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Subject[RFC PATCH v2 10/10] powerpc/32: Switch VDSO to C implementation.
Date
This is a tentative to switch powerpc/32 vdso to
generic C implementation.

It will likely not work on 64 bits or even build properly
at the moment, hence the RFC status.

powerpc is a bit special for VDSO as well as system calls in the
way that it requires setting CR SO bit which cannot be done in C.
Therefore, entry/exit and fallback needs to be performed in ASM.

On powerpc 8xx, performance is degraded by 30-40% for gettime and
by 15-20% for getres

On a powerpc885 at 132MHz:
With current powerpc/32 ASM VDSO:

gettimeofday: vdso: 737 nsec/call
clock-getres-realtime-coarse: vdso: 3081 nsec/call
clock-gettime-realtime-coarse: vdso: 2861 nsec/call
clock-getres-realtime: vdso: 475 nsec/call
clock-gettime-realtime: vdso: 892 nsec/call
clock-getres-boottime: vdso: 2621 nsec/call
clock-gettime-boottime: vdso: 3857 nsec/call
clock-getres-tai: vdso: 2620 nsec/call
clock-gettime-tai: vdso: 3854 nsec/call
clock-getres-monotonic-raw: vdso: 2621 nsec/call
clock-gettime-monotonic-raw: vdso: 3499 nsec/call
clock-getres-monotonic-coarse: vdso: 3083 nsec/call
clock-gettime-monotonic-coarse: vdso: 3082 nsec/call
clock-getres-monotonic: vdso: 475 nsec/call
clock-gettime-monotonic: vdso: 1014 nsec/call

Once switched to C implementation:

gettimeofday: vdso: 1016 nsec/call
clock-getres-realtime-coarse: vdso: 614 nsec/call
clock-gettime-realtime-coarse: vdso: 760 nsec/call
clock-getres-realtime: vdso: 560 nsec/call
clock-gettime-realtime: vdso: 1192 nsec/call
clock-getres-boottime: vdso: 560 nsec/call
clock-gettime-boottime: vdso: 1194 nsec/call
clock-getres-tai: vdso: 560 nsec/call
clock-gettime-tai: vdso: 1192 nsec/call
clock-getres-monotonic-raw: vdso: 560 nsec/call
clock-gettime-monotonic-raw: vdso: 1248 nsec/call
clock-getres-monotonic-coarse: vdso: 614 nsec/call
clock-gettime-monotonic-coarse: vdso: 760 nsec/call
clock-getres-monotonic: vdso: 560 nsec/call
clock-gettime-monotonic: vdso: 1192 nsec/call

On a powerpc 8321 running at 333MHz
With current powerpc/32 ASM VDSO:

gettimeofday: vdso: 190 nsec/call
clock-getres-realtime-coarse: vdso: 1449 nsec/call
clock-gettime-realtime-coarse: vdso: 1352 nsec/call
clock-getres-realtime: vdso: 135 nsec/call
clock-gettime-realtime: vdso: 244 nsec/call
clock-getres-boottime: vdso: 1313 nsec/call
clock-gettime-boottime: vdso: 1701 nsec/call
clock-getres-tai: vdso: 1268 nsec/call
clock-gettime-tai: vdso: 1742 nsec/call
clock-getres-monotonic-raw: vdso: 1310 nsec/call
clock-gettime-monotonic-raw: vdso: 1584 nsec/call
clock-getres-monotonic-coarse: vdso: 1488 nsec/call
clock-gettime-monotonic-coarse: vdso: 1503 nsec/call
clock-getres-monotonic: vdso: 135 nsec/call
clock-gettime-monotonic: vdso: 283 nsec/call

Once switched to C implementation:

