x86, vdso: Reimplement vdso.so preparation in build-time C
authorAndy Lutomirski <luto@amacapital.net>
Mon, 5 May 2014 19:19:34 +0000 (12:19 -0700)
committerH. Peter Anvin <hpa@linux.intel.com>
Mon, 5 May 2014 20:18:51 +0000 (13:18 -0700)
Currently, vdso.so files are prepared and analyzed by a combination
of objcopy, nm, some linker script tricks, and some simple ELF
parsers in the kernel.  Replace all of that with plain C code that
runs at build time.

All five vdso images now generate .c files that are compiled and
linked in to the kernel image.

This should cause only one userspace-visible change: the loaded vDSO
images are stripped more heavily than they used to be.  Everything
outside the loadable segment is dropped.  In particular, this causes
the section table and section name strings to be missing.  This
should be fine: real dynamic loaders don't load or inspect these
tables anyway.  The result is roughly equivalent to eu-strip's
--strip-sections option.

The purpose of this change is to enable the vvar and hpet mappings
to be moved to the page following the vDSO load segment.  Currently,
it is possible for the section table to extend into the page after
the load segment, so, if we map it, it risks overlapping the vvar or
hpet page.  This happens whenever the load segment is just under a
multiple of PAGE_SIZE.

The only real subtlety here is that the old code had a C file with
inline assembler that did 'call VDSO32_vsyscall' and a linker script
that defined 'VDSO32_vsyscall = __kernel_vsyscall'.  This most
likely worked by accident: the linker script entry defines a symbol
associated with an address as opposed to an alias for the real
dynamic symbol __kernel_vsyscall.  That caused ld to relocate the
reference at link time instead of leaving an interposable dynamic
relocation.  Since the VDSO32_vsyscall hack is no longer needed, I
now use 'call __kernel_vsyscall', and I added -Bsymbolic to make it
work.  vdso2c will generate an error and abort the build if the
resulting image contains any dynamic relocations, so we won't
silently generate bad vdso images.

(Dynamic relocations are a problem because nothing will even attempt
to relocate the vdso.)

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/2c4fcf45524162a34d87fdda1eb046b2a5cecee7.1399317206.git.luto@amacapital.net
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
18 files changed:
arch/x86/ia32/ia32_signal.c
arch/x86/include/asm/elf.h
arch/x86/include/asm/mmu.h
arch/x86/include/asm/vdso.h
arch/x86/kernel/signal.c
arch/x86/mm/init_64.c
arch/x86/vdso/.gitignore
arch/x86/vdso/Makefile
arch/x86/vdso/vclock_gettime.c
arch/x86/vdso/vdso.S [deleted file]
arch/x86/vdso/vdso2c.c [new file with mode: 0644]
arch/x86/vdso/vdso2c.h [new file with mode: 0644]
arch/x86/vdso/vdso32-setup.c
arch/x86/vdso/vdso32.S [deleted file]
arch/x86/vdso/vdso32/vdso32.lds.S
arch/x86/vdso/vdsox32.S [deleted file]
arch/x86/vdso/vma.c
arch/x86/xen/setup.c

index 220675795e08c9a3d9be1e2e538628e29b1b5543..f9e181aaba979190be8d3d18ebf437c2e3a22e69 100644 (file)
@@ -383,8 +383,8 @@ int ia32_setup_frame(int sig, struct ksignal *ksig,
        } else {
                /* Return stub is in 32bit vsyscall page */
                if (current->mm->context.vdso)
-                       restorer = VDSO32_SYMBOL(current->mm->context.vdso,
-                                                sigreturn);
+                       restorer = current->mm->context.vdso +
+                               selected_vdso32->sym___kernel_sigreturn;
                else
                        restorer = &frame->retcode;
        }
@@ -462,8 +462,8 @@ int ia32_setup_rt_frame(int sig, struct ksignal *ksig,
                if (ksig->ka.sa.sa_flags & SA_RESTORER)
                        restorer = ksig->ka.sa.sa_restorer;
                else
-                       restorer = VDSO32_SYMBOL(current->mm->context.vdso,
-                                                rt_sigreturn);
+                       restorer = current->mm->context.vdso +
+                               selected_vdso32->sym___kernel_rt_sigreturn;
                put_user_ex(ptr_to_compat(restorer), &frame->pretcode);
 
                /*
index e96df2c0dd6910a343d2754821373d923d698105..65b21bcbe9f7fa16eae5962ce2778821859ed9c9 100644 (file)
@@ -299,7 +299,7 @@ do {                                                                        \
 do {                                                                   \
        if (vdso64_enabled)                                             \
                NEW_AUX_ENT(AT_SYSINFO_EHDR,                            \
-                           (unsigned long)current->mm->context.vdso);  \
+                           (unsigned long __force)current->mm->context.vdso); \
 } while (0)
 
 /* As a historical oddity, the x32 and x86_64 vDSOs are controlled together. */
@@ -307,7 +307,7 @@ do {                                                                        \
 do {                                                                   \
        if (vdso64_enabled)                                             \
                NEW_AUX_ENT(AT_SYSINFO_EHDR,                            \
-                           (unsigned long)current->mm->context.vdso);  \
+                           (unsigned long __force)current->mm->context.vdso); \
 } while (0)
 
