Commit 98a96f20 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 vdso updates from Ingo Molnar:
 "Further simplifications and improvements to the VDSO code, by Andy
  Lutomirski"

* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86_64/vsyscall: Fix warn_bad_vsyscall log output
  x86/vdso: Set VM_MAYREAD for the vvar vma
  x86, vdso: Get rid of the fake section mechanism
  x86, vdso: Move the vvar area before the vdso text
parents 5637a2a3 53b884ac
...@@ -18,15 +18,15 @@ struct vdso_image { ...@@ -18,15 +18,15 @@ struct vdso_image {
unsigned long alt, alt_len; unsigned long alt, alt_len;
unsigned long sym_end_mapping; /* Total size of the mapping */ long sym_vvar_start; /* Negative offset to the vvar area */
unsigned long sym_vvar_page; long sym_vvar_page;
unsigned long sym_hpet_page; long sym_hpet_page;
unsigned long sym_VDSO32_NOTE_MASK; long sym_VDSO32_NOTE_MASK;
unsigned long sym___kernel_sigreturn; long sym___kernel_sigreturn;
unsigned long sym___kernel_rt_sigreturn; long sym___kernel_rt_sigreturn;
unsigned long sym___kernel_vsyscall; long sym___kernel_vsyscall;
unsigned long sym_VDSO32_SYSENTER_RETURN; long sym_VDSO32_SYSENTER_RETURN;
}; };
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
......
...@@ -81,7 +81,7 @@ static void warn_bad_vsyscall(const char *level, struct pt_regs *regs, ...@@ -81,7 +81,7 @@ static void warn_bad_vsyscall(const char *level, struct pt_regs *regs,
if (!show_unhandled_signals) if (!show_unhandled_signals)
return; return;
pr_notice_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n", printk_ratelimited("%s%s[%d] %s ip:%lx cs:%lx sp:%lx ax:%lx si:%lx di:%lx\n",
level, current->comm, task_pid_nr(current), level, current->comm, task_pid_nr(current),
message, regs->ip, regs->cs, message, regs->ip, regs->cs,
regs->sp, regs->ax, regs->si, regs->di); regs->sp, regs->ax, regs->si, regs->di);
......
...@@ -10,7 +10,7 @@ VDSO32-$(CONFIG_X86_32) := y ...@@ -10,7 +10,7 @@ VDSO32-$(CONFIG_X86_32) := y
VDSO32-$(CONFIG_COMPAT) := y VDSO32-$(CONFIG_COMPAT) := y
# files to link into the vdso # files to link into the vdso
vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o vdso-fakesections.o vobjs-y := vdso-note.o vclock_gettime.o vgetcpu.o
# files to link into kernel # files to link into kernel
obj-y += vma.o obj-y += vma.o
...@@ -37,7 +37,8 @@ vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg) ...@@ -37,7 +37,8 @@ vdso_img_sodbg := $(vdso_img-y:%=vdso%.so.dbg)
obj-y += $(vdso_img_objs) obj-y += $(vdso_img_objs)
targets += $(vdso_img_cfiles) targets += $(vdso_img_cfiles)
targets += $(vdso_img_sodbg) targets += $(vdso_img_sodbg)
.SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) .SECONDARY: $(vdso_img-y:%=$(obj)/vdso-image-%.c) \
$(vdso_img-y:%=$(obj)/vdso%.so)
export CPPFLAGS_vdso.lds += -P -C export CPPFLAGS_vdso.lds += -P -C
...@@ -54,10 +55,10 @@ hostprogs-y += vdso2c ...@@ -54,10 +55,10 @@ hostprogs-y += vdso2c
quiet_cmd_vdso2c = VDSO2C $@ quiet_cmd_vdso2c = VDSO2C $@
define cmd_vdso2c define cmd_vdso2c
$(obj)/vdso2c $< $@ $(obj)/vdso2c $< $(<:%.dbg=%) $@
endef endef
$(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso2c FORCE $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
$(call if_changed,vdso2c) $(call if_changed,vdso2c)
# #
...@@ -113,6 +114,10 @@ $(obj)/%-x32.o: $(obj)/%.o FORCE ...@@ -113,6 +114,10 @@ $(obj)/%-x32.o: $(obj)/%.o FORCE
targets += vdsox32.lds $(vobjx32s-y) targets += vdsox32.lds $(vobjx32s-y)
$(obj)/%.so: OBJCOPYFLAGS := -S
$(obj)/%.so: $(obj)/%.so.dbg
$(call if_changed,objcopy)
$(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE $(obj)/vdsox32.so.dbg: $(src)/vdsox32.lds $(vobjx32s) FORCE
$(call if_changed,vdso) $(call if_changed,vdso)
...@@ -134,7 +139,7 @@ override obj-dirs = $(dir $(obj)) $(obj)/vdso32/ ...@@ -134,7 +139,7 @@ override obj-dirs = $(dir $(obj)) $(obj)/vdso32/
targets += vdso32/vdso32.lds targets += vdso32/vdso32.lds
targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o) targets += vdso32/note.o vdso32/vclock_gettime.o $(vdso32.so-y:%=vdso32/%.o)
targets += vdso32/vclock_gettime.o vdso32/vdso-fakesections.o targets += vdso32/vclock_gettime.o
$(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%) $(obj)/vdso32.o: $(vdso32-images:%=$(obj)/%)
...@@ -156,7 +161,6 @@ $(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) ...@@ -156,7 +161,6 @@ $(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
$(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \ $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \
$(obj)/vdso32/vdso32.lds \ $(obj)/vdso32/vdso32.lds \
$(obj)/vdso32/vclock_gettime.o \ $(obj)/vdso32/vclock_gettime.o \
$(obj)/vdso32/vdso-fakesections.o \
$(obj)/vdso32/note.o \ $(obj)/vdso32/note.o \
$(obj)/vdso32/%.o $(obj)/vdso32/%.o
$(call if_changed,vdso) $(call if_changed,vdso)
......