gettimeofday: vdso: 347 nsec/call
clock-getres-realtime-coarse: vdso: 169 nsec/call
clock-gettime-realtime-coarse: vdso: 271 nsec/call
clock-getres-realtime: vdso: 150 nsec/call
clock-gettime-realtime: vdso: 383 nsec/call
clock-getres-boottime: vdso: 157 nsec/call
clock-gettime-boottime: vdso: 377 nsec/call
clock-getres-tai: vdso: 150 nsec/call
clock-gettime-tai: vdso: 380 nsec/call
clock-getres-monotonic-raw: vdso: 153 nsec/call
clock-gettime-monotonic-raw: vdso: 407 nsec/call
clock-getres-monotonic-coarse: vdso: 169 nsec/call
clock-gettime-monotonic-coarse: vdso: 271 nsec/call
clock-getres-monotonic: vdso: 153 nsec/call
clock-gettime-monotonic: vdso: 377 nsec/call
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/Kconfig | 2 +
arch/powerpc/include/asm/vdso/gettimeofday.h | 45 +++++
arch/powerpc/include/asm/vdso/vsyscall.h | 27 +++
arch/powerpc/include/asm/vdso_datapage.h | 18 +-
arch/powerpc/kernel/asm-offsets.c | 23 +--
arch/powerpc/kernel/time.c | 92 +---------
arch/powerpc/kernel/vdso.c | 19 +-
arch/powerpc/kernel/vdso32/Makefile | 19 +-
arch/powerpc/kernel/vdso32/gettimeofday.S | 261 ++++-----------------------
arch/powerpc/kernel/vdso32/vgettimeofday.c | 32 ++++
10 files changed, 178 insertions(+), 360 deletions(-)
create mode 100644 arch/powerpc/include/asm/vdso/gettimeofday.h
create mode 100644 arch/powerpc/include/asm/vdso/vsyscall.h
create mode 100644 arch/powerpc/kernel/vdso32/vgettimeofday.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 1ec34e16ed65..bd04c68baf91 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -169,6 +169,7 @@ config PPC
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
select GENERIC_TIME_VSYSCALL
+ select GENERIC_GETTIMEOFDAY
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_HUGE_VMAP if PPC_BOOK3S_64 && PPC_RADIX_MMU
select HAVE_ARCH_JUMP_LABEL
@@ -198,6 +199,7 @@ config PPC
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER
select HAVE_GCC_PLUGINS if GCC_VERSION >= 50200 # plugin support on gcc <= 5.1 is buggy on PPC
+ select HAVE_GENERIC_VDSO
select HAVE_HW_BREAKPOINT if PERF_EVENTS && (PPC_BOOK3S || PPC_8xx)
select HAVE_IDE
select HAVE_IOREMAP_PROT
diff --git a/arch/powerpc/include/asm/vdso/gettimeofday.h b/arch/powerpc/include/asm/vdso/gettimeofday.h
new file mode 100644
index 000000000000..e170e12a78bb
--- /dev/null
+++ b/arch/powerpc/include/asm/vdso/gettimeofday.h
@@ -0,0 +1,45 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_VDSO_GETTIMEOFDAY_H
+#define __ASM_VDSO_GETTIMEOFDAY_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/time.h>
+#include <asm/unistd.h>
+#include <uapi/linux/time.h>
+
+#define VDSO_HAS_CLOCK_GETRES 1
+
+#define VDSO_HAS_TIME 1
+
+static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
+{
+ /*
+ * clock_mode == 0 implies that vDSO are enabled otherwise
+ * fallback on syscall.
+ */
+ if (clock_mode)
+ return ULLONG_MAX;
+
+ return get_tb() & LLONG_MAX;
+}
+
+/*
+ * powerpc specific delta calculation.
+ *
+ * This variant removes the masking of the subtraction because the
+ * clocksource mask of all VDSO capable clocksources on powerpc is U64_MAX
+ * which would result in a pointless operation. The compiler cannot
+ * optimize it away as the mask comes from the vdso data and is not compile
+ * time constant.
+ */
+static __always_inline
+u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult)
+{
+ return (cycles - last) * mult;
+}
+#define vdso_calc_delta vdso_calc_delta
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_GETTIMEOFDAY_H */
diff --git a/arch/powerpc/include/asm/vdso/vsyscall.h b/arch/powerpc/include/asm/vdso/vsyscall.h
new file mode 100644
index 000000000000..d12c2298cbb8
--- /dev/null
+++ b/arch/powerpc/include/asm/vdso/vsyscall.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_VDSO_VSYSCALL_H
+#define __ASM_VDSO_VSYSCALL_H
+
+#ifndef __ASSEMBLY__
+
+#include <linux/timekeeper_internal.h>
+#include <asm/vdso_datapage.h>
+
+extern struct vdso_arch_data *vdso_arch_data;
+
+/*
+ * Update the vDSO data page to keep in sync with kernel timekeeping.
+ */
+static __always_inline
+struct vdso_data *__powerpc_get_k_vdso_data(void)
+{
+ return vdso_arch_data->data;
+}
+#define __arch_get_k_vdso_data __powerpc_get_k_vdso_data
+
+/* The asm-generic header needs to be included after the definitions above */
+#include <asm-generic/vdso/vsyscall.h>
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_VSYSCALL_H */
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h
index ee5319a6f4e3..6b9424ca91c4 100644
--- a/arch/powerpc/include/asm/vdso_datapage.h
+++ b/arch/powerpc/include/asm/vdso_datapage.h
@@ -36,6 +36,7 @@

