Re: [PATCH v17 02/13] linux-user: Add LoongArch signal support

[Richard Henderson]

On 6/16/22 05:16, Song Gao wrote:
> +static void copy_fpu_to_sigcontext(CPULoongArchState *env,
> +                                   struct extctx_layout *extctx)
> +{
> +    int i;
> +    struct target_sctx_info *info = (struct target_sctx_info 
> *)extctx->fpu.addr;
> +    struct target_fpu_context *fpu_ctx = get_ctx(info);
> +
> +    for (i = 1; i < 32; ++i) {
> +        __put_user(env->fpr[i], &fpu_ctx->regs[i]);
> +    }
> +
> +    fpu_ctx->fcc = read_all_fcc(env);
> +    __put_user(env->fcsr0, &fpu_ctx->fcsr);
> +    __put_user(extctx->fpu.size, &info->size);
> +}

You've failed to set magic.

> +
> +static abi_ulong extframe_alloc(struct extctx_layout *extctx,
> +                                struct ctx_layout *layout,
> +                                size_t size, abi_ulong base)
> +{
> +    abi_ulong new_base = base - size;
> +
> +    new_base -= sizeof(struct target_sctx_info);

Missing ROUND_DOWN.

> +    layout->addr = new_base;
> +    layout->size = (unsigned int)(base - new_base);

Cast not required.

> +static int parse_extcontext(struct target_sigcontext *sc,
> +                             struct extctx_layout *extctx)
> +{
> +    unsigned int size;
> +    struct target_sctx_info *info = (struct target_sctx_info *)
> +                                    &sc->sc_extcontext;
> +
> +    __get_user(size, &info->size);
> +
> +    if (size < (sizeof(struct target_sctx_info) +
> +                sizeof(struct target_fpu_context))) {
> +        return -TARGET_EINVAL;
> +    }
> +
> +    extctx->fpu.addr = (abi_ulong)info;
> +    info = (struct target_sctx_info *)((char *)info + size);
> +
> +    return 0;
> +}

This does not even closely resemble the kernel's parse_extcontext.
You *really* have to be more careful about this.


r~