Re: [PATCH v4 06/15] mm/execmem, arch: convert simple overrides of module_alloc to execmem

[Peter Zijlstra]

On Thu, Apr 11, 2024 at 07:00:42PM +0300, Mike Rapoport wrote:
> +static struct execmem_info execmem_info __ro_after_init = {
> +     .ranges = {
> +             [EXECMEM_DEFAULT] = {
> +                     .start = MODULES_VADDR,
> +                     .end = MODULES_END,
> +                     .alignment = 1,
> +             },
> +     },
> +};
> +
> +struct execmem_info __init *execmem_arch_setup(void)
>  {
> +     execmem_info.ranges[EXECMEM_DEFAULT].pgprot = PAGE_KERNEL;
> +
> +     return &execmem_info;
>  }

> +static struct execmem_info execmem_info __ro_after_init = {
> +     .ranges = {
> +             [EXECMEM_DEFAULT] = {
> +                     .start = MODULES_VADDR,
> +                     .end = MODULES_END,
> +                     .pgprot = PAGE_KERNEL_EXEC,
> +                     .alignment = 1,
> +             },
> +     },
> +};
> +
> +struct execmem_info __init *execmem_arch_setup(void)
>  {
> +     return &execmem_info;
>  }

> +static struct execmem_info execmem_info __ro_after_init = {
> +     .ranges = {
> +             [EXECMEM_DEFAULT] = {
> +                     .pgprot = PAGE_KERNEL_RWX,
> +                     .alignment = 1,
> +             },
> +     },
> +};
> +
> +struct execmem_info __init *execmem_arch_setup(void)
>  {
> +     execmem_info.ranges[EXECMEM_DEFAULT].start = VMALLOC_START;
> +     execmem_info.ranges[EXECMEM_DEFAULT].end = VMALLOC_END;
> +
> +     return &execmem_info;
>  }

> +static struct execmem_info execmem_info __ro_after_init = {
> +     .ranges = {
> +             [EXECMEM_DEFAULT] = {
> +                     .pgprot = PAGE_KERNEL,
> +                     .alignment = 1,
> +             },
> +     },
> +};
> +
> +struct execmem_info __init *execmem_arch_setup(void)
>  {
> +     execmem_info.ranges[EXECMEM_DEFAULT].start = MODULES_VADDR;
> +     execmem_info.ranges[EXECMEM_DEFAULT].end = MODULES_END;
> +
> +     return &execmem_info;
>  }

> +static struct execmem_info execmem_info __ro_after_init = {
> +     .ranges = {
> +             [EXECMEM_DEFAULT] = {
>  #ifdef CONFIG_SPARC64
> +                     .start = MODULES_VADDR,
> +                     .end = MODULES_END,
>  #else
> +                     .start = VMALLOC_START,
> +                     .end = VMALLOC_END,
> +#endif
> +                     .alignment = 1,
> +             },
> +     },
> +};
> +
> +struct execmem_info __init *execmem_arch_setup(void)
>  {
> +     execmem_info.ranges[EXECMEM_DEFAULT].pgprot = PAGE_KERNEL;
>  
> +     return &execmem_info;
>  }

I'm amazed by the weird and inconsistent breakup of initializations.

What exactly is wrong with something like:

static struct execmem_info execmem_info __ro_after_init;

struct execmem_info __init *execmem_arch_setup(void)
{
        execmem_info = (struct execmem_info){
                .ranges = {
                        [EXECMEM_DEFAULT] = {
                                .start  = MODULES_VADDR,
                                .end    = MODULES_END,
                                .pgprot = PAGE_KERNEL,
                                .alignment = 1,
                        },
                },
        };
        return &execmem_info;
}