drm: radeon: Fix unaligned access in r300_scratch().
In compat mode, the cmdbuf->buf 64-bit address cookie can
potentially be only 32-bit aligned. Dereferencing this as
64-bit causes expensive unaligned traps on platforms like
sparc64.
Use get_unaligned() to fix.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r300_cmdbuf.c b/drivers/gpu/drm/radeon/r300_cmdbuf.c
index cace396..3efa633 100644
--- a/drivers/gpu/drm/radeon/r300_cmdbuf.c
+++ b/drivers/gpu/drm/radeon/r300_cmdbuf.c
@@ -37,6 +37,8 @@
#include "radeon_drv.h"
#include "r300_reg.h"
+#include <asm/unaligned.h>
+
#define R300_SIMULTANEOUS_CLIPRECTS 4
/* Values for R300_RE_CLIPRECT_CNTL depending on the number of cliprects
@@ -917,6 +919,7 @@
{
u32 *ref_age_base;
u32 i, buf_idx, h_pending;
+ u64 ptr_addr;
RING_LOCALS;
if (cmdbuf->bufsz <
@@ -930,7 +933,8 @@
dev_priv->scratch_ages[header.scratch.reg]++;
- ref_age_base = (u32 *)(unsigned long)*((uint64_t *)cmdbuf->buf);
+ ptr_addr = get_unaligned((u64 *)cmdbuf->buf);
+ ref_age_base = (u32 *)(unsigned long)ptr_addr;
cmdbuf->buf += sizeof(u64);
cmdbuf->bufsz -= sizeof(u64);