 #define AT_SYSINFO             32
@@ -325,7 +325,8 @@ else                                                                        \
 #define VDSO_CURRENT_BASE      ((unsigned long)current->mm->context.vdso)
 
 #define VDSO_ENTRY                                                     \
-       ((unsigned long)VDSO32_SYMBOL(VDSO_CURRENT_BASE, vsyscall))
+       ((unsigned long)current->mm->context.vdso +                     \
+        selected_vdso32->sym___kernel_vsyscall)
 
 struct linux_binprm;
 
index 5f55e69627692f9a353355bbb426ef8bf73fc44c..876e74e8eec76696b5523210292e71e1c861d5f6 100644 (file)
@@ -18,7 +18,7 @@ typedef struct {
 #endif
 
        struct mutex lock;
-       void *vdso;
+       void __user *vdso;
 } mm_context_t;
 
 #ifdef CONFIG_SMP
index d1dc55404ff127b48e481fe2c31bd73e1e15a5bf..389fe2ca27c2ccebb32f7b272d5eda3c2efcfa3f 100644 (file)
@@ -3,63 +3,43 @@
 
 #include <asm/page_types.h>
 #include <linux/linkage.h>
+#include <linux/init.h>
 
-#ifdef __ASSEMBLER__
+#ifndef __ASSEMBLER__
 
-#define DEFINE_VDSO_IMAGE(symname, filename)                           \
-__PAGE_ALIGNED_DATA ;                                                  \
-       .globl symname##_start, symname##_end ;                         \
-       .align PAGE_SIZE ;                                              \
-       symname##_start: ;                                              \
-       .incbin filename ;                                              \
-       symname##_end: ;                                                \
-       .align PAGE_SIZE /* extra data here leaks to userspace. */ ;    \
-                                                                       \
-.previous ;                                                            \
-                                                                       \
-       .globl symname##_pages ;                                        \
-       .bss ;                                                          \
-       .align 8 ;                                                      \
-       .type symname##_pages, @object ;                                \
-       symname##_pages: ;                                              \
-       .zero (symname##_end - symname##_start + PAGE_SIZE - 1) / PAGE_SIZE * (BITS_PER_LONG / 8) ; \
-       .size symname##_pages, .-symname##_pages
+struct vdso_image {
+       void *data;
+       unsigned long size;   /* Always a multiple of PAGE_SIZE */
+       struct page **pages;  /* Big enough for data/size page pointers */
 
-#else
+       unsigned long alt, alt_len;
 
-#define DECLARE_VDSO_IMAGE(symname)                            \
-       extern char symname##_start[], symname##_end[];         \
-       extern struct page *symname##_pages[]
+       unsigned long sym_VDSO32_NOTE_MASK;
+       unsigned long sym___kernel_sigreturn;
+       unsigned long sym___kernel_rt_sigreturn;
+       unsigned long sym___kernel_vsyscall;
+       unsigned long sym_VDSO32_SYSENTER_RETURN;
+};
 
-#if defined CONFIG_X86_32 || defined CONFIG_COMPAT
+#ifdef CONFIG_X86_64
+extern const struct vdso_image vdso_image_64;
+#endif
 
-#include <asm/vdso32.h>
+#ifdef CONFIG_X86_X32
+extern const struct vdso_image vdso_image_x32;
+#endif
 
-DECLARE_VDSO_IMAGE(vdso32_int80);
+#if defined CONFIG_X86_32 || defined CONFIG_COMPAT
+extern const struct vdso_image vdso_image_32_int80;
 #ifdef CONFIG_COMPAT
-DECLARE_VDSO_IMAGE(vdso32_syscall);
+extern const struct vdso_image vdso_image_32_syscall;
 #endif
-DECLARE_VDSO_IMAGE(vdso32_sysenter);
+extern const struct vdso_image vdso_image_32_sysenter;
 
-/*
- * Given a pointer to the vDSO image, find the pointer to VDSO32_name
- * as that symbol is defined in the vDSO sources or linker script.
- */
-#define VDSO32_SYMBOL(base, name)                                      \
-({                                                                     \
-       extern const char VDSO32_##name[];                              \
-       (void __user *)(VDSO32_##name + (unsigned long)(base));         \
-})
+extern const struct vdso_image *selected_vdso32;
 #endif
 
-/*
- * These symbols are defined with the addresses in the vsyscall page.
- * See vsyscall-sigreturn.S.
- */
-extern void __user __kernel_sigreturn;
-extern void __user __kernel_rt_sigreturn;
-
-void __init patch_vdso32(void *vdso, size_t len);
+extern void __init init_vdso_image(const struct vdso_image *image);
 
 #endif /* __ASSEMBLER__ */
 
index 9e5de6813e1fa7dfa11eab1beff350fa188afb97..a0da58db43a86ea9f2ec85154cd46bc2828c822e 100644 (file)
@@ -298,7 +298,8 @@ __setup_frame(int sig, struct ksignal *ksig, sigset_t *set,
        }
 
        if (current->mm->context.vdso)
-               restorer = VDSO32_SYMBOL(current->mm->context.vdso, sigreturn);
+               restorer = current->mm->context.vdso +
+                       selected_vdso32->sym___kernel_sigreturn;
        else
                restorer = &frame->retcode;
        if (ksig->ka.sa.sa_flags & SA_RESTORER)
@@ -361,7 +362,8 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
                save_altstack_ex(&frame->uc.uc_stack, regs->sp);
 