#include <linux/unistd.h>
#include <linux/time.h>
+#include <vdso/datapage.h>

#define SYSCALL_MAP_SIZE ((NR_syscalls + 31) / 32)

@@ -93,20 +94,9 @@ struct vdso_data {
/*
* And here is the simpler 32 bits version
*/
-struct vdso_data {
- __u64 tb_orig_stamp; /* Timebase at boot 0x30 */
+struct vdso_arch_data {
+ struct vdso_data data[CS_BASES];
__u64 tb_ticks_per_sec; /* Timebase tics / sec 0x38 */
- __u64 tb_to_xs; /* Inverse of TB to 2^20 0x40 */
- __u64 stamp_xsec; /* 0x48 */
- __u32 tb_update_count; /* Timebase atomicity ctr 0x50 */
- __u32 tz_minuteswest; /* Minutes west of Greenwich 0x58 */
- __u32 tz_dsttime; /* Type of dst correction 0x5C */
- __s32 wtom_clock_sec; /* Wall to monotonic clock */
- __s32 wtom_clock_nsec;
- __s32 stamp_xtime_sec; /* xtime seconds as at tb_orig_stamp */
- __s32 stamp_xtime_nsec; /* xtime nsecs as at tb_orig_stamp */
- __u32 stamp_sec_fraction; /* fractional seconds of stamp_xtime */
- __u32 hrtimer_res; /* hrtimer resolution */
__u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
__u32 dcache_block_size; /* L1 d-cache block size */
__u32 icache_block_size; /* L1 i-cache block size */
@@ -116,7 +106,7 @@ struct vdso_data {

#endif /* CONFIG_PPC64 */

-extern struct vdso_data *vdso_data;
+extern struct vdso_arch_data *vdso_arch_data;

#else /* __ASSEMBLY__ */

diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 3d47aec7becf..5927c9cf9cc7 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -376,23 +376,12 @@ int main(void)
#endif /* ! CONFIG_PPC64 */

/* datapage offsets for use by vdso */
- OFFSET(CFG_TB_ORIG_STAMP, vdso_data, tb_orig_stamp);
- OFFSET(CFG_TB_TICKS_PER_SEC, vdso_data, tb_ticks_per_sec);
- OFFSET(CFG_TB_TO_XS, vdso_data, tb_to_xs);
- OFFSET(CFG_TB_UPDATE_COUNT, vdso_data, tb_update_count);
- OFFSET(CFG_TZ_MINUTEWEST, vdso_data, tz_minuteswest);
- OFFSET(CFG_TZ_DSTTIME, vdso_data, tz_dsttime);
- OFFSET(CFG_SYSCALL_MAP32, vdso_data, syscall_map_32);
- OFFSET(WTOM_CLOCK_SEC, vdso_data, wtom_clock_sec);
- OFFSET(WTOM_CLOCK_NSEC, vdso_data, wtom_clock_nsec);
- OFFSET(STAMP_XTIME_SEC, vdso_data, stamp_xtime_sec);
- OFFSET(STAMP_XTIME_NSEC, vdso_data, stamp_xtime_nsec);
- OFFSET(STAMP_SEC_FRAC, vdso_data, stamp_sec_fraction);
- OFFSET(CLOCK_HRTIMER_RES, vdso_data, hrtimer_res);
- OFFSET(CFG_ICACHE_BLOCKSZ, vdso_data, icache_block_size);
- OFFSET(CFG_DCACHE_BLOCKSZ, vdso_data, dcache_block_size);
- OFFSET(CFG_ICACHE_LOGBLOCKSZ, vdso_data, icache_log_block_size);
- OFFSET(CFG_DCACHE_LOGBLOCKSZ, vdso_data, dcache_log_block_size);
+ OFFSET(CFG_TB_TICKS_PER_SEC, vdso_arch_data, tb_ticks_per_sec);
+ OFFSET(CFG_SYSCALL_MAP32, vdso_arch_data, syscall_map_32);
+ OFFSET(CFG_ICACHE_BLOCKSZ, vdso_arch_data, icache_block_size);
+ OFFSET(CFG_DCACHE_BLOCKSZ, vdso_arch_data, dcache_block_size);
+ OFFSET(CFG_ICACHE_LOGBLOCKSZ, vdso_arch_data, icache_log_block_size);
+ OFFSET(CFG_DCACHE_LOGBLOCKSZ, vdso_arch_data, dcache_log_block_size);
#ifdef CONFIG_PPC64
OFFSET(CFG_SYSCALL_MAP64, vdso_data, syscall_map_64);
OFFSET(TVAL64_TV_SEC, __kernel_old_timeval, tv_sec);
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 1168e8b37e30..e0c8023db42c 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -882,95 +882,6 @@ static notrace u64 timebase_read(struct clocksource *cs)
return (u64)get_tb();
}

