Commit d73e5f41 authored by David S. Miller's avatar David S. Miller

Merge branch 'bpf-misc-updates'

Daniel Borkmann says:

====================
Misc BPF updates

This series contains a couple of misc updates to the BPF code, besides
others a new helper bpf_skb_load_bytes(), moving clearing of A/X to the
classic converter, etc. Please see individual patches for details.

Thanks!
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 59ce9670 9dd2af83
......@@ -152,8 +152,6 @@ static void build_prologue(struct jit_ctx *ctx)
const u8 r8 = bpf2a64[BPF_REG_8];
const u8 r9 = bpf2a64[BPF_REG_9];
const u8 fp = bpf2a64[BPF_REG_FP];
const u8 ra = bpf2a64[BPF_REG_A];
const u8 rx = bpf2a64[BPF_REG_X];
const u8 tmp1 = bpf2a64[TMP_REG_1];
const u8 tmp2 = bpf2a64[TMP_REG_2];
......@@ -200,10 +198,6 @@ static void build_prologue(struct jit_ctx *ctx)
/* Set up function call stack */
emit(A64_SUB_I(1, A64_SP, A64_SP, STACK_SIZE), ctx);
/* Clear registers A and X */
emit_a64_mov_i64(ra, 0, ctx);
emit_a64_mov_i64(rx, 0, ctx);
}
static void build_epilogue(struct jit_ctx *ctx)
......
......@@ -408,7 +408,7 @@ static void emit_load_skb_data_hlen(struct bpf_jit *jit)
* 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, bool is_classic)
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) */
......@@ -448,15 +448,6 @@ static void bpf_jit_prologue(struct bpf_jit *jit, bool is_classic)
/* stg %b1,ST_OFF_SKBP(%r0,%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0, REG_15,
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);
}
}
/*
......@@ -1245,7 +1236,7 @@ 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_prog_was_classic(fp));
bpf_jit_prologue(jit);
for (i = 0; i < fp->len; i += insn_count) {
insn_count = bpf_jit_insn(jit, fp, i);
if (insn_count < 0)
......
......@@ -193,7 +193,7 @@ struct jit_context {
32 /* space for rbx, r13, r14, r15 */ + \
8 /* space for skb_copy_bits() buffer */)
#define PROLOGUE_SIZE 51
#define PROLOGUE_SIZE 48
/* emit x64 prologue code for BPF program and check it's size.
* bpf_tail_call helper will skip it while jumping into another program
......@@ -229,11 +229,15 @@ static void emit_prologue(u8 **pprog)
/* mov qword ptr [rbp-X],r15 */
EMIT3_off32(0x4C, 0x89, 0xBD, -STACKSIZE + 24);
/* clear A and X registers */
EMIT2(0x31, 0xc0); /* xor eax, eax */
EMIT3(0x4D, 0x31, 0xED); /* xor r13, r13 */
/* Clear the tail call counter (tail_call_cnt): for eBPF tail calls
* we need to reset the counter to 0. It's done in two instructions,
* resetting rax register to 0 (xor on eax gets 0 extended), and
* moving it to the counter location.
*/
/* clear tail_cnt: mov qword ptr [rbp-X], rax */
/* xor eax, eax */
EMIT2(0x31, 0xc0);
/* mov qword ptr [rbp-X], rax */
EMIT3_off32(0x48, 0x89, 0x85, -STACKSIZE + 32);
BUILD_BUG_ON(cnt != PROLOGUE_SIZE);
......@@ -455,6 +459,18 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
}
case BPF_ALU | BPF_MOV | BPF_K:
/* optimization: if imm32 is zero, use 'xor <dst>,<dst>'
* to save 3 bytes.
*/
if (imm32 == 0) {
if (is_ereg(dst_reg))
EMIT1(add_2mod(0x40, dst_reg, dst_reg));
b2 = 0x31; /* xor */
b3 = 0xC0;
EMIT2(b2, add_2reg(b3, dst_reg, dst_reg));
break;
}
/* mov %eax, imm32 */
if (is_ereg(dst_reg))
EMIT1(add_1mod(0x40, dst_reg));
......@@ -469,6 +485,20 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
return -EINVAL;
}
/* optimization: if imm64 is zero, use 'xor <dst>,<dst>'
* to save 7 bytes.
