diff options
Diffstat (limited to 'arch/s390/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/s390/net/bpf_jit_comp.c | 106 |
1 files changed, 104 insertions, 2 deletions
diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c index 55423d8be580..d3766dd67e23 100644 --- a/arch/s390/net/bpf_jit_comp.c +++ b/arch/s390/net/bpf_jit_comp.c @@ -21,6 +21,7 @@ #include <linux/netdevice.h> #include <linux/filter.h> #include <linux/init.h> +#include <linux/bpf.h> #include <asm/cacheflush.h> #include <asm/dis.h> #include "bpf_jit.h" @@ -40,6 +41,8 @@ struct bpf_jit { int base_ip; /* Base address for literal pool */ int ret0_ip; /* Address of return 0 */ int exit_ip; /* Address of exit */ + int tail_call_start; /* Tail call start offset */ + int labels[1]; /* Labels for local jumps */ }; #define BPF_SIZE_MAX 4096 /* Max size for program */ @@ -49,6 +52,7 @@ struct bpf_jit { #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_STACK (SEEN_FUNC | SEEN_MEM | SEEN_SKB) /* @@ -60,6 +64,7 @@ struct bpf_jit { #define REG_L (__MAX_BPF_REG+3) /* Literal pool register */ #define REG_15 (__MAX_BPF_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 */ #define REG_14 BPF_REG_0 /* Register 14 */ @@ -223,6 +228,24 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1) REG_SET_SEEN(b3); \ }) +#define EMIT6_PCREL_LABEL(op1, op2, b1, b2, label, mask) \ +({ \ + int rel = (jit->labels[label] - jit->prg) >> 1; \ + _EMIT6(op1 | reg(b1, b2) << 16 | (rel & 0xffff), \ + op2 | mask << 12); \ + REG_SET_SEEN(b1); \ + REG_SET_SEEN(b2); \ +}) + +#define EMIT6_PCREL_IMM_LABEL(op1, op2, b1, imm, label, mask) \ +({ \ + int rel = (jit->labels[label] - jit->prg) >> 1; \ + _EMIT6(op1 | (reg_high(b1) | mask) << 16 | \ + (rel & 0xffff), op2 | (imm & 0xff) << 8); \ + REG_SET_SEEN(b1); \ + BUILD_BUG_ON(((unsigned long) imm) > 0xff); \ +}) + #define EMIT6_PCREL(op1, op2, b1, b2, i, off, mask) \ ({ \ /* Branch instruction needs 6 bytes */ \ @@ -286,7 +309,7 @@ static void jit_fill_hole(void *area, unsigned int size) */ static void save_regs(struct bpf_jit *jit, u32 rs, u32 re) { - u32 off = 72 + (rs - 6) * 8; + u32 off = STK_OFF_R6 + (rs - 6) * 8; if (rs == re) /* stg %rs,off(%r15) */ @@ -301,7 +324,7 @@ static void save_regs(struct bpf_jit *jit, u32 rs, u32 re) */ static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re) { - u32 off = 72 + (rs - 6) * 8; + u32 off = STK_OFF_R6 + (rs - 6) * 8; if (jit->seen & SEEN_STACK) off += STK_OFF; @@ -374,6 +397,16 @@ static void save_restore_regs(struct bpf_jit *jit, int op) */ static void bpf_jit_prologue(struct bpf_jit *jit) { + if (jit->seen & SEEN_TAIL_CALL) { + /* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */ + _EMIT6(0xd703f000 | STK_OFF_TCCNT, 0xf000 | STK_OFF_TCCNT); + } else { + /* j tail_call_start: NOP if no tail calls are used */ + EMIT4_PCREL(0xa7f40000, 6); + _EMIT2(0); + } + /* Tail calls have to skip above initialization */ + jit->tail_call_start = jit->prg; /* Save registers */ save_restore_regs(jit, REGS_SAVE); /* Setup literal pool */ @@ -951,6 +984,75 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i EMIT4(0xb9040000, BPF_REG_0, REG_2); break; } + case BPF_JMP | BPF_CALL | BPF_X: + /* + * Implicit input: + * B1: pointer to ctx + * B2: pointer to bpf_array + * B3: index in bpf_array + */ + jit->seen |= SEEN_TAIL_CALL; + + /* + * if (index >= array->map.max_entries) + * goto out; + */ + + /* llgf %w1,map.max_entries(%b2) */ + EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_2, + offsetof(struct bpf_array, map.max_entries)); + /* clgrj %b3,%w1,0xa,label0: if %b3 >= %w1 goto out */ + EMIT6_PCREL_LABEL(0xec000000, 0x0065, BPF_REG_3, + REG_W1, 0, 0xa); + + /* + * if (tail_call_cnt++ > MAX_TAIL_CALL_CNT) + * goto out; + */ + + if (jit->seen & SEEN_STACK) + off = STK_OFF_TCCNT + STK_OFF; + else + off = STK_OFF_TCCNT; + /* lhi %w0,1 */ + EMIT4_IMM(0xa7080000, REG_W0, 1); + /* laal %w1,%w0,off(%r15) */ + EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W1, REG_W0, REG_15, off); + /* clij %w1,MAX_TAIL_CALL_CNT,0x2,label0 */ + EMIT6_PCREL_IMM_LABEL(0xec000000, 0x007f, REG_W1, + MAX_TAIL_CALL_CNT, 0, 0x2); + + /* + * prog = array->prog[index]; + * if (prog == NULL) + * goto out; + */ + + /* sllg %r1,%b3,3: %r1 = index * 8 */ + EMIT6_DISP_LH(0xeb000000, 0x000d, REG_1, BPF_REG_3, REG_0, 3); + /* lg %r1,prog(%b2,%r1) */ + EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, BPF_REG_2, + REG_1, offsetof(struct bpf_array, prog)); + /* clgij %r1,0,0x8,label0 */ + EMIT6_PCREL_IMM_LABEL(0xec000000, 0x007d, REG_1, 0, 0, 0x8); + + /* + * Restore registers before calling function + */ + save_restore_regs(jit, REGS_RESTORE); + + /* + * goto *(prog->bpf_func + tail_call_start); + */ + + /* lg %r1,bpf_func(%r1) */ + EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, REG_1, REG_0, + offsetof(struct bpf_prog, bpf_func)); + /* bc 0xf,tail_call_start(%r1) */ + _EMIT4(0x47f01000 + jit->tail_call_start); + /* out: */ + jit->labels[0] = jit->prg; + break; case BPF_JMP | BPF_EXIT: /* return b0 */ last = (i == fp->len - 1) ? 1 : 0; if (last && !(jit->seen & SEEN_RET0)) |