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sparc: Fix VDSO build with older binutils.

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Older versions of bintutils do not allow symbol math across different
segments on sparc:

====================
Assembler messages:
99: Error: operation combines symbols in different segments
====================

This is controlled by whether or not DIFF_EXPR_OK is defined in
gas/config/tc-*.h and for sparc this was not the case until mid-2017.

So we have to patch between %stick and %tick another way.

Do what powerpc does and emit two versions of the relevant functions,
one using %tick and one using %stick, and patch the symbols in the
dynamic symbol table.

Fixes: 2f6c9bf31a ("sparc: Improve VDSO instruction patching.")
Reported-by: Meelis Roos <mroos@linux.ee>
Tested-by: Meelis Roos <mroos@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2018-10-25 10:36:19 -07:00
parent 44adbac8f7
commit caf539cd10
7 changed files with 337 additions and 64 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/sparc/include/asm/vdso.h
View File

@ -9,8 +9,6 @@ struct vdso_image {
void *data;
unsigned long size; /* Always a multiple of PAGE_SIZE */
unsigned long tick_patch, tick_patch_len;
long sym_vvar_start; /* Negative offset to the vvar area */
};

149
arch/sparc/vdso/vclock_gettime.c
View File

@ -90,16 +90,15 @@ notrace static __always_inline u64 vread_tick(void)
{
u64 ret;
__asm__ __volatile__("1:\n\t"
"rd %%tick, %0\n\t"
".pushsection .tick_patch, \"a\"\n\t"
".word 1b - ., 1f - .\n\t"
".popsection\n\t"
".pushsection .tick_patch_replacement, \"ax\"\n\t"
"1:\n\t"
"rd %%asr24, %0\n\t"
".popsection\n"
: "=r" (ret));
__asm__ __volatile__("rd %%tick, %0" : "=r" (ret));
return ret;
}
notrace static __always_inline u64 vread_tick_stick(void)
{
u64 ret;
__asm__ __volatile__("rd %%asr24, %0" : "=r" (ret));
return ret;
}
#else
@ -107,16 +106,18 @@ notrace static __always_inline u64 vread_tick(void)
{
register unsigned long long ret asm("o4");
__asm__ __volatile__("1:\n\t"
"rd %%tick, %L0\n\t"
"srlx %L0, 32, %H0\n\t"
".pushsection .tick_patch, \"a\"\n\t"
".word 1b - ., 1f - .\n\t"
".popsection\n\t"
".pushsection .tick_patch_replacement, \"ax\"\n\t"
"1:\n\t"
"rd %%asr24, %L0\n\t"
".popsection\n"
__asm__ __volatile__("rd %%tick, %L0\n\t"
"srlx %L0, 32, %H0"
: "=r" (ret));
return ret;
}
notrace static __always_inline u64 vread_tick_stick(void)
{
register unsigned long long ret asm("o4");
__asm__ __volatile__("rd %%asr24, %L0\n\t"
"srlx %L0, 32, %H0"
: "=r" (ret));
return ret;
}
@ -132,6 +133,16 @@ notrace static __always_inline u64 vgetsns(struct vvar_data *vvar)
return v * vvar->clock.mult;
}
notrace static __always_inline u64 vgetsns_stick(struct vvar_data *vvar)
{
u64 v;
u64 cycles;
cycles = vread_tick_stick();
v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
return v * vvar->clock.mult;
}
notrace static __always_inline int do_realtime(struct vvar_data *vvar,
struct timespec *ts)
{
@ -152,6 +163,26 @@ notrace static __always_inline int do_realtime(struct vvar_data *vvar,
return 0;
}
notrace static __always_inline int do_realtime_stick(struct vvar_data *vvar,
struct timespec *ts)
{
unsigned long seq;
u64 ns;
do {
seq = vvar_read_begin(vvar);
ts->tv_sec = vvar->wall_time_sec;
ns = vvar->wall_time_snsec;
ns += vgetsns_stick(vvar);
ns >>= vvar->clock.shift;
} while (unlikely(vvar_read_retry(vvar, seq)));
ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
ts->tv_nsec = ns;
return 0;
}
notrace static __always_inline int do_monotonic(struct vvar_data *vvar,
struct timespec *ts)
{
@ -172,6 +203,26 @@ notrace static __always_inline int do_monotonic(struct vvar_data *vvar,
return 0;
}
notrace static __always_inline int do_monotonic_stick(struct vvar_data *vvar,
struct timespec *ts)
{
unsigned long seq;
u64 ns;
do {
seq = vvar_read_begin(vvar);
ts->tv_sec = vvar->monotonic_time_sec;
ns = vvar->monotonic_time_snsec;
ns += vgetsns_stick(vvar);
ns >>= vvar->clock.shift;
} while (unlikely(vvar_read_retry(vvar, seq)));
ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
ts->tv_nsec = ns;
return 0;
}
notrace static int do_realtime_coarse(struct vvar_data *vvar,
struct timespec *ts)
{
@ -227,6 +278,31 @@ int
clock_gettime(clockid_t, struct timespec *)
__attribute__((weak, alias("__vdso_clock_gettime")));
notrace int
__vdso_clock_gettime_stick(clockid_t clock, struct timespec *ts)
{
struct vvar_data *vvd = get_vvar_data();
switch (clock) {
case CLOCK_REALTIME:
if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
break;
return do_realtime_stick(vvd, ts);
case CLOCK_MONOTONIC:
if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
break;
return do_monotonic_stick(vvd, ts);
case CLOCK_REALTIME_COARSE:
return do_realtime_coarse(vvd, ts);
case CLOCK_MONOTONIC_COARSE:
return do_monotonic_coarse(vvd, ts);
}
/*
* Unknown clock ID ? Fall back to the syscall.
*/
return vdso_fallback_gettime(clock, ts);
}
notrace int
__vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
@ -262,3 +338,36 @@ __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
int
gettimeofday(struct timeval *, struct timezone *)
__attribute__((weak, alias("__vdso_gettimeofday")));
notrace int
__vdso_gettimeofday_stick(struct timeval *tv, struct timezone *tz)
{
struct vvar_data *vvd = get_vvar_data();
if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
if (likely(tv != NULL)) {
union tstv_t {
struct timespec ts;
struct timeval tv;
} *tstv = (union tstv_t *) tv;
do_realtime_stick(vvd, &tstv->ts);
/*
* Assign before dividing to ensure that the division is
* done in the type of tv_usec, not tv_nsec.
*
* There cannot be > 1 billion usec in a second:
* do_realtime() has already distributed such overflow
* into tv_sec. So we can assign it to an int safely.
*/
tstv->tv.tv_usec = tstv->ts.tv_nsec;
tstv->tv.tv_usec /= 1000;
}
if (unlikely(tz != NULL)) {
/* Avoid memcpy. Some old compilers fail to inline it */
tz->tz_minuteswest = vvd->tz_minuteswest;
tz->tz_dsttime = vvd->tz_dsttime;
}
return 0;
}
return vdso_fallback_gettimeofday(tv, tz);
}

