From: Will Deacon <will@kernel.org>
Date: Mon, 29 Jul 2019 11:06:17 +0100
Subject: arm64: compat: Allow single-byte watchpoints on all addresses
Git-commit: 849adec41203ac5837c40c2d7e08490ffdef3c2c
Patch-mainline: v5.3-rc3
References: git-fixes

Commit d968d2b801d8 ("ARM: 7497/1: hw_breakpoint: allow single-byte
watchpoints on all addresses") changed the validation requirements for
hardware watchpoints on arch/arm/. Update our compat layer to implement
the same relaxation.

Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Ivan T. Ivanov <iivanov@suse.de>
---
 arch/arm64/kernel/hw_breakpoint.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/arch/arm64/kernel/hw_breakpoint.c
+++ b/arch/arm64/kernel/hw_breakpoint.c
@@ -555,6 +555,10 @@ int arch_validate_hwbkpt_settings(struct
 			/* Allow halfword watchpoints and breakpoints. */
 			if (info->ctrl.len == ARM_BREAKPOINT_LEN_2)
 				break;
+		case 3:
+			/* Allow single byte watchpoint. */
+			if (info->ctrl.len == ARM_BREAKPOINT_LEN_1)
+				break;
 		default:
 			return -EINVAL;
 		}