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bpf, arm64: save 4 bytes of unneeded stack space

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Follow-up to 816d9ef32a ("bpf, arm64: remove ld_abs/ld_ind") in
that the extra 4 byte JIT scratchpad is not needed anymore since it
was in ld_abs/ld_ind as stack buffer for bpf_load_pointer().

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Daniel Borkmann 2018-05-14 23:22:31 +02:00 committed by Alexei Starovoitov
parent 38ca930601
commit 09ece3d0f2
1 changed files with 2 additions and 5 deletions
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7
arch/arm64/net/bpf_jit_comp.c
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@ -21,7 +21,6 @@
#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/printk.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <asm/byteorder.h>
@ -188,7 +187,7 @@ static int build_prologue(struct jit_ctx *ctx)
* | ... | BPF prog stack
* | |
* +-----+ <= (BPF_FP - prog->aux->stack_depth)
* |RSVD | JIT scratchpad
* |RSVD | padding
* current A64_SP => +-----+ <= (BPF_FP - ctx->stack_size)
* | |
* | ... | Function call stack
@ -220,9 +219,7 @@ static int build_prologue(struct jit_ctx *ctx)
return -1;
}
/* 4 byte extra for skb_copy_bits buffer */
ctx->stack_size = prog->aux->stack_depth + 4;
ctx->stack_size = STACK_ALIGN(ctx->stack_size);
ctx->stack_size = STACK_ALIGN(prog->aux->stack_depth);
/* Set up function call stack */
emit(A64_SUB_I(1, A64_SP, A64_SP, ctx->stack_size), ctx);