With hash translation use DSISR_KEYFAULT to identify a wrong access.
With Radix we look at the AMR value and type of fault.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.ibm.com>
---
arch/powerpc/include/asm/book3s/64/kup.h | 7 ------
arch/powerpc/mm/fault.c | 27 +++++++++++++++++++++++-
2 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/kup.h
b/arch/powerpc/include/asm/book3s/64/kup.h
index 590c1d9455d1..f564d909e195 100644
--- a/arch/powerpc/include/asm/book3s/64/kup.h
+++ b/arch/powerpc/include/asm/book3s/64/kup.h
@@ -280,13 +280,6 @@ static inline void restore_user_access(unsigned long flags)
set_kuap(flags);
}
-static inline bool
-bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool is_write)
-{
- return WARN(mmu_has_feature(MMU_FTR_KUAP) &&
- (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE :
AMR_KUAP_BLOCK_READ)),
- "Bug: %s fault blocked by AMR!", is_write ? "Write" :
"Read");
-}
#else /* CONFIG_PPC_KUAP */
static inline void kuap_restore_amr(struct pt_regs *regs)
{
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 84af6c8eecf7..4f866b11512c 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -198,6 +198,31 @@ static int mm_fault_error(struct pt_regs *regs, unsigned
long addr,
return 0;
}
+#define RADIX_KUAP_BLOCK_READ UL(0x4000000000000000)
+#define RADIX_KUAP_BLOCK_WRITE UL(0x8000000000000000)
+
+static bool bad_kuap_fault(struct pt_regs *regs, unsigned long address,
+ bool is_write, unsigned long error_code)
+{
+ if (!mmu_has_feature(MMU_FTR_KUAP))
+ return false;
+
+ if (radix_enabled()) {
+ /*
+ * Will be a storage protection fault.
+ * Only check the details of AMR[0]
+ */
+ return WARN((regs->kuap & (is_write ? RADIX_KUAP_BLOCK_WRITE :
RADIX_KUAP_BLOCK_READ)),
+ "Bug: %s fault blocked by AMR!", is_write ? "Write"
: "Read");
+ }
+ /*
+ * We don't want to WARN here because userspace can setup
+ * keys such that a kernel access to user address can cause
+ * fault
+ */
+ return !!(error_code & DSISR_KEYFAULT);
+}
+
/* Is this a bad kernel fault ? */
static bool bad_kernel_fault(struct pt_regs *regs, unsigned long error_code,
unsigned long address, bool is_write)
@@ -233,7 +258,7 @@ static bool bad_kernel_fault(struct pt_regs *regs, unsigned
long error_code,
// Read/write fault in a valid region (the exception table search passed
// above), but blocked by KUAP is bad, it can never succeed.
- if (bad_kuap_fault(regs, address, is_write))
+ if (bad_kuap_fault(regs, address, is_write, error_code))
return true;
// What's left? Kernel fault on user in well defined regions (extable
--
2.25.3