/*
* Copyright 2014 Andy Lutomirski
* Subject to the GNU Public License, v.2
*
* String table for loadable section headers. See vdso2c.h for why
* this exists.
*/
const char fake_shstrtab[] __attribute__((section(".fake_shstrtab"))) =
".hash\0"
".dynsym\0"
".dynstr\0"
".gnu.version\0"
".gnu.version_d\0"
".dynamic\0"
".rodata\0"
".fake_shstrtab\0" /* Yay, self-referential code. */
".note\0"
".eh_frame_hdr\0"
".eh_frame\0"
".text";
...@@ -18,6 +18,25 @@ ...@@ -18,6 +18,25 @@
SECTIONS SECTIONS
{ {
/*
* User/kernel shared data is before the vDSO. This may be a little
* uglier than putting it after the vDSO, but it avoids issues with
* non-allocatable things that dangle past the end of the PT_LOAD
* segment.
*/
vvar_start = . - 2 * PAGE_SIZE;
vvar_page = vvar_start;
/* Place all vvars at the offsets in asm/vvar.h. */
#define EMIT_VVAR(name, offset) vvar_ ## name = vvar_page + offset;
#define __VVAR_KERNEL_LDS
#include <asm/vvar.h>
#undef __VVAR_KERNEL_LDS
#undef EMIT_VVAR
hpet_page = vvar_start + PAGE_SIZE;
. = SIZEOF_HEADERS; . = SIZEOF_HEADERS;
.hash : { *(.hash) } :text .hash : { *(.hash) } :text
...@@ -74,31 +93,6 @@ SECTIONS ...@@ -74,31 +93,6 @@ SECTIONS
.altinstructions : { *(.altinstructions) } :text .altinstructions : { *(.altinstructions) } :text
.altinstr_replacement : { *(.altinstr_replacement) } :text .altinstr_replacement : { *(.altinstr_replacement) } :text
/*
* The remainder of the vDSO consists of special pages that are
* shared between the kernel and userspace. It needs to be at the
* end so that it doesn't overlap the mapping of the actual
* vDSO image.
*/
. = ALIGN(PAGE_SIZE);
vvar_page = .;
/* Place all vvars at the offsets in asm/vvar.h. */
#define EMIT_VVAR(name, offset) vvar_ ## name = vvar_page + offset;
#define __VVAR_KERNEL_LDS
#include <asm/vvar.h>
#undef __VVAR_KERNEL_LDS
#undef EMIT_VVAR
. = vvar_page + PAGE_SIZE;
hpet_page = .;
. = . + PAGE_SIZE;
. = ALIGN(PAGE_SIZE);
end_mapping = .;
/DISCARD/ : { /DISCARD/ : {
*(.discard) *(.discard)
*(.discard.*) *(.discard.*)
......
/*
* vdso2c - A vdso image preparation tool
* Copyright (c) 2014 Andy Lutomirski and others
* Licensed under the GPL v2
*
* vdso2c requires stripped and unstripped input. It would be trivial
* to fully strip the input in here, but, for reasons described below,
* we need to write a section table. Doing this is more or less
* equivalent to dropping all non-allocatable sections, but it's
* easier to let objcopy handle that instead of doing it ourselves.
* If we ever need to do something fancier than what objcopy provides,
* it would be straightforward to add here.
*
* We're keep a section table for a few reasons:
*
* The Go runtime had a couple of bugs: it would read the section
* table to try to figure out how many dynamic symbols there were (it
* shouldn't have looked at the section table at all) and, if there
* were no SHT_SYNDYM section table entry, it would use an
* uninitialized value for the number of symbols. An empty DYNSYM
* table would work, but I see no reason not to write a valid one (and
* keep full performance for old Go programs). This hack is only
* needed on x86_64.