                /* Set up to return from userspace.  */
-               restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
+               restorer = current->mm->context.vdso +
+                       selected_vdso32->sym___kernel_sigreturn;
                if (ksig->ka.sa.sa_flags & SA_RESTORER)
                        restorer = ksig->ka.sa.sa_restorer;
                put_user_ex(restorer, &frame->pretcode);
index f35c66c5959ac0042fbf9ff43a76cf55f89d9d0f..563849600d3eac66f1a6522342d738683aa4d4ac 100644 (file)
@@ -1223,7 +1223,8 @@ int in_gate_area_no_mm(unsigned long addr)
 
 const char *arch_vma_name(struct vm_area_struct *vma)
 {
-       if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
+       if (vma->vm_mm && vma->vm_start ==
+           (long __force)vma->vm_mm->context.vdso)
                return "[vdso]";
        if (vma == &gate_vma)
                return "[vsyscall]";
index 3282874bc61dd11bce83fd65687edff744dacf6c..aae8ffdd58808a16573bcdf97ea261f7d0754b18 100644 (file)
@@ -1,8 +1,7 @@
 vdso.lds
-vdso-syms.lds
 vdsox32.lds
-vdsox32-syms.lds
-vdso32-syms.lds
 vdso32-syscall-syms.lds
 vdso32-sysenter-syms.lds
 vdso32-int80-syms.lds
+vdso-image-*.c
+vdso2c
index c580d1210ffe98866aa72582a5a56c81089362a8..895d4b16b7e32ad834971f2509887ba63e476655 100644 (file)
@@ -24,15 +24,30 @@ vobj64s := $(filter-out $(vobjx32s-compat),$(vobjs-y))
 
 # files to link into kernel
 obj-y                          += vma.o
-obj-$(VDSO64-y)                        += vdso.o
-obj-$(VDSOX32-y)               += vdsox32.o
-obj-$(VDSO32-y)                        += vdso32.o vdso32-setup.o
+
+# vDSO images to build
+vdso_img-$(VDSO64-y)           += 64
+vdso_img-$(VDSOX32-y)          += x32
+vdso_img-$(VDSO32-y)           += 32-int80
+vdso_img-$(CONFIG_COMPAT)      += 32-syscall
+vdso_img-$(VDSO32-y)           += 32-sysenter
+
+obj-$(VDSO32-y)                        += vdso32-setup.o
 
 vobjs := $(foreach F,$(vobj64s),$(obj)/$F)
 
 $(obj)/vdso.o: $(obj)/vdso.so
 
-targets += vdso.so vdso.so.dbg vdso.lds $(vobjs-y)
+targets += vdso.lds $(vobjs-y)
+
+# Build the vDSO image C files and link them in.
+vdso_img_objs := $(vdso_img-y:%=vdso-image-%.o)
+vdso_img_cfiles := $(vdso_img-y:%=vdso-image-%.c)
+vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
+obj-y += $(vdso_img_objs)
+targets += $(vdso_img_cfiles)
+targets += $(vdso_img_sodbg)
+.SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c)
 
 export CPPFLAGS_vdso.lds += -P -C
 
@@ -41,14 +56,18 @@ VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
                        -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 \
                        $(DISABLE_LTO)
 
-$(obj)/vdso.o: $(src)/vdso.S $(obj)/vdso.so
-
-$(obj)/vdso.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
+$(obj)/vdso64.so.dbg: $(src)/vdso.lds $(vobjs) FORCE
        $(call if_changed,vdso)
 
-$(obj)/%.so: OBJCOPYFLAGS := -S
-$(obj)/%.so: $(obj)/%.so.dbg FORCE
-       $(call if_changed,objcopy)
+hostprogs-y                    += vdso2c
+
+quiet_cmd_vdso2c = VDSO2C  $@
+define cmd_vdso2c
+       $(obj)/vdso2c $< $@
+endef
+
+$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso2c FORCE
+       $(call if_changed,vdso2c)
 
 #
 # Don't omit frame pointers for ease of userspace debugging, but do
@@ -68,22 +87,6 @@ CFLAGS_REMOVE_vclock_gettime.o = -pg
 CFLAGS_REMOVE_vgetcpu.o = -pg
 CFLAGS_REMOVE_vvar.o = -pg
 
-targets += vdso-syms.lds
-obj-$(VDSO64-y)                        += vdso-syms.lds
-
-#
-# Match symbols in the DSO that look like VDSO*; produce a file of constants.
-#
-sed-vdsosym := -e 's/^00*/0/' \
-       -e 's/^\([0-9a-fA-F]*\) . \(VDSO[a-zA-Z0-9_]*\)$$/\2 = 0x\1;/p'
-quiet_cmd_vdsosym = VDSOSYM $@
-define cmd_vdsosym
-       $(NM) $< | LC_ALL=C sed -n $(sed-vdsosym) | LC_ALL=C sort > $@
-endef
-
-$(obj)/%-syms.lds: $(obj)/%.so.dbg FORCE
-       $(call if_changed,vdsosym)
-
 #
 # X32 processes use x32 vDSO to access 64bit kernel data.
 #
@@ -94,9 +97,6 @@ $(obj)/%-syms.lds: $(obj)/%.so.dbg FORCE
 # so that it can reach 64bit address space with 64bit pointers.
 #
 
