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authorDaniel Borkmann <daniel@iogearbox.net>2017-06-11 03:55:27 +0200
committerDavid S. Miller <davem@davemloft.net>2017-06-11 18:18:32 -0400
commitf1c9eed7f437d0fc75b35d65bb45eab281706321 (patch)
tree311caa9372c1f59ba8e9190b51577d51cf6ac2a6 /arch/arm64/net
parentMerge tag 'mlx5-updates-2017-06-11' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux (diff)
downloadlinux-dev-f1c9eed7f437d0fc75b35d65bb45eab281706321.tar.xz
linux-dev-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.c22
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);