*
* The bug was introduced on 2012-08-31 by:
* https://code.google.com/p/go/source/detail?r=56ea40aac72b
* and was fixed on 2014-06-13 by:
* https://code.google.com/p/go/source/detail?r=fc1cd5e12595
*
* Binutils has issues debugging the vDSO: it reads the section table to
* find SHT_NOTE; it won't look at PT_NOTE for the in-memory vDSO, which
* would break build-id if we removed the section table. Binutils
* also requires that shstrndx != 0. See:
* https://sourceware.org/bugzilla/show_bug.cgi?id=17064
*
* elfutils might not look for PT_NOTE if there is a section table at
* all. I don't know whether this matters for any practical purpose.
*
* For simplicity, rather than hacking up a partial section table, we
* just write a mostly complete one. We omit non-dynamic symbols,
* though, since they're rather large.
*
* Once binutils gets fixed, we might be able to drop this for all but
* the 64-bit vdso, since build-id only works in kernel RPMs, and
* systems that update to new enough kernel RPMs will likely update
* binutils in sync. build-id has never worked for home-built kernel
* RPMs without manual symlinking, and I suspect that no one ever does
* that.
*/
#include <inttypes.h> #include <inttypes.h>
#include <stdint.h> #include <stdint.h>
#include <unistd.h> #include <unistd.h>
...@@ -20,9 +70,9 @@ const char *outfilename; ...@@ -20,9 +70,9 @@ const char *outfilename;
/* Symbols that we need in vdso2c. */ /* Symbols that we need in vdso2c. */
enum { enum {
sym_vvar_start,
sym_vvar_page, sym_vvar_page,
sym_hpet_page, sym_hpet_page,
sym_end_mapping,
sym_VDSO_FAKE_SECTION_TABLE_START, sym_VDSO_FAKE_SECTION_TABLE_START,
sym_VDSO_FAKE_SECTION_TABLE_END, sym_VDSO_FAKE_SECTION_TABLE_END,
}; };
...@@ -38,9 +88,9 @@ struct vdso_sym { ...@@ -38,9 +88,9 @@ struct vdso_sym {
}; };
struct vdso_sym required_syms[] = { struct vdso_sym required_syms[] = {
[sym_vvar_start] = {"vvar_start", true},
[sym_vvar_page] = {"vvar_page", true}, [sym_vvar_page] = {"vvar_page", true},
[sym_hpet_page] = {"hpet_page", true}, [sym_hpet_page] = {"hpet_page", true},
[sym_end_mapping] = {"end_mapping", true},
[sym_VDSO_FAKE_SECTION_TABLE_START] = { [sym_VDSO_FAKE_SECTION_TABLE_START] = {
"VDSO_FAKE_SECTION_TABLE_START", false "VDSO_FAKE_SECTION_TABLE_START", false
}, },
...@@ -61,6 +111,7 @@ static void fail(const char *format, ...) ...@@ -61,6 +111,7 @@ static void fail(const char *format, ...)
va_start(ap, format); va_start(ap, format);
fprintf(stderr, "Error: "); fprintf(stderr, "Error: ");
vfprintf(stderr, format, ap); vfprintf(stderr, format, ap);
if (outfilename)
unlink(outfilename); unlink(outfilename);
exit(1); exit(1);
va_end(ap); va_end(ap);
...@@ -96,9 +147,11 @@ extern void bad_put_le(void); ...@@ -96,9 +147,11 @@ extern void bad_put_le(void);
#define NSYMS (sizeof(required_syms) / sizeof(required_syms[0])) #define NSYMS (sizeof(required_syms) / sizeof(required_syms[0]))
#define BITSFUNC3(name, bits) name##bits #define BITSFUNC3(name, bits, suffix) name##bits##suffix
#define BITSFUNC2(name, bits) BITSFUNC3(name, bits) #define BITSFUNC2(name, bits, suffix) BITSFUNC3(name, bits, suffix)
#define BITSFUNC(name) BITSFUNC2(name, ELF_BITS) #define BITSFUNC(name) BITSFUNC2(name, ELF_BITS, )
#define INT_BITS BITSFUNC2(int, ELF_BITS, _t)
#define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x #define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x
#define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x) #define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x)
...@@ -112,30 +165,53 @@ extern void bad_put_le(void); ...@@ -112,30 +165,53 @@ extern void bad_put_le(void);
#include "vdso2c.h" #include "vdso2c.h"
#undef ELF_BITS #undef ELF_BITS
static void go(void *addr, size_t len, FILE *outfile, const char *name) static void go(void *raw_addr, size_t raw_len,
void *stripped_addr, size_t stripped_len,
FILE *outfile, const char *name)
{ {
Elf64_Ehdr *hdr = (Elf64_Ehdr *)addr; Elf64_Ehdr *hdr = (Elf64_Ehdr *)raw_addr;
if (hdr->e_ident[EI_CLASS] == ELFCLASS64) { if (hdr->e_ident[EI_CLASS] == ELFCLASS64) {