3
arch/sparc/vdso/vdso-layout.lds.S
View File

@ -73,9 +73,6 @@ SECTIONS
.text : { *(.text*) } :text =0x90909090,
.tick_patch : { *(.tick_patch) } :text
.tick_patch_insns : { *(.tick_patch_insns) } :text
/DISCARD/ : {
*(.discard)
*(.discard.*)

2
arch/sparc/vdso/vdso.lds.S
View File

@ -18,8 +18,10 @@ VERSION {
global:
clock_gettime;
__vdso_clock_gettime;
__vdso_clock_gettime_stick;
gettimeofday;
__vdso_gettimeofday;
__vdso_gettimeofday_stick;
local: *;
};
}

17
arch/sparc/vdso/vdso2c.h
View File

@ -17,11 +17,9 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
unsigned long mapping_size;
int i;
unsigned long j;
ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
*patch_sec = NULL;
ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr;
ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
ELF(Dyn) *dyn = 0, *dyn_end = 0;
const char *secstrings;
INT_BITS syms[NSYMS] = {};
ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_BE(&hdr->e_phoff));
@ -64,18 +62,11 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
}
/* Walk the section table */
secstrings_hdr = raw_addr + GET_BE(&hdr->e_shoff) +
GET_BE(&hdr->e_shentsize)*GET_BE(&hdr->e_shstrndx);
secstrings = raw_addr + GET_BE(&secstrings_hdr->sh_offset);
for (i = 0; i < GET_BE(&hdr->e_shnum); i++) {
ELF(Shdr) *sh = raw_addr + GET_BE(&hdr->e_shoff) +
GET_BE(&hdr->e_shentsize) * i;
if (GET_BE(&sh->sh_type) == SHT_SYMTAB)
symtab_hdr = sh;
if (!strcmp(secstrings + GET_BE(&sh->sh_name),
".tick_patch"))
patch_sec = sh;
}
if (!symtab_hdr)
@ -142,12 +133,6 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
fprintf(outfile, "const struct vdso_image %s_builtin = {\n", name);
fprintf(outfile, "\t.data = raw_data,\n");
fprintf(outfile, "\t.size = %lu,\n", mapping_size);
if (patch_sec) {
fprintf(outfile, "\t.tick_patch = %lu,\n",
(unsigned long)GET_BE(&patch_sec->sh_offset));
fprintf(outfile, "\t.tick_patch_len = %lu,\n",
(unsigned long)GET_BE(&patch_sec->sh_size));
}
for (i = 0; i < NSYMS; i++) {
if (required_syms[i].export && syms[i])
fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",

