Skip to contentSkip to conversation

agp/uninorth: Fix oops caused by flushing too much

PATCH In review Paul Mackerras 2 participants 2 messages Jun 2, 2010 – Jun 8, 2010 Agpgart driver

lore
Share & tools
lore

Paul Mackerras

author
#0 lore raw

PATCH 1/1 agp/uninorth: Fix oops caused by flushing too much

This fixes a sporadic oops at boot on G5 Power Macs. The table_end variable has the address of the last byte of the table. Adding on PAGE_SIZE means we flush too much, and if the page after the table is not mapped for any reason, the kernel will oops. Instead we add on 1 because flush_dcache_range() interprets its second argument as the first byte past the range to be flushed.

Signed-off-by Paul Mackerras <[email protected]>

---

drivers/char/agp/uninorth-agp.c +1 -1
index 6f48931..9aaa0eb 100644
@@ -413,7 +413,7 @@ static int uninorth_create_gatt_table(struct agp_bridge_data *bridge)
 	bridge->gatt_table_real = (u32 *) table;
 	/* Need to clear out any dirty data still sitting in caches */
 	flush_dcache_range((unsigned long)table,
-			   (unsigned long)(table_end + PAGE_SIZE));
+			   (unsigned long)table_end + 1);
 	bridge->gatt_table = vmap(pages, (1 << page_order), 0, PAGE_KERNEL_NCG);
 
 	if (bridge->gatt_table == NULL)
Reviewed-by Tested-by on v1 1/1
#1 lore raw

On Mit, 2010-06-02 at 15:33 +1000, Paul Mackerras wrote:=20

Quoted 8 lines

This fixes a sporadic oops at boot on G5 Power Macs. The table_end variable has the address of the last byte of the table. Adding on PAGE_SIZE means we flush too much, and if the page after the table is not mapped for any reason, the kernel will oops. Instead we add on 1 because flush_dcache_range() interprets its second argument as the first byte past the range to be flushed.
=20

Signed-off-by Paul Mackerras <[email protected]>
Reviewed-by Michel D=C3=A4nzer <[email protected]>
Tested-by Michel D=C3=A4nzer <[email protected]>

Thanks for the good catch, Paul.

drivers/char/agp/uninorth-=

Quoted 3 lines

---
=20

drivers/char/agp/uninorth-= renamed from drivers/char/agp/uninorth-agp.c +0 -0

agp.c

drivers/char/agp/uninorth-agp.c static int uninorth_create_gatt_table(struct agp_brid=

Quoted 4 lines

index 6f48931..9aaa0eb 100644

drivers/char/agp/uninorth-agp.c +0 -0
@@ -413,7 +413,7 @@ static int uninorth_create_gatt_table(struct agp_brid=

ge_data *bridge)

drivers/char/agp/uninorth-agp.c static int uninorth_create_gatt_table(struct agp_bridge_data *bridge)

Quoted 6 lines
drivers/char/agp/uninorth-agp.c +1 -1
 	bridge->gatt_table_real =3D (u32 *) table;
 	/* Need to clear out any dirty data still sitting in caches */
 	flush_dcache_range((unsigned long)table,
-			   (unsigned long)(table_end + PAGE_SIZE));
+			   (unsigned long)table_end + 1);
 	bridge->gatt_table =3D vmap(pages, (1 << page_order), 0, PAGE_KERNEL_NC=

G);

Quoted 2 lines

=20
if (bridge->gatt_table =3D=3D NULL)

--=20
Earthling Michel D=C3=A4nzer | http://www.vmware.c=
om
Libre software enthusiast | Debian, X and DRI developer