-targets += vdsox32-syms.lds
-obj-$(VDSOX32-y)               += vdsox32-syms.lds
-
 CPPFLAGS_vdsox32.lds = $(CPPFLAGS_vdso.lds)
 VDSO_LDFLAGS_vdsox32.lds = -Wl,-m,elf32_x86_64 \
                           -Wl,-soname=linux-vdso.so.1 \
@@ -113,9 +113,7 @@ quiet_cmd_x32 = X32     $@
 $(obj)/%-x32.o: $(obj)/%.o FORCE
        $(call if_changed,x32)
 
-targets += vdsox32.so vdsox32.so.dbg vdsox32.lds $(vobjx32s-y)
-
-$(obj)/vdsox32.o: $(src)/vdsox32.S $(obj)/vdsox32.so
+targets += vdsox32.lds $(vobjx32s-y)
 
 $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
        $(call if_changed,vdso)
@@ -123,7 +121,6 @@ $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
 #
 # Build multiple 32-bit vDSO images to choose from at boot time.
 #
-obj-$(VDSO32-y)                        += vdso32-syms.lds
 vdso32.so-$(VDSO32-y)          += int80
 vdso32.so-$(CONFIG_COMPAT)     += syscall
 vdso32.so-$(VDSO32-y)          += sysenter
@@ -138,10 +135,8 @@ VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf_i386 -Wl,-soname=linux-gate.so.1
 override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
 
 targets += vdso32/vdso32.lds
-targets += $(vdso32-images) $(vdso32-images:=.dbg)
 targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o)
-
-extra-y        += $(vdso32-images)
+targets += vdso32/vclock_gettime.o
 
 $(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%)
 
@@ -166,27 +161,6 @@ $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
                                 $(obj)/vdso32/%.o
        $(call if_changed,vdso)
 
-# Make vdso32-*-syms.lds from each image, and then make sure they match.
-# The only difference should be that some do not define VDSO32_SYSENTER_RETURN.
-
-targets += vdso32-syms.lds $(vdso32.so-y:%=vdso32-%-syms.lds)
-
-quiet_cmd_vdso32sym = VDSOSYM $@
-define cmd_vdso32sym
-       if LC_ALL=C sort -u $(filter-out FORCE,$^) > $(@D)/.tmp_$(@F) && \
-          $(foreach H,$(filter-out FORCE,$^),\
-                    if grep -q VDSO32_SYSENTER_RETURN $H; \
-                    then diff -u $(@D)/.tmp_$(@F) $H; \
-                    else sed /VDSO32_SYSENTER_RETURN/d $(@D)/.tmp_$(@F) | \
-                         diff -u - $H; fi &&) : ;\
-       then mv -f $(@D)/.tmp_$(@F) $@; \
-       else rm -f $(@D)/.tmp_$(@F); exit 1; \
-       fi
-endef
-
-$(obj)/vdso32-syms.lds: $(vdso32.so-y:%=$(obj)/vdso32-%-syms.lds) FORCE
-       $(call if_changed,vdso32sym)
-
 #
 # The DSO images are built using a special linker script.
 #
@@ -197,7 +171,7 @@ quiet_cmd_vdso = VDSO    $@
                 sh $(srctree)/$(src)/checkundef.sh '$(NM)' '$@'
 
 VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \
-               $(LTO_CFLAGS)
+       -Wl,-Bsymbolic $(LTO_CFLAGS)
 GCOV_PROFILE := n
 
