Re: [PATCH v6 07/19] linux-user: Load vdso image if available

[Philippe Mathieu-Daudé]

On 30/9/23 04:15, Richard Henderson wrote:
> The vdso image will be pre-processed into a C data array, with
> a simple list of relocations to perform, and identifying the
> location of signal trampolines.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   linux-user/elfload.c | 90 +++++++++++++++++++++++++++++++++++++++-----
>   1 file changed, 81 insertions(+), 9 deletions(-)


> @@ -3691,7 +3759,7 @@ int load_elf_binary(struct linux_binprm *bprm, struct 
> image_info *info)
>        * and let elf_load_image do any swapping that may be required.
>        */
>       struct elfhdr ehdr;
> -    struct image_info interp_info;
> +    struct image_info interp_info, vdso_info;
>       char *elf_interpreter = NULL;
>       char *scratch;
>   
> @@ -3772,10 +3840,13 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)
>       }
>   
>       /*
> -     * TODO: load a vdso, which would also contain the signal trampolines.
> -     * Otherwise, allocate a private page to hold them.
> +     * Load a vdso if available, which will amongst other things contain the
> +     * signal trampolines.  Otherwise, allocate a separate page for them.
>        */
> -    if (TARGET_ARCH_HAS_SIGTRAMP_PAGE) {
> +    const VdsoImageInfo *vdso = vdso_image_info();

Declare in prologue? Otherwise,

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> +    if (vdso) {
> +        load_elf_vdso(&vdso_info, vdso);
> +    } else if (TARGET_ARCH_HAS_SIGTRAMP_PAGE) {
>           abi_long tramp_page = target_mmap(0, TARGET_PAGE_SIZE,
>                                             PROT_READ | PROT_WRITE,
>                                             MAP_PRIVATE | MAP_ANON, -1, 0);