Handle Data and Instruction exceptions caused by memory
protection-key.
The CPU will detect the key fault if the HPTE is already
programmed with the key.
However if the HPTE is not hashed, a key fault will not
be detected by the hardware. The software will detect
pkey violation in such a case.
Signed-off-by: Ram Pai <linux...@us.ibm.com>
---
arch/powerpc/mm/fault.c | 37 ++++++++++++++++++++++++++++++++-----
1 files changed, 32 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 4797d08..a16bc43 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -145,6 +145,23 @@ static noinline int bad_area(struct pt_regs *regs,
unsigned long address)
return __bad_area(regs, address, SEGV_MAPERR);
}
+static int bad_page_fault_exception(struct pt_regs *regs, unsigned long
address,
+ int si_code)
+{
+ int sig = SIGBUS;
+ int code = BUS_OBJERR;
+
+#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+ if (si_code & DSISR_KEYFAULT) {
+ sig = SIGSEGV;
+ code = SEGV_PKUERR;
+ }
+#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
+
+ _exception(sig, regs, code, address);
+ return 0;
+}
+
static int do_sigbus(struct pt_regs *regs, unsigned long address,
unsigned int fault)
{
@@ -391,11 +408,9 @@ static int __do_page_fault(struct pt_regs *regs, unsigned
long address,
return 0;
if (unlikely(page_fault_is_bad(error_code))) {
- if (is_user) {
- _exception(SIGBUS, regs, BUS_OBJERR, address);
- return 0;
- }
- return SIGBUS;
+ if (!is_user)
+ return SIGBUS;
+ return bad_page_fault_exception(regs, address, error_code);
}
/* Additional sanity check(s) */
@@ -492,6 +507,18 @@ static int __do_page_fault(struct pt_regs *regs, unsigned
long address,
if (unlikely(access_error(is_write, is_exec, vma)))
return bad_area(regs, address);
+#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+ if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
+ is_exec, 0))
+ return __bad_area(regs, address, SEGV_PKUERR);
+#endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
+
+
+ /* handle_mm_fault() needs to know if its a instruction access
+ * fault.
+ */
+ if (is_exec)
+ flags |= FAULT_FLAG_INSTRUCTION;
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
--
1.7.1
