Commit 33143c44 authored by Laurent Vivier's avatar Laurent Vivier
Browse files

linux-user: fix ELF load alignment error 



When we try to use some targets on ppc64, it can happen the target
doesn't support the host page size to align ELF load sections and
fails with:

  ELF load command alignment not page-aligned

Since commit a70daba3 ("linux-user: Tell guest about big host
page sizes") the host page size is used to align ELF sections, but
this doesn't work if the alignment required by the load section is
smaller than the host one.  For these cases, we continue to use the
TARGET_PAGE_SIZE instead of the host one.

I have tested this change on ppc64, and it fixes qemu linux-user for:
  s390x, m68k, i386, arm, aarch64, hppa
and I have tested it doesn't break the following targets:
  x86_64, mips64el, sh4
mips and mipsel abort, but I think for another reason.

Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
[lv: fixed "info->alignment = 0"]
Message-Id: <20180716195349.29959-1-laurent@vivier.eu>
parent 5b3ecd3d

linux-user/elfload.c

+9 −1
Original line number Diff line number Diff line
@@ -1875,7 +1875,13 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, 
    NEW_AUX_ENT(AT_PHDR, (abi_ulong)(info->load_addr + exec->e_phoff));

    NEW_AUX_ENT(AT_PHENT, (abi_ulong)(sizeof (struct elf_phdr)));

    NEW_AUX_ENT(AT_PHNUM, (abi_ulong)(exec->e_phnum));

    NEW_AUX_ENT(AT_PAGESZ, (abi_ulong)(MAX(TARGET_PAGE_SIZE, getpagesize())));

    if ((info->alignment & ~qemu_host_page_mask) != 0) {

        /* Target doesn't support host page size alignment */

        NEW_AUX_ENT(AT_PAGESZ, (abi_ulong)(TARGET_PAGE_SIZE));

    } else {

        NEW_AUX_ENT(AT_PAGESZ, (abi_ulong)(MAX(TARGET_PAGE_SIZE,

                                               qemu_host_page_size)));

    }

    NEW_AUX_ENT(AT_BASE, (abi_ulong)(interp_info ? interp_info->load_addr : 0));

    NEW_AUX_ENT(AT_FLAGS, (abi_ulong)0);

    NEW_AUX_ENT(AT_ENTRY, info->entry);
@@ -2202,6 +2208,7 @@ static void load_elf_image(const char *image_name, int image_fd, 
    /* Find the maximum size of the image and allocate an appropriate

       amount of memory to handle that.  */

    loaddr = -1, hiaddr = 0;

    info->alignment = 0;

    for (i = 0; i < ehdr->e_phnum; ++i) {

        if (phdr[i].p_type == PT_LOAD) {

            abi_ulong a = phdr[i].p_vaddr - phdr[i].p_offset;
@@ -2213,6 +2220,7 @@ static void load_elf_image(const char *image_name, int image_fd, 
                hiaddr = a;

            }

            ++info->nsegs;

            info->alignment |= phdr[i].p_align;

        }

    }

linux-user/qemu.h

+1 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ struct image_info { 
        abi_ulong       file_string;

        uint32_t        elf_flags;

	int		personality;

        abi_ulong       alignment;



        /* The fields below are used in FDPIC mode.  */

        abi_ulong       loadmap_addr;