go64(addr, len, outfile, name); go64(raw_addr, raw_len, stripped_addr, stripped_len,
outfile, name);
} else if (hdr->e_ident[EI_CLASS] == ELFCLASS32) { } else if (hdr->e_ident[EI_CLASS] == ELFCLASS32) {
go32(addr, len, outfile, name); go32(raw_addr, raw_len, stripped_addr, stripped_len,
outfile, name);
} else { } else {
fail("unknown ELF class\n"); fail("unknown ELF class\n");
} }
} }
static void map_input(const char *name, void **addr, size_t *len, int prot)
{
off_t tmp_len;
int fd = open(name, O_RDONLY);
if (fd == -1)
err(1, "%s", name);
tmp_len = lseek(fd, 0, SEEK_END);
if (tmp_len == (off_t)-1)
err(1, "lseek");
*len = (size_t)tmp_len;
*addr = mmap(NULL, tmp_len, prot, MAP_PRIVATE, fd, 0);
if (*addr == MAP_FAILED)
err(1, "mmap");
close(fd);
}
int main(int argc, char **argv) int main(int argc, char **argv)
{ {
int fd; size_t raw_len, stripped_len;
off_t len; void *raw_addr, *stripped_addr;
void *addr;
FILE *outfile; FILE *outfile;
char *name, *tmp; char *name, *tmp;
int namelen; int namelen;
if (argc != 3) { if (argc != 4) {
printf("Usage: vdso2c INPUT OUTPUT\n"); printf("Usage: vdso2c RAW_INPUT STRIPPED_INPUT OUTPUT\n");
return 1; return 1;
} }
...@@ -143,7 +219,7 @@ int main(int argc, char **argv) ...@@ -143,7 +219,7 @@ int main(int argc, char **argv)
* Figure out the struct name. If we're writing to a .so file, * Figure out the struct name. If we're writing to a .so file,
* generate raw output insted. * generate raw output insted.
*/ */
name = strdup(argv[2]); name = strdup(argv[3]);
namelen = strlen(name); namelen = strlen(name);
if (namelen >= 3 && !strcmp(name + namelen - 3, ".so")) { if (namelen >= 3 && !strcmp(name + namelen - 3, ".so")) {
name = NULL; name = NULL;
...@@ -159,26 +235,18 @@ int main(int argc, char **argv) ...@@ -159,26 +235,18 @@ int main(int argc, char **argv)
*tmp = '_'; *tmp = '_';
} }
fd = open(argv[1], O_RDONLY); map_input(argv[1], &raw_addr, &raw_len, PROT_READ);
if (fd == -1) map_input(argv[2], &stripped_addr, &stripped_len, PROT_READ);
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");
outfilename = argv[2]; outfilename = argv[3];
outfile = fopen(outfilename, "w"); outfile = fopen(outfilename, "w");
if (!outfile) if (!outfile)
err(1, "%s", argv[2]); err(1, "%s", argv[2]);
go(addr, (size_t)len, outfile, name); go(raw_addr, raw_len, stripped_addr, stripped_len, outfile, name);
munmap(addr, len); munmap(raw_addr, raw_len);
munmap(stripped_addr, stripped_len);
fclose(outfile); fclose(outfile);
return 0; return 0;
......
...@@ -4,139 +4,23 @@ ...@@ -4,139 +4,23 @@
* are built for 32-bit userspace. * are built for 32-bit userspace.
*/ */
/* static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
* We're writing a section table for a few reasons: void *stripped_addr, size_t stripped_len,
*
* The Go runtime had a couple of bugs: it would read the section
* table to try to figure out how many dynamic symbols there were (it
* shouldn't have looked at the section table at all) and, if there
* were no SHT_SYNDYM section table entry, it would use an
* uninitialized value for the number of symbols. An empty DYNSYM
* table would work, but I see no reason not to write a valid one (and
* keep full performance for old Go programs). This hack is only
* needed on x86_64.
*
* The bug was introduced on 2012-08-31 by:
* https://code.google.com/p/go/source/detail?r=56ea40aac72b
* and was fixed on 2014-06-13 by:
* https://code.google.com/p/go/source/detail?r=fc1cd5e12595
*
* Binutils has issues debugging the vDSO: it reads the section table to
* find SHT_NOTE; it won't look at PT_NOTE for the in-memory vDSO, which
* would break build-id if we removed the section table. Binutils
* also requires that shstrndx != 0. See:
* https://sourceware.org/bugzilla/show_bug.cgi?id=17064
*
* elfutils might not look for PT_NOTE if there is a section table at
* all. I don't know whether this matters for any practical purpose.
*
* For simplicity, rather than hacking up a partial section table, we
* just write a mostly complete one. We omit non-dynamic symbols,
* though, since they're rather large.
