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

Pull arm64 updates from Catalin Marinas:

 - struct thread_info moved off-stack (also touching
   include/linux/thread_info.h and include/linux/restart_block.h)

 - cpus_have_cap() reworked to avoid __builtin_constant_p() for static
   key use (also touching drivers/irqchip/irq-gic-v3.c)

 - uprobes support (currently only for native 64-bit tasks)

 - Emulation of kernel Privileged Access Never (PAN) using TTBR0_EL1
   switching to a reserved page table

 - CPU capacity information passing via DT or sysfs (used by the
   scheduler)

 - support for systems without FP/SIMD (IOW, kernel avoids touching
   these registers; there is no soft-float ABI, nor kernel emulation for
   AArch64 FP/SIMD)

 - handling of hardware watchpoint with unaligned addresses, varied
   lengths and offsets from base

 - use of the page table contiguous hint for kernel mappings

 - hugetlb fixes for sizes involving the contiguous hint

 - remove unnecessary I-cache invalidation in flush_cache_range()

 - CNTHCTL_EL2 access fix for CPUs with VHE support (ARMv8.1)

 - boot-time checks for writable+executable kernel mappings

 - simplify asm/opcodes.h and avoid including the 32-bit ARM counterpart
   and make the arm64 kernel headers self-consistent (Xen headers patch
   merged separately)

 - Workaround for broken .inst support in certain binutils versions

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (60 commits)
  arm64: Disable PAN on uaccess_enable()
  arm64: Work around broken .inst when defective gas is detected
  arm64: Add detection code for broken .inst support in binutils
  arm64: Remove reference to asm/opcodes.h
  arm64: Get rid of asm/opcodes.h
  arm64: smp: Prevent raw_smp_processor_id() recursion
  arm64: head.S: Fix CNTHCTL_EL2 access on VHE system
  arm64: Remove I-cache invalidation from flush_cache_range()
  arm64: Enable HIBERNATION in defconfig
  arm64: Enable CONFIG_ARM64_SW_TTBR0_PAN
  arm64: xen: Enable user access before a privcmd hvc call
  arm64: Handle faults caused by inadvertent user access with PAN enabled
  arm64: Disable TTBR0_EL1 during normal kernel execution
  arm64: Introduce uaccess_{disable,enable} functionality based on TTBR0_EL1
  arm64: Factor out TTBR0_EL1 post-update workaround into a specific asm macro
  arm64: Factor out PAN enabling/disabling into separate uaccess_* macros
  arm64: Update the synchronous external abort fault description
  selftests: arm64: add test for unaligned/inexact watchpoint handling
  arm64: Allow hw watchpoint of length 3,5,6 and 7
  arm64: hw_breakpoint: Handle inexact watchpoint addresses
  ...

1 files changed, 23 insertions, 17 deletions

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 73ae90ef434c..605df76f0a06 100644
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -226,6 +226,8 @@ static void send_user_sigtrap(int si_code)
 static int single_step_handler(unsigned long addr, unsigned int esr,
 			       struct pt_regs *regs)
 {
+	bool handler_found = false;
+
 	/*
 	 * If we are stepping a pending breakpoint, call the hw_breakpoint
 	 * handler first.
@@ -233,7 +235,14 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
 	if (!reinstall_suspended_bps(regs))
 		return 0;
 
-	if (user_mode(regs)) {
+#ifdef	CONFIG_KPROBES
+	if (kprobe_single_step_handler(regs, esr) == DBG_HOOK_HANDLED)
+		handler_found = true;
+#endif
+	if (!handler_found && call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
+		handler_found = true;
+
+	if (!handler_found && user_mode(regs)) {
 		send_user_sigtrap(TRAP_TRACE);
 
 		/*
@@ -243,15 +252,8 @@ static int single_step_handler(unsigned long addr, unsigned int esr,
 		 * to the active-not-pending state).
 		 */
 		user_rewind_single_step(current);
-	} else {
-#ifdef	CONFIG_KPROBES
-		if (kprobe_single_step_handler(regs, esr) == DBG_HOOK_HANDLED)
-			return 0;
-#endif
-		if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED)
-			return 0;
-
-		pr_warning("Unexpected kernel single-step exception at EL1\n");
+	} else if (!handler_found) {
+		pr_warn("Unexpected kernel single-step exception at EL1\n");
 		/*
 		 * Re-enable stepping since we know that we will be
 		 * returning to regs.
@@ -304,16 +306,20 @@ NOKPROBE_SYMBOL(call_break_hook);
 static int brk_handler(unsigned long addr, unsigned int esr,
 		       struct pt_regs *regs)
 {
-	if (user_mode(regs)) {
-		send_user_sigtrap(TRAP_BRKPT);
-	}
+	bool handler_found = false;
+
 #ifdef	CONFIG_KPROBES
-	else if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) {
-		if (kprobe_breakpoint_handler(regs, esr) != DBG_HOOK_HANDLED)
-			return -EFAULT;
+	if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) {
+		if (kprobe_breakpoint_handler(regs, esr) == DBG_HOOK_HANDLED)
+			handler_found = true;
 	}
 #endif
-	else if (call_break_hook(regs, esr) != DBG_HOOK_HANDLED) {
+	if (!handler_found && call_break_hook(regs, esr) == DBG_HOOK_HANDLED)
+		handler_found = true;
+
+	if (!handler_found && user_mode(regs)) {
+		send_user_sigtrap(TRAP_BRKPT);
+	} else if (!handler_found) {
 		pr_warn("Unexpected kernel BRK exception at EL1\n");
 		return -EFAULT;
 	}