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sparc64: vdso: Replace code patching with runtime conditional
The patching logic is unnecessarily complicated and stands in the way of the adoption of the generic vDSO framework. Replace it by a simple runtime switch, similar to other architectures. Suggested-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: Andreas Larsson <andreas@gaisler.com> Reviewed-by: Andreas Larsson <andreas@gaisler.com> Acked-by: Andreas Larsson <andreas@gaisler.com> Link: https://lore.kernel.org/lkml/87ecu9tfhw.ffs@tglx/ Link: https://patch.msgid.link/20260304-vdso-sparc64-generic-2-v6-6-d8eb3b0e1410@linutronix.de
This commit is contained in:
Thomas Weißschuh
Thomas Gleixner
parent
9fc4fe6e14
commit
7b4ee085e7
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@ -148,17 +148,11 @@ notrace static __always_inline u64 vgetsns(struct vvar_data *vvar)
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u64 v;
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u64 cycles;
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cycles = vread_tick();
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v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
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return v * vvar->clock.mult;
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}
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if (likely(vvar->vclock_mode == VCLOCK_STICK))
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cycles = vread_tick_stick();
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else
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cycles = vread_tick();
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notrace static __always_inline u64 vgetsns_stick(struct vvar_data *vvar)
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{
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u64 v;
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u64 cycles;
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cycles = vread_tick_stick();
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v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
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return v * vvar->clock.mult;
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}
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@ -183,26 +177,6 @@ notrace static __always_inline int do_realtime(struct vvar_data *vvar,
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return 0;
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}
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notrace static __always_inline int do_realtime_stick(struct vvar_data *vvar,
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struct __kernel_old_timespec *ts)
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{
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unsigned long seq;
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u64 ns;
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do {
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seq = vvar_read_begin(vvar);
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ts->tv_sec = vvar->wall_time_sec;
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ns = vvar->wall_time_snsec;
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ns += vgetsns_stick(vvar);
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ns = __shr64(ns, vvar->clock.shift);
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} while (unlikely(vvar_read_retry(vvar, seq)));
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ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
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ts->tv_nsec = ns;
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return 0;
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}
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notrace static __always_inline int do_monotonic(struct vvar_data *vvar,
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struct __kernel_old_timespec *ts)
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{
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@ -223,26 +197,6 @@ notrace static __always_inline int do_monotonic(struct vvar_data *vvar,
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return 0;
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}
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notrace static __always_inline int do_monotonic_stick(struct vvar_data *vvar,
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struct __kernel_old_timespec *ts)
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{
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unsigned long seq;
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u64 ns;
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do {
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seq = vvar_read_begin(vvar);
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ts->tv_sec = vvar->monotonic_time_sec;
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ns = vvar->monotonic_time_snsec;
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ns += vgetsns_stick(vvar);
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ns = __shr64(ns, vvar->clock.shift);
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} while (unlikely(vvar_read_retry(vvar, seq)));
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ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
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ts->tv_nsec = ns;
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return 0;
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}
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notrace static int do_realtime_coarse(struct vvar_data *vvar,
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struct __kernel_old_timespec *ts)
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{
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@ -298,31 +252,6 @@ int
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clock_gettime(clockid_t, struct __kernel_old_timespec *)
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__attribute__((weak, alias("__vdso_clock_gettime")));
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notrace int
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__vdso_clock_gettime_stick(clockid_t clock, struct __kernel_old_timespec *ts)
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{
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struct vvar_data *vvd = get_vvar_data();
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switch (clock) {
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case CLOCK_REALTIME:
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if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
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break;
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return do_realtime_stick(vvd, ts);
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case CLOCK_MONOTONIC:
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if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
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break;
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return do_monotonic_stick(vvd, ts);
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case CLOCK_REALTIME_COARSE:
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return do_realtime_coarse(vvd, ts);
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case CLOCK_MONOTONIC_COARSE:
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return do_monotonic_coarse(vvd, ts);
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}
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/*
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* Unknown clock ID ? Fall back to the syscall.
