diff options
| -rw-r--r-- | arch/arm/net/bpf_jit_32.c | 6 | ||||
| -rw-r--r-- | arch/arm/net/bpf_jit_32.h | 14 |
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 */ |