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-rw-r--r--arch/arm/net/bpf_jit_32.c6
-rw-r--r--arch/arm/net/bpf_jit_32.h14
2 files changed, 17 insertions, 3 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c
index 6b45f649eff0..e1268f905026 100644
--- a/arch/arm/net/bpf_jit_32.c
+++ b/arch/arm/net/bpf_jit_32.c
@@ -16,6 +16,7 @@
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/if_vlan.h>
+
#include <asm/cacheflush.h>
#include <asm/hwcap.h>
#include <asm/opcodes.h>
@@ -175,11 +176,10 @@ static inline bool is_load_to_a(u16 inst)
static void jit_fill_hole(void *area, unsigned int size)
{
- /* Insert illegal UND instructions. */
- u32 *ptr, fill_ins = 0xe7ffffff;
+ u32 *ptr;
/* We are guaranteed to have aligned memory. */
for (ptr = area; size >= sizeof(u32); size -= sizeof(u32))
- *ptr++ = fill_ins;
+ *ptr++ = __opcode_to_mem_arm(ARM_INST_UDF);
}
static void build_prologue(struct jit_ctx *ctx)
diff --git a/arch/arm/net/bpf_jit_32.h b/arch/arm/net/bpf_jit_32.h
index afb84621ff6f..b2d7d92859d3 100644
--- a/arch/arm/net/bpf_jit_32.h
+++ b/arch/arm/net/bpf_jit_32.h
@@ -114,6 +114,20 @@
#define ARM_INST_UMULL 0x00800090
+/*
+ * Use a suitable undefined instruction to use for ARM/Thumb2 faulting.
+ * We need to be careful not to conflict with those used by other modules
+ * (BUG, kprobes, etc) and the register_undef_hook() system.
+ *
+ * The ARM architecture reference manual guarantees that the following
+ * instruction space will produce an undefined instruction exception on
+ * all CPUs:
+ *
+ * ARM: xxxx 0111 1111 xxxx xxxx xxxx 1111 xxxx ARMv7-AR, section A5.4
+ * Thumb: 1101 1110 xxxx xxxx ARMv7-M, section A5.2.6
+ */
+#define ARM_INST_UDF 0xe7fddef1
+
/* register */
#define _AL3_R(op, rd, rn, rm) ((op ## _R) | (rd) << 12 | (rn) << 16 | (rm))
/* immediate */