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*/
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return vdso_fallback_gettime(clock, ts);
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}
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notrace int
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__vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
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{
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@ -358,36 +287,3 @@ __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz)
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int
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gettimeofday(struct __kernel_old_timeval *, struct timezone *)
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__attribute__((weak, alias("__vdso_gettimeofday")));
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notrace int
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__vdso_gettimeofday_stick(struct __kernel_old_timeval *tv, struct timezone *tz)
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{
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struct vvar_data *vvd = get_vvar_data();
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if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
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if (likely(tv != NULL)) {
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union tstv_t {
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struct __kernel_old_timespec ts;
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struct __kernel_old_timeval tv;
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} *tstv = (union tstv_t *) tv;
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do_realtime_stick(vvd, &tstv->ts);
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/*
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* Assign before dividing to ensure that the division is
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* done in the type of tv_usec, not tv_nsec.
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*
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* There cannot be > 1 billion usec in a second:
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* do_realtime() has already distributed such overflow
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* into tv_sec. So we can assign it to an int safely.
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*/
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tstv->tv.tv_usec = tstv->ts.tv_nsec;
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tstv->tv.tv_usec /= 1000;
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}
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if (unlikely(tz != NULL)) {
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/* Avoid memcpy. Some old compilers fail to inline it */
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tz->tz_minuteswest = vvd->tz_minuteswest;
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tz->tz_dsttime = vvd->tz_dsttime;
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}
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return 0;
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}
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return vdso_fallback_gettimeofday(tv, tz);
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}
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@ -18,10 +18,8 @@ VERSION {
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global:
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clock_gettime;
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__vdso_clock_gettime;
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__vdso_clock_gettime_stick;
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gettimeofday;
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__vdso_gettimeofday;
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__vdso_gettimeofday_stick;
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local: *;
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};
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}
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@ -17,10 +17,8 @@ VERSION {
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global:
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clock_gettime;
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__vdso_clock_gettime;
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__vdso_clock_gettime_stick;
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gettimeofday;
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__vdso_gettimeofday;
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__vdso_gettimeofday_stick;
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local: *;
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};
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}
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@ -42,203 +42,6 @@ static struct vm_special_mapping vdso_mapping32 = {
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struct vvar_data *vvar_data;
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struct vdso_elfinfo32 {
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Elf32_Ehdr *hdr;
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Elf32_Sym *dynsym;
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unsigned long dynsymsize;
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const char *dynstr;
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unsigned long text;
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};
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struct vdso_elfinfo64 {
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Elf64_Ehdr *hdr;
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Elf64_Sym *dynsym;
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unsigned long dynsymsize;
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const char *dynstr;
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unsigned long text;
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};
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struct vdso_elfinfo {
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union {
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struct vdso_elfinfo32 elf32;
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struct vdso_elfinfo64 elf64;
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} u;
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};
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static void *one_section64(struct vdso_elfinfo64 *e, const char *name,
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unsigned long *size)
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{
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const char *snames;
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Elf64_Shdr *shdrs;
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unsigned int i;
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shdrs = (void *)e->hdr + e->hdr->e_shoff;
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snames = (void *)e->hdr + shdrs[e->hdr->e_shstrndx].sh_offset;
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for (i = 1; i < e->hdr->e_shnum; i++) {
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if (!strcmp(snames+shdrs[i].sh_name, name)) {
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if (size)
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*size = shdrs[i].sh_size;
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return (void *)e->hdr + shdrs[i].sh_offset;
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}
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}
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return NULL;
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}
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static int find_sections64(const struct vdso_image *image, struct vdso_elfinfo *_e)
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{
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struct vdso_elfinfo64 *e = &_e->u.elf64;
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e->hdr = image->data;
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e->dynsym = one_section64(e, ".dynsym", &e->dynsymsize);
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e->dynstr = one_section64(e, ".dynstr", NULL);
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if (!e->dynsym || !e->dynstr) {
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pr_err("VDSO64: Missing symbol sections.\n");
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return -ENODEV;
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}
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return 0;
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}
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static Elf64_Sym *find_sym64(const struct vdso_elfinfo64 *e, const char *name)
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{
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unsigned int i;
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for (i = 0; i < (e->dynsymsize / sizeof(Elf64_Sym)); i++) {
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Elf64_Sym *s = &e->dynsym[i];
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if (s->st_name == 0)
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continue;
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if (!strcmp(e->dynstr + s->st_name, name))
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return s;
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}
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return NULL;
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}
