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

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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: Luke Shumaker <lukeshu@parabola.nu>
Message-Id: <20171228180814.9749-9-lukeshu@lukeshu.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Luke Shumaker 2017-12-28 13:08:11 -05:00 committed by Laurent Vivier
parent 7ad75eea86
commit aac362e46f
1 changed files with 5 additions and 5 deletions
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10
linux-user/elfload.c
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@ -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,