#define pr_fmt(fmt) "bpf_jit: " fmt
+#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/printk.h>
#include <linux/skbuff.h>
int bpf_jit_enable __read_mostly;
-#define TMP_REG_1 (MAX_BPF_REG + 0)
-#define TMP_REG_2 (MAX_BPF_REG + 1)
+#define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
+#define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
+#define TCALL_CNT (MAX_BPF_JIT_REG + 2)
/* Map BPF registers to A64 registers */
static const int bpf2a64[] = {
[BPF_REG_9] = A64_R(22),
/* read-only frame pointer to access stack */
[BPF_REG_FP] = A64_R(25),
- /* temporary register for internal BPF JIT */
- [TMP_REG_1] = A64_R(23),
- [TMP_REG_2] = A64_R(24),
+ /* temporary registers for internal BPF JIT */
+ [TMP_REG_1] = A64_R(10),
+ [TMP_REG_2] = A64_R(11),
+ /* tail_call_cnt */
+ [TCALL_CNT] = A64_R(26),
+ /* temporary register for blinding constants */
+ [BPF_REG_AX] = A64_R(9),
};
struct jit_ctx {
const struct bpf_prog *prog;
int idx;
- int tmp_used;
int epilogue_offset;
int *offset;
u32 *image;
#define STACK_SIZE STACK_ALIGN(_STACK_SIZE)
-static void build_prologue(struct jit_ctx *ctx)
+#define PROLOGUE_OFFSET 8
+
+static int build_prologue(struct jit_ctx *ctx)
{
const u8 r6 = bpf2a64[BPF_REG_6];
const u8 r7 = bpf2a64[BPF_REG_7];
const u8 r8 = bpf2a64[BPF_REG_8];
const u8 r9 = bpf2a64[BPF_REG_9];
const u8 fp = bpf2a64[BPF_REG_FP];
- const u8 tmp1 = bpf2a64[TMP_REG_1];
- const u8 tmp2 = bpf2a64[TMP_REG_2];
+ const u8 tcc = bpf2a64[TCALL_CNT];
+ const int idx0 = ctx->idx;
+ int cur_offset;
/*
* BPF prog stack layout
* |FP/LR|
* current A64_FP => -16:+-----+
* | ... | callee saved registers
- * +-----+
- * | | x25/x26
- * BPF fp register => -80:+-----+ <= (BPF_FP)
+ * BPF fp register => -64:+-----+ <= (BPF_FP)
* | |
* | ... | BPF prog stack
* | |
emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
emit(A64_MOV(1, A64_FP, A64_SP), ctx);
- /* Save callee-saved register */
+ /* Save callee-saved registers */
emit(A64_PUSH(r6, r7, A64_SP), ctx);
emit(A64_PUSH(r8, r9, A64_SP), ctx);
- if (ctx->tmp_used)
- emit(A64_PUSH(tmp1, tmp2, A64_SP), ctx);
+ emit(A64_PUSH(fp, tcc, A64_SP), ctx);
- /* Save fp (x25) and x26. SP requires 16 bytes alignment */
- emit(A64_PUSH(fp, A64_R(26), A64_SP), ctx);
-
- /* Set up BPF prog stack base register (x25) */
+ /* Set up BPF prog stack base register */
emit(A64_MOV(1, fp, A64_SP), ctx);
+ /* Initialize tail_call_cnt */
+ emit(A64_MOVZ(1, tcc, 0, 0), ctx);
+
/* Set up function call stack */
emit(A64_SUB_I(1, A64_SP, A64_SP, STACK_SIZE), ctx);
+
+ cur_offset = ctx->idx - idx0;
+ if (cur_offset != PROLOGUE_OFFSET) {
+ pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
+ cur_offset, PROLOGUE_OFFSET);
+ return -1;
+ }
+ return 0;
+}
+
+static int out_offset = -1; /* initialized on the first pass of build_body() */
+static int emit_bpf_tail_call(struct jit_ctx *ctx)
+{
+ /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
+ const u8 r2 = bpf2a64[BPF_REG_2];
+ const u8 r3 = bpf2a64[BPF_REG_3];
+
+ const u8 tmp = bpf2a64[TMP_REG_1];
+ const u8 prg = bpf2a64[TMP_REG_2];
+ const u8 tcc = bpf2a64[TCALL_CNT];
+ const int idx0 = ctx->idx;
+#define cur_offset (ctx->idx - idx0)
+#define jmp_offset (out_offset - (cur_offset))
+ size_t off;
+
+ /* if (index >= array->map.max_entries)
+ * goto out;
+ */
+ off = offsetof(struct bpf_array, map.max_entries);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_LDR32(tmp, r2, tmp), ctx);
+ emit(A64_CMP(0, r3, tmp), ctx);
