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Commit 09ece3d0 authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Alexei Starovoitov
Browse files

bpf, arm64: save 4 bytes of unneeded stack space 



Follow-up to 816d9ef3 ("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: default avatarDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 38ca9306

arch/arm64/net/bpf_jit_comp.c

+2 −5
Original line number Diff line number Diff line
@@ -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);