[PATCH 6.0 084/157] ARM: 9278/1: kfence: only handle translation faults

Greg Kroah-Hartman
2022-12-12T13:40:57Z

From: Wang Kefeng <wangkefeng.wang@huawei.com>

commit 73a0b6ee5d6269f92df43e1d09b3278a2886bf8a upstream.

This is a similar fixup like arm64 does, only handle translation faults
in case of unexpected kfence report when alignment faults on ARM, see
more from commit 0bb1fbffc631 ("arm64: mm: kfence: only handle translation
faults").

Fixes: 75969686ec0d ("ARM: 9166/1: Support KFENCE for ARM")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm/mm/fault.c | 18 ++++++++++++++++--
arch/arm/mm/fault.h | 9 ++++++---
2 files changed, 22 insertions(+), 5 deletions(-)

--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -105,6 +105,19 @@ static inline bool is_write_fault(unsign
return (fsr & FSR_WRITE) && !(fsr & FSR_CM);
}

+static inline bool is_translation_fault(unsigned int fsr)
+{
+ int fs = fsr_fs(fsr);
+#ifdef CONFIG_ARM_LPAE
+ if ((fs & FS_MMU_NOLL_MASK) == FS_TRANS_NOLL)
+ return true;
+#else
+ if (fs == FS_L1_TRANS || fs == FS_L2_TRANS)
+ return true;
+#endif
+ return false;
+}
+
static void die_kernel_fault(const char *msg, struct mm_struct *mm,
unsigned long addr, unsigned int fsr,
struct pt_regs *regs)
@@ -140,7 +153,8 @@ __do_kernel_fault(struct mm_struct *mm,
if (addr < PAGE_SIZE) {
msg = "NULL pointer dereference";
} else {
- if (kfence_handle_page_fault(addr, is_write_fault(fsr), regs))
+ if (is_translation_fault(fsr) &&
+ kfence_handle_page_fault(addr, is_write_fault(fsr), regs))
return;

msg = "paging request";
@@ -208,7 +222,7 @@ static inline bool is_permission_fault(u
{
int fs = fsr_fs(fsr);
#ifdef CONFIG_ARM_LPAE
- if ((fs & FS_PERM_NOLL_MASK) == FS_PERM_NOLL)
+ if ((fs & FS_MMU_NOLL_MASK) == FS_PERM_NOLL)
return true;
#else
if (fs == FS_L1_PERM || fs == FS_L2_PERM)
--- a/arch/arm/mm/fault.h
+++ b/arch/arm/mm/fault.h
@@ -14,8 +14,9 @@

#ifdef CONFIG_ARM_LPAE
#define FSR_FS_AEA 17
+#define FS_TRANS_NOLL 0x4
#define FS_PERM_NOLL 0xC
-#define FS_PERM_NOLL_MASK 0x3C
+#define FS_MMU_NOLL_MASK 0x3C

static inline int fsr_fs(unsigned int fsr)
{
@@ -23,8 +24,10 @@ static inline int fsr_fs(unsigned int fs
}
#else
#define FSR_FS_AEA 22
-#define FS_L1_PERM 0xD
-#define FS_L2_PERM 0xF
+#define FS_L1_TRANS 0x5
+#define FS_L2_TRANS 0x7
+#define FS_L1_PERM 0xD
+#define FS_L2_PERM 0xF

static inline int fsr_fs(unsigned int fsr)
{