+ emit(A64_B_(A64_COND_GE, jmp_offset), ctx);
+
+ /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
+ * goto out;
+ * tail_call_cnt++;
+ */
+ emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
+ emit(A64_CMP(1, tcc, tmp), ctx);
+ emit(A64_B_(A64_COND_GT, jmp_offset), ctx);
+ emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
+
+ /* prog = array->ptrs[index];
+ * if (prog == NULL)
+ * goto out;
+ */
+ off = offsetof(struct bpf_array, ptrs);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_LDR64(tmp, r2, tmp), ctx);
+ emit(A64_LDR64(prg, tmp, r3), ctx);
+ emit(A64_CBZ(1, prg, jmp_offset), ctx);
+
+ /* goto *(prog->bpf_func + prologue_size); */
+ off = offsetof(struct bpf_prog, bpf_func);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_LDR64(tmp, prg, tmp), ctx);
+ emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx);
+ emit(A64_BR(tmp), ctx);
+
+ /* out: */
+ if (out_offset == -1)
+ out_offset = cur_offset;
+ if (cur_offset != out_offset) {
+ pr_err_once("tail_call out_offset = %d, expected %d!\n",
+ cur_offset, out_offset);
+ return -1;
+ }
+ return 0;
+#undef cur_offset
+#undef jmp_offset
}
static void build_epilogue(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 tmp1 = bpf2a64[TMP_REG_1];
- const u8 tmp2 = bpf2a64[TMP_REG_2];
/* We're done with BPF stack */
emit(A64_ADD_I(1, A64_SP, A64_SP, STACK_SIZE), ctx);
emit(A64_POP(fp, A64_R(26), A64_SP), ctx);
/* Restore callee-saved register */
- if (ctx->tmp_used)
- emit(A64_POP(tmp1, tmp2, A64_SP), ctx);
emit(A64_POP(r8, r9, A64_SP), ctx);
emit(A64_POP(r6, r7, A64_SP), ctx);
emit(A64_UDIV(is64, dst, dst, src), ctx);
break;
case BPF_MOD:
- ctx->tmp_used = 1;
emit(A64_UDIV(is64, tmp, dst, src), ctx);
emit(A64_MUL(is64, tmp, tmp, src), ctx);
emit(A64_SUB(is64, dst, dst, tmp), ctx);
/* dst = dst OP imm */
case BPF_ALU | BPF_ADD | BPF_K:
case BPF_ALU64 | BPF_ADD | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(is64, tmp, imm, ctx);
emit(A64_ADD(is64, dst, dst, tmp), ctx);
break;
case BPF_ALU | BPF_SUB | BPF_K:
case BPF_ALU64 | BPF_SUB | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(is64, tmp, imm, ctx);
emit(A64_SUB(is64, dst, dst, tmp), ctx);
break;
case BPF_ALU | BPF_AND | BPF_K:
case BPF_ALU64 | BPF_AND | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(is64, tmp, imm, ctx);
emit(A64_AND(is64, dst, dst, tmp), ctx);
break;
case BPF_ALU | BPF_OR | BPF_K:
case BPF_ALU64 | BPF_OR | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(is64, tmp, imm, ctx);
emit(A64_ORR(is64, dst, dst, tmp), ctx);
break;
case BPF_ALU | BPF_XOR | BPF_K:
case BPF_ALU64 | BPF_XOR | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(is64, tmp, imm, ctx);
emit(A64_EOR(is64, dst, dst, tmp), ctx);
break;
case BPF_ALU | BPF_MUL | BPF_K:
case BPF_ALU64 | BPF_MUL | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(is64, tmp, imm, ctx);
emit(A64_MUL(is64, dst, dst, tmp), ctx);
break;
case BPF_ALU | BPF_DIV | BPF_K:
case BPF_ALU64 | BPF_DIV | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(is64, tmp, imm, ctx);
emit(A64_UDIV(is64, dst, dst, tmp), ctx);
break;
case BPF_ALU | BPF_MOD | BPF_K:
case BPF_ALU64 | BPF_MOD | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(is64, tmp2, imm, ctx);
emit(A64_UDIV(is64, tmp, dst, tmp2), ctx);
emit(A64_MUL(is64, tmp, tmp, tmp2), ctx);
case BPF_JMP | BPF_JNE | BPF_K:
case BPF_JMP | BPF_JSGT | BPF_K:
case BPF_JMP | BPF_JSGE | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(1, tmp, imm, ctx);
emit(A64_CMP(1, dst, tmp), ctx);
