diff options
Diffstat (limited to 'linux-user/elfload.c')
| -rw-r--r-- | linux-user/elfload.c | 90 |
1 files changed, 81 insertions, 9 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 88c2b01402..b0723071e2 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -33,6 +33,19 @@ #undef ELF_ARCH #endif +#ifndef TARGET_ARCH_HAS_SIGTRAMP_PAGE +#define TARGET_ARCH_HAS_SIGTRAMP_PAGE 0 +#endif + +typedef struct { + const uint8_t *image; + const uint32_t *relocs; + unsigned image_size; + unsigned reloc_count; + unsigned sigreturn_ofs; + unsigned rt_sigreturn_ofs; +} VdsoImageInfo; + #define ELF_OSABI ELFOSABI_SYSV /* from personality.h */ @@ -2471,7 +2484,8 @@ static abi_ulong loader_build_fdpic_loadmap(struct image_info *info, abi_ulong s static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, struct elfhdr *exec, struct image_info *info, - struct image_info *interp_info) + struct image_info *interp_info, + struct image_info *vdso_info) { abi_ulong sp; abi_ulong u_argc, u_argv, u_envp, u_auxv; @@ -2559,10 +2573,15 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, } size = (DLINFO_ITEMS + 1) * 2; - if (k_base_platform) + if (k_base_platform) { + size += 2; + } + if (k_platform) { size += 2; - if (k_platform) + } + if (vdso_info) { size += 2; + } #ifdef DLINFO_ARCH_ITEMS size += DLINFO_ARCH_ITEMS * 2; #endif @@ -2644,6 +2663,9 @@ static abi_ulong create_elf_tables(abi_ulong p, int argc, int envc, if (u_platform) { NEW_AUX_ENT(AT_PLATFORM, u_platform); } + if (vdso_info) { + NEW_AUX_ENT(AT_SYSINFO_EHDR, vdso_info->load_addr); + } NEW_AUX_ENT (AT_NULL, 0); #undef NEW_AUX_ENT @@ -3521,6 +3543,52 @@ static void load_elf_interp(const char *filename, struct image_info *info, load_elf_image(filename, &src, info, &ehdr, NULL); } +#ifdef VDSO_HEADER +#include VDSO_HEADER +#define vdso_image_info() &vdso_image_info +#else +#define vdso_image_info() NULL +#endif + +static void load_elf_vdso(struct image_info *info, const VdsoImageInfo *vdso) +{ + ImageSource src; + struct elfhdr ehdr; + abi_ulong load_bias, load_addr; + + src.fd = -1; + src.cache = vdso->image; + src.cache_size = vdso->image_size; + + load_elf_image("<internal-vdso>", &src, info, &ehdr, NULL); + load_addr = info->load_addr; + load_bias = info->load_bias; + + /* + * We need to relocate the VDSO image. The one built into the kernel + * is built for a fixed address. The one built for QEMU is not, since + * that requires close control of the guest address space. + * We pre-processed the image to locate all of the addresses that need + * to be updated. + */ + for (unsigned i = 0, n = vdso->reloc_count; i < n; i++) { + abi_ulong *addr = g2h_untagged(load_addr + vdso->relocs[i]); + *addr = tswapal(tswapal(*addr) + load_bias); + } + + /* Install signal trampolines, if present. */ + if (vdso->sigreturn_ofs) { + default_sigreturn = load_addr + vdso->sigreturn_ofs; + } + if (vdso->rt_sigreturn_ofs) { + default_rt_sigreturn = load_addr + vdso->rt_sigreturn_ofs; + } + + /* Remove write from VDSO segment. */ + target_mprotect(info->start_data, info->end_data - info->start_data, + PROT_READ | PROT_EXEC); +} + static int symfind(const void *s0, const void *s1) { struct elf_sym *sym = (struct elf_sym *)s1; @@ -3726,7 +3794,7 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info) * and let elf_load_image do any swapping that may be required. */ struct elfhdr ehdr; - struct image_info interp_info; + struct image_info interp_info, vdso_info; char *elf_interpreter = NULL; char *scratch; @@ -3807,10 +3875,13 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info) } /* - * TODO: load a vdso, which would also contain the signal trampolines. - * Otherwise, allocate a private page to hold them. + * Load a vdso if available, which will amongst other things contain the + * signal trampolines. Otherwise, allocate a separate page for them. */ - if (TARGET_ARCH_HAS_SIGTRAMP_PAGE) { + const VdsoImageInfo *vdso = vdso_image_info(); + if (vdso) { + load_elf_vdso(&vdso_info, vdso); + } else if (TARGET_ARCH_HAS_SIGTRAMP_PAGE) { abi_long tramp_page = target_mmap(0, TARGET_PAGE_SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0); @@ -3822,8 +3893,9 @@ int load_elf_binary(struct linux_binprm *bprm, struct image_info *info) target_mprotect(tramp_page, TARGET_PAGE_SIZE, PROT_READ | PROT_EXEC); } - bprm->p = create_elf_tables(bprm->p, bprm->argc, bprm->envc, &ehdr, - info, (elf_interpreter ? &interp_info : NULL)); + bprm->p = create_elf_tables(bprm->p, bprm->argc, bprm->envc, &ehdr, info, + elf_interpreter ? &interp_info : NULL, + vdso ? &vdso_info : NULL); info->start_stack = bprm->p; /* If we have an interpreter, set that as the program's entry point. |