
- generic = estatus_node->generic;
- ghes_print_estatus(NULL, generic, estatus);
- llnode = llnode->next;
- }
-}
-
-/* Save estatus for further processing in IRQ context */
-static void __process_error(struct ghes *ghes)
-{
-#ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG
- u32 len, node_len;
- struct ghes_estatus_node *estatus_node;
- struct acpi_hest_generic_status *estatus;
-
- if (ghes_estatus_cached(ghes->estatus))
- return;
-
- len = cper_estatus_len(ghes->estatus);
- node_len = GHES_ESTATUS_NODE_LEN(len);
-
- estatus_node = (void *)gen_pool_alloc(ghes_estatus_pool, node_len);
- if (!estatus_node)
- return;
-
- estatus_node->ghes = ghes;
- estatus_node->generic = ghes->generic;
- estatus = GHES_ESTATUS_FROM_NODE(estatus_node);
- memcpy(estatus, ghes->estatus, len);
- llist_add(&estatus_node->llnode, &ghes_estatus_llist);
-#endif
-}
-
static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
{
struct ghes *ghes;
@@ -967,26 +1001,6 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
return ret;
}

-static unsigned long ghes_esource_prealloc_size(
- const struct acpi_hest_generic *generic)
-{
- unsigned long block_length, prealloc_records, prealloc_size;
-
- block_length = min_t(unsigned long, generic->error_block_length,
- GHES_ESTATUS_MAX_SIZE);
- prealloc_records = max_t(unsigned long,
- generic->records_to_preallocate, 1);
- prealloc_size = min_t(unsigned long, block_length * prealloc_records,
- GHES_ESOURCE_PREALLOC_MAX_SIZE);
-
- return prealloc_size;
-}
-
-static void ghes_estatus_pool_shrink(unsigned long len)
-{
- ghes_estatus_pool_size_request -= PAGE_ALIGN(len);
-}
-
static void ghes_nmi_add(struct ghes *ghes)
{
unsigned long len;
@@ -1018,14 +1032,9 @@ static void ghes_nmi_remove(struct ghes *ghes)
ghes_estatus_pool_shrink(len);
}

-static void ghes_nmi_init_cxt(void)
-{
- init_irq_work(&ghes_proc_irq_work, ghes_proc_in_irq);
-}
#else /* CONFIG_HAVE_ACPI_APEI_NMI */
static inline void ghes_nmi_add(struct ghes *ghes) { }
static inline void ghes_nmi_remove(struct ghes *ghes) { }
-static inline void ghes_nmi_init_cxt(void) { }
#endif /* CONFIG_HAVE_ACPI_APEI_NMI */

static int ghes_probe(struct platform_device *ghes_dev)
--
2.19.0