goto emit_cond_jmp;
case BPF_JMP | BPF_JSET | BPF_K:
- ctx->tmp_used = 1;
emit_a64_mov_i(1, tmp, imm, ctx);
emit(A64_TST(1, dst, tmp), ctx);
goto emit_cond_jmp;
const u8 r0 = bpf2a64[BPF_REG_0];
const u64 func = (u64)__bpf_call_base + imm;
- ctx->tmp_used = 1;
emit_a64_mov_i64(tmp, func, ctx);
- emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
- emit(A64_MOV(1, A64_FP, A64_SP), ctx);
emit(A64_BLR(tmp), ctx);
emit(A64_MOV(1, r0, A64_R(0)), ctx);
- emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
break;
}
+ /* tail call */
+ case BPF_JMP | BPF_CALL | BPF_X:
+ if (emit_bpf_tail_call(ctx))
+ return -EFAULT;
+ break;
/* function return */
case BPF_JMP | BPF_EXIT:
/* Optimization: when last instruction is EXIT,
case BPF_LDX | BPF_MEM | BPF_H:
case BPF_LDX | BPF_MEM | BPF_B:
case BPF_LDX | BPF_MEM | BPF_DW:
- ctx->tmp_used = 1;
emit_a64_mov_i(1, tmp, off, ctx);
switch (BPF_SIZE(code)) {
case BPF_W:
case BPF_ST | BPF_MEM | BPF_B:
case BPF_ST | BPF_MEM | BPF_DW:
/* Load imm to a register then store it */
- ctx->tmp_used = 1;
emit_a64_mov_i(1, tmp2, off, ctx);
emit_a64_mov_i(1, tmp, imm, ctx);
switch (BPF_SIZE(code)) {
case BPF_STX | BPF_MEM | BPF_H:
case BPF_STX | BPF_MEM | BPF_B:
case BPF_STX | BPF_MEM | BPF_DW:
- ctx->tmp_used = 1;
emit_a64_mov_i(1, tmp, off, ctx);
switch (BPF_SIZE(code)) {
case BPF_W:
/* Nothing to do here. We support Internal BPF. */
}
-void bpf_int_jit_compile(struct bpf_prog *prog)
+struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
{
+ struct bpf_prog *tmp, *orig_prog = prog;
struct bpf_binary_header *header;
+ bool tmp_blinded = false;
struct jit_ctx ctx;
int image_size;
u8 *image_ptr;
if (!bpf_jit_enable)
- return;
+ return orig_prog;
- if (!prog || !prog->len)
- return;
+ tmp = bpf_jit_blind_constants(prog);
+ /* If blinding was requested and we failed during blinding,
+ * we must fall back to the interpreter.
+ */
+ if (IS_ERR(tmp))
+ return orig_prog;
+ if (tmp != prog) {
+ tmp_blinded = true;
+ prog = tmp;
+ }
memset(&ctx, 0, sizeof(ctx));
ctx.prog = prog;
ctx.offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
- if (ctx.offset == NULL)
- return;
+ if (ctx.offset == NULL) {
+ prog = orig_prog;
+ goto out;
+ }
/* 1. Initial fake pass to compute ctx->idx. */
- /* Fake pass to fill in ctx->offset and ctx->tmp_used. */
- if (build_body(&ctx))
- goto out;
+ /* Fake pass to fill in ctx->offset. */
+ if (build_body(&ctx)) {
+ prog = orig_prog;
+ goto out_off;
+ }
- build_prologue(&ctx);
+ if (build_prologue(&ctx)) {
+ prog = orig_prog;
+ goto out_off;
+ }
ctx.epilogue_offset = ctx.idx;
build_epilogue(&ctx);
image_size = sizeof(u32) * ctx.idx;
header = bpf_jit_binary_alloc(image_size, &image_ptr,
sizeof(u32), jit_fill_hole);
- if (header == NULL)
- goto out;
+ if (header == NULL) {
+ prog = orig_prog;
+ goto out_off;
+ }
/* 2. Now, the actual pass. */
if (build_body(&ctx)) {
bpf_jit_binary_free(header);
- goto out;
+ prog = orig_prog;
+ goto out_off;
}
build_epilogue(&ctx);
/* 3. Extra pass to validate JITed code. */
if (validate_code(&ctx)) {
bpf_jit_binary_free(header);
- goto out;
+ prog = orig_prog;
+ goto out_off;
}
/* And we're done. */
set_memory_ro((unsigned long)header, header->pages);
prog->bpf_func = (void *)ctx.image;
prog->jited = 1;
-out:
+
+out_off:
kfree(ctx.offset);
+out:
+ if (tmp_blinded)
+ bpf_jit_prog_release_other(prog, prog == orig_prog ?
+ tmp : orig_prog);
+ return prog;
}
void bpf_jit_free(struct bpf_prog *prog)
projects / cascardo / linux.git / blobdiff