bpf, s390x: remove ld_abs/ld_ind
Since LD_ABS/LD_IND instructions are now removed from the core and
reimplemented through a combination of inlined BPF instructions and
a slow-path helper, we can get rid of the complexity from s390x JIT.
Tested on s390x instance on LinuxONE.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 78a19c9..b020bea 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -47,23 +47,21 @@ struct bpf_jit {
#define BPF_SIZE_MAX 0xffff /* Max size for program (16 bit branches) */
-#define SEEN_SKB 1 /* skb access */
-#define SEEN_MEM 2 /* use mem[] for temporary storage */
-#define SEEN_RET0 4 /* ret0_ip points to a valid return 0 */
-#define SEEN_LITERAL 8 /* code uses literals */
-#define SEEN_FUNC 16 /* calls C functions */
-#define SEEN_TAIL_CALL 32 /* code uses tail calls */
-#define SEEN_REG_AX 64 /* code uses constant blinding */
-#define SEEN_STACK (SEEN_FUNC | SEEN_MEM | SEEN_SKB)
+#define SEEN_MEM (1 << 0) /* use mem[] for temporary storage */
+#define SEEN_RET0 (1 << 1) /* ret0_ip points to a valid return 0 */
+#define SEEN_LITERAL (1 << 2) /* code uses literals */
+#define SEEN_FUNC (1 << 3) /* calls C functions */
+#define SEEN_TAIL_CALL (1 << 4) /* code uses tail calls */
+#define SEEN_REG_AX (1 << 5) /* code uses constant blinding */
+#define SEEN_STACK (SEEN_FUNC | SEEN_MEM)
/*
* s390 registers
*/
#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_L (MAX_BPF_JIT_REG + 2) /* Literal pool register */
+#define REG_15 (MAX_BPF_JIT_REG + 3) /* Register 15 */
#define REG_0 REG_W0 /* Register 0 */
#define REG_1 REG_W1 /* Register 1 */
#define REG_2 BPF_REG_1 /* Register 2 */
@@ -88,10 +86,8 @@ static const int reg2hex[] = {
[BPF_REG_9] = 10,
/* BPF stack pointer */
[BPF_REG_FP] = 13,
- /* Register for blinding (shared with REG_SKB_DATA) */
+ /* Register for blinding */
[BPF_REG_AX] = 12,
- /* SKB data pointer */
- [REG_SKB_DATA] = 12,
/* Work registers for s390x backend */
[REG_W0] = 0,
[REG_W1] = 1,
@@ -385,27 +381,6 @@ static void save_restore_regs(struct bpf_jit *jit, int op, u32 stack_depth)
}
/*
- * 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 if BPF_REG_AX is not used.
- */
-static void emit_load_skb_data_hlen(struct bpf_jit *jit)
-{
- /* Header length: llgf %w1,<len>(%b1) */
- EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_1,
- offsetof(struct sk_buff, len));
- /* s %w1,<data_len>(%b1) */
- EMIT4_DISP(0x5b000000, REG_W1, BPF_REG_1,
- 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);
- 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));
-}
-
-/*
* Emit function prologue
*
* Save registers and create stack frame if necessary.
@@ -445,12 +420,6 @@ static void bpf_jit_prologue(struct bpf_jit *jit, u32 stack_depth)
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0,
REG_15, 152);
}
- if (jit->seen & SEEN_SKB) {
- emit_load_skb_data_hlen(jit);
- /* stg %b1,ST_OFF_SKBP(%r0,%r15) */
- EMIT6_DISP_LH(0xe3000000, 0x0024, BPF_REG_1, REG_0, REG_15,
- STK_OFF_SKBP);
- }
}
/*
@@ -483,12 +452,12 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
{
struct bpf_insn *insn = &fp->insnsi[i];
int jmp_off, last, insn_count = 1;
- unsigned int func_addr, mask;
u32 dst_reg = insn->dst_reg;
u32 src_reg = insn->src_reg;
u32 *addrs = jit->addrs;
s32 imm = insn->imm;
s16 off = insn->off;
+ unsigned int mask;
if (dst_reg == BPF_REG_AX || src_reg == BPF_REG_AX)
jit->seen |= SEEN_REG_AX;
@@ -970,13 +939,6 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
EMIT2(0x0d00, REG_14, REG_W1);
/* lgr %b0,%r2: load return value into %b0 */
EMIT4(0xb9040000, BPF_REG_0, REG_2);
- if ((jit->seen & SEEN_SKB) &&
- bpf_helper_changes_pkt_data((void *)func)) {
- /* lg %b1,ST_OFF_SKBP(%r15) */
- EMIT6_DISP_LH(0xe3000000, 0x0004, BPF_REG_1, REG_0,
- REG_15, STK_OFF_SKBP);
- emit_load_skb_data_hlen(jit);
- }
break;
}
case BPF_JMP | BPF_TAIL_CALL:
@@ -1176,73 +1138,6 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
jmp_off = addrs[i + off + 1] - (addrs[i + 1] - 4);
EMIT4_PCREL(0xa7040000 | mask << 8, jmp_off);
break;
- /*
- * BPF_LD
- */
- case BPF_LD | BPF_ABS | BPF_B: /* b0 = *(u8 *) (skb->data+imm) */
- case BPF_LD | BPF_IND | BPF_B: /* b0 = *(u8 *) (skb->data+imm+src) */
- if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
- func_addr = __pa(sk_load_byte_pos);
- else
- func_addr = __pa(sk_load_byte);
- goto call_fn;
- case BPF_LD | BPF_ABS | BPF_H: /* b0 = *(u16 *) (skb->data+imm) */
- case BPF_LD | BPF_IND | BPF_H: /* b0 = *(u16 *) (skb->data+imm+src) */
- if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
- func_addr = __pa(sk_load_half_pos);
- else
- func_addr = __pa(sk_load_half);
- goto call_fn;
- case BPF_LD | BPF_ABS | BPF_W: /* b0 = *(u32 *) (skb->data+imm) */
- case BPF_LD | BPF_IND | BPF_W: /* b0 = *(u32 *) (skb->data+imm+src) */
- if ((BPF_MODE(insn->code) == BPF_ABS) && (imm >= 0))
- func_addr = __pa(sk_load_word_pos);
- else
- func_addr = __pa(sk_load_word);
- goto call_fn;
-call_fn:
- jit->seen |= SEEN_SKB | SEEN_RET0 | SEEN_FUNC;
- REG_SET_SEEN(REG_14); /* Return address of possible func call */
-
- /*
- * Implicit input:
- * BPF_REG_6 (R7) : skb 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
- * BPF_REG_5 (R6) : return address
- *
- * Output:
- * BPF_REG_0 (R14): data read from skb
- *
- * Scratch registers (BPF_REG_1-5)
- */
-
- /* Call function: llilf %w1,func_addr */
- EMIT6_IMM(0xc00f0000, REG_W1, func_addr);
-
- /* Offset: lgfi %b2,imm */
- EMIT6_IMM(0xc0010000, BPF_REG_2, imm);
- if (BPF_MODE(insn->code) == BPF_IND)
- /* 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);
-
- /*
- * Note: For fast access we jump directly after the
- * jnz instruction from bpf_jit.S
- */
- /* jnz <ret0> */
- EMIT4_PCREL(0xa7740000, jit->ret0_ip - jit->prg);
- break;
default: /* too complex, give up */
pr_err("Unknown opcode %02x\n", insn->code);
return -1;