From 1a21d4e095ef720abf81299000afc038206d571b Mon Sep 17 00:00:00 2001 From: "H. J. Lu" Date: Sun, 19 Feb 2012 11:38:06 -0800 Subject: x32: Add x32 VDSO support Add support for the x32 VDSO. The x32 VDSO takes advantage of the similarity between the x86-64 and the x32 ABIs to contain the same content, only the container is different, as the x32 VDSO obviously is an x32 shared object. Signed-off-by: H. Peter Anvin --- arch/x86/vdso/vma.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 70 insertions(+), 8 deletions(-) (limited to 'arch/x86/vdso/vma.c') diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c index 153407c35b75..1bbcc6205ace 100644 --- a/arch/x86/vdso/vma.c +++ b/arch/x86/vdso/vma.c @@ -24,7 +24,44 @@ extern unsigned short vdso_sync_cpuid; extern struct page *vdso_pages[]; static unsigned vdso_size; -static void __init patch_vdso(void *vdso, size_t len) +#ifdef CONFIG_X86_X32_ABI +extern char vdsox32_start[], vdsox32_end[]; +extern struct page *vdsox32_pages[]; +static unsigned vdsox32_size; + +static void __init patch_vdsox32(void *vdso, size_t len) +{ + Elf32_Ehdr *hdr = vdso; + Elf32_Shdr *sechdrs, *alt_sec = 0; + char *secstrings; + void *alt_data; + int i; + + BUG_ON(len < sizeof(Elf32_Ehdr)); + BUG_ON(memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0); + + sechdrs = (void *)hdr + hdr->e_shoff; + secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; + + for (i = 1; i < hdr->e_shnum; i++) { + Elf32_Shdr *shdr = &sechdrs[i]; + if (!strcmp(secstrings + shdr->sh_name, ".altinstructions")) { + alt_sec = shdr; + goto found; + } + } + + /* If we get here, it's probably a bug. */ + pr_warning("patch_vdsox32: .altinstructions not found\n"); + return; /* nothing to patch */ + +found: + alt_data = (void *)hdr + alt_sec->sh_offset; + apply_alternatives(alt_data, alt_data + alt_sec->sh_size); +} +#endif + +static void __init patch_vdso64(void *vdso, size_t len) { Elf64_Ehdr *hdr = vdso; Elf64_Shdr *sechdrs, *alt_sec = 0; @@ -47,7 +84,7 @@ static void __init patch_vdso(void *vdso, size_t len) } /* If we get here, it's probably a bug. */ - pr_warning("patch_vdso: .altinstructions not found\n"); + pr_warning("patch_vdso64: .altinstructions not found\n"); return; /* nothing to patch */ found: @@ -60,12 +97,20 @@ static int __init init_vdso(void) int npages = (vdso_end - vdso_start + PAGE_SIZE - 1) / PAGE_SIZE; int i; - patch_vdso(vdso_start, vdso_end - vdso_start); + patch_vdso64(vdso_start, vdso_end - vdso_start); vdso_size = npages << PAGE_SHIFT; for (i = 0; i < npages; i++) vdso_pages[i] = virt_to_page(vdso_start + i*PAGE_SIZE); +#ifdef CONFIG_X86_X32_ABI + patch_vdsox32(vdsox32_start, vdsox32_end - vdsox32_start); + npages = (vdsox32_end - vdsox32_start + PAGE_SIZE - 1) / PAGE_SIZE; + vdsox32_size = npages << PAGE_SHIFT; + for (i = 0; i < npages; i++) + vdsox32_pages[i] = virt_to_page(vdsox32_start + i*PAGE_SIZE); +#endif + return 0; } subsys_initcall(init_vdso); @@ -103,7 +148,10 @@ static unsigned long vdso_addr(unsigned long start, unsigned len) /* Setup a VMA at program startup for the vsyscall page. Not called for compat tasks */ -int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +static int setup_additional_pages(struct linux_binprm *bprm, + int uses_interp, + struct page **pages, + unsigned size) { struct mm_struct *mm = current->mm; unsigned long addr; @@ -113,8 +161,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) return 0; down_write(&mm->mmap_sem); - addr = vdso_addr(mm->start_stack, vdso_size); - addr = get_unmapped_area(NULL, addr, vdso_size, 0, 0); + addr = vdso_addr(mm->start_stack, size); + addr = get_unmapped_area(NULL, addr, size, 0, 0); if (IS_ERR_VALUE(addr)) { ret = addr; goto up_fail; @@ -122,11 +170,11 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) current->mm->context.vdso = (void *)addr; - ret = install_special_mapping(mm, addr, vdso_size, + ret = install_special_mapping(mm, addr, size, VM_READ|VM_EXEC| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC| VM_ALWAYSDUMP, - vdso_pages); + pages); if (ret) { current->mm->context.vdso = NULL; goto up_fail; @@ -137,6 +185,20 @@ up_fail: return ret; } +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + return setup_additional_pages (bprm, uses_interp, vdso_pages, + vdso_size); +} + +#ifdef CONFIG_X86_X32_ABI +int x32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + return setup_additional_pages (bprm, uses_interp, vdsox32_pages, + vdsox32_size); +} +#endif + static __init int vdso_setup(char *s) { vdso_enabled = simple_strtoul(s, NULL, 0); -- cgit v1.2.3 From 22e842d4d90ffec9677cc114487a5cefd39b5643 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Tue, 21 Feb 2012 14:32:19 -0800 Subject: x32: Fix coding style violations in the x32 VDSO code Move the prototype for x32_setup_additional_pages() to a header file, and adjust the coding style to match standard. Signed-off-by: H. Peter Anvin Cc: H. J. Lu --- arch/x86/include/asm/elf.h | 2 ++ arch/x86/vdso/vdso32-setup.c | 3 +-- arch/x86/vdso/vma.c | 8 ++++---- 3 files changed, 7 insertions(+), 6 deletions(-) (limited to 'arch/x86/vdso/vma.c') diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index 83aabea95dd7..1e40634591a4 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -331,6 +331,8 @@ struct linux_binprm; #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1 extern int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp); +extern int x32_setup_additional_pages(struct linux_binprm *bprm, + int uses_interp); extern int syscall32_setup_pages(struct linux_binprm *, int exstack); #define compat_arch_setup_additional_pages syscall32_setup_pages diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c index 01b8a0df5e0e..10f9f59477db 100644 --- a/arch/x86/vdso/vdso32-setup.c +++ b/arch/x86/vdso/vdso32-setup.c @@ -318,9 +318,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) bool compat; #ifdef CONFIG_X86_X32_ABI - extern int x32_setup_additional_pages(struct linux_binprm *, int); if (test_thread_flag(TIF_X32)) - return x32_setup_additional_pages (bprm, uses_interp); + return x32_setup_additional_pages(bprm, uses_interp); #endif if (vdso_enabled == VDSO_DISABLED) diff --git a/arch/x86/vdso/vma.c b/arch/x86/vdso/vma.c index 1bbcc6205ace..d7dce1dbf8c9 100644 --- a/arch/x86/vdso/vma.c +++ b/arch/x86/vdso/vma.c @@ -187,15 +187,15 @@ up_fail: int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { - return setup_additional_pages (bprm, uses_interp, vdso_pages, - vdso_size); + return setup_additional_pages(bprm, uses_interp, vdso_pages, + vdso_size); } #ifdef CONFIG_X86_X32_ABI int x32_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { - return setup_additional_pages (bprm, uses_interp, vdsox32_pages, - vdsox32_size); + return setup_additional_pages(bprm, uses_interp, vdsox32_pages, + vdsox32_size); } #endif -- cgit v1.2.3