The following commit has been merged into the x86/urgent branch of tip:
Commit-ID: a3f547addcaa10df5a226526bc9e2d9a94542344
Gitweb: https://git.kernel.org/tip/a3f547addcaa10df5a226526bc9e2d9a94542344
Author: Michal Koutný <mkoutny(a)suse.com>
AuthorDate: Mon, 06 Mar 2023 20:31:44 +01:00
Committer: Dave Hansen <dave.hansen(a)linux.intel.com>
CommitterDate: Wed, 22 Mar 2023 10:42:47 -07:00
x86/mm: Do not shuffle CPU entry areas without KASLR
The commit 97e3d26b5e5f ("x86/mm: Randomize per-cpu entry area") fixed
an omission of KASLR on CPU entry areas. It doesn't take into account
KASLR switches though, which may result in unintended non-determinism
when a user wants to avoid it (e.g. debugging, benchmarking).
Generate only a single combination of CPU entry areas offsets -- the
linear array that existed prior randomization when KASLR is turned off.
Since we have 3f148f331814 ("x86/kasan: Map shadow for percpu pages on
demand") and followups, we can use the more relaxed guard
kasrl_enabled() (in contrast to kaslr_memory_enabled()).
Fixes: 97e3d26b5e5f ("x86/mm: Randomize per-cpu entry area")
Signed-off-by: Michal Koutný <mkoutny(a)suse.com>
Signed-off-by: Dave Hansen <dave.hansen(a)linux.intel.com>
Cc: stable(a)vger.kernel.org
Link: https://lore.kernel.org/all/20230306193144.24605-1-mkoutny%40suse.com
---
arch/x86/mm/cpu_entry_area.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/mm/cpu_entry_area.c b/arch/x86/mm/cpu_entry_area.c
index 7316a82..e91500a 100644
--- a/arch/x86/mm/cpu_entry_area.c
+++ b/arch/x86/mm/cpu_entry_area.c
@@ -10,6 +10,7 @@
#include <asm/fixmap.h>
#include <asm/desc.h>
#include <asm/kasan.h>
+#include <asm/setup.h>
static DEFINE_PER_CPU_PAGE_ALIGNED(struct entry_stack_page, entry_stack_storage);
@@ -29,6 +30,12 @@ static __init void init_cea_offsets(void)
unsigned int max_cea;
unsigned int i, j;
+ if (!kaslr_enabled()) {
+ for_each_possible_cpu(i)
+ per_cpu(_cea_offset, i) = i;
+ return;
+ }
+
max_cea = (CPU_ENTRY_AREA_MAP_SIZE - PAGE_SIZE) / CPU_ENTRY_AREA_SIZE;
/* O(sodding terrible) */
From: Matheus Castello <matheus.castello(a)toradex.com>
Returns EPROBE_DEFER when of_drm_find_bridge() fails, this is consistent
with what all the other DRM bridge drivers are doing and this is
required since the bridge might not be there when the driver is probed
and this should not be a fatal failure.
Cc: <stable(a)vger.kernel.org>
Fixes: 30e2ae943c26 ("drm/bridge: Introduce LT8912B DSI to HDMI bridge")
Signed-off-by: Matheus Castello <matheus.castello(a)toradex.com>
Signed-off-by: Francesco Dolcini <francesco.dolcini(a)toradex.com>
---
v2: use dev_err_probe() instead of dev_dbg() (Laurent)
---
drivers/gpu/drm/bridge/lontium-lt8912b.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/bridge/lontium-lt8912b.c b/drivers/gpu/drm/bridge/lontium-lt8912b.c
index 2019a8167d69..b40baced1331 100644
--- a/drivers/gpu/drm/bridge/lontium-lt8912b.c
+++ b/drivers/gpu/drm/bridge/lontium-lt8912b.c
@@ -676,8 +676,8 @@ static int lt8912_parse_dt(struct lt8912 *lt)
lt->hdmi_port = of_drm_find_bridge(port_node);
if (!lt->hdmi_port) {
- dev_err(lt->dev, "%s: Failed to get hdmi port\n", __func__);
- ret = -ENODEV;
+ ret = -EPROBE_DEFER;
+ dev_err_probe(lt->dev, ret, "%s: Failed to get hdmi port\n", __func__);
goto err_free_host_node;
}
--
2.25.1