2
arch/sparc/vdso/vdso32/vdso32.lds.S
View File

@ -17,8 +17,10 @@ VERSION {
global:
clock_gettime;
__vdso_clock_gettime;
__vdso_clock_gettime_stick;
gettimeofday;
__vdso_gettimeofday;
__vdso_gettimeofday_stick;
local: *;
};
}

226
arch/sparc/vdso/vma.c
View File

@ -42,24 +42,201 @@ static struct vm_special_mapping vdso_mapping32 = {
struct vvar_data *vvar_data;
struct tick_patch_entry {
s32 orig, repl;
struct vdso_elfinfo32 {
Elf32_Ehdr *hdr;
Elf32_Sym *dynsym;
unsigned long dynsymsize;
const char *dynstr;
unsigned long text;
};
static void stick_patch(const struct vdso_image *image)
struct vdso_elfinfo64 {
Elf64_Ehdr *hdr;
Elf64_Sym *dynsym;
unsigned long dynsymsize;
const char *dynstr;
unsigned long text;
};
struct vdso_elfinfo {
union {
struct vdso_elfinfo32 elf32;
struct vdso_elfinfo64 elf64;
} u;
};
static void *one_section64(struct vdso_elfinfo64 *e, const char *name,
unsigned long *size)
{
struct tick_patch_entry *p, *p_end;
const char *snames;
Elf64_Shdr *shdrs;
unsigned int i;
p = image->data + image->tick_patch;
p_end = (void *)p + image->tick_patch_len;
while (p < p_end) {
u32 *instr = (void *)&p->orig + p->orig;
u32 *repl = (void *)&p->repl + p->repl;
*instr = *repl;
flushi(instr);
p++;
shdrs = (void *)e->hdr + e->hdr->e_shoff;
snames = (void *)e->hdr + shdrs[e->hdr->e_shstrndx].sh_offset;
for (i = 1; i < e->hdr->e_shnum; i++) {
if (!strcmp(snames+shdrs[i].sh_name, name)) {
if (size)
*size = shdrs[i].sh_size;
return (void *)e->hdr + shdrs[i].sh_offset;
}
}
return NULL;
}
static int find_sections64(const struct vdso_image *image, struct vdso_elfinfo *_e)
{
struct vdso_elfinfo64 *e = &_e->u.elf64;
e->hdr = image->data;
e->dynsym = one_section64(e, ".dynsym", &e->dynsymsize);
e->dynstr = one_section64(e, ".dynstr", NULL);
if (!e->dynsym || !e->dynstr) {
pr_err("VDSO64: Missing symbol sections.\n");
return -ENODEV;
}
return 0;
}
static Elf64_Sym *find_sym64(const struct vdso_elfinfo64 *e, const char *name)
{
unsigned int i;
for (i = 0; i < (e->dynsymsize / sizeof(Elf64_Sym)); i++) {
Elf64_Sym *s = &e->dynsym[i];
if (s->st_name == 0)
continue;
if (!strcmp(e->dynstr + s->st_name, name))
return s;
}
return NULL;
}
static int patchsym64(struct vdso_elfinfo *_e, const char *orig,
const char *new)
{
struct vdso_elfinfo64 *e = &_e->u.elf64;
Elf64_Sym *osym = find_sym64(e, orig);
Elf64_Sym *nsym = find_sym64(e, new);
if (!nsym || !osym) {
pr_err("VDSO64: Missing symbols.\n");
return -ENODEV;
}
osym->st_value = nsym->st_value;
osym->st_size = nsym->st_size;
osym->st_info = nsym->st_info;
osym->st_other = nsym->st_other;
osym->st_shndx = nsym->st_shndx;
return 0;
}
static void *one_section32(struct vdso_elfinfo32 *e, const char *name,
unsigned long *size)
{
const char *snames;
Elf32_Shdr *shdrs;
unsigned int i;
shdrs = (void *)e->hdr + e->hdr->e_shoff;
snames = (void *)e->hdr + shdrs[e->hdr->e_shstrndx].sh_offset;
for (i = 1; i < e->hdr->e_shnum; i++) {
if (!strcmp(snames+shdrs[i].sh_name, name)) {
if (size)
*size = shdrs[i].sh_size;
return (void *)e->hdr + shdrs[i].sh_offset;
}
}
return NULL;
}
static int find_sections32(const struct vdso_image *image, struct vdso_elfinfo *_e)
