This is a note to let you know that I've just added the patch titled
ARM: fix cacheflush with PAN
to the 6.11-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-fix-cacheflush-with-pan.patch
and it can be found in the queue-6.11 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e34e26fd70f46e095238fcb902f33ee36c34824b
Author: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Date: Tue Nov 12 10:16:13 2024 +0000
ARM: fix cacheflush with PAN
[ Upstream commit ca29cfcc4a21083d671522ad384532e28a43f033 ]
It seems that the cacheflush syscall got broken when PAN for LPAE was
implemented. User access was not enabled around the cache maintenance
instructions, causing them to fault.
Fixes: 7af5b901e847 ("ARM: 9358/2: Implement PAN for LPAE by TTBR0 page table walks disablement")
Reported-by: Michał Pecio <michal.pecio@xxxxxxxxx>
Tested-by: Michał Pecio <michal.pecio@xxxxxxxxx>
Signed-off-by: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 480e307501bb4..6ea645939573f 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -570,6 +570,7 @@ static int bad_syscall(int n, struct pt_regs *regs)
static inline int
__do_cache_op(unsigned long start, unsigned long end)
{
+ unsigned int ua_flags;
int ret;
do {
@@ -578,7 +579,9 @@ __do_cache_op(unsigned long start, unsigned long end)
if (fatal_signal_pending(current))
return 0;
+ ua_flags = uaccess_save_and_enable();
ret = flush_icache_user_range(start, start + chunk);
+ uaccess_restore(ua_flags);
if (ret)
return ret;