*/
if (insn[0].imm == 0 && insn[1].imm == 0) {
b1 = add_2mod(0x48, dst_reg, dst_reg);
b2 = 0x31; /* xor */
b3 = 0xC0;
EMIT3(b1, b2, add_2reg(b3, dst_reg, dst_reg));
insn++;
i++;
break;
}
/* movabsq %rax, imm64 */
EMIT2(add_1mod(0x48, dst_reg), add_1reg(0xB8, dst_reg));
EMIT(insn[0].imm, 4);
......
......@@ -269,6 +269,7 @@ enum bpf_func_id {
* Return: 0 on success
*/
BPF_FUNC_perf_event_output,
BPF_FUNC_skb_load_bytes,
__BPF_FUNC_MAX_ID,
};
......
......@@ -306,10 +306,6 @@ static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
ARG1 = (u64) (unsigned long) ctx;
/* Registers used in classic BPF programs need to be reset first. */
regs[BPF_REG_A] = 0;
regs[BPF_REG_X] = 0;
select_insn:
goto *jumptable[insn->code];
......
......@@ -1685,6 +1685,126 @@ static struct bpf_test tests[] = {
{ },
{ { 0, 0x35d97ef2 } }
},
{ /* Mainly checking JIT here. */
"MOV REG64",
.u.insns_int = {
BPF_LD_IMM64(R0, 0xffffffffffffffffLL),
BPF_MOV64_REG(R1, R0),
BPF_MOV64_REG(R2, R1),
BPF_MOV64_REG(R3, R2),
BPF_MOV64_REG(R4, R3),
BPF_MOV64_REG(R5, R4),
BPF_MOV64_REG(R6, R5),
BPF_MOV64_REG(R7, R6),
BPF_MOV64_REG(R8, R7),
BPF_MOV64_REG(R9, R8),
BPF_ALU64_IMM(BPF_MOV, R0, 0),
BPF_ALU64_IMM(BPF_MOV, R1, 0),
BPF_ALU64_IMM(BPF_MOV, R2, 0),
BPF_ALU64_IMM(BPF_MOV, R3, 0),
BPF_ALU64_IMM(BPF_MOV, R4, 0),
BPF_ALU64_IMM(BPF_MOV, R5, 0),
BPF_ALU64_IMM(BPF_MOV, R6, 0),
BPF_ALU64_IMM(BPF_MOV, R7, 0),
BPF_ALU64_IMM(BPF_MOV, R8, 0),
BPF_ALU64_IMM(BPF_MOV, R9, 0),
BPF_ALU64_REG(BPF_ADD, R0, R0),
BPF_ALU64_REG(BPF_ADD, R0, R1),
BPF_ALU64_REG(BPF_ADD, R0, R2),
BPF_ALU64_REG(BPF_ADD, R0, R3),
BPF_ALU64_REG(BPF_ADD, R0, R4),
BPF_ALU64_REG(BPF_ADD, R0, R5),
BPF_ALU64_REG(BPF_ADD, R0, R6),
BPF_ALU64_REG(BPF_ADD, R0, R7),
BPF_ALU64_REG(BPF_ADD, R0, R8),
BPF_ALU64_REG(BPF_ADD, R0, R9),
BPF_ALU64_IMM(BPF_ADD, R0, 0xfefe),
BPF_EXIT_INSN(),
},
INTERNAL,
{ },
{ { 0, 0xfefe } }
},
{ /* Mainly checking JIT here. */
"MOV REG32",
.u.insns_int = {
BPF_LD_IMM64(R0, 0xffffffffffffffffLL),
