ARM: 6268/1: ARMv6K and ARMv7 use fault statuses 3 and 6 as Access Flag fault

Statuses 3 (0b00011) and 6 (0x00110) of DFSR are Access Flags faults on
ARMv6K and ARMv7. Let's patch fsr_info[] at runtime if we are on ARMv7
or later.

Unfortunately, we don't have runtime check for 'K' extension, so we
can't check for it.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mm/alignment.c

@@ -926,8 +926,18 @@ static int __init alignment_init(void)
 
 	hook_fault_code(1, do_alignment, SIGBUS, BUS_ADRALN,
 			"alignment exception");
-	hook_fault_code(3, do_alignment, SIGBUS, BUS_ADRALN,
-			"alignment exception");
+
+	/*
+	 * ARMv6K and ARMv7 use fault status 3 (0b00011) as Access Flag section
+	 * fault, not as alignment error.
+	 *
+	 * TODO: handle ARMv6K properly. Runtime check for 'K' extension is
+	 * needed.
+	 */
+	if (cpu_architecture() <= CPU_ARCH_ARMv6) {
+		hook_fault_code(3, do_alignment, SIGBUS, BUS_ADRALN,
+				"alignment exception");
+	}
 
 	return 0;
 }

arch/arm/mm/fault.c

@@ -607,6 +607,17 @@ static int __init exceptions_init(void)
 				"I-cache maintenance fault");
 	}
 
+	if (cpu_architecture() >= CPU_ARCH_ARMv7) {
+		/*
+		 * TODO: Access flag faults introduced in ARMv6K.
+		 * Runtime check for 'K' extension is needed
+		 */
+		hook_fault_code(3, do_bad, SIGSEGV, SEGV_MAPERR,
+				"section access flag fault");
+		hook_fault_code(6, do_bad, SIGSEGV, SEGV_MAPERR,
+				"section access flag fault");
+	}
+
 	return 0;
 }