Commit aac362e4 authored by Luke Shumaker's avatar Luke Shumaker Committed by Laurent Vivier
Browse files

linux-user: init_guest_space: Don't try to align if we'll reject it 



If the ensure-alignment code gets triggered, then the
"if (host_start && real_start != current_start)" check will always trigger,
so save 2 syscalls and put that check first.

Note that we can't just switch to using MAP_FIXED for that check, because
then we couldn't differentiate between a failure because "there isn't
enough space" and "there isn't enough space *here*".

Signed-off-by: default avatarLuke Shumaker <lukeshu@parabola.nu>
Message-Id: <20171228180814.9749-9-lukeshu@lukeshu.com>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
parent 7ad75eea

linux-user/elfload.c

+5 −5
Original line number Diff line number Diff line
@@ -1845,6 +1845,11 @@ unsigned long init_guest_space(unsigned long host_start, 
            return (unsigned long)-1;

        }



        /* Check to see if the address is valid.  */

        if (host_start && real_start != current_start) {

            goto try_again;

        }



        /* Ensure the address is properly aligned.  */

        if (real_start & ~qemu_host_page_mask) {

            /* Ideally, we adjust like
@@ -1879,11 +1884,6 @@ unsigned long init_guest_space(unsigned long host_start, 
            aligned_start = real_start;

        }



        /* Check to see if the address is valid.  */

        if (host_start && aligned_start != current_start) {

            goto try_again;

        }



#if defined(TARGET_ARM) && !defined(TARGET_AARCH64)

        /* On 32-bit ARM, we need to also be able to map the commpage.  */

        int valid = init_guest_commpage(aligned_start - guest_start,