diff options
Diffstat (limited to 'arch/arm64/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/arm64/net/bpf_jit_comp.c | 85 |
1 files changed, 68 insertions, 17 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index cf3c7d4a1b58..b162ad70effc 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -50,7 +50,7 @@ static const int bpf2a64[] = { [BPF_REG_8] = A64_R(21), [BPF_REG_9] = A64_R(22), /* read-only frame pointer to access stack */ - [BPF_REG_FP] = A64_FP, + [BPF_REG_FP] = A64_R(25), /* temporary register for internal BPF JIT */ [TMP_REG_1] = A64_R(23), [TMP_REG_2] = A64_R(24), @@ -139,6 +139,12 @@ static inline int epilogue_offset(const struct jit_ctx *ctx) /* Stack must be multiples of 16B */ #define STACK_ALIGN(sz) (((sz) + 15) & ~15) +#define _STACK_SIZE \ + (MAX_BPF_STACK \ + + 4 /* extra for skb_copy_bits buffer */) + +#define STACK_SIZE STACK_ALIGN(_STACK_SIZE) + static void build_prologue(struct jit_ctx *ctx) { const u8 r6 = bpf2a64[BPF_REG_6]; @@ -150,10 +156,35 @@ static void build_prologue(struct jit_ctx *ctx) const u8 rx = bpf2a64[BPF_REG_X]; const u8 tmp1 = bpf2a64[TMP_REG_1]; const u8 tmp2 = bpf2a64[TMP_REG_2]; - int stack_size = MAX_BPF_STACK; - stack_size += 4; /* extra for skb_copy_bits buffer */ - stack_size = STACK_ALIGN(stack_size); + /* + * BPF prog stack layout + * + * high + * original A64_SP => 0:+-----+ BPF prologue + * |FP/LR| + * current A64_FP => -16:+-----+ + * | ... | callee saved registers + * +-----+ + * | | x25/x26 + * BPF fp register => -80:+-----+ <= (BPF_FP) + * | | + * | ... | BPF prog stack + * | | + * +-----+ <= (BPF_FP - MAX_BPF_STACK) + * |RSVD | JIT scratchpad + * current A64_SP => +-----+ <= (BPF_FP - STACK_SIZE) + * | | + * | ... | Function call stack + * | | + * +-----+ + * low + * + */ + + /* Save FP and LR registers to stay align with ARM64 AAPCS */ + emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); + emit(A64_MOV(1, A64_FP, A64_SP), ctx); /* Save callee-saved register */ emit(A64_PUSH(r6, r7, A64_SP), ctx); @@ -161,12 +192,15 @@ static void build_prologue(struct jit_ctx *ctx) if (ctx->tmp_used) emit(A64_PUSH(tmp1, tmp2, A64_SP), ctx); - /* Set up BPF stack */ - emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx); + /* Save fp (x25) and x26. SP requires 16 bytes alignment */ + emit(A64_PUSH(fp, A64_R(26), A64_SP), ctx); - /* Set up frame pointer */ + /* Set up BPF prog stack base register (x25) */ emit(A64_MOV(1, fp, A64_SP), 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); @@ -182,13 +216,12 @@ static void build_epilogue(struct jit_ctx *ctx) const u8 fp = bpf2a64[BPF_REG_FP]; const u8 tmp1 = bpf2a64[TMP_REG_1]; const u8 tmp2 = bpf2a64[TMP_REG_2]; - int stack_size = MAX_BPF_STACK; - - stack_size += 4; /* extra for skb_copy_bits buffer */ - stack_size = STACK_ALIGN(stack_size); /* We're done with BPF stack */ - emit(A64_ADD_I(1, A64_SP, A64_SP, stack_size), ctx); + emit(A64_ADD_I(1, A64_SP, A64_SP, STACK_SIZE), ctx); + + /* Restore fs (x25) and x26 */ + emit(A64_POP(fp, A64_R(26), A64_SP), ctx); /* Restore callee-saved register */ if (ctx->tmp_used) @@ -196,8 +229,8 @@ static void build_epilogue(struct jit_ctx *ctx) emit(A64_POP(r8, r9, A64_SP), ctx); emit(A64_POP(r6, r7, A64_SP), ctx); - /* Restore frame pointer */ - emit(A64_MOV(1, fp, A64_SP), ctx); + /* Restore FP/LR registers */ + emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx); /* Set return value */ emit(A64_MOV(1, A64_R(0), r0), ctx); @@ -557,7 +590,25 @@ emit_cond_jmp: case BPF_ST | BPF_MEM | BPF_H: case BPF_ST | BPF_MEM | BPF_B: case BPF_ST | BPF_MEM | BPF_DW: - goto notyet; + /* 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_W: + emit(A64_STR32(tmp, dst, tmp2), ctx); + break; + case BPF_H: + emit(A64_STRH(tmp, dst, tmp2), ctx); + break; + case BPF_B: + emit(A64_STRB(tmp, dst, tmp2), ctx); + break; + case BPF_DW: + emit(A64_STR64(tmp, dst, tmp2), ctx); + break; + } + break; /* STX: *(size *)(dst + off) = src */ case BPF_STX | BPF_MEM | BPF_W: @@ -624,7 +675,7 @@ emit_cond_jmp: return -EINVAL; } emit_a64_mov_i64(r3, size, ctx); - emit(A64_ADD_I(1, r4, fp, MAX_BPF_STACK), ctx); + emit(A64_SUB_I(1, r4, fp, STACK_SIZE), ctx); emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx); emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); emit(A64_MOV(1, A64_FP, A64_SP), ctx); @@ -758,7 +809,7 @@ void bpf_int_jit_compile(struct bpf_prog *prog) if (bpf_jit_enable > 1) bpf_jit_dump(prog->len, image_size, 2, ctx.image); - bpf_flush_icache(ctx.image, ctx.image + ctx.idx); + bpf_flush_icache(header, ctx.image + ctx.idx); set_memory_ro((unsigned long)header, header->pages); prog->bpf_func = (void *)ctx.image; |