*
* Once binutils gets fixed, we might be able to drop this for all but
* the 64-bit vdso, since build-id only works in kernel RPMs, and
* systems that update to new enough kernel RPMs will likely update
* binutils in sync. build-id has never worked for home-built kernel
* RPMs without manual symlinking, and I suspect that no one ever does
* that.
*/
struct BITSFUNC(fake_sections)
{
ELF(Shdr) *table;
unsigned long table_offset;
int count, max_count;
int in_shstrndx;
unsigned long shstr_offset;
const char *shstrtab;
size_t shstrtab_len;
int out_shstrndx;
};
static unsigned int BITSFUNC(find_shname)(struct BITSFUNC(fake_sections) *out,
const char *name)
{
const char *outname = out->shstrtab;
while (outname - out->shstrtab < out->shstrtab_len) {
if (!strcmp(name, outname))
return (outname - out->shstrtab) + out->shstr_offset;
outname += strlen(outname) + 1;
}
if (*name)
printf("Warning: could not find output name \"%s\"\n", name);
return out->shstr_offset + out->shstrtab_len - 1; /* Use a null. */
}
static void BITSFUNC(init_sections)(struct BITSFUNC(fake_sections) *out)
{
if (!out->in_shstrndx)
fail("didn't find the fake shstrndx\n");
memset(out->table, 0, out->max_count * sizeof(ELF(Shdr)));
if (out->max_count < 1)
fail("we need at least two fake output sections\n");
PUT_LE(&out->table[0].sh_type, SHT_NULL);
PUT_LE(&out->table[0].sh_name, BITSFUNC(find_shname)(out, ""));
out->count = 1;
}
static void BITSFUNC(copy_section)(struct BITSFUNC(fake_sections) *out,
int in_idx, const ELF(Shdr) *in,
const char *name)
{
uint64_t flags = GET_LE(&in->sh_flags);
bool copy = flags & SHF_ALLOC &&
(GET_LE(&in->sh_size) ||
(GET_LE(&in->sh_type) != SHT_RELA &&
GET_LE(&in->sh_type) != SHT_REL)) &&
strcmp(name, ".altinstructions") &&
strcmp(name, ".altinstr_replacement");
if (!copy)
return;
if (out->count >= out->max_count)
fail("too many copied sections (max = %d)\n", out->max_count);
if (in_idx == out->in_shstrndx)
out->out_shstrndx = out->count;
out->table[out->count] = *in;
PUT_LE(&out->table[out->count].sh_name,
BITSFUNC(find_shname)(out, name));
/* elfutils requires that a strtab have the correct type. */
if (!strcmp(name, ".fake_shstrtab"))
PUT_LE(&out->table[out->count].sh_type, SHT_STRTAB);
out->count++;
}
static void BITSFUNC(go)(void *addr, size_t len,
FILE *outfile, const char *name) FILE *outfile, const char *name)
{ {
int found_load = 0; int found_load = 0;
unsigned long load_size = -1; /* Work around bogus warning */ unsigned long load_size = -1; /* Work around bogus warning */
unsigned long data_size; unsigned long mapping_size;
ELF(Ehdr) *hdr = (ELF(Ehdr) *)addr; ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
int i; int i;
unsigned long j; unsigned long j;
ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr, ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
*alt_sec = NULL; *alt_sec = NULL;
ELF(Dyn) *dyn = 0, *dyn_end = 0; ELF(Dyn) *dyn = 0, *dyn_end = 0;
const char *secstrings; const char *secstrings;
uint64_t syms[NSYMS] = {}; INT_BITS syms[NSYMS] = {};
struct BITSFUNC(fake_sections) fake_sections = {};
ELF(Phdr) *pt = (ELF(Phdr) *)(addr + GET_LE(&hdr->e_phoff)); ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_LE(&hdr->e_phoff));
/* Walk the segment table. */ /* Walk the segment table. */
for (i = 0; i < GET_LE(&hdr->e_phnum); i++) { for (i = 0; i < GET_LE(&hdr->e_phnum); i++) {
...@@ -154,14 +38,16 @@ static void BITSFUNC(go)(void *addr, size_t len, ...@@ -154,14 +38,16 @@ static void BITSFUNC(go)(void *addr, size_t len,