 #
index 16d686171e9af802161a82e89b3b507a7162b6c0..091554c20bc931103ed29d3498472afcfef0a8a4 100644 (file)
@@ -154,7 +154,7 @@ notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
        asm(
                "mov %%ebx, %%edx \n"
                "mov %2, %%ebx \n"
-               "call VDSO32_vsyscall \n"
+               "call __kernel_vsyscall \n"
                "mov %%edx, %%ebx \n"
                : "=a" (ret)
                : "0" (__NR_clock_gettime), "g" (clock), "c" (ts)
@@ -169,7 +169,7 @@ notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
        asm(
                "mov %%ebx, %%edx \n"
                "mov %2, %%ebx \n"
-               "call VDSO32_vsyscall \n"
+               "call __kernel_vsyscall \n"
                "mov %%edx, %%ebx \n"
                : "=a" (ret)
                : "0" (__NR_gettimeofday), "g" (tv), "c" (tz)
diff --git a/arch/x86/vdso/vdso.S b/arch/x86/vdso/vdso.S
deleted file mode 100644 (file)
index be3f23b..0000000
+++ /dev/null
@@ -1,3 +0,0 @@
-#include <asm/vdso.h>
-
-DEFINE_VDSO_IMAGE(vdso, "arch/x86/vdso/vdso.so")
diff --git a/arch/x86/vdso/vdso2c.c b/arch/x86/vdso/vdso2c.c
new file mode 100644 (file)
index 0000000..976e8e4
--- /dev/null
@@ -0,0 +1,142 @@
+#include <inttypes.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+#include <err.h>
+
+#include <sys/mman.h>
+#include <sys/types.h>
+
+#include <linux/elf.h>
+#include <linux/types.h>
+
+/* Symbols that we need in vdso2c. */
+char const * const required_syms[] = {
+       "VDSO32_NOTE_MASK",
+       "VDSO32_SYSENTER_RETURN",
+       "__kernel_vsyscall",
+       "__kernel_sigreturn",
+       "__kernel_rt_sigreturn",
+};
+
+__attribute__((format(printf, 1, 2))) __attribute__((noreturn))
+static void fail(const char *format, ...)
+{
+       va_list ap;
+       va_start(ap, format);
+       fprintf(stderr, "Error: ");
+       vfprintf(stderr, format, ap);
+       exit(1);
+       va_end(ap);
+}
+
+#define NSYMS (sizeof(required_syms) / sizeof(required_syms[0]))
+
+#define BITS 64
+#define GOFUNC go64
+#define Elf_Ehdr Elf64_Ehdr
+#define Elf_Shdr Elf64_Shdr
+#define Elf_Phdr Elf64_Phdr
+#define Elf_Sym Elf64_Sym
+#define Elf_Dyn Elf64_Dyn
+#include "vdso2c.h"
+#undef BITS
+#undef GOFUNC
+#undef Elf_Ehdr
+#undef Elf_Shdr
+#undef Elf_Phdr
+#undef Elf_Sym
+#undef Elf_Dyn
+
+#define BITS 32
+#define GOFUNC go32
+#define Elf_Ehdr Elf32_Ehdr
+#define Elf_Shdr Elf32_Shdr
+#define Elf_Phdr Elf32_Phdr
+#define Elf_Sym Elf32_Sym
+#define Elf_Dyn Elf32_Dyn
+#include "vdso2c.h"
+#undef BITS
+#undef GOFUNC
+#undef Elf_Ehdr
+#undef Elf_Shdr
+#undef Elf_Phdr
+#undef Elf_Sym
+#undef Elf_Dyn
+
+static int go(void *addr, size_t len, FILE *outfile, const char *name)
+{
+       Elf64_Ehdr *hdr = (Elf64_Ehdr *)addr;
+
+       if (hdr->e_ident[EI_CLASS] == ELFCLASS64) {
+               return go64(addr, len, outfile, name);
+       } else if (hdr->e_ident[EI_CLASS] == ELFCLASS32) {
+               return go32(addr, len, outfile, name);
+       } else {
+               fprintf(stderr, "Error: unknown ELF class\n");
+               return 1;
+       }
+}
+
+int main(int argc, char **argv)
+{
+       int fd;
+       off_t len;
+       void *addr;
+       FILE *outfile;
+       int ret;
+       char *name, *tmp;
+       int namelen;
+
+       if (argc != 3) {
+               printf("Usage: vdso2c INPUT OUTPUT\n");
+               return 1;
+       }
+
+       /*
+        * Figure out the struct name.  If we're writing to a .so file,
+        * generate raw output insted.
+        */
+       name = strdup(argv[2]);
+       namelen = strlen(name);
+       if (namelen >= 3 && !strcmp(name + namelen - 3, ".so")) {
+               name = NULL;
+       } else {
+               tmp = strrchr(name, '/');
+               if (tmp)
+                       name = tmp + 1;
+               tmp = strchr(name, '.');
+               if (tmp)
+                       *tmp = '\0';
+               for (tmp = name; *tmp; tmp++)
+                       if (*tmp == '-')
+                               *tmp = '_';
+       }
+
+       fd = open(argv[1], O_RDONLY);
+       if (fd == -1)
+               err(1, "%s", argv[1]);
+
+       len = lseek(fd, 0, SEEK_END);
+       if (len == (off_t)-1)
+               err(1, "lseek");
+
+       addr = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
+       if (addr == MAP_FAILED)
+               err(1, "mmap");
+
+       outfile = fopen(argv[2], "w");
+       if (!outfile)
+               err(1, "%s", argv[2]);
+
+       ret = go(addr, (size_t)len, outfile, name);
+
+       munmap(addr, len);
+       fclose(outfile);
+
+       return ret;
+}
diff --git a/arch/x86/vdso/vdso2c.h b/arch/x86/vdso/vdso2c.h
new file mode 100644 (file)
index 0000000..9276e52
--- /dev/null
@@ -0,0 +1,137 @@
+/*
+ * This file is included twice from vdso2c.c.  It generates code for 32-bit
+ * and 64-bit vDSOs.  We need both for 64-bit builds, since 32-bit vDSOs
+ * are built for 32-bit userspace.
+ */
+
+static int GOFUNC(void *addr, size_t len, FILE *outfile, const char *name)
+{
+       int found_load = 0;
+       unsigned long load_size = -1;  /* Work around bogus warning */
