From: Ira Weiny
When only user space pkeys are enabled faulting within the kernel was an
unexpected condition which should never happen, therefore a WARN_ON was
added to the kernel fault handler to detect if it ever did. Now that
PKS can be enabled this is no longer the case.
Report a Pkey fault with a normal splat and add the PKRS state to the
fault splat text. Note the PKS register is reset during an exception
therefore the saved PKRS value from before the beginning of the
exception is passed down.
If PKS is not enabled, or not active, maintain the WARN_ON_ONCE() from
before.
Because each fault has its own state the pkrs information will be
correctly reported even if a fault 'faults'.
Suggested-by: Andy Lutomirski
Signed-off-by: Ira Weiny
---
arch/x86/mm/fault.c | 59 ++---
1 file changed, 34 insertions(+), 25 deletions(-)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index e55bc4bff389..ee761c993f58 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -504,7 +504,8 @@ static void show_ldttss(const struct desc_ptr *gdt, const
char *name, u16 index)
}
static void
-show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long
address)
+show_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long
address,
+ irqentry_state_t *irq_state)
{
if (!oops_may_print())
return;
@@ -548,6 +549,11 @@ show_fault_oops(struct pt_regs *regs, unsigned long
error_code, unsigned long ad
(error_code & X86_PF_PK)? "protection keys violation" :
"permissions violation");
+#ifdef CONFIG_ARCH_HAS_SUPERVISOR_PKEYS
+ if (irq_state && (error_code & X86_PF_PK))
+ pr_alert("PKRS: 0x%x\n", irq_state->pkrs);
+#endif
+
if (!(error_code & X86_PF_USER) && user_mode(regs)) {
struct desc_ptr idt, gdt;
u16 ldtr, tr;
@@ -626,7 +632,8 @@ static void set_signal_archinfo(unsigned long address,
static noinline void
no_context(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, int signal, int si_code)
+ unsigned long address, int signal, int si_code,
+ irqentry_state_t *irq_state)
{
struct task_struct *tsk = current;
unsigned long flags;
@@ -732,7 +739,7 @@ no_context(struct pt_regs *regs, unsigned long error_code,
*/
flags = oops_begin();
- show_fault_oops(regs, error_code, address);
+ show_fault_oops(regs, error_code, address, irq_state);
if (task_stack_end_corrupted(tsk))
printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
@@ -785,7 +792,8 @@ static bool is_vsyscall_vaddr(unsigned long vaddr)
static void
__bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
- unsigned long address, u32 pkey, int si_code)
+ unsigned long address, u32 pkey, int si_code,
+ irqentry_state_t *state)
{
struct task_struct *tsk = current;
@@ -832,14 +840,14 @@ __bad_area_nosemaphore(struct pt_regs *regs, unsigned
long error_code,
if (is_f00f_bug(regs, address))
return;
- no_context(regs, error_code, address, SIGSEGV, si_code);
+ no_context(regs, error_code, address, SIGSEGV, si_code, state);
}
static noinline void
bad_area_nosemaphore(struct pt_regs *regs, unsigned long error_code,
-unsigned long address)
+unsigned long address, irqentry_state_t *state)
{
- __bad_area_nosemaphore(regs, error_code, address, 0, SEGV_MAPERR);
+ __bad_area_nosemaphore(regs, error_code, address, 0, SEGV_MAPERR,
state);
}
static void
@@ -853,7 +861,7 @@ __bad_area(struct pt_regs *regs, unsigned long error_code,
*/
mmap_read_unlock(mm);
- __bad_area_nosemaphore(regs, error_code, address, pkey, si_code);
+ __bad_area_nosemaphore(regs, error_code, address, pkey, si_code, NULL);
}
static noinline void
@@ -923,7 +931,7 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code,
unsigned long address,
{
/* Kernel mode? Handle exceptions or die: */
if (!(error_code & X86_PF_USER)) {
- no_context(regs, error_code, address, SIGBUS, BUS_ADRERR);
+ no_context(regs, error_code, address, SIGBUS, BUS_ADRERR, NULL);
return;
}
@@ -957,7 +965,7 @@ mm_fault_error(struct pt_regs *regs, unsigned long
error_code,
unsigned long address, vm_fault_t fault)
{
if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) {
- no_context(regs, error_code, address, 0, 0);
+ no_context(regs, error_code, address, 0, 0, NULL);
return;
}
@@ -965,7 +973,7 @@ mm_fault_error(struct pt_regs *regs, unsigned long
error_code,