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SubjectRe: [PATCHv2 2/6] x86/vdso: introduce do_map_vdso() and vdso_type enum
On Wed, Jun 29, 2016 at 3:57 AM, Dmitry Safonov <dsafonov@virtuozzo.com> wrote:
> Make in-kernel API to map vDSO blobs on x86.

I think the addr calculation was already confusing and is now even
worse. How about simplifying it? Get rid of calculate_addr entirely
and push the vdso_addr calls into arch_setup_additional_pages, etc.
Then just use addr directly in the map_vdso code.

> +int do_map_vdso(vdso_type type, unsigned long addr, bool randomize_addr)
> {
> - if (vdso32_enabled != 1) /* Other values all mean "disabled" */
> - return 0;
> -
> - return map_vdso(&vdso_image_32, false);
> -}
> + switch (type) {
> +#if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION)
> + case VDSO_32:
> + if (vdso32_enabled != 1) /* Other values all mean "disabled" */
> + return 0;
> + /* vDSO aslr turned off for i386 vDSO */
> + return map_vdso(&vdso_image_32, addr, false);
> +#endif
> +#ifdef CONFIG_X86_64
> + case VDSO_64:
> + if (!vdso64_enabled)
> + return 0;
> + return map_vdso(&vdso_image_64, addr, randomize_addr);
> +#endif
> +#ifdef CONFIG_X86_X32_ABI
> + case VDSO_X32:
> + if (!vdso64_enabled)
> + return 0;
> + return map_vdso(&vdso_image_x32, addr, randomize_addr);
> #endif
> + default:
> + return -EINVAL;
> + }
> +}

Why is this better than just passing the vdso_image pointer in?

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