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Diffstat (limited to 'arch/arm64/mm/fault.c')
-rw-r--r--arch/arm64/mm/fault.c87
1 files changed, 73 insertions, 14 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 95df28bc875f..5954881a35ac 100644
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -81,6 +81,56 @@ void show_pte(struct mm_struct *mm, unsigned long addr)
printk("\n");
}
+#ifdef CONFIG_ARM64_HW_AFDBM
+/*
+ * This function sets the access flags (dirty, accessed), as well as write
+ * permission, and only to a more permissive setting.
+ *
+ * It needs to cope with hardware update of the accessed/dirty state by other
+ * agents in the system and can safely skip the __sync_icache_dcache() call as,
+ * like set_pte_at(), the PTE is never changed from no-exec to exec here.
+ *
+ * Returns whether or not the PTE actually changed.
+ */
+int ptep_set_access_flags(struct vm_area_struct *vma,
+ unsigned long address, pte_t *ptep,
+ pte_t entry, int dirty)
+{
+ pteval_t old_pteval;
+ unsigned int tmp;
+
+ if (pte_same(*ptep, entry))
+ return 0;
+
+ /* only preserve the access flags and write permission */
+ pte_val(entry) &= PTE_AF | PTE_WRITE | PTE_DIRTY;
+
+ /*
+ * PTE_RDONLY is cleared by default in the asm below, so set it in
+ * back if necessary (read-only or clean PTE).
+ */
+ if (!pte_write(entry) || !dirty)
+ pte_val(entry) |= PTE_RDONLY;
+
+ /*
+ * Setting the flags must be done atomically to avoid racing with the
+ * hardware update of the access/dirty state.
+ */
+ asm volatile("// ptep_set_access_flags\n"
+ " prfm pstl1strm, %2\n"
+ "1: ldxr %0, %2\n"
+ " and %0, %0, %3 // clear PTE_RDONLY\n"
+ " orr %0, %0, %4 // set flags\n"
+ " stxr %w1, %0, %2\n"
+ " cbnz %w1, 1b\n"
+ : "=&r" (old_pteval), "=&r" (tmp), "+Q" (pte_val(*ptep))
+ : "L" (~PTE_RDONLY), "r" (pte_val(entry)));
+
+ flush_tlb_fix_spurious_fault(vma, address);
+ return 1;
+}
+#endif
+
/*
* The kernel tried to access some page that wasn't present.
*/
@@ -212,10 +262,6 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr,
tsk = current;
mm = tsk->mm;
- /* Enable interrupts if they were enabled in the parent context. */
- if (interrupts_enabled(regs))
- local_irq_enable();
-
/*
* If we're in an interrupt or have no user context, we must not take
* the fault.
@@ -555,20 +601,33 @@ asmlinkage int __exception do_debug_exception(unsigned long addr,
{
const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
struct siginfo info;
+ int rv;
- if (!inf->fn(addr, esr, regs))
- return 1;
+ /*
+ * Tell lockdep we disabled irqs in entry.S. Do nothing if they were
+ * already disabled to preserve the last enabled/disabled addresses.
+ */
+ if (interrupts_enabled(regs))
+ trace_hardirqs_off();
- pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
- inf->name, esr, addr);
+ if (!inf->fn(addr, esr, regs)) {
+ rv = 1;
+ } else {
+ pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
+ inf->name, esr, addr);
+
+ info.si_signo = inf->sig;
+ info.si_errno = 0;
+ info.si_code = inf->code;
+ info.si_addr = (void __user *)addr;
+ arm64_notify_die("", regs, &info, 0);
+ rv = 0;
+ }
- info.si_signo = inf->sig;
- info.si_errno = 0;
- info.si_code = inf->code;
- info.si_addr = (void __user *)addr;
- arm64_notify_die("", regs, &info, 0);
+ if (interrupts_enabled(regs))
+ trace_hardirqs_on();
- return 0;
+ return rv;
}
#ifdef CONFIG_ARM64_PAN