From af65d64845a90c8f2fc90b97e2148ff74672e979 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Wed, 30 Jan 2008 13:30:43 +0100 Subject: x86 vDSO: consolidate vdso32 This makes x86_64's ia32 emulation support share the sources used in the 32-bit kernel for the 32-bit vDSO and much of its setup code. The 32-bit vDSO mapping now behaves the same on x86_64 as on native 32-bit. The abi.syscall32 sysctl on x86_64 now takes the same values that vm.vdso_enabled takes on the 32-bit kernel. That is, 1 means a randomized vDSO location, 2 means the fixed old address. The CONFIG_COMPAT_VDSO option is now available to make this the default setting, the same meaning it has for the 32-bit kernel. (This does not affect the 64-bit vDSO.) The argument vdso32=[012] can be used on both 32-bit and 64-bit kernels to set this paramter at boot time. The vdso=[012] argument still does this same thing on the 32-bit kernel. Signed-off-by: Roland McGrath Cc: Andrew Morton Cc: Linus Torvalds Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/x86/vdso/Makefile | 2 +- arch/x86/vdso/vdso32-setup.c | 119 +++++++++++++++++++++++++++++++++---------- arch/x86/vdso/vdso32.S | 16 +++--- 3 files changed, 104 insertions(+), 33 deletions(-) (limited to 'arch/x86/vdso') diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile index 1127c716df02..47bc2760e6a8 100644 --- a/arch/x86/vdso/Makefile +++ b/arch/x86/vdso/Makefile @@ -15,7 +15,7 @@ vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vvar.o # files to link into kernel obj-$(VDSO64-y) += vma.o vdso.o -obj-$(CONFIG_X86_32) += vdso32.o vdso32-setup.o +obj-$(VDSO32-y) += vdso32.o vdso32-setup.o vobjs := $(foreach F,$(vobjs-y),$(obj)/$F) diff --git a/arch/x86/vdso/vdso32-setup.c b/arch/x86/vdso/vdso32-setup.c index fb71a93c5dce..d97a6d7d062b 100644 --- a/arch/x86/vdso/vdso32-setup.c +++ b/arch/x86/vdso/vdso32-setup.c @@ -24,6 +24,7 @@ #include #include #include +#include enum { VDSO_DISABLED = 0, @@ -37,14 +38,24 @@ enum { #define VDSO_DEFAULT VDSO_ENABLED #endif +#ifdef CONFIG_X86_64 +#define vdso_enabled sysctl_vsyscall32 +#define arch_setup_additional_pages syscall32_setup_pages +#endif + +/* + * This is the difference between the prelinked addresses in the vDSO images + * and the VDSO_HIGH_BASE address where CONFIG_COMPAT_VDSO places the vDSO + * in the user address space. + */ +#define VDSO_ADDR_ADJUST (VDSO_HIGH_BASE - (unsigned long)VDSO32_PRELINK) + /* * Should the kernel map a VDSO page into processes and pass its * address down to glibc upon exec()? */ unsigned int __read_mostly vdso_enabled = VDSO_DEFAULT; -EXPORT_SYMBOL_GPL(vdso_enabled); - static int __init vdso_setup(char *s) { vdso_enabled = simple_strtoul(s, NULL, 0); @@ -52,9 +63,18 @@ static int __init vdso_setup(char *s) return 1; } -__setup("vdso=", vdso_setup); +/* + * For consistency, the argument vdso32=[012] affects the 32-bit vDSO + * behavior on both 64-bit and 32-bit kernels. + * On 32-bit kernels, vdso=[012] means the same thing. + */ +__setup("vdso32=", vdso_setup); -extern asmlinkage void ia32_sysenter_target(void); +#ifdef