load_size = GET_LE(&pt[i].p_memsz); load_size = GET_LE(&pt[i].p_memsz);
found_load = 1; found_load = 1;
} else if (GET_LE(&pt[i].p_type) == PT_DYNAMIC) { } else if (GET_LE(&pt[i].p_type) == PT_DYNAMIC) {
dyn = addr + GET_LE(&pt[i].p_offset); dyn = raw_addr + GET_LE(&pt[i].p_offset);
dyn_end = addr + GET_LE(&pt[i].p_offset) + dyn_end = raw_addr + GET_LE(&pt[i].p_offset) +
GET_LE(&pt[i].p_memsz); GET_LE(&pt[i].p_memsz);
} }
} }
if (!found_load) if (!found_load)
fail("no PT_LOAD seg\n"); fail("no PT_LOAD seg\n");
data_size = (load_size + 4095) / 4096 * 4096;
if (stripped_len < load_size)
fail("stripped input is too short\n");
/* Walk the dynamic table */ /* Walk the dynamic table */
for (i = 0; dyn + i < dyn_end && for (i = 0; dyn + i < dyn_end &&
...@@ -173,11 +59,11 @@ static void BITSFUNC(go)(void *addr, size_t len, ...@@ -173,11 +59,11 @@ static void BITSFUNC(go)(void *addr, size_t len,
} }
/* Walk the section table */ /* Walk the section table */
secstrings_hdr = addr + GET_LE(&hdr->e_shoff) + secstrings_hdr = raw_addr + GET_LE(&hdr->e_shoff) +
GET_LE(&hdr->e_shentsize)*GET_LE(&hdr->e_shstrndx); GET_LE(&hdr->e_shentsize)*GET_LE(&hdr->e_shstrndx);
secstrings = addr + GET_LE(&secstrings_hdr->sh_offset); secstrings = raw_addr + GET_LE(&secstrings_hdr->sh_offset);
for (i = 0; i < GET_LE(&hdr->e_shnum); i++) { for (i = 0; i < GET_LE(&hdr->e_shnum); i++) {
ELF(Shdr) *sh = addr + GET_LE(&hdr->e_shoff) + ELF(Shdr) *sh = raw_addr + GET_LE(&hdr->e_shoff) +
GET_LE(&hdr->e_shentsize) * i; GET_LE(&hdr->e_shentsize) * i;
if (GET_LE(&sh->sh_type) == SHT_SYMTAB) if (GET_LE(&sh->sh_type) == SHT_SYMTAB)
symtab_hdr = sh; symtab_hdr = sh;
...@@ -190,7 +76,7 @@ static void BITSFUNC(go)(void *addr, size_t len, ...@@ -190,7 +76,7 @@ static void BITSFUNC(go)(void *addr, size_t len,
if (!symtab_hdr) if (!symtab_hdr)
fail("no symbol table\n"); fail("no symbol table\n");
strtab_hdr = addr + GET_LE(&hdr->e_shoff) + strtab_hdr = raw_addr + GET_LE(&hdr->e_shoff) +
GET_LE(&hdr->e_shentsize) * GET_LE(&symtab_hdr->sh_link); GET_LE(&hdr->e_shentsize) * GET_LE(&symtab_hdr->sh_link);
/* Walk the symbol table */ /* Walk the symbol table */
...@@ -198,9 +84,9 @@ static void BITSFUNC(go)(void *addr, size_t len, ...@@ -198,9 +84,9 @@ static void BITSFUNC(go)(void *addr, size_t len,
i < GET_LE(&symtab_hdr->sh_size) / GET_LE(&symtab_hdr->sh_entsize); i < GET_LE(&symtab_hdr->sh_size) / GET_LE(&symtab_hdr->sh_entsize);
i++) { i++) {
int k; int k;
ELF(Sym) *sym = addr + GET_LE(&symtab_hdr->sh_offset) + ELF(Sym) *sym = raw_addr + GET_LE(&symtab_hdr->sh_offset) +
GET_LE(&symtab_hdr->sh_entsize) * i; GET_LE(&symtab_hdr->sh_entsize) * i;
const char *name = addr + GET_LE(&strtab_hdr->sh_offset) + const char *name = raw_addr + GET_LE(&strtab_hdr->sh_offset) +
GET_LE(&sym->st_name); GET_LE(&sym->st_name);
for (k = 0; k < NSYMS; k++) { for (k = 0; k < NSYMS; k++) {
...@@ -209,51 +95,17 @@ static void BITSFUNC(go)(void *addr, size_t len, ...@@ -209,51 +95,17 @@ static void BITSFUNC(go)(void *addr, size_t len,
fail("duplicate symbol %s\n", fail("duplicate symbol %s\n",
required_syms[k].name); required_syms[k].name);
} }
syms[k] = GET_LE(&sym->st_value);
}
}
if (!strcmp(name, "fake_shstrtab")) {
ELF(Shdr) *sh;
fake_sections.in_shstrndx = GET_LE(&sym->st_shndx); /*
fake_sections.shstrtab = addr + GET_LE(&sym->st_value); * Careful: we use negative addresses, but
fake_sections.shstrtab_len = GET_LE(&sym->st_size); * st_value is unsigned, so we rely
sh = addr + GET_LE(&hdr->e_shoff) + * on syms[k] being a signed type of the
GET_LE(&hdr->e_shentsize) * * correct width.