+       unsigned long data_size;
+       Elf_Ehdr *hdr = (Elf_Ehdr *)addr;
+       int i;
+       unsigned long j;
+       Elf_Shdr *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
+               *alt_sec = NULL;
+       Elf_Dyn *dyn = 0, *dyn_end = 0;
+       const char *secstrings;
+       uint64_t syms[NSYMS] = {};
+
+       Elf_Phdr *pt = (Elf_Phdr *)(addr + hdr->e_phoff);
+
+       /* Walk the segment table. */
+       for (i = 0; i < hdr->e_phnum; i++) {
+               if (pt[i].p_type == PT_LOAD) {
+                       if (found_load)
+                               fail("multiple PT_LOAD segs\n");
+
+                       if (pt[i].p_offset != 0 || pt[i].p_vaddr != 0)
+                               fail("PT_LOAD in wrong place\n");
+
+                       if (pt[i].p_memsz != pt[i].p_filesz)
+                               fail("cannot handle memsz != filesz\n");
+
+                       load_size = pt[i].p_memsz;
+                       found_load = 1;
+               } else if (pt[i].p_type == PT_DYNAMIC) {
+                       dyn = addr + pt[i].p_offset;
+                       dyn_end = addr + pt[i].p_offset + pt[i].p_memsz;
+               }
+       }
+       if (!found_load)
+               fail("no PT_LOAD seg\n");
+       data_size = (load_size + 4095) / 4096 * 4096;
+
+       /* Walk the dynamic table */
+       for (i = 0; dyn + i < dyn_end && dyn[i].d_tag != DT_NULL; i++) {
+               if (dyn[i].d_tag == DT_REL || dyn[i].d_tag == DT_RELSZ ||
+                   dyn[i].d_tag == DT_RELENT || dyn[i].d_tag == DT_TEXTREL)
+                       fail("vdso image contains dynamic relocations\n");
+       }
+
+       /* Walk the section table */
+       secstrings_hdr = addr + hdr->e_shoff + hdr->e_shentsize*hdr->e_shstrndx;
+       secstrings = addr + secstrings_hdr->sh_offset;
+       for (i = 0; i < hdr->e_shnum; i++) {
+               Elf_Shdr *sh = addr + hdr->e_shoff + hdr->e_shentsize * i;
+               if (sh->sh_type == SHT_SYMTAB)
+                       symtab_hdr = sh;
+
+               if (!strcmp(secstrings + sh->sh_name, ".altinstructions"))
+                       alt_sec = sh;
+       }
+
+       if (!symtab_hdr) {
+               fail("no symbol table\n");
+               return 1;
+       }
+
+       strtab_hdr = addr + hdr->e_shoff +
+               hdr->e_shentsize * symtab_hdr->sh_link;
+
+       /* Walk the symbol table */
+       for (i = 0; i < symtab_hdr->sh_size / symtab_hdr->sh_entsize; i++) {
+               int k;
+               Elf_Sym *sym = addr + symtab_hdr->sh_offset +
+                       symtab_hdr->sh_entsize * i;
+               const char *name = addr + strtab_hdr->sh_offset + sym->st_name;
+               for (k = 0; k < NSYMS; k++) {
+                       if (!strcmp(name, required_syms[k])) {
+                               if (syms[k]) {
+                                       fail("duplicate symbol %s\n",
+                                            required_syms[k]);
+                               }
+                               syms[k] = sym->st_value;
+                       }
+               }
+       }
+
+       /* Remove sections. */
+       hdr->e_shoff = 0;
+       hdr->e_shentsize = 0;
+       hdr->e_shnum = 0;
+       hdr->e_shstrndx = SHN_UNDEF;
+
+       if (!name) {
+               fwrite(addr, load_size, 1, outfile);
+               return 0;
+       }
+
+       fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
+       fprintf(outfile, "#include <linux/linkage.h>\n");
+       fprintf(outfile, "#include <asm/page_types.h>\n");
+       fprintf(outfile, "#include <asm/vdso.h>\n");
+       fprintf(outfile, "\n");
+       fprintf(outfile,
+               "static unsigned char raw_data[%lu] __page_aligned_data = {",
+               data_size);
+       for (j = 0; j < load_size; j++) {
+               if (j % 10 == 0)
+                       fprintf(outfile, "\n\t");
+               fprintf(outfile, "0x%02X, ", (int)((unsigned char *)addr)[j]);
+       }
+       fprintf(outfile, "\n};\n\n");
+
+       fprintf(outfile, "static struct page *pages[%lu];\n\n",
+               data_size / 4096);
+
+       fprintf(outfile, "const struct vdso_image %s = {\n", name);
+       fprintf(outfile, "\t.data = raw_data,\n");
+       fprintf(outfile, "\t.size = %lu,\n", data_size);
+       fprintf(outfile, "\t.pages = pages,\n");
+       if (alt_sec) {
+               fprintf(outfile, "\t.alt = %lu,\n",
+                       (unsigned long)alt_sec->sh_offset);
+               fprintf(outfile, "\t.alt_len = %lu,\n",
+                       (unsigned long)alt_sec->sh_size);
+       }
+       for (i = 0; i < NSYMS; i++) {
+               if (syms[i])
+                       fprintf(outfile, "\t.sym_%s = 0x%" PRIx64 ",\n",
+                               required_syms[i], syms[i]);
+       }
+       fprintf(outfile, "};\n");
+
+       return 0;
+}
index 9c78d5b24874d8f873962ebb10d61f7e4c45c263..d41460118a28d530da7b3c99dc611cb6dc2b5510 100644 (file)
@@ -29,6 +29,7 @@
 #include <asm/fixmap.h>
 #include <asm/hpet.h>
 #include <asm/vvar.h>
+#include <asm/vdso32.h>
 