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static int patchsym64(struct vdso_elfinfo *_e, const char *orig,
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const char *new)
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{
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struct vdso_elfinfo64 *e = &_e->u.elf64;
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Elf64_Sym *osym = find_sym64(e, orig);
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Elf64_Sym *nsym = find_sym64(e, new);
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if (!nsym || !osym) {
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pr_err("VDSO64: Missing symbols.\n");
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return -ENODEV;
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}
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osym->st_value = nsym->st_value;
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osym->st_size = nsym->st_size;
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osym->st_info = nsym->st_info;
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osym->st_other = nsym->st_other;
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osym->st_shndx = nsym->st_shndx;
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return 0;
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}
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static void *one_section32(struct vdso_elfinfo32 *e, const char *name,
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unsigned long *size)
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{
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const char *snames;
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Elf32_Shdr *shdrs;
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unsigned int i;
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shdrs = (void *)e->hdr + e->hdr->e_shoff;
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snames = (void *)e->hdr + shdrs[e->hdr->e_shstrndx].sh_offset;
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for (i = 1; i < e->hdr->e_shnum; i++) {
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if (!strcmp(snames+shdrs[i].sh_name, name)) {
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if (size)
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*size = shdrs[i].sh_size;
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return (void *)e->hdr + shdrs[i].sh_offset;
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}
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}
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return NULL;
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}
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static int find_sections32(const struct vdso_image *image, struct vdso_elfinfo *_e)
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{
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struct vdso_elfinfo32 *e = &_e->u.elf32;
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e->hdr = image->data;
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e->dynsym = one_section32(e, ".dynsym", &e->dynsymsize);
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e->dynstr = one_section32(e, ".dynstr", NULL);
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if (!e->dynsym || !e->dynstr) {
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pr_err("VDSO32: Missing symbol sections.\n");
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return -ENODEV;
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}
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return 0;
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}
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static Elf32_Sym *find_sym32(const struct vdso_elfinfo32 *e, const char *name)
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{
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unsigned int i;
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for (i = 0; i < (e->dynsymsize / sizeof(Elf32_Sym)); i++) {
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Elf32_Sym *s = &e->dynsym[i];
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if (s->st_name == 0)
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continue;
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if (!strcmp(e->dynstr + s->st_name, name))
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return s;
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}
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return NULL;
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}
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static int patchsym32(struct vdso_elfinfo *_e, const char *orig,
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const char *new)
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{
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struct vdso_elfinfo32 *e = &_e->u.elf32;
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Elf32_Sym *osym = find_sym32(e, orig);
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Elf32_Sym *nsym = find_sym32(e, new);
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if (!nsym || !osym) {
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pr_err("VDSO32: Missing symbols.\n");
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return -ENODEV;
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}
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osym->st_value = nsym->st_value;
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osym->st_size = nsym->st_size;
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osym->st_info = nsym->st_info;
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osym->st_other = nsym->st_other;
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osym->st_shndx = nsym->st_shndx;
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return 0;
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}
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static int find_sections(const struct vdso_image *image, struct vdso_elfinfo *e,
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bool elf64)
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{
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if (elf64)
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return find_sections64(image, e);
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else
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return find_sections32(image, e);
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}
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static int patch_one_symbol(struct vdso_elfinfo *e, const char *orig,
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const char *new_target, bool elf64)
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{
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if (elf64)
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return patchsym64(e, orig, new_target);
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else
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return patchsym32(e, orig, new_target);
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}
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static int stick_patch(const struct vdso_image *image, struct vdso_elfinfo *e, bool elf64)
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{
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int err;
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err = find_sections(image, e, elf64);
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if (err)
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return err;
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err = patch_one_symbol(e,
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"__vdso_gettimeofday",
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"__vdso_gettimeofday_stick", elf64);
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if (err)
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return err;
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return patch_one_symbol(e,
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"__vdso_clock_gettime",
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"__vdso_clock_gettime_stick", elf64);
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return 0;
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}
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/*
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* Allocate pages for the vdso and vvar, and copy in the vdso text from the
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* kernel image.
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@ -250,15 +53,8 @@ static int __init init_vdso_image(const struct vdso_image *image,
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int cnpages = (image->size) / PAGE_SIZE;
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struct page *dp, **dpp = NULL;
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struct page *cp, **cpp = NULL;
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struct vdso_elfinfo ei;
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int i, dnpages = 0;
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if (tlb_type != spitfire) {
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int err = stick_patch(image, &ei, elf64);
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if (err)
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return err;
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}
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/*
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* First, the vdso text. This is initialied data, an integral number of
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* pages long.
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