CONFIG_X86_32 +__setup_param("vdso=", vdso32_setup, vdso_setup, 0); + +EXPORT_SYMBOL_GPL(vdso_enabled); +#endif static __init void reloc_symtab(Elf32_Ehdr *ehdr, unsigned offset, unsigned size) @@ -79,7 +99,7 @@ static __init void reloc_symtab(Elf32_Ehdr *ehdr, case STT_FUNC: case STT_SECTION: case STT_FILE: - sym->st_value += VDSO_HIGH_BASE; + sym->st_value += VDSO_ADDR_ADJUST; } } } @@ -105,7 +125,7 @@ static __init void reloc_dyn(Elf32_Ehdr *ehdr, unsigned offset) case DT_VERNEED: case DT_ADDRRNGLO ... DT_ADDRRNGHI: /* definitely pointers needing relocation */ - dyn->d_un.d_ptr += VDSO_HIGH_BASE; + dyn->d_un.d_ptr += VDSO_ADDR_ADJUST; break; case DT_ENCODING ... OLD_DT_LOOS-1: @@ -114,7 +134,7 @@ static __init void reloc_dyn(Elf32_Ehdr *ehdr, unsigned offset) they're even */ if (dyn->d_tag >= DT_ENCODING && (dyn->d_tag & 1) == 0) - dyn->d_un.d_ptr += VDSO_HIGH_BASE; + dyn->d_un.d_ptr += VDSO_ADDR_ADJUST; break; case DT_VERDEFNUM: @@ -143,15 +163,15 @@ static __init void relocate_vdso(Elf32_Ehdr *ehdr) int i; BUG_ON(memcmp(ehdr->e_ident, ELFMAG, 4) != 0 || - !elf_check_arch(ehdr) || + !elf_check_arch_ia32(ehdr) || ehdr->e_type != ET_DYN); - ehdr->e_entry += VDSO_HIGH_BASE; + ehdr->e_entry += VDSO_ADDR_ADJUST; /* rebase phdrs */ phdr = (void *)ehdr + ehdr->e_phoff; for (i = 0; i < ehdr->e_phnum; i++) { - phdr[i].p_vaddr += VDSO_HIGH_BASE; + phdr[i].p_vaddr += VDSO_ADDR_ADJUST; /* relocate dynamic stuff */ if (phdr[i].p_type == PT_DYNAMIC) @@ -164,7 +184,7 @@ static __init void relocate_vdso(Elf32_Ehdr *ehdr) if (!(shdr[i].sh_flags & SHF_ALLOC)) continue; - shdr[i].sh_addr += VDSO_HIGH_BASE; + shdr[i].sh_addr += VDSO_ADDR_ADJUST; if (shdr[i].sh_type == SHT_SYMTAB || shdr[i].sh_type == SHT_DYNSYM) @@ -173,6 +193,45 @@ static __init void relocate_vdso(Elf32_Ehdr *ehdr) } } +/* + * These symbols are defined by vdso32.S to mark the bounds + * of the ELF DSO images included therein. + */ +extern const char vdso32_default_start, vdso32_default_end; +extern const char vdso32_sysenter_start, vdso32_sysenter_end; +static struct page *vdso32_pages[1]; + +#ifdef CONFIG_X86_64 + +static int use_sysenter __read_mostly = -1; + +#define vdso32_sysenter() (use_sysenter > 0) + +/* May not be __init: called during resume */ +void syscall32_cpu_init(void) +{ + if (use_sysenter < 0) + use_sysenter = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL); + + /* Load these always in case some future AMD CPU supports + SYSENTER from compat mode too. */ + checking_wrmsrl(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS); + checking_wrmsrl(MSR_IA32_SYSENTER_ESP, 0ULL); + checking_wrmsrl(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target); + + wrmsrl(MSR_CSTAR, ia32_cstar_target); +} + +#define compat_uses_vma 1 + +static inline void map_compat_vdso(int map) +{ +} + +#else /* CONFIG_X86_32 */ + +#define vdso32_sysenter() (boot_cpu_has(X86_FEATURE_SEP)) + void enable_sep_cpu(void) { int cpu = get_cpu(); @@ -210,13 +269,7 @@ static int __init gate_vma_init(void) return 0; } -/* - * These symbols are defined by vsyscall.o to mark the