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Diffstat (limited to 'arch/arm64/mm/fault.c')
-rw-r--r--arch/arm64/mm/fault.c55
1 files changed, 36 insertions, 19 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 1b35b8bddbfb..37b95dff0b07 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -174,12 +174,33 @@ static bool is_el1_instruction_abort(unsigned int esr)
return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_CUR;
}
+static inline bool is_permission_fault(unsigned int esr, struct pt_regs *regs,
+ unsigned long addr)
+{
+ unsigned int ec = ESR_ELx_EC(esr);
+ unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
+
+ if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR)
+ return false;
+
+ if (fsc_type == ESR_ELx_FSC_PERM)
+ return true;
+
+ if (addr < USER_DS && system_uses_ttbr0_pan())
+ return fsc_type == ESR_ELx_FSC_FAULT &&
+ (regs->pstate & PSR_PAN_BIT);
+
+ return false;
+}
+
/*
* The kernel tried to access some page that wasn't present.
*/
static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
unsigned int esr, struct pt_regs *regs)
{
+ const char *msg;
+
/*
* Are we prepared to handle this kernel fault?
* We are almost certainly not prepared to handle instruction faults.
@@ -191,9 +212,20 @@ static void __do_kernel_fault(struct mm_struct *mm, unsigned long addr,
* No handler, we'll have to terminate things with extreme prejudice.
*/
bust_spinlocks(1);
- pr_alert("Unable to handle kernel %s at virtual address %08lx\n",
- (addr < PAGE_SIZE) ? "NULL pointer dereference" :
- "paging request", addr);
+
+ if (is_permission_fault(esr, regs, addr)) {
+ if (esr & ESR_ELx_WNR)
+ msg = "write to read-only memory";
+ else
+ msg = "read from unreadable memory";
+ } else if (addr < PAGE_SIZE) {
+ msg = "NULL pointer dereference";
+ } else {
+ msg = "paging request";
+ }
+
+ pr_alert("Unable to handle kernel %s at virtual address %08lx\n", msg,
+ addr);
show_pte(mm, addr);
die("Oops", regs, esr);
@@ -287,21 +319,6 @@ out:
return fault;
}
-static inline bool is_permission_fault(unsigned int esr, struct pt_regs *regs)
-{
- unsigned int ec = ESR_ELx_EC(esr);
- unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE;
-
- if (ec != ESR_ELx_EC_DABT_CUR && ec != ESR_ELx_EC_IABT_CUR)
- return false;
-
- if (system_uses_ttbr0_pan())
- return fsc_type == ESR_ELx_FSC_FAULT &&
- (regs->pstate & PSR_PAN_BIT);
- else
- return fsc_type == ESR_ELx_FSC_PERM;
-}
-
static bool is_el0_instruction_abort(unsigned int esr)
{
return ESR_ELx_EC(esr) == ESR_ELx_EC_IABT_LOW;
@@ -339,7 +356,7 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
mm_flags |= FAULT_FLAG_WRITE;
}
- if (addr < USER_DS && is_permission_fault(esr, regs)) {
+ if (addr < USER_DS && is_permission_fault(esr, regs, addr)) {
/* regs->orig_addr_limit may be 0 if we entered from EL0 */
if (regs->orig_addr_limit == KERNEL_DS)
die("Accessing user space memory with fs=KERNEL_DS", regs, esr);