diff options
Diffstat (limited to 'kernel/arch/s390/net')
| -rw-r--r-- | kernel/arch/s390/net/bpf_jit.h | 15 | ||||
| -rw-r--r-- | kernel/arch/s390/net/bpf_jit_comp.c | 197 |
2 files changed, 166 insertions, 46 deletions
diff --git a/kernel/arch/s390/net/bpf_jit.h b/kernel/arch/s390/net/bpf_jit.h index de156ba3b..f010c93a8 100644 --- a/kernel/arch/s390/net/bpf_jit.h +++ b/kernel/arch/s390/net/bpf_jit.h @@ -28,11 +28,16 @@ extern u8 sk_load_word[], sk_load_half[], sk_load_byte[]; * | old backchain | | * +---------------+ | * | r15 - r6 | | + * +---------------+ | + * | 4 byte align | | + * | tail_call_cnt | | * BFP -> +===============+ | * | | | * | BPF stack | | * | | | * +---------------+ | + * | 8 byte skbp | | + * R15+170 -> +---------------+ | * | 8 byte hlen | | * R15+168 -> +---------------+ | * | 4 byte align | | @@ -46,13 +51,17 @@ extern u8 sk_load_word[], sk_load_half[], sk_load_byte[]; * R15 -> +---------------+ + low * * We get 160 bytes stack space from calling function, but only use - * 11 * 8 byte (old backchain + r15 - r6) for storing registers. + * 12 * 8 byte for old backchain, r15..r6, and tail_call_cnt. */ -#define STK_SPACE (MAX_BPF_STACK + 8 + 4 + 4 + 160) -#define STK_160_UNUSED (160 - 11 * 8) +#define STK_SPACE (MAX_BPF_STACK + 8 + 8 + 4 + 4 + 160) +#define STK_160_UNUSED (160 - 12 * 8) #define STK_OFF (STK_SPACE - STK_160_UNUSED) #define STK_OFF_TMP 160 /* Offset of tmp buffer on stack */ #define STK_OFF_HLEN 168 /* Offset of SKB header length on stack */ +#define STK_OFF_SKBP 170 /* Offset of SKB pointer on stack */ + +#define STK_OFF_R6 (160 - 11 * 8) /* Offset of r6 on stack */ +#define STK_OFF_TCCNT (160 - 12 * 8) /* Offset of tail_call_cnt on stack */ /* Offset to skip condition code check */ #define OFF_OK 4 diff --git a/kernel/arch/s390/net/bpf_jit_comp.c b/kernel/arch/s390/net/bpf_jit_comp.c index dc2d7aa56..9a0c4c22e 100644 --- a/kernel/arch/s390/net/bpf_jit_comp.c +++ b/kernel/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" @@ -40,15 +41,19 @@ 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 */ +#define BPF_SIZE_MAX 0x7ffff /* Max size for program (20 bit signed displ) */ #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_SKB_CHANGE 64 /* code changes skb data */ #define SEEN_STACK (SEEN_FUNC | SEEN_MEM | SEEN_SKB) /* @@ -60,6 +65,7 @@ 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 */ @@ -198,19 +204,11 @@ static inline void reg_set_seen(struct bpf_jit *jit, u32 b1) _EMIT6(op1 | __disp, op2); \ }) -#define EMIT6_DISP(op1, op2, b1, b2, b3, disp) \ -({ \ - _EMIT6_DISP(op1 | reg(b1, b2) << 16 | \ - reg_high(b3) << 8, op2, disp); \ - REG_SET_SEEN(b1); \ - REG_SET_SEEN(b2); \ - REG_SET_SEEN(b3); \ -}) - #define _EMIT6_DISP_LH(op1, op2, disp) \ ({ \ - unsigned int __disp_h = ((u32)disp) & 0xff000; \ - unsigned int __disp_l = ((u32)disp) & 0x00fff; \ + u32 _disp = (u32) disp; \ + unsigned int __disp_h = _disp & 0xff000; \ + unsigned int __disp_l = _disp & 0x00fff; \ _EMIT6(op1 | __disp_l, op2 | __disp_h >> 4); \ }) @@ -223,6 +221,24 @@ 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 +302,7 @@ 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 +317,7 @@ 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; @@ -367,13 +383,43 @@ 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. + */ +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); + /* 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. * See stack frame layout desription in "bpf_jit.h"! */ -static void bpf_jit_prologue(struct bpf_jit *jit) +static void bpf_jit_prologue(struct bpf_jit *jit, bool is_classic) { + 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 */ @@ -396,32 +442,21 @@ static void bpf_jit_prologue(struct bpf_jit *jit) EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15, 152); } - /* - * 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 (jit->seen & SEEN_SKB) { - /* 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) */ + if (jit->seen & SEEN_SKB) + emit_load_skb_data_hlen(jit); + if (jit->seen & SEEN_SKB_CHANGE) + /* stg %b1,ST_OFF_SKBP(%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)); + STK_OFF_SKBP); + /* Clear A (%b0) and X (%b7) registers for converted BPF programs */ + if (is_classic) { + if (REG_SEEN(BPF_REG_A)) + /* lghi %ba,0 */ + EMIT4_IMM(0xa7090000, BPF_REG_A, 0); + if (REG_SEEN(BPF_REG_X)) + /* lghi %bx,0 */ + EMIT4_IMM(0xa7090000, BPF_REG_X, 0); } - /* BPF compatibility: clear A (%b0) and X (%b7) registers */ - if (REG_SEEN(BPF_REG_A)) - /* lghi %ba,0 */ - EMIT4_IMM(0xa7090000, BPF_REG_A, 0); - if (REG_SEEN(BPF_REG_X)) - /* lghi %bx,0 */ - EMIT4_IMM(0xa7090000, BPF_REG_X, 0); } /* @@ -943,14 +978,90 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i REG_SET_SEEN(BPF_REG_5); jit->seen |= SEEN_FUNC; /* lg %w1,<d(imm)>(%l) */ - EMIT6_DISP(0xe3000000, 0x0004, REG_W1, REG_0, REG_L, - EMIT_CONST_U64(func)); + EMIT6_DISP_LH(0xe3000000, 0x0004, REG_W1, REG_0, REG_L, + EMIT_CONST_U64(func)); /* basr %r14,%w1 */ EMIT2(0x0d00, REG_14, REG_W1); /* lgr %b0,%r2: load return value into %b0 */ EMIT4(0xb9040000, BPF_REG_0, REG_2); + if (bpf_helper_changes_skb_data((void *)func)) { + jit->seen |= SEEN_SKB_CHANGE; + /* 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_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->ptrs[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, ptrs)); + /* 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)) @@ -1134,7 +1245,7 @@ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp) jit->lit = jit->lit_start; jit->prg = 0; - bpf_jit_prologue(jit); + bpf_jit_prologue(jit, bpf_prog_was_classic(fp)); for (i = 0; i < fp->len; i += insn_count) { insn_count = bpf_jit_insn(jit, fp, i); if (insn_count < 0) @@ -1199,7 +1310,7 @@ void bpf_int_jit_compile(struct bpf_prog *fp) if (jit.prg_buf) { set_memory_ro((unsigned long)header, header->pages); fp->bpf_func = (void *) jit.prg_buf; - fp->jited = true; + fp->jited = 1; } free_addrs: kfree(jit.addrs); |