bounds - * of the ELF DSO images included therein. - */ -extern const char vsyscall_int80_start, vsyscall_int80_end; -extern const char vsyscall_sysenter_start, vsyscall_sysenter_end; -static struct page *syscall_pages[1]; +#define compat_uses_vma 0 static void map_compat_vdso(int map) { @@ -227,31 +280,35 @@ static void map_compat_vdso(int map) vdso_mapped = map; - __set_fixmap(FIX_VDSO, page_to_pfn(syscall_pages[0]) << PAGE_SHIFT, + __set_fixmap(FIX_VDSO, page_to_pfn(vdso32_pages[0]) << PAGE_SHIFT, map ? PAGE_READONLY_EXEC : PAGE_NONE); /* flush stray tlbs */ flush_tlb_all(); } +#endif /* CONFIG_X86_64 */ + int __init sysenter_setup(void) { void *syscall_page = (void *)get_zeroed_page(GFP_ATOMIC); const void *vsyscall; size_t vsyscall_len; - syscall_pages[0] = virt_to_page(syscall_page); + vdso32_pages[0] = virt_to_page(syscall_page); +#ifdef CONFIG_X86_32 gate_vma_init(); printk("Compat vDSO mapped to %08lx.\n", __fix_to_virt(FIX_VDSO)); +#endif - if (!boot_cpu_has(X86_FEATURE_SEP)) { - vsyscall = &vsyscall_int80_start; - vsyscall_len = &vsyscall_int80_end - &vsyscall_int80_start; + if (!vdso32_sysenter()) { + vsyscall = &vdso32_default_start; + vsyscall_len = &vdso32_default_end - &vdso32_default_start; } else { - vsyscall = &vsyscall_sysenter_start; - vsyscall_len = &vsyscall_sysenter_end - &vsyscall_sysenter_start; + vsyscall = &vdso32_sysenter_start; + vsyscall_len = &vdso32_sysenter_end - &vdso32_sysenter_start; } memcpy(syscall_page, vsyscall, vsyscall_len); @@ -284,7 +341,9 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack) ret = addr; goto up_fail; } + } + if (compat_uses_vma || !compat) { /* * MAYWRITE to allow gdb to COW and set breakpoints * @@ -298,7 +357,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack) VM_READ|VM_EXEC| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC| VM_ALWAYSDUMP, - syscall_pages); + vdso32_pages); if (ret) goto up_fail; @@ -314,6 +373,12 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int exstack) return ret; } +#ifdef CONFIG_X86_64 + +__initcall(sysenter_setup); + +#else /* CONFIG_X86_32 */ + const char *arch_vma_name(struct vm_area_struct *vma) { if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) @@ -342,3 +407,5 @@ int in_gate_area_no_task(unsigned long addr) { return 0; } + +#endif /* CONFIG_X86_64 */ diff --git a/arch/x86/vdso/vdso32.S b/arch/x86/vdso/vdso32.S index cab020c99c3d..1e36f72cab86 100644 --- a/arch/x86/vdso/vdso32.S +++ b/arch/x86/vdso/vdso32.S @@ -2,14 +2,18 @@ __INITDATA - .globl vsyscall_int80_start, vsyscall_int80_end -vsyscall_int80_start: + .globl vdso32_default_start, vdso32_default_end +vdso32_default_start: +#ifdef CONFIG_X86_32 .incbin "arch/x86/vdso/vdso32-int80.so" -vsyscall_int80_end: +#else + .incbin "arch/x86/vdso/vdso32-syscall.so" +#endif +vdso32_default_end: - .globl vsyscall_sysenter_start, vsyscall_sysenter_end -vsyscall_sysenter_start: + .globl vdso32_sysenter_start, vdso32_sysenter_end +vdso32_sysenter_start: .incbin "arch/x86/vdso/vdso32-sysenter.so" -vsyscall_sysenter_end: +vdso32_sysenter_end: __FINIT -- cgit v1.2.3