BPF_MOV64_REG(R1, R0),
BPF_MOV64_REG(R2, R1),
BPF_MOV64_REG(R3, R2),
BPF_MOV64_REG(R4, R3),
BPF_MOV64_REG(R5, R4),
BPF_MOV64_REG(R6, R5),
BPF_MOV64_REG(R7, R6),
BPF_MOV64_REG(R8, R7),
BPF_MOV64_REG(R9, R8),
BPF_ALU32_IMM(BPF_MOV, R0, 0),
BPF_ALU32_IMM(BPF_MOV, R1, 0),
BPF_ALU32_IMM(BPF_MOV, R2, 0),
BPF_ALU32_IMM(BPF_MOV, R3, 0),
BPF_ALU32_IMM(BPF_MOV, R4, 0),
BPF_ALU32_IMM(BPF_MOV, R5, 0),
BPF_ALU32_IMM(BPF_MOV, R6, 0),
BPF_ALU32_IMM(BPF_MOV, R7, 0),
BPF_ALU32_IMM(BPF_MOV, R8, 0),
BPF_ALU32_IMM(BPF_MOV, R9, 0),
BPF_ALU64_REG(BPF_ADD, R0, R0),
BPF_ALU64_REG(BPF_ADD, R0, R1),
BPF_ALU64_REG(BPF_ADD, R0, R2),
BPF_ALU64_REG(BPF_ADD, R0, R3),
BPF_ALU64_REG(BPF_ADD, R0, R4),
BPF_ALU64_REG(BPF_ADD, R0, R5),
BPF_ALU64_REG(BPF_ADD, R0, R6),
BPF_ALU64_REG(BPF_ADD, R0, R7),
BPF_ALU64_REG(BPF_ADD, R0, R8),
BPF_ALU64_REG(BPF_ADD, R0, R9),
BPF_ALU64_IMM(BPF_ADD, R0, 0xfefe),
BPF_EXIT_INSN(),
},
INTERNAL,
{ },
{ { 0, 0xfefe } }
},
{ /* Mainly checking JIT here. */
"LD IMM64",
.u.insns_int = {
BPF_LD_IMM64(R0, 0xffffffffffffffffLL),
BPF_MOV64_REG(R1, R0),
BPF_MOV64_REG(R2, R1),
BPF_MOV64_REG(R3, R2),
BPF_MOV64_REG(R4, R3),
BPF_MOV64_REG(R5, R4),
BPF_MOV64_REG(R6, R5),
BPF_MOV64_REG(R7, R6),
BPF_MOV64_REG(R8, R7),
BPF_MOV64_REG(R9, R8),
BPF_LD_IMM64(R0, 0x0LL),
BPF_LD_IMM64(R1, 0x0LL),
BPF_LD_IMM64(R2, 0x0LL),
BPF_LD_IMM64(R3, 0x0LL),
BPF_LD_IMM64(R4, 0x0LL),
BPF_LD_IMM64(R5, 0x0LL),
BPF_LD_IMM64(R6, 0x0LL),
BPF_LD_IMM64(R7, 0x0LL),
BPF_LD_IMM64(R8, 0x0LL),
BPF_LD_IMM64(R9, 0x0LL),
BPF_ALU64_REG(BPF_ADD, R0, R0),
BPF_ALU64_REG(BPF_ADD, R0, R1),
BPF_ALU64_REG(BPF_ADD, R0, R2),
BPF_ALU64_REG(BPF_ADD, R0, R3),
BPF_ALU64_REG(BPF_ADD, R0, R4),
BPF_ALU64_REG(BPF_ADD, R0, R5),
BPF_ALU64_REG(BPF_ADD, R0, R6),
BPF_ALU64_REG(BPF_ADD, R0, R7),
BPF_ALU64_REG(BPF_ADD, R0, R8),
BPF_ALU64_REG(BPF_ADD, R0, R9),
BPF_ALU64_IMM(BPF_ADD, R0, 0xfefe),
BPF_EXIT_INSN(),
},
INTERNAL,
{ },
{ { 0, 0xfefe } }
},
{
"INT: ALU MIX",
.u.insns_int = {
......
