diff options
Diffstat (limited to 'linux-user/elfload.c')
| -rw-r--r-- | linux-user/elfload.c | 130 |
1 files changed, 73 insertions, 57 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index a4aabd5..a13eb7b 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -1288,6 +1288,78 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, return sp; } +static void probe_guest_base(const char *image_name, + abi_ulong loaddr, abi_ulong hiaddr) +{ + /* Probe for a suitable guest base address, if the user has not set + * it explicitly, and set guest_base appropriately. + * In case of error we will print a suitable message and exit. + */ +#if defined(CONFIG_USE_GUEST_BASE) + const char *errmsg; + if (!have_guest_base && !reserved_va) { + unsigned long host_start, real_start, host_size; + + /* Round addresses to page boundaries. */ + loaddr &= qemu_host_page_mask; + hiaddr = HOST_PAGE_ALIGN(hiaddr); + + if (loaddr < mmap_min_addr) { + host_start = HOST_PAGE_ALIGN(mmap_min_addr); + } else { + host_start = loaddr; + if (host_start != loaddr) { + errmsg = "Address overflow loading ELF binary"; + goto exit_errmsg; + } + } + host_size = hiaddr - loaddr; + while (1) { + /* Do not use mmap_find_vma here because that is limited to the + guest address space. We are going to make the + guest address space fit whatever we're given. */ + real_start = (unsigned long) + mmap((void *)host_start, host_size, PROT_NONE, + MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE, -1, 0); + if (real_start == (unsigned long)-1) { + goto exit_perror; + } + if (real_start == host_start) { + break; + } + /* That address didn't work. Unmap and try a different one. + The address the host picked because is typically right at + the top of the host address space and leaves the guest with + no usable address space. Resort to a linear search. We + already compensated for mmap_min_addr, so this should not + happen often. Probably means we got unlucky and host + address space randomization put a shared library somewhere + inconvenient. */ + munmap((void *)real_start, host_size); + host_start += qemu_host_page_size; + if (host_start == loaddr) { + /* Theoretically possible if host doesn't have any suitably + aligned areas. Normally the first mmap will fail. */ + errmsg = "Unable to find space for application"; + goto exit_errmsg; + } + } + qemu_log("Relocating guest address space from 0x" + TARGET_ABI_FMT_lx " to 0x%lx\n", + loaddr, real_start); + guest_base = real_start - loaddr; + } + return; + +exit_perror: + errmsg = strerror(errno); +exit_errmsg: + fprintf(stderr, "%s: %s\n", image_name, errmsg); + exit(-1); +#endif +} + + /* Load an ELF image into the address space. IMAGE_NAME is the filename of the image, to use in error messages. @@ -1373,63 +1445,7 @@ static void load_elf_image(const char *image_name, int image_fd, /* This is the main executable. Make sure that the low address does not conflict with MMAP_MIN_ADDR or the QEMU application itself. */ -#if defined(CONFIG_USE_GUEST_BASE) - /* - * In case where user has not explicitly set the guest_base, we - * probe here that should we set it automatically. - */ - if (!have_guest_base && !reserved_va) { - unsigned long host_start, real_start, host_size; - - /* Round addresses to page boundaries. */ - loaddr &= qemu_host_page_mask; - hiaddr = HOST_PAGE_ALIGN(hiaddr); - - if (loaddr < mmap_min_addr) { - host_start = HOST_PAGE_ALIGN(mmap_min_addr); - } else { - host_start = loaddr; - if (host_start != loaddr) { - errmsg = "Address overflow loading ELF binary"; - goto exit_errmsg; - } - } - host_size = hiaddr - loaddr; - while (1) { - /* Do not use mmap_find_vma here because that is limited to the - guest address space. We are going to make the - guest address space fit whatever we're given. */ - real_start = (unsigned long) - mmap((void *)host_start, host_size, PROT_NONE, - MAP_ANONYMOUS | MAP_PRIVATE | MAP_NORESERVE, -1, 0); - if (real_start == (unsigned long)-1) { - goto exit_perror; - } - if (real_start == host_start) { - break; - } - /* That address didn't work. Unmap and try a different one. - The address the host picked because is typically right at - the top of the host address space and leaves the guest with - no usable address space. Resort to a linear search. We - already compensated for mmap_min_addr, so this should not - happen often. Probably means we got unlucky and host - address space randomization put a shared library somewhere - inconvenient. */ - munmap((void *)real_start, host_size); - host_start += qemu_host_page_size; - if (host_start == loaddr) { - /* Theoretically possible if host doesn't have any suitably - aligned areas. Normally the first mmap will fail. */ - errmsg = "Unable to find space for application"; - goto exit_errmsg; - } - } - qemu_log("Relocating guest address space from 0x" - TARGET_ABI_FMT_lx " to 0x%lx\n", loaddr, real_start); - guest_base = real_start - loaddr; - } -#endif + probe_guest_base(image_name, loaddr, hiaddr); } load_bias = load_addr - loaddr; |
