Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Will Deacon:
 "Unfortunately, we still have a number of outstanding issues so there
  will be more fixes to come, but this lot are a good start.

   - Fix handling of watchpoints triggered by uaccess routines

   - Fix initialisation of gigantic pages for CMA buffers

   - Raise minimum clang version for BTI to avoid miscompilation

   - Fix data race in SVE vector length configuration code

   - Ensure address tags are ignored in kern_addr_valid()

   - Dump register state on fatal BTI exception

   - kexec_file() cleanup to use struct_size() macro"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: hw_breakpoint: Don't invoke overflow handler on uaccess watchpoints
  arm64: kexec_file: Use struct_size() in kmalloc()
  arm64: mm: reserve hugetlb CMA after numa_init
  arm64: bti: Require clang >= 10.0.1 for in-kernel BTI support
  arm64: sve: Fix build failure when ARM64_SVE=y and SYSCTL=n
  arm64: pgtable: Clear the GP bit for non-executable kernel pages
  arm64: mm: reset address tag set by kasan sw tagging
  arm64: traps: Dump registers prior to panic() in bad_mode()
  arm64/sve: Eliminate data races on sve_default_vl
  docs/arm64: Fix typo'd #define in sve.rst
  arm64: remove TEXT_OFFSET randomization

1 files changed, 26 insertions, 18 deletions

diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c
index 0b727edf4104..af234a1e08b7 100644
--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -730,6 +730,27 @@ static u64 get_distance_from_watchpoint(unsigned long addr, u64 val,
 		return 0;
 }
 
+static int watchpoint_report(struct perf_event *wp, unsigned long addr,
+			     struct pt_regs *regs)
+{
+	int step = is_default_overflow_handler(wp);
+	struct arch_hw_breakpoint *info = counter_arch_bp(wp);
+
+	info->trigger = addr;
+
+	/*
+	 * If we triggered a user watchpoint from a uaccess routine, then
+	 * handle the stepping ourselves since userspace really can't help
+	 * us with this.
+	 */
+	if (!user_mode(regs) && info->ctrl.privilege == AARCH64_BREAKPOINT_EL0)
+		step = 1;
+	else
+		perf_bp_event(wp, regs);
+
+	return step;
+}
+
 static int watchpoint_handler(unsigned long addr, unsigned int esr,
 			      struct pt_regs *regs)
 {
@@ -739,7 +760,6 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
 	u64 val;
 	struct perf_event *wp, **slots;
 	struct debug_info *debug_info;
-	struct arch_hw_breakpoint *info;
 	struct arch_hw_breakpoint_ctrl ctrl;
 
 	slots = this_cpu_ptr(wp_on_reg);
@@ -777,25 +797,13 @@ static int watchpoint_handler(unsigned long addr, unsigned int esr,
 		if (dist != 0)
 			continue;
 
-		info = counter_arch_bp(wp);
-		info->trigger = addr;
-		perf_bp_event(wp, regs);
-
-		/* Do we need to handle the stepping? */
-		if (is_default_overflow_handler(wp))
-			step = 1;
+		step = watchpoint_report(wp, addr, regs);
 	}
-	if (min_dist > 0 && min_dist != -1) {
-		/* No exact match found. */
-		wp = slots[closest_match];
-		info = counter_arch_bp(wp);
-		info->trigger = addr;
-		perf_bp_event(wp, regs);
 
-		/* Do we need to handle the stepping? */
-		if (is_default_overflow_handler(wp))
-			step = 1;
-	}
+	/* No exact match found? */
+	if (min_dist > 0 && min_dist != -1)
+		step = watchpoint_report(slots[closest_match], addr, regs);
+
 	rcu_read_unlock();
 
 	if (!step)