bpf: take advantage of stack_depth tracking in x64 JIT
Take advantage of stack_depth tracking in x64 JIT. Round up allocated stack by 8 bytes to make sure it stays aligned for functions called from JITed bpf program. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -206,7 +206,7 @@ struct jit_context {
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/* emit x64 prologue code for BPF program and check it's size.
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* bpf_tail_call helper will skip it while jumping into another program
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*/
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static void emit_prologue(u8 **pprog)
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static void emit_prologue(u8 **pprog, u32 stack_depth)
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{
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u8 *prog = *pprog;
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int cnt = 0;
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@ -214,8 +214,9 @@ static void emit_prologue(u8 **pprog)
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EMIT1(0x55); /* push rbp */
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EMIT3(0x48, 0x89, 0xE5); /* mov rbp,rsp */
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/* sub rsp, MAX_BPF_STACK + AUX_STACK_SPACE */
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EMIT3_off32(0x48, 0x81, 0xEC, MAX_BPF_STACK + AUX_STACK_SPACE);
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/* sub rsp, rounded_stack_depth + AUX_STACK_SPACE */
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EMIT3_off32(0x48, 0x81, 0xEC,
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round_up(stack_depth, 8) + AUX_STACK_SPACE);
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/* sub rbp, AUX_STACK_SPACE */
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EMIT4(0x48, 0x83, 0xED, AUX_STACK_SPACE);
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@ -363,7 +364,7 @@ static int do_jit(struct bpf_prog *bpf_prog, int *addrs, u8 *image,
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int proglen = 0;
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u8 *prog = temp;
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emit_prologue(&prog);
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emit_prologue(&prog, bpf_prog->aux->stack_depth);
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if (seen_ld_abs)
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emit_load_skb_data_hlen(&prog);
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