diff options
Diffstat (limited to 'arch/s390/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/s390/net/bpf_jit_comp.c | 77 |
1 files changed, 59 insertions, 18 deletions
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 2662fcc67..bee281f31 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -54,16 +54,17 @@ struct bpf_jit { #define SEEN_FUNC 16 /* calls C functions */ #define SEEN_TAIL_CALL 32 /* code uses tail calls */ #define SEEN_SKB_CHANGE 64 /* code changes skb data */ +#define SEEN_REG_AX 128 /* code uses constant blinding */ #define SEEN_STACK (SEEN_FUNC | SEEN_MEM | SEEN_SKB) /* * s390 registers */ -#define REG_W0 (__MAX_BPF_REG+0) /* Work register 1 (even) */ -#define REG_W1 (__MAX_BPF_REG+1) /* Work register 2 (odd) */ -#define REG_SKB_DATA (__MAX_BPF_REG+2) /* SKB data register */ -#define REG_L (__MAX_BPF_REG+3) /* Literal pool register */ -#define REG_15 (__MAX_BPF_REG+4) /* Register 15 */ +#define REG_W0 (MAX_BPF_JIT_REG + 0) /* Work register 1 (even) */ +#define REG_W1 (MAX_BPF_JIT_REG + 1) /* Work register 2 (odd) */ +#define REG_SKB_DATA (MAX_BPF_JIT_REG + 2) /* SKB data register */ +#define REG_L (MAX_BPF_JIT_REG + 3) /* Literal pool register */ +#define REG_15 (MAX_BPF_JIT_REG + 4) /* Register 15 */ #define REG_0 REG_W0 /* Register 0 */ #define REG_1 REG_W1 /* Register 1 */ #define REG_2 BPF_REG_1 /* Register 2 */ @@ -88,6 +89,8 @@ static const int reg2hex[] = { [BPF_REG_9] = 10, /* BPF stack pointer */ [BPF_REG_FP] = 13, + /* Register for blinding (shared with REG_SKB_DATA) */ + [BPF_REG_AX] = 12, /* SKB data pointer */ [REG_SKB_DATA] = 12, /* Work registers for s390x backend */ @@ -385,7 +388,7 @@ static void save_restore_regs(struct bpf_jit *jit, int op) /* * For SKB access %b1 contains the SKB pointer. For "bpf_jit.S" * we store the SKB header length on the stack and the SKB data - * pointer in REG_SKB_DATA. + * pointer in REG_SKB_DATA if BPF_REG_AX is not used. */ static void emit_load_skb_data_hlen(struct bpf_jit *jit) { @@ -397,9 +400,10 @@ static void emit_load_skb_data_hlen(struct bpf_jit *jit) offsetof(struct sk_buff, data_len)); /* stg %w1,ST_OFF_HLEN(%r0,%r15) */ EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15, STK_OFF_HLEN); - /* lg %skb_data,data_off(%b1) */ - EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0, - BPF_REG_1, offsetof(struct sk_buff, data)); + if (!(jit->seen & SEEN_REG_AX)) + /* lg %skb_data,data_off(%b1) */ + EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0, + BPF_REG_1, offsetof(struct sk_buff, data)); } /* @@ -487,6 +491,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i s32 imm = insn->imm; s16 off = insn->off; + if (dst_reg == BPF_REG_AX || src_reg == BPF_REG_AX) + jit->seen |= SEEN_REG_AX; switch (insn->code) { /* * BPF_MOV @@ -1188,7 +1194,7 @@ call_fn: /* * Implicit input: * BPF_REG_6 (R7) : skb pointer - * REG_SKB_DATA (R12): skb data pointer + * REG_SKB_DATA (R12): skb data pointer (if no BPF_REG_AX) * * Calculated input: * BPF_REG_2 (R3) : offset of byte(s) to fetch in skb @@ -1209,6 +1215,11 @@ call_fn: /* agfr %b2,%src (%src is s32 here) */ EMIT4(0xb9180000, BPF_REG_2, src_reg); + /* Reload REG_SKB_DATA if BPF_REG_AX is used */ + if (jit->seen & SEEN_REG_AX) + /* lg %skb_data,data_off(%b6) */ + EMIT6_DISP_LH(0xe3000000, 0x0004, REG_SKB_DATA, REG_0, + BPF_REG_6, offsetof(struct sk_buff, data)); /* basr %b5,%w1 (%b5 is call saved) */ EMIT2(0x0d00, BPF_REG_5, REG_W1); @@ -1262,37 +1273,62 @@ void bpf_jit_compile(struct bpf_prog *fp) /* * Compile eBPF program "fp" */ -void bpf_int_jit_compile(struct bpf_prog *fp) +struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) { + struct bpf_prog *tmp, *orig_fp = fp; struct bpf_binary_header *header; + bool tmp_blinded = false; struct bpf_jit jit; int pass; if (!bpf_jit_enable) - return; + return orig_fp; + + tmp = bpf_jit_blind_constants(fp); + /* + * If blinding was requested and we failed during blinding, + * we must fall back to the interpreter. + */ + if (IS_ERR(tmp)) + return orig_fp; + if (tmp != fp) { + tmp_blinded = true; + fp = tmp; + } + memset(&jit, 0, sizeof(jit)); jit.addrs = kcalloc(fp->len + 1, sizeof(*jit.addrs), GFP_KERNEL); - if (jit.addrs == NULL) - return; + if (jit.addrs == NULL) { + fp = orig_fp; + goto out; + } /* * Three initial passes: * - 1/2: Determine clobbered registers * - 3: Calculate program size and addrs arrray */ for (pass = 1; pass <= 3; pass++) { - if (bpf_jit_prog(&jit, fp)) + if (bpf_jit_prog(&jit, fp)) { + fp = orig_fp; goto free_addrs; + } } /* * Final pass: Allocate and generate program */ - if (jit.size >= BPF_SIZE_MAX) + if (jit.size >= BPF_SIZE_MAX) { + fp = orig_fp; goto free_addrs; + } header = bpf_jit_binary_alloc(jit.size, &jit.prg_buf, 2, jit_fill_hole); - if (!header) + if (!header) { + fp = orig_fp; goto free_addrs; - if (bpf_jit_prog(&jit, fp)) + } + if (bpf_jit_prog(&jit, fp)) { + fp = orig_fp; goto free_addrs; + } if (bpf_jit_enable > 1) { bpf_jit_dump(fp->len, jit.size, pass, jit.prg_buf); if (jit.prg_buf) @@ -1305,6 +1341,11 @@ void bpf_int_jit_compile(struct bpf_prog *fp) } free_addrs: kfree(jit.addrs); +out: + if (tmp_blinded) + bpf_jit_prog_release_other(fp, fp == orig_fp ? + tmp : orig_fp); + return fp; } /* |