diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2017-06-11 03:55:27 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-06-11 18:18:32 -0400 |
| commit | f1c9eed7f437d0fc75b35d65bb45eab281706321 (patch) | |
| tree | 311caa9372c1f59ba8e9190b51577d51cf6ac2a6 /arch/arm64/net | |
| parent | 66e037ca57f967bb344fbd381fa0651a502cb1f4 (diff) | |
| download | lwn-f1c9eed7f437d0fc75b35d65bb45eab281706321.tar.gz lwn-f1c9eed7f437d0fc75b35d65bb45eab281706321.zip | |
bpf, arm64: take advantage of stack_depth tracking
Make use of recently implemented stack_depth tracking for arm64 JIT,
so that stack usage can be reduced heavily for programs not using
tail calls at least.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/arm64/net')
| -rw-r--r-- | arch/arm64/net/bpf_jit_comp.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 4f95873d7142..73de2c71cfb0 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -69,6 +69,7 @@ struct jit_ctx { int epilogue_offset; int *offset; u32 *image; + u32 stack_size; }; static inline void emit(const u32 insn, struct jit_ctx *ctx) @@ -145,16 +146,11 @@ 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) - #define PROLOGUE_OFFSET 8 static int build_prologue(struct jit_ctx *ctx) { + const struct bpf_prog *prog = ctx->prog; const u8 r6 = bpf2a64[BPF_REG_6]; const u8 r7 = bpf2a64[BPF_REG_7]; const u8 r8 = bpf2a64[BPF_REG_8]; @@ -176,9 +172,9 @@ static int build_prologue(struct jit_ctx *ctx) * | | * | ... | BPF prog stack * | | - * +-----+ <= (BPF_FP - MAX_BPF_STACK) + * +-----+ <= (BPF_FP - prog->aux->stack_depth) * |RSVD | JIT scratchpad - * current A64_SP => +-----+ <= (BPF_FP - STACK_SIZE) + * current A64_SP => +-----+ <= (BPF_FP - ctx->stack_size) * | | * | ... | Function call stack * | | @@ -202,8 +198,12 @@ static int build_prologue(struct jit_ctx *ctx) /* Initialize tail_call_cnt */ emit(A64_MOVZ(1, tcc, 0, 0), ctx); + /* 4 byte extra for skb_copy_bits buffer */ + ctx->stack_size = prog->aux->stack_depth + 4; + ctx->stack_size = STACK_ALIGN(ctx->stack_size); + /* Set up function call stack */ - emit(A64_SUB_I(1, A64_SP, A64_SP, STACK_SIZE), ctx); + emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx); cur_offset = ctx->idx - idx0; if (cur_offset != PROLOGUE_OFFSET) { @@ -288,7 +288,7 @@ static void build_epilogue(struct jit_ctx *ctx) const u8 fp = bpf2a64[BPF_REG_FP]; /* 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, ctx->stack_size), ctx); /* Restore fs (x25) and x26 */ emit(A64_POP(fp, A64_R(26), A64_SP), ctx); @@ -732,7 +732,7 @@ emit_cond_jmp: return -EINVAL; } emit_a64_mov_i64(r3, size, ctx); - emit(A64_SUB_I(1, r4, fp, STACK_SIZE), ctx); + emit(A64_SUB_I(1, r4, fp, ctx->stack_size), ctx); emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx); emit(A64_BLR(r5), ctx); emit(A64_MOV(1, r0, A64_R(0)), ctx); |