diff options
| -rw-r--r-- | arch/x86/net/bpf_jit_comp.c | 66 |
1 files changed, 53 insertions, 13 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index 6b2d23ea3590..fe04a04dab8e 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -110,11 +110,16 @@ static void bpf_flush_icache(void *start, void *end) ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset) /* pick a register outside of BPF range for JIT internal work */ -#define AUX_REG (MAX_BPF_REG + 1) +#define AUX_REG (MAX_BPF_JIT_REG + 1) -/* the following table maps BPF registers to x64 registers. - * x64 register r12 is unused, since if used as base address register - * in load/store instructions, it always needs an extra byte of encoding +/* The following table maps BPF registers to x64 registers. + * + * x64 register r12 is unused, since if used as base address + * register in load/store instructions, it always needs an + * extra byte of encoding and is callee saved. + * + * r9 caches skb->len - skb->data_len + * r10 caches skb->data, and used for blinding (if enabled) */ static const int reg2hex[] = { [BPF_REG_0] = 0, /* rax */ @@ -128,6 +133,7 @@ static const int reg2hex[] = { [BPF_REG_8] = 6, /* r14 callee saved */ [BPF_REG_9] = 7, /* r15 callee saved */ [BPF_REG_FP] = 5, /* rbp readonly */ + [BPF_REG_AX] = 2, /* r10 temp register */ [AUX_REG] = 3, /* r11 temp register */ }; @@ -141,7 +147,8 @@ static bool is_ereg(u32 reg) BIT(AUX_REG) | BIT(BPF_REG_7) | BIT(BPF_REG_8) | - BIT(BPF_REG_9)); + BIT(BPF_REG_9) | + BIT(BPF_REG_AX)); } /* add modifiers if 'reg' maps to x64 registers r8..r15 */ @@ -182,6 +189,7 @@ static void jit_fill_hole(void *area, unsigned int size) struct jit_context { int cleanup_addr; /* epilogue code offset */ bool seen_ld_abs; + bool seen_ax_reg; }; /* maximum number of bytes emitted while JITing one eBPF insn */ @@ -345,6 +353,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, struct bpf_insn *insn = bpf_prog->insnsi; int insn_cnt = bpf_prog->len; bool seen_ld_abs = ctx->seen_ld_abs | (oldproglen == 0); + bool seen_ax_reg = ctx->seen_ax_reg | (oldproglen == 0); bool seen_exit = false; u8 temp[BPF_MAX_INSN_SIZE + BPF_INSN_SAFETY]; int i, cnt = 0; @@ -367,6 +376,9 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image, int ilen; u8 *func; + if (dst_reg == BPF_REG_AX || src_reg == BPF_REG_AX) + ctx->seen_ax_reg = seen_ax_reg = true; + switch (insn->code) { /* ALU */ case BPF_ALU | BPF_ADD | BPF_X: @@ -1002,6 +1014,10 @@ common_load: * sk_load_* helpers also use %r10 and %r9d. * See bpf_jit.S */ + if (seen_ax_reg) + /* r10 = skb->data, mov %r10, off32(%rbx) */ + EMIT3_off32(0x4c, 0x8b, 0x93, + offsetof(struct sk_buff, data)); EMIT1_off32(0xE8, jmp_offset); /* call */ break; @@ -1076,19 +1092,34 @@ void bpf_jit_compile(struct bpf_prog *prog) struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) { struct bpf_binary_header *header = NULL; + struct bpf_prog *tmp, *orig_prog = prog; int proglen, oldproglen = 0; struct jit_context ctx = {}; + bool tmp_blinded = false; u8 *image = NULL; int *addrs; int pass; int i; if (!bpf_jit_enable) - return prog; + return orig_prog; + + tmp = bpf_jit_blind_constants(prog); + /* If blinding was requested and we failed during blinding, + * we must fall back to the interpreter. + */ + if (IS_ERR(tmp)) + return orig_prog; + if (tmp != prog) { + tmp_blinded = true; + prog = tmp; + } addrs = kmalloc(prog->len * sizeof(*addrs), GFP_KERNEL); - if (!addrs) - return prog; + if (!addrs) { + prog = orig_prog; + goto out; + } /* Before first pass, make a rough estimation of addrs[] * each bpf instruction is translated to less than 64 bytes @@ -1110,21 +1141,25 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) image = NULL; if (header) bpf_jit_binary_free(header); - goto out; + prog = orig_prog; + goto out_addrs; } if (image) { if (proglen != oldproglen) { pr_err("bpf_jit: proglen=%d != oldproglen=%d\n", proglen, oldproglen); - goto out; + prog = orig_prog; + goto out_addrs; } break; } if (proglen == oldproglen) { header = bpf_jit_binary_alloc(proglen, &image, 1, jit_fill_hole); - if (!header) - goto out; + if (!header) { + prog = orig_prog; + goto out_addrs; + } } oldproglen = proglen; } @@ -1138,8 +1173,13 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) prog->bpf_func = (void *)image; prog->jited = 1; } -out: + +out_addrs: kfree(addrs); +out: + if (tmp_blinded) + bpf_jit_prog_release_other(prog, prog == orig_prog ? + tmp : orig_prog); return prog; } |