{
struct vdso_elfinfo32 *e = &_e->u.elf32;
e->hdr = image->data;
e->dynsym = one_section32(e, ".dynsym", &e->dynsymsize);
e->dynstr = one_section32(e, ".dynstr", NULL);
if (!e->dynsym || !e->dynstr) {
pr_err("VDSO32: Missing symbol sections.\n");
return -ENODEV;
}
return 0;
}
static Elf32_Sym *find_sym32(const struct vdso_elfinfo32 *e, const char *name)
{
unsigned int i;
for (i = 0; i < (e->dynsymsize / sizeof(Elf32_Sym)); i++) {
Elf32_Sym *s = &e->dynsym[i];
if (s->st_name == 0)
continue;
if (!strcmp(e->dynstr + s->st_name, name))
return s;
}
return NULL;
}
static int patchsym32(struct vdso_elfinfo *_e, const char *orig,
const char *new)
{
struct vdso_elfinfo32 *e = &_e->u.elf32;
Elf32_Sym *osym = find_sym32(e, orig);
Elf32_Sym *nsym = find_sym32(e, new);
if (!nsym || !osym) {
pr_err("VDSO32: Missing symbols.\n");
return -ENODEV;
}
osym->st_value = nsym->st_value;
osym->st_size = nsym->st_size;
osym->st_info = nsym->st_info;
osym->st_other = nsym->st_other;
osym->st_shndx = nsym->st_shndx;
return 0;
}
static int find_sections(const struct vdso_image *image, struct vdso_elfinfo *e,
bool elf64)
{
if (elf64)
return find_sections64(image, e);
else
return find_sections32(image, e);
}
static int patch_one_symbol(struct vdso_elfinfo *e, const char *orig,
const char *new_target, bool elf64)
{
if (elf64)
return patchsym64(e, orig, new_target);
else
return patchsym32(e, orig, new_target);
}
static int stick_patch(const struct vdso_image *image, struct vdso_elfinfo *e, bool elf64)
{
int err;
err = find_sections(image, e, elf64);
if (err)
return err;
err = patch_one_symbol(e,
"__vdso_gettimeofday",
"__vdso_gettimeofday_stick", elf64);
if (err)
return err;
return patch_one_symbol(e,
"__vdso_clock_gettime",
"__vdso_clock_gettime_stick", elf64);
return 0;
}
/*
@ -67,13 +244,19 @@ static void stick_patch(const struct vdso_image *image)
* kernel image.
*/
int __init init_vdso_image(const struct vdso_image *image,
struct vm_special_mapping *vdso_mapping)
struct vm_special_mapping *vdso_mapping, bool elf64)
{
int i;
struct page *dp, **dpp = NULL;
int dnpages = 0;
struct page *cp, **cpp = NULL;
int cnpages = (image->size) / PAGE_SIZE;
struct page *dp, **dpp = NULL;
struct page *cp, **cpp = NULL;
struct vdso_elfinfo ei;
int i, dnpages = 0;
if (tlb_type != spitfire) {
int err = stick_patch(image, &ei, elf64);
if (err)
return err;
}
/*
* First, the vdso text. This is initialied data, an integral number of
@ -88,9 +271,6 @@ int __init init_vdso_image(const struct vdso_image *image,
if (!cpp)
goto oom;
if (tlb_type != spitfire)
stick_patch(image);
for (i = 0; i < cnpages; i++) {
cp = alloc_page(GFP_KERNEL);
if (!cp)
@ -153,13 +333,13 @@ static int __init init_vdso(void)
{
int err = 0;
#ifdef CONFIG_SPARC64
err = init_vdso_image(&vdso_image_64_builtin, &vdso_mapping64);
err = init_vdso_image(&vdso_image_64_builtin, &vdso_mapping64, true);
if (err)
return err;
#endif
#ifdef CONFIG_COMPAT
err = init_vdso_image(&vdso_image_32_builtin, &vdso_mapping32);
err = init_vdso_image(&vdso_image_32_builtin, &vdso_mapping32, false);
#endif
return err;