6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Russell King (Oracle) <rmk+kernel@xxxxxxxxxxxxxxx>
[ 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>
---
arch/arm/kernel/traps.c | 3 +++
1 file changed, 3 insertions(+)
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;
--
2.43.0