fake_sections.in_shstrndx; */
fake_sections.shstr_offset = GET_LE(&sym->st_value) - syms[k] = GET_LE(&sym->st_value);
GET_LE(&sh->sh_addr);
} }
} }
/* Build the output section table. */
if (!syms[sym_VDSO_FAKE_SECTION_TABLE_START] ||
!syms[sym_VDSO_FAKE_SECTION_TABLE_END])
fail("couldn't find fake section table\n");
if ((syms[sym_VDSO_FAKE_SECTION_TABLE_END] -
syms[sym_VDSO_FAKE_SECTION_TABLE_START]) % sizeof(ELF(Shdr)))
fail("fake section table size isn't a multiple of sizeof(Shdr)\n");
fake_sections.table = addr + syms[sym_VDSO_FAKE_SECTION_TABLE_START];
fake_sections.table_offset = syms[sym_VDSO_FAKE_SECTION_TABLE_START];
fake_sections.max_count = (syms[sym_VDSO_FAKE_SECTION_TABLE_END] -
syms[sym_VDSO_FAKE_SECTION_TABLE_START]) /
sizeof(ELF(Shdr));
BITSFUNC(init_sections)(&fake_sections);
for (i = 0; i < GET_LE(&hdr->e_shnum); i++) {
ELF(Shdr) *sh = addr + GET_LE(&hdr->e_shoff) +
GET_LE(&hdr->e_shentsize) * i;
BITSFUNC(copy_section)(&fake_sections, i, sh,
secstrings + GET_LE(&sh->sh_name));
} }
if (!fake_sections.out_shstrndx)
fail("didn't generate shstrndx?!?\n");
PUT_LE(&hdr->e_shoff, fake_sections.table_offset);
PUT_LE(&hdr->e_shentsize, sizeof(ELF(Shdr)));
PUT_LE(&hdr->e_shnum, fake_sections.count);
PUT_LE(&hdr->e_shstrndx, fake_sections.out_shstrndx);
/* Validate mapping addresses. */ /* Validate mapping addresses. */
for (i = 0; i < sizeof(special_pages) / sizeof(special_pages[0]); i++) { for (i = 0; i < sizeof(special_pages) / sizeof(special_pages[0]); i++) {
...@@ -263,21 +115,23 @@ static void BITSFUNC(go)(void *addr, size_t len, ...@@ -263,21 +115,23 @@ static void BITSFUNC(go)(void *addr, size_t len,
if (syms[i] % 4096) if (syms[i] % 4096)
fail("%s must be a multiple of 4096\n", fail("%s must be a multiple of 4096\n",
required_syms[i].name); required_syms[i].name);
if (syms[i] < data_size) if (syms[sym_vvar_start] > syms[i] + 4096)
fail("%s must be after the text mapping\n", fail("%s underruns begin_vvar\n",
required_syms[i].name); required_syms[i].name);
if (syms[sym_end_mapping] < syms[i] + 4096) if (syms[i] + 4096 > 0)
fail("%s overruns end_mapping\n", fail("%s is on the wrong side of the vdso text\n",
required_syms[i].name); required_syms[i].name);
} }
if (syms[sym_end_mapping] % 4096) if (syms[sym_vvar_start] % 4096)
fail("end_mapping must be a multiple of 4096\n"); fail("vvar_begin must be a multiple of 4096\n");
if (!name) { if (!name) {
fwrite(addr, load_size, 1, outfile); fwrite(stripped_addr, stripped_len, 1, outfile);
return; return;
} }
mapping_size = (stripped_len + 4095) / 4096 * 4096;
fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n"); fprintf(outfile, "/* AUTOMATICALLY GENERATED -- DO NOT EDIT */\n\n");
fprintf(outfile, "#include <linux/linkage.h>\n"); fprintf(outfile, "#include <linux/linkage.h>\n");
fprintf(outfile, "#include <asm/page_types.h>\n"); fprintf(outfile, "#include <asm/page_types.h>\n");
...@@ -285,20 +139,21 @@ static void BITSFUNC(go)(void *addr, size_t len, ...@@ -285,20 +139,21 @@ static void BITSFUNC(go)(void *addr, size_t len,
fprintf(outfile, "\n"); fprintf(outfile, "\n");
fprintf(outfile, fprintf(outfile,
"static unsigned char raw_data[%lu] __page_aligned_data = {", "static unsigned char raw_data[%lu] __page_aligned_data = {",
data_size); mapping_size);
for (j = 0; j < load_size; j++) { for (j = 0; j < stripped_len; j++) {
if (j % 10 == 0) if (j % 10 == 0)
fprintf(outfile, "\n\t"); fprintf(outfile, "\n\t");
fprintf(outfile, "0x%02X, ", (int)((unsigned char *)addr)[j]); fprintf(outfile, "0x%02X, ",
(int)((unsigned char *)stripped_addr)[j]);
} }
fprintf(outfile, "\n};\n\n"); fprintf(outfile, "\n};\n\n");
fprintf(outfile, "static struct page *pages[%lu];\n\n", fprintf(outfile, "static struct page *pages[%lu];\n\n",
data_size / 4096); mapping_size / 4096);
fprintf(outfile, "const struct vdso_image %s = {\n", name); fprintf(outfile, "const struct vdso_image %s = {\n", name);
fprintf(outfile, "\t.data = raw_data,\n"); fprintf(outfile, "\t.data = raw_data,\n");
