* [PATCH] sim: bpf: remove negi, neg32i insns
@ 2023-08-21 17:02 David Faust
2023-08-21 17:05 ` Jose E. Marchesi
0 siblings, 1 reply; 2+ messages in thread
From: David Faust @ 2023-08-21 17:02 UTC (permalink / raw)
To: gdb-patches; +Cc: jose.marchesi
The BPF virtual machine does not support neg instructions operating on
immediates, and these erroneous instructions were recently removed from
gas. Remove them from the simulator as well.
binutils patch:
[PATCH] bpf: correct neg and neg32 instruction encoding
https://sourceware.org/pipermail/binutils/2023-August/129135.html
---
sim/bpf/bpf-sim.c | 8 --------
1 file changed, 8 deletions(-)
diff --git a/sim/bpf/bpf-sim.c b/sim/bpf/bpf-sim.c
index 5e01ddeca9f..a4af22b2308 100644
--- a/sim/bpf/bpf-sim.c
+++ b/sim/bpf/bpf-sim.c
@@ -730,10 +730,6 @@ execute (SIM_CPU *cpu, struct bpf_insn *insn)
BPF_TRACE ("BPF_INSN_NEGR\n");
bpf_regs[insn->dst] = - (int64_t) bpf_regs[insn->dst];
break;
- case BPF_INSN_NEGI:
- BPF_TRACE ("BPF_INSN_NEGI\n");
- bpf_regs[insn->dst] = - (int64_t) insn->imm32;
- break;
case BPF_INSN_LSHR:
BPF_TRACE ("BPF_INSN_LSHR\n");
bpf_regs[insn->dst] <<= bpf_regs[insn->src];
@@ -867,10 +863,6 @@ execute (SIM_CPU *cpu, struct bpf_insn *insn)
BPF_TRACE ("BPF_INSN_NEG32R\n");
bpf_regs[insn->dst] = (uint32_t) (- (int32_t) bpf_regs[insn->dst]);
break;
- case BPF_INSN_NEG32I:
- BPF_TRACE ("BPF_INSN_NEG32I\n");
- bpf_regs[insn->dst] = (uint32_t) - (int32_t) insn->imm32;
- break;
case BPF_INSN_LSH32R:
BPF_TRACE ("BPF_INSN_LSH32R\n");
bpf_regs[insn->dst] = (uint32_t) bpf_regs[insn->dst] << bpf_regs[insn->src];
--
2.40.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] sim: bpf: remove negi, neg32i insns
2023-08-21 17:02 [PATCH] sim: bpf: remove negi, neg32i insns David Faust
@ 2023-08-21 17:05 ` Jose E. Marchesi
0 siblings, 0 replies; 2+ messages in thread
From: Jose E. Marchesi @ 2023-08-21 17:05 UTC (permalink / raw)
To: David Faust; +Cc: gdb-patches
Hi Faust.
OK. Thanks.
> The BPF virtual machine does not support neg instructions operating on
> immediates, and these erroneous instructions were recently removed from
> gas. Remove them from the simulator as well.
>
> binutils patch:
> [PATCH] bpf: correct neg and neg32 instruction encoding
> https://sourceware.org/pipermail/binutils/2023-August/129135.html
>
> ---
> sim/bpf/bpf-sim.c | 8 --------
> 1 file changed, 8 deletions(-)
>
> diff --git a/sim/bpf/bpf-sim.c b/sim/bpf/bpf-sim.c
> index 5e01ddeca9f..a4af22b2308 100644
> --- a/sim/bpf/bpf-sim.c
> +++ b/sim/bpf/bpf-sim.c
> @@ -730,10 +730,6 @@ execute (SIM_CPU *cpu, struct bpf_insn *insn)
> BPF_TRACE ("BPF_INSN_NEGR\n");
> bpf_regs[insn->dst] = - (int64_t) bpf_regs[insn->dst];
> break;
> - case BPF_INSN_NEGI:
> - BPF_TRACE ("BPF_INSN_NEGI\n");
> - bpf_regs[insn->dst] = - (int64_t) insn->imm32;
> - break;
> case BPF_INSN_LSHR:
> BPF_TRACE ("BPF_INSN_LSHR\n");
> bpf_regs[insn->dst] <<= bpf_regs[insn->src];
> @@ -867,10 +863,6 @@ execute (SIM_CPU *cpu, struct bpf_insn *insn)
> BPF_TRACE ("BPF_INSN_NEG32R\n");
> bpf_regs[insn->dst] = (uint32_t) (- (int32_t) bpf_regs[insn->dst]);
> break;
> - case BPF_INSN_NEG32I:
> - BPF_TRACE ("BPF_INSN_NEG32I\n");
> - bpf_regs[insn->dst] = (uint32_t) - (int32_t) insn->imm32;
> - break;
> case BPF_INSN_LSH32R:
> BPF_TRACE ("BPF_INSN_LSH32R\n");
> bpf_regs[insn->dst] = (uint32_t) bpf_regs[insn->dst] << bpf_regs[insn->src];
^ permalink raw reply [flat|nested] 2+ messages in thread
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2023-08-21 17:05 ` Jose E. Marchesi
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