......@@ -348,12 +348,6 @@ static bool convert_bpf_extensions(struct sock_filter *fp,
* jump offsets, 2nd pass remapping:
* new_prog = kmalloc(sizeof(struct bpf_insn) * new_len);
* bpf_convert_filter(old_prog, old_len, new_prog, &new_len);
*
* User BPF's register A is mapped to our BPF register 6, user BPF
* register X is mapped to BPF register 7; frame pointer is always
* register 10; Context 'void *ctx' is stored in register 1, that is,
* for socket filters: ctx == 'struct sk_buff *', for seccomp:
* ctx == 'struct seccomp_data *'.
*/
static int bpf_convert_filter(struct sock_filter *prog, int len,
struct bpf_insn *new_prog, int *new_len)
......@@ -381,9 +375,22 @@ static int bpf_convert_filter(struct sock_filter *prog, int len,
new_insn = new_prog;
fp = prog;
if (new_insn)
*new_insn = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
new_insn++;
/* Classic BPF related prologue emission. */
if (new_insn) {
/* Classic BPF expects A and X to be reset first. These need
* to be guaranteed to be the first two instructions.
*/
*new_insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_A, BPF_REG_A);
*new_insn++ = BPF_ALU64_REG(BPF_XOR, BPF_REG_X, BPF_REG_X);
/* All programs must keep CTX in callee saved BPF_REG_CTX.
* In eBPF case it's done by the compiler, here we need to
* do this ourself. Initial CTX is present in BPF_REG_ARG1.
*/
*new_insn++ = BPF_MOV64_REG(BPF_REG_CTX, BPF_REG_ARG1);
} else {
new_insn += 3;
}
for (i = 0; i < len; fp++, i++) {
struct bpf_insn tmp_insns[6] = { };
......@@ -1245,6 +1252,7 @@ int sk_attach_bpf(u32 ufd, struct sock *sk)
}
#define BPF_RECOMPUTE_CSUM(flags) ((flags) & 1)
#define BPF_LDST_LEN 16U
static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags)
{
......@@ -1252,7 +1260,7 @@ static u64 bpf_skb_store_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 flags)
int offset = (int) r2;
void *from = (void *) (long) r3;
unsigned int len = (unsigned int) r4;
char buf[16];
char buf[BPF_LDST_LEN];
void *ptr;
/* bpf verifier guarantees that:
......@@ -1299,6 +1307,36 @@ const struct bpf_func_proto bpf_skb_store_bytes_proto = {
.arg5_type = ARG_ANYTHING,
};
static u64 bpf_skb_load_bytes(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
const struct sk_buff *skb = (const struct sk_buff *)(unsigned long) r1;
int offset = (int) r2;
void *to = (void *)(unsigned long) r3;
unsigned int len = (unsigned int) r4;
void *ptr;
if (unlikely((u32) offset > 0xffff || len > BPF_LDST_LEN))
return -EFAULT;
ptr = skb_header_pointer(skb, offset, len, to);
if (unlikely(!ptr))
return -EFAULT;
if (ptr != to)
memcpy(to, ptr, len);
return 0;
}
const struct bpf_func_proto bpf_skb_load_bytes_proto = {
.func = bpf_skb_load_bytes,
.gpl_only = false,
.ret_type = RET_INTEGER,
.arg1_type = ARG_PTR_TO_CTX,
.arg2_type = ARG_ANYTHING,
.arg3_type = ARG_PTR_TO_STACK,
.arg4_type = ARG_CONST_STACK_SIZE,
};
#define BPF_HEADER_FIELD_SIZE(flags) ((flags) & 0x0f)
#define BPF_IS_PSEUDO_HEADER(flags) ((flags) & 0x10)
......@@ -1654,6 +1692,8 @@ tc_cls_act_func_proto(enum bpf_func_id func_id)
switch (func_id) {
case BPF_FUNC_skb_store_bytes:
return &bpf_skb_store_bytes_proto;
case BPF_FUNC_skb_load_bytes:
return &bpf_skb_load_bytes_proto;
case BPF_FUNC_l3_csum_replace:
return &bpf_l3_csum_replace_proto;
case BPF_FUNC_l4_csum_replace:
......
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