 #ifdef CONFIG_COMPAT_VDSO
 #define VDSO_DEFAULT   0
@@ -67,9 +68,6 @@ __setup("vdso32=", vdso32_setup);
 __setup_param("vdso=", vdso_setup, vdso32_setup, 0);
 #endif
 
-static struct page **vdso32_pages;
-static unsigned vdso32_size;
-
 #ifdef CONFIG_X86_64
 
 #define        vdso32_sysenter()       (boot_cpu_has(X86_FEATURE_SYSENTER32))
@@ -82,34 +80,23 @@ static unsigned vdso32_size;
 
 #endif /* CONFIG_X86_64 */
 
+#if defined(CONFIG_X86_32) || defined(CONFIG_COMPAT)
+const struct vdso_image *selected_vdso32;
+#endif
+
 int __init sysenter_setup(void)
 {
-       char *vdso32_start, *vdso32_end;
-       int npages, i;
-
 #ifdef CONFIG_COMPAT
-       if (vdso32_syscall()) {
-               vdso32_start = vdso32_syscall_start;
-               vdso32_end = vdso32_syscall_end;
-               vdso32_pages = vdso32_syscall_pages;
-       } else
+       if (vdso32_syscall())
+               selected_vdso32 = &vdso_image_32_syscall;
+       else
 #endif
-       if (vdso32_sysenter()) {
-               vdso32_start = vdso32_sysenter_start;
-               vdso32_end = vdso32_sysenter_end;
-               vdso32_pages = vdso32_sysenter_pages;
-       } else {
-               vdso32_start = vdso32_int80_start;
-               vdso32_end = vdso32_int80_end;
-               vdso32_pages = vdso32_int80_pages;
-       }
-
-       npages = ((vdso32_end - vdso32_start) + PAGE_SIZE - 1) / PAGE_SIZE;
-       vdso32_size = npages << PAGE_SHIFT;
-       for (i = 0; i < npages; i++)
-               vdso32_pages[i] = virt_to_page(vdso32_start + i*PAGE_SIZE);
+       if (vdso32_sysenter())
+               selected_vdso32 = &vdso_image_32_sysenter;
+       else
+               selected_vdso32 = &vdso_image_32_int80;
 
-       patch_vdso32(vdso32_start, vdso32_size);
+       init_vdso_image(selected_vdso32);
 
        return 0;
 }
@@ -121,6 +108,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
        unsigned long addr;
        int ret = 0;
        struct vm_area_struct *vma;
+       unsigned long vdso32_size = selected_vdso32->size;
 
 #ifdef CONFIG_X86_X32_ABI
        if (test_thread_flag(TIF_X32))
@@ -140,7 +128,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
        addr += VDSO_OFFSET(VDSO_PREV_PAGES);
 
-       current->mm->context.vdso = (void *)addr;
+       current->mm->context.vdso = (void __user *)addr;
 
        /*
         * MAYWRITE to allow gdb to COW and set breakpoints
@@ -150,7 +138,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
                        vdso32_size,
                        VM_READ|VM_EXEC|
                        VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
-                       vdso32_pages);
+                       selected_vdso32->pages);
 
        if (ret)
                goto up_fail;
@@ -188,8 +176,10 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
        }
 #endif
 
-       current_thread_info()->sysenter_return =
-               VDSO32_SYMBOL(addr, SYSENTER_RETURN);
+       if (selected_vdso32->sym_VDSO32_SYSENTER_RETURN)
+               current_thread_info()->sysenter_return =
+                       current->mm->context.vdso +
+                       selected_vdso32->sym_VDSO32_SYSENTER_RETURN;
 
