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path: root/arch/arm64/net/bpf_jit_comp.c
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Diffstat (limited to 'arch/arm64/net/bpf_jit_comp.c')
-rw-r--r--arch/arm64/net/bpf_jit_comp.c43
1 files changed, 31 insertions, 12 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index f8912e45be7a..ef9f1d5e989d 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -143,14 +143,17 @@ static inline void emit_addr_mov_i64(const int reg, const u64 val,
}
}
-static inline int bpf2a64_offset(int bpf_to, int bpf_from,
+static inline int bpf2a64_offset(int bpf_insn, int off,
const struct jit_ctx *ctx)
{
- int to = ctx->offset[bpf_to];
- /* -1 to account for the Branch instruction */
- int from = ctx->offset[bpf_from] - 1;
-
- return to - from;
+ /* BPF JMP offset is relative to the next instruction */
+ bpf_insn++;
+ /*
+ * Whereas arm64 branch instructions encode the offset
+ * from the branch itself, so we must subtract 1 from the
+ * instruction offset.
+ */
+ return ctx->offset[bpf_insn + off] - (ctx->offset[bpf_insn] - 1);
}
static void jit_fill_hole(void *area, unsigned int size)
@@ -642,7 +645,7 @@ emit_bswap_uxt:
/* JUMP off */
case BPF_JMP | BPF_JA:
- jmp_offset = bpf2a64_offset(i + off, i, ctx);
+ jmp_offset = bpf2a64_offset(i, off, ctx);
check_imm26(jmp_offset);
emit(A64_B(jmp_offset), ctx);
break;
@@ -669,7 +672,7 @@ emit_bswap_uxt:
case BPF_JMP32 | BPF_JSLE | BPF_X:
emit(A64_CMP(is64, dst, src), ctx);
emit_cond_jmp:
- jmp_offset = bpf2a64_offset(i + off, i, ctx);
+ jmp_offset = bpf2a64_offset(i, off, ctx);
check_imm19(jmp_offset);
switch (BPF_OP(code)) {
case BPF_JEQ:
@@ -908,10 +911,21 @@ static int build_body(struct jit_ctx *ctx, bool extra_pass)
const struct bpf_prog *prog = ctx->prog;
int i;
+ /*
+ * - offset[0] offset of the end of prologue,
+ * start of the 1st instruction.
+ * - offset[1] - offset of the end of 1st instruction,
+ * start of the 2nd instruction
+ * [....]
+ * - offset[3] - offset of the end of 3rd instruction,
+ * start of 4th instruction
+ */
for (i = 0; i < prog->len; i++) {
const struct bpf_insn *insn = &prog->insnsi[i];
int ret;
+ if (ctx->image == NULL)
+ ctx->offset[i] = ctx->idx;
ret = build_insn(insn, ctx, extra_pass);
if (ret > 0) {
i++;
@@ -919,11 +933,16 @@ static int build_body(struct jit_ctx *ctx, bool extra_pass)
ctx->offset[i] = ctx->idx;
continue;
}
- if (ctx->image == NULL)
- ctx->offset[i] = ctx->idx;
if (ret)
return ret;
}
+ /*
+ * offset is allocated with prog->len + 1 so fill in
+ * the last element with the offset after the last
+ * instruction (end of program)
+ */
+ if (ctx->image == NULL)
+ ctx->offset[i] = ctx->idx;
return 0;
}
@@ -1002,7 +1021,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
memset(&ctx, 0, sizeof(ctx));
ctx.prog = prog;
- ctx.offset = kcalloc(prog->len, sizeof(int), GFP_KERNEL);
+ ctx.offset = kcalloc(prog->len + 1, sizeof(int), GFP_KERNEL);
if (ctx.offset == NULL) {
prog = orig_prog;
goto out_off;
@@ -1089,7 +1108,7 @@ skip_init_ctx:
prog->jited_len = prog_size;
if (!prog->is_func || extra_pass) {
- bpf_prog_fill_jited_linfo(prog, ctx.offset);
+ bpf_prog_fill_jited_linfo(prog, ctx.offset + 1);
out_off:
kfree(ctx.offset);
kfree(jit_data);