diff options
Diffstat (limited to 'libre/qemu-user-static/0005-linux-user-init_guest_space-Clarify-page-alignment-l.patch')
| -rw-r--r-- | libre/qemu-user-static/0005-linux-user-init_guest_space-Clarify-page-alignment-l.patch | 120 |
1 files changed, 0 insertions, 120 deletions
diff --git a/libre/qemu-user-static/0005-linux-user-init_guest_space-Clarify-page-alignment-l.patch b/libre/qemu-user-static/0005-linux-user-init_guest_space-Clarify-page-alignment-l.patch deleted file mode 100644 index 1570774ee..000000000 --- a/libre/qemu-user-static/0005-linux-user-init_guest_space-Clarify-page-alignment-l.patch +++ /dev/null @@ -1,120 +0,0 @@ -From b2432d1b415143a55083782712f11241f194c0ba Mon Sep 17 00:00:00 2001 -From: Luke Shumaker <lukeshu@parabola.nu> -Date: Wed, 27 Dec 2017 20:05:52 -0500 -Subject: [PATCH 05/10] linux-user: init_guest_space: Clarify page alignment - logic - -There are 3 parts to this change: - - Add a comment showing the relative sizes and positions of the blocks of - memory - - introduce and use new aligned_{start,size} instead of adjusting - real_{start_size} - - When we clean up (on failure), munmap(real_start, real_size) instead of - munmap(aligned_start, aligned_size). It *shouldn't* make any - difference, but I will admit that this does mean we are making the - syscall with different values, so this isn't quite a no-op patch. - -Signed-off-by: Luke Shumaker <lukeshu@parabola.nu> ---- - linux-user/elfload.c | 43 +++++++++++++++++++++++++++++++++---------- - 1 file changed, 33 insertions(+), 10 deletions(-) - -diff --git a/linux-user/elfload.c b/linux-user/elfload.c -index f41cecc3cb..22f2632dfa 100644 ---- a/linux-user/elfload.c -+++ b/linux-user/elfload.c -@@ -1827,7 +1827,7 @@ unsigned long init_guest_space(unsigned long host_start, - unsigned long guest_start, - bool fixed) - { -- unsigned long current_start, real_start; -+ unsigned long current_start, aligned_start; - int flags; - - assert(host_start || host_size); -@@ -1853,7 +1853,8 @@ unsigned long init_guest_space(unsigned long host_start, - /* Otherwise, a non-zero size region of memory needs to be mapped - * and validated. */ - while (1) { -- unsigned long real_size = host_size; -+ unsigned long real_start, real_size, aligned_size; -+ aligned_size = real_size = host_size; - - /* Do not use mmap_find_vma here because that is limited to the - * guest address space. We are going to make the -@@ -1867,26 +1868,48 @@ unsigned long init_guest_space(unsigned long host_start, - - /* Ensure the address is properly aligned. */ - if (real_start & ~qemu_host_page_mask) { -+ /* Ideally, we adjust like -+ * -+ * pages: [ ][ ][ ][ ][ ] -+ * old: [ real ] -+ * [ aligned ] -+ * new: [ real ] -+ * [ aligned ] -+ * -+ * But if there is something else mapped right after it, -+ * then obviously it won't have room to grow, and the -+ * kernel will put the new larger real someplace else with -+ * unknown alignment (if we made it to here, then -+ * fixed=false). Which is why we grow real by a full page -+ * size, instead of by part of one; so that even if we get -+ * moved, we can still guarantee alignment. But this does -+ * mean that there is a padding of < 1 page both before -+ * and after the aligned range; the "after" could could -+ * cause problems for ARM emulation where it could butt in -+ * to where we need to put the commpage. -+ */ - munmap((void *)real_start, host_size); -- real_size = host_size + qemu_host_page_size; -+ real_size = aligned_size + qemu_host_page_size; - real_start = (unsigned long) - mmap((void *)real_start, real_size, PROT_NONE, flags, -1, 0); - if (real_start == (unsigned long)-1) { - return (unsigned long)-1; - } -- real_start = HOST_PAGE_ALIGN(real_start); -+ aligned_start = HOST_PAGE_ALIGN(real_start); -+ } else { -+ aligned_start = real_start; - } - - /* Check to see if the address is valid. */ -- if (!host_start || real_start == current_start) { -+ if (!host_start || aligned_start == current_start) { - #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(real_start - guest_start, -- real_size + guest_start); -+ int valid = init_guest_commpage(aligned_start - guest_start, -+ aligned_size + guest_start); - if (valid == 1) { - break; - } else if (valid == -1) { -- munmap((void *)real_start, host_size); -+ munmap((void *)real_start, real_size); - return (unsigned long)-1; - } - /* valid == 0, so try again. */ -@@ -1905,7 +1928,7 @@ unsigned long init_guest_space(unsigned long host_start, - * address space randomization put a shared library somewhere - * inconvenient. - */ -- munmap((void *)real_start, host_size); -+ munmap((void *)real_start, real_size); - current_start += qemu_host_page_size; - if (host_start == current_start) { - /* Theoretically possible if host doesn't have any suitably -@@ -1917,7 +1940,7 @@ unsigned long init_guest_space(unsigned long host_start, - - qemu_log_mask(CPU_LOG_PAGE, "Reserved 0x%lx bytes of guest address space\n", host_size); - -- return real_start; -+ return aligned_start; - } - - static void probe_guest_base(const char *image_name, --- -2.15.1 - |