[PATCH 7/7] acpi, apei, ghes: Factor out ioremap virtual memory for IRQ and NMI context.

Tomasz Nowicki
2014-04-09T15:15:18Z

GHES currently maps two pages with atomic_ioremap. From now
on, NMI is optional so there is no need to allocate an NMI page
for platforms without NMI support.

To make it possible to not use a second page, swap the existing
page order so that the IRQ context page is first, and the optional
NMI context page is second. Then, use CONFIG_ACPI_APEI_NMI to decide
at runtime how many pages are to be allocated. Finally, put in
sanity checks to avoid accessing unallocated memory.

Signed-off-by: Tomasz Nowicki <tomasz.nowicki@linaro.org>
---
drivers/acpi/apei/ghes.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 624878b..20377ac 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -109,12 +109,11 @@ static DEFINE_MUTEX(ghes_list_mutex);
*/

/*
- * Two virtual pages are used, one for NMI context, the other for
- * IRQ/PROCESS context
+ * Two virtual pages are used, one for IRQ/PROCESS context, the other for
+ * NMI context (optionally).
*/
-#define GHES_IOREMAP_PAGES 2
-#define GHES_IOREMAP_NMI_PAGE(base) (base)
-#define GHES_IOREMAP_IRQ_PAGE(base) ((base) + PAGE_SIZE)
+#define GHES_IOREMAP_IRQ_PAGE(base) (base)
+#define GHES_IOREMAP_NMI_PAGE(base) ((base) + PAGE_SIZE)

/* virtual memory area for atomic ioremap */
static struct vm_struct *ghes_ioremap_area;
@@ -141,7 +140,8 @@ static struct ghes_notify_setup ghes_notify_tab[];

static int ghes_ioremap_init(void)
{
- ghes_ioremap_area = __get_vm_area(PAGE_SIZE * GHES_IOREMAP_PAGES,
+ ghes_ioremap_area = __get_vm_area(
+ PAGE_SIZE * (IS_ENABLED(CONFIG_ACPI_APEI_NMI) ? 2 : 1),
VM_IOREMAP, VMALLOC_START, VMALLOC_END);
if (!ghes_ioremap_area) {
pr_err(GHES_PFX "Failed to allocate virtual memory area for atomic ioremap.\n");
@@ -310,6 +310,8 @@ static void ghes_copy_tofrom_phys(void *buffer, u64 paddr, u32 len,
u64 offset;
u32 trunk;

+ BUG_ON(in_nmi && !IS_ENABLED(CONFIG_ACPI_APEI_NMI));
+
while (len > 0) {
offset = paddr - (paddr & PAGE_MASK);
if (in_nmi) {
--
1.7.9.5