/* 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).
- */
+ /* set PTE_RDONLY if actual read-only or clean PTE */
if (!pte_write(entry) || !pte_sw_dirty(entry))
pte_val(entry) |= PTE_RDONLY;
/*
* Setting the flags must be done atomically to avoid racing with the
- * hardware update of the access/dirty state.
+ * hardware update of the access/dirty state. The PTE_RDONLY bit must
+ * be set to the most permissive (lowest value) of *ptep and entry
+ * (calculated as: a & b == ~(~a | ~b)).
*/
+ pte_val(entry) ^= PTE_RDONLY;
asm volatile("// ptep_set_access_flags\n"
" prfm pstl1strm, %2\n"
"1: ldxr %0, %2\n"
- " and %0, %0, %3 // clear PTE_RDONLY\n"
+ " eor %0, %0, %3 // negate PTE_RDONLY in *ptep\n"
" orr %0, %0, %4 // set flags\n"
+ " eor %0, %0, %3 // negate final PTE_RDONLY\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)));
+ : "L" (PTE_RDONLY), "r" (pte_val(entry)));
flush_tlb_fix_spurious_fault(vma, address);
return 1;
debug_fault_info[nr].name = name;
}
-asmlinkage int __exception do_debug_exception(unsigned long addr,
+asmlinkage int __exception do_debug_exception(unsigned long addr_if_watchpoint,
unsigned int esr,
struct pt_regs *regs)
{
const struct fault_info *inf = debug_fault_info + DBG_ESR_EVT(esr);
+ unsigned long pc = instruction_pointer(regs);
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_if_watchpoint, esr, regs)) {
+ rv = 1;
+ } else {
+ pr_alert("Unhandled debug exception: %s (0x%08x) at 0x%016lx\n",
+ inf->name, esr, pc);
+
+ info.si_signo = inf->sig;
+ info.si_errno = 0;
+ info.si_code = inf->code;
+ info.si_addr = (void __user *)pc;
+ 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