ACPI: Use ioremap_cache()

Although the temporary boot-time ACPI table mappings
were set up with CPU caching enabled, the permanent table
mappings and AML run-time region memory accesses were
set up with ioremap(), which on x86 is a synonym for
ioremap_nocache().

Changing this to ioremap_cache() improves performance as
seen when accessing the tables via acpidump,
or /sys/firmware/acpi/tables.  It should also improve
AML run-time performance.

No change on ia64.

Reported-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

2 files changed, 8 insertions, 3 deletions

diff --git a/arch/ia64/include/asm/io.h b/arch/ia64/include/asm/io.h
index cc8335eb3110..e5a6c3530c6c 100644
--- a/arch/ia64/include/asm/io.h
+++ b/arch/ia64/include/asm/io.h
@@ -426,6 +426,11 @@ extern void __iomem * ioremap_nocache (unsigned long offset, unsigned long size)
 extern void iounmap (volatile void __iomem *addr);
 extern void __iomem * early_ioremap (unsigned long phys_addr, unsigned long size);
 extern void early_iounmap (volatile void __iomem *addr, unsigned long size);
+static inline void __iomem * ioremap_cache (unsigned long phys_addr, unsigned long size)
+{
+        return ioremap(phys_addr, size);
+}
+
 
 /*
  * String version of IO memory access ops:
diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 055d7b701fff..3a7b4879fd99 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -320,7 +320,7 @@ acpi_os_map_memory(acpi_physical_address phys, acpi_size size)
 
         pg_off = round_down(phys, PAGE_SIZE);
         pg_sz = round_up(phys + size, PAGE_SIZE) - pg_off;
-        virt = ioremap(pg_off, pg_sz);
+        virt = ioremap_cache(pg_off, pg_sz);
         if (!virt) {
                 kfree(map);
                 return NULL;
@@ -642,7 +642,7 @@ acpi_os_read_memory(acpi_physical_address phys_addr, u32 * value, u32 width)
         virt_addr = acpi_map_vaddr_lookup(phys_addr, size);
         rcu_read_unlock();
         if (!virt_addr) {
-                virt_addr = ioremap(phys_addr, size);
+                virt_addr = ioremap_cache(phys_addr, size);
                 unmap = 1;
         }
         if (!value)
@@ -678,7 +678,7 @@ acpi_os_write_memory(acpi_physical_address phys_addr, u32 value, u32 width)
         virt_addr = acpi_map_vaddr_lookup(phys_addr, size);
         rcu_read_unlock();
         if (!virt_addr) {
-                virt_addr = ioremap(phys_addr, size);
+                virt_addr = ioremap_cache(phys_addr, size);
                 unmap = 1;
         }