   up_fail:
        if (ret)
diff --git a/arch/x86/vdso/vdso32.S b/arch/x86/vdso/vdso32.S
deleted file mode 100644 (file)
index 018bcd9..0000000
+++ /dev/null
@@ -1,9 +0,0 @@
-#include <asm/vdso.h>
-
-DEFINE_VDSO_IMAGE(vdso32_int80, "arch/x86/vdso/vdso32-int80.so")
-
-#ifdef CONFIG_COMPAT
-DEFINE_VDSO_IMAGE(vdso32_syscall, "arch/x86/vdso/vdso32-syscall.so")
-#endif
-
-DEFINE_VDSO_IMAGE(vdso32_sysenter, "arch/x86/vdso/vdso32-sysenter.so")
index aadb8b9994cd00b31e65c07e95af8a6f245ddebd..f072095d6427d00187e3391b0dbb7ad38c6ed56b 100644 (file)
@@ -38,13 +38,3 @@ VERSION
        local: *;
        };
 }
-
-/*
- * Symbols we define here called VDSO* get their values into vdso32-syms.h.
- */
-VDSO32_vsyscall                = __kernel_vsyscall;
-VDSO32_sigreturn       = __kernel_sigreturn;
-VDSO32_rt_sigreturn    = __kernel_rt_sigreturn;
-VDSO32_clock_gettime   = clock_gettime;
-VDSO32_gettimeofday    = gettimeofday;
-VDSO32_time            = time;
diff --git a/arch/x86/vdso/vdsox32.S b/arch/x86/vdso/vdsox32.S
deleted file mode 100644 (file)
index f4aa34e..0000000
+++ /dev/null
@@ -1,3 +0,0 @@
-#include <asm/vdso.h>
-
-DEFINE_VDSO_IMAGE(vdsox32, "arch/x86/vdso/vdsox32.so")
index 8b790398ed1dbec8e503c7eb2d21c575262503cb..cf217626fb47051d06a64c85a901b02b8dbd54b8 100644 (file)
 #if defined(CONFIG_X86_64)
 unsigned int __read_mostly vdso64_enabled = 1;
 
-DECLARE_VDSO_IMAGE(vdso);
 extern unsigned short vdso_sync_cpuid;
-static unsigned vdso_size;
-
-#ifdef CONFIG_X86_X32_ABI
-DECLARE_VDSO_IMAGE(vdsox32);
-static unsigned vdsox32_size;
-#endif
 #endif
 
-#if defined(CONFIG_X86_32) || defined(CONFIG_X86_X32_ABI) || \
-       defined(CONFIG_COMPAT)
-void __init patch_vdso32(void *vdso, size_t len)
+void __init init_vdso_image(const struct vdso_image *image)
 {
-       Elf32_Ehdr *hdr = vdso;
-       Elf32_Shdr *sechdrs, *alt_sec = 0;
-       char *secstrings;
-       void *alt_data;
        int i;
+       int npages = (image->size) / PAGE_SIZE;
 
-       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_vdso32: .altinstructions not found\n");
-       return;  /* nothing to patch */
+       BUG_ON(image->size % PAGE_SIZE != 0);
+       for (i = 0; i < npages; i++)
+               image->pages[i] = virt_to_page(image->data + i*PAGE_SIZE);
 
-found:
-       alt_data = (void *)hdr + alt_sec->sh_offset;
-       apply_alternatives(alt_data, alt_data + alt_sec->sh_size);
+       apply_alternatives((struct alt_instr *)(image->data + image->alt),
+                          (struct alt_instr *)(image->data + image->alt +
+                                               image->alt_len));
 }
-#endif
-
-#if defined(CONFIG_X86_64)
-static void __init patch_vdso64(void *vdso, size_t len)
-{
-       Elf64_Ehdr *hdr = vdso;
-       Elf64_Shdr *sechdrs, *alt_sec = 0;
-       char *secstrings;
-       void *alt_data;
-       int i;
 
-       BUG_ON(len < sizeof(Elf64_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++) {
-               Elf64_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_vdso64: .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);
-}
 
+#if defined(CONFIG_X86_64)
 static int __init init_vdso(void)
 {
-       int npages = (vdso_end - vdso_start + PAGE_SIZE - 1) / PAGE_SIZE;
-       int i;
-
-       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);
+       init_vdso_image(&vdso_image_64);
 
 #ifdef CONFIG_X86_X32_ABI
-       patch_vdso32(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);
+       init_vdso_image(&vdso_image_x32);
 #endif
 
        return 0;
@@ -171,7 +103,7 @@ static int setup_additional_pages(struct linux_binprm *bprm,
                goto up_fail;
        }
 
-       current->mm->context.vdso = (void *)addr;
+       current->mm->context.vdso = (void __user *)addr;
 
        ret = install_special_mapping(mm, addr, size,
                                      VM_READ|VM_EXEC|
@@ -189,15 +121,15 @@ 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_image_64.pages,
+                                     vdso_image_64.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, vdso_image_x32.pages,
+                                     vdso_image_x32.size);
 }
 #endif
 
index 0982233b9b8433a97d6905de4aad3369c6f4c0a5..7225a9557ee298fff05fe1fe21a1761342e61d55 100644 (file)
@@ -516,10 +516,17 @@ char * __init xen_memory_setup(void)
 static void __init fiddle_vdso(void)
 {
 #ifdef CONFIG_X86_32
+       /*
+        * This could be called before selected_vdso32 is initialized, so
+        * just fiddle with both possible images.  vdso_image_32_syscall
+        * can't be selected, since it only exists on 64-bit systems.
+        */
        u32 *mask;
-       mask = VDSO32_SYMBOL(&vdso32_int80_start, NOTE_MASK);
+       mask = vdso_image_32_int80.data +
+               vdso_image_32_int80.sym_VDSO32_NOTE_MASK;
        *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
-       mask = VDSO32_SYMBOL(&vdso32_sysenter_start, NOTE_MASK);
+       mask = vdso_image_32_sysenter.data +
+               vdso_image_32_sysenter.sym_VDSO32_NOTE_MASK;
        *mask |= 1 << VDSO_NOTE_NONEGSEG_BIT;
 #endif
 }