fprintf(outfile, "\t.size = %lu,\n", data_size); fprintf(outfile, "\t.size = %lu,\n", mapping_size);
fprintf(outfile, "\t.text_mapping = {\n"); fprintf(outfile, "\t.text_mapping = {\n");
fprintf(outfile, "\t\t.name = \"[vdso]\",\n"); fprintf(outfile, "\t\t.name = \"[vdso]\",\n");
fprintf(outfile, "\t\t.pages = pages,\n"); fprintf(outfile, "\t\t.pages = pages,\n");
...@@ -311,8 +166,8 @@ static void BITSFUNC(go)(void *addr, size_t len, ...@@ -311,8 +166,8 @@ static void BITSFUNC(go)(void *addr, size_t len,
} }
for (i = 0; i < NSYMS; i++) { for (i = 0; i < NSYMS; i++) {
if (required_syms[i].export && syms[i]) if (required_syms[i].export && syms[i])
fprintf(outfile, "\t.sym_%s = 0x%" PRIx64 ",\n", fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
required_syms[i].name, syms[i]); required_syms[i].name, (int64_t)syms[i]);
} }
fprintf(outfile, "};\n"); fprintf(outfile, "};\n");
} }
...@@ -93,7 +93,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) ...@@ -93,7 +93,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
{ {
struct mm_struct *mm = current->mm; struct mm_struct *mm = current->mm;
struct vm_area_struct *vma; struct vm_area_struct *vma;
unsigned long addr; unsigned long addr, text_start;
int ret = 0; int ret = 0;
static struct page *no_pages[] = {NULL}; static struct page *no_pages[] = {NULL};
static struct vm_special_mapping vvar_mapping = { static struct vm_special_mapping vvar_mapping = {
...@@ -103,26 +103,28 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) ...@@ -103,26 +103,28 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
if (calculate_addr) { if (calculate_addr) {
addr = vdso_addr(current->mm->start_stack, addr = vdso_addr(current->mm->start_stack,
image->sym_end_mapping); image->size - image->sym_vvar_start);
} else { } else {
addr = 0; addr = 0;
} }
down_write(&mm->mmap_sem); down_write(&mm->mmap_sem);
addr = get_unmapped_area(NULL, addr, image->sym_end_mapping, 0, 0); addr = get_unmapped_area(NULL, addr,
image->size - image->sym_vvar_start, 0, 0);
if (IS_ERR_VALUE(addr)) { if (IS_ERR_VALUE(addr)) {
ret = addr; ret = addr;
goto up_fail; goto up_fail;
} }
current->mm->context.vdso = (void __user *)addr; text_start = addr - image->sym_vvar_start;
current->mm->context.vdso = (void __user *)text_start;
/* /*
* MAYWRITE to allow gdb to COW and set breakpoints * MAYWRITE to allow gdb to COW and set breakpoints
*/ */
vma = _install_special_mapping(mm, vma = _install_special_mapping(mm,
addr, text_start,
image->size, image->size,
VM_READ|VM_EXEC| VM_READ|VM_EXEC|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
...@@ -134,9 +136,9 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) ...@@ -134,9 +136,9 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
} }
vma = _install_special_mapping(mm, vma = _install_special_mapping(mm,
addr + image->size, addr,
image->sym_end_mapping - image->size, -image->sym_vvar_start,
VM_READ, VM_READ|VM_MAYREAD,
&vvar_mapping); &vvar_mapping);
if (IS_ERR(vma)) { if (IS_ERR(vma)) {
...@@ -146,7 +148,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) ...@@ -146,7 +148,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
if (image->sym_vvar_page) if (image->sym_vvar_page)
ret = remap_pfn_range(vma, ret = remap_pfn_range(vma,
addr + image->sym_vvar_page, text_start + image->sym_vvar_page,
__pa_symbol(&__vvar_page) >> PAGE_SHIFT, __pa_symbol(&__vvar_page) >> PAGE_SHIFT,
PAGE_SIZE, PAGE_SIZE,
PAGE_READONLY); PAGE_READONLY);
...@@ -157,7 +159,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) ...@@ -157,7 +159,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr)
#ifdef CONFIG_HPET_TIMER #ifdef CONFIG_HPET_TIMER
if (hpet_address && image->sym_hpet_page) { if (hpet_address && image->sym_hpet_page) {
ret = io_remap_pfn_range(vma, ret = io_remap_pfn_range(vma,
addr + image->sym_hpet_page, text_start + image->sym_hpet_page,
hpet_address >> PAGE_SHIFT, hpet_address >> PAGE_SHIFT,
PAGE_SIZE, PAGE_SIZE,
pgprot_noncached(PAGE_READONLY)); pgprot_noncached(PAGE_READONLY));
......
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