diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 64 |
1 files changed, 46 insertions, 18 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 2e586f579945..f438bd3b7689 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -203,8 +203,9 @@ struct jit_context { /* Maximum number of bytes emitted while JITing one eBPF insn */ #define BPF_MAX_INSN_SIZE 128 #define BPF_INSN_SAFETY 64 -/* number of bytes emit_call() needs to generate call instruction */ -#define X86_CALL_SIZE 5 + +/* Number of bytes emit_patch() needs to generate instructions */ +#define X86_PATCH_SIZE 5 #define PROLOGUE_SIZE 25 @@ -215,7 +216,7 @@ struct jit_context { static void emit_prologue(u8 **pprog, u32 stack_depth, bool ebpf_from_cbpf) { u8 *prog = *pprog; - int cnt = X86_CALL_SIZE; + int cnt = X86_PATCH_SIZE; /* BPF trampoline can be made to work without these nops, * but let's waste 5 bytes for now and optimize later @@ -480,64 +481,91 @@ static void emit_stx(u8 **pprog, u32 size, u32 dst_reg, u32 src_reg, int off) *pprog = prog; } -static int emit_call(u8 **pprog, void *func, void *ip) +static int emit_patch(u8 **pprog, void *func, void *ip, u8 opcode) { u8 *prog = *pprog; int cnt = 0; s64 offset; - offset = func - (ip + X86_CALL_SIZE); + offset = func - (ip + X86_PATCH_SIZE); if (!is_simm32(offset)) { pr_err("Target call %p is out of range\n", func); return -EINVAL; } - EMIT1_off32(0xE8, offset); + EMIT1_off32(opcode, offset); *pprog = prog; return 0; } +static int emit_call(u8 **pprog, void *func, void *ip) +{ + return emit_patch(pprog, func, ip, 0xE8); +} + +static int emit_jump(u8 **pprog, void *func, void *ip) +{ + return emit_patch(pprog, func, ip, 0xE9); +} + int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t, void *old_addr, void *new_addr) { - u8 old_insn[X86_CALL_SIZE] = {}; - u8 new_insn[X86_CALL_SIZE] = {}; + int (*emit_patch_fn)(u8 **pprog, void *func, void *ip); + u8 old_insn[X86_PATCH_SIZE] = {}; + u8 new_insn[X86_PATCH_SIZE] = {}; u8 *prog; int ret; if (!is_kernel_text((long)ip) && !is_bpf_text_address((long)ip)) - /* BPF trampoline in modules is not supported */ + /* BPF poking in modules is not supported */ return -EINVAL; + switch (t) { + case BPF_MOD_NOP_TO_CALL ... BPF_MOD_CALL_TO_NOP: + emit_patch_fn = emit_call; + break; + case BPF_MOD_NOP_TO_JUMP ... BPF_MOD_JUMP_TO_NOP: + emit_patch_fn = emit_jump; + break; + default: + return -ENOTSUPP; + } + if (old_addr) { prog = old_insn; - ret = emit_call(&prog, old_addr, (void *)ip); + ret = emit_patch_fn(&prog, old_addr, (void *)ip); if (ret) return ret; } if (new_addr) { prog = new_insn; - ret = emit_call(&prog, new_addr, (void *)ip); + ret = emit_patch_fn(&prog, new_addr, (void *)ip); if (ret) return ret; } + ret = -EBUSY; mutex_lock(&text_mutex); switch (t) { case BPF_MOD_NOP_TO_CALL: - if (memcmp(ip, ideal_nops[NOP_ATOMIC5], X86_CALL_SIZE)) + case BPF_MOD_NOP_TO_JUMP: + if (memcmp(ip, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE)) goto out; - text_poke_bp(ip, new_insn, X86_CALL_SIZE, NULL); + text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL); break; case BPF_MOD_CALL_TO_CALL: - if (memcmp(ip, old_insn, X86_CALL_SIZE)) + case BPF_MOD_JUMP_TO_JUMP: + if (memcmp(ip, old_insn, X86_PATCH_SIZE)) goto out; - text_poke_bp(ip, new_insn, X86_CALL_SIZE, NULL); + text_poke_bp(ip, new_insn, X86_PATCH_SIZE, NULL); break; case BPF_MOD_CALL_TO_NOP: - if (memcmp(ip, old_insn, X86_CALL_SIZE)) + case BPF_MOD_JUMP_TO_NOP: + if (memcmp(ip, old_insn, X86_PATCH_SIZE)) goto out; - text_poke_bp(ip, ideal_nops[NOP_ATOMIC5], X86_CALL_SIZE, NULL); + text_poke_bp(ip, ideal_nops[NOP_ATOMIC5], X86_PATCH_SIZE, + NULL); break; } ret = 0; @@ -1394,7 +1422,7 @@ int arch_prepare_bpf_trampoline(void *image, struct btf_func_model *m, u32 flags /* skip patched call instruction and point orig_call to actual * body of the kernel function. */ - orig_call += X86_CALL_SIZE; + orig_call += X86_PATCH_SIZE; prog = image; |