Re: [PATCH v2 4/5] linux-user: Add x86_64 vsyscall page to /proc/self/maps

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 1/16/20 8:43 PM, Richard Henderson wrote:
> The page isn't (necessarily) present in the host /proc/self/maps,
> and even if it might be it isn't present in page_flags, and even
> if it was it might not have the same set of page permissions.
> 
> The easiest thing to do, particularly when it comes to the
> "[vsyscall]" note at the end of line, is to special case it.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>   linux-user/syscall.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 171c0caef3..eb867a5296 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -7005,6 +7005,15 @@ static int open_self_maps(void *cpu_env, int fd)
>           }
>       }
>   
> +#ifdef TARGET_X86_64
> +    /*
> +     * We only support execution from the vsyscall page.
> +     * This is as if CONFIG_LEGACY_VSYSCALL_XONLY=y from v5.3.
> +     */
> +    dprintf(fd, "ffffffffff600000-ffffffffff601000 --xp 00000000 00:00 0"
> +                "          [vsyscall]\n");

Can we add a definition for 0xffffffffff600000ull in the previous patch, 
and use it with TARGET_PAGE_MASK here?

> +#endif
> +
>       free(line);
>       fclose(fp);
>   
>