-
-void update_vsyscall(struct timekeeper *tk)
-{
- struct timespec64 xt;
- struct clocksource *clock = tk->tkr_mono.clock;
- u32 mult = tk->tkr_mono.mult;
- u32 shift = tk->tkr_mono.shift;
- u64 cycle_last = tk->tkr_mono.cycle_last;
- u64 new_tb_to_xs, new_stamp_xsec;
- u64 frac_sec;
-
- if (clock != &clocksource_timebase)
- return;
-
- xt.tv_sec = tk->xtime_sec;
- xt.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
-
- /* Make userspace gettimeofday spin until we're done. */
- ++vdso_data->tb_update_count;
- smp_mb();
-
- /*
- * This computes ((2^20 / 1e9) * mult) >> shift as a
- * 0.64 fixed-point fraction.
- * The computation in the else clause below won't overflow
- * (as long as the timebase frequency is >= 1.049 MHz)
- * but loses precision because we lose the low bits of the constant
- * in the shift. Note that 19342813113834067 ~= 2^(20+64) / 1e9.
- * For a shift of 24 the error is about 0.5e-9, or about 0.5ns
- * over a second. (Shift values are usually 22, 23 or 24.)
- * For high frequency clocks such as the 512MHz timebase clock
- * on POWER[6789], the mult value is small (e.g. 32768000)
- * and so we can shift the constant by 16 initially
- * (295147905179 ~= 2^(20+64-16) / 1e9) and then do the
- * remaining shifts after the multiplication, which gives a
- * more accurate result (e.g. with mult = 32768000, shift = 24,
- * the error is only about 1.2e-12, or 0.7ns over 10 minutes).
- */
- if (mult <= 62500000 && clock->shift >= 16)
- new_tb_to_xs = ((u64) mult * 295147905179ULL) >> (clock->shift - 16);
- else
- new_tb_to_xs = (u64) mult * (19342813113834067ULL >> clock->shift);
-
- /*
- * Compute the fractional second in units of 2^-32 seconds.
- * The fractional second is tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift
- * in nanoseconds, so multiplying that by 2^32 / 1e9 gives
- * it in units of 2^-32 seconds.
- * We assume shift <= 32 because clocks_calc_mult_shift()
- * generates shift values in the range 0 - 32.
- */
- frac_sec = tk->tkr_mono.xtime_nsec << (32 - shift);
- do_div(frac_sec, NSEC_PER_SEC);
-
- /*
- * Work out new stamp_xsec value for any legacy users of systemcfg.
- * stamp_xsec is in units of 2^-20 seconds.
- */
- new_stamp_xsec = frac_sec >> 12;
- new_stamp_xsec += tk->xtime_sec * XSEC_PER_SEC;
-
- /*
- * tb_update_count is used to allow the userspace gettimeofday code
- * to assure itself that it sees a consistent view of the tb_to_xs and
- * stamp_xsec variables. It reads the tb_update_count, then reads
- * tb_to_xs and stamp_xsec and then reads tb_update_count again. If
- * the two values of tb_update_count match and are even then the
- * tb_to_xs and stamp_xsec values are consistent. If not, then it
- * loops back and reads them again until this criteria is met.
- */
- vdso_data->tb_orig_stamp = cycle_last;
- vdso_data->stamp_xsec = new_stamp_xsec;
- vdso_data->tb_to_xs = new_tb_to_xs;
- vdso_data->wtom_clock_sec = tk->wall_to_monotonic.tv_sec;
- vdso_data->wtom_clock_nsec = tk->wall_to_monotonic.tv_nsec;
- vdso_data->stamp_xtime_sec = xt.tv_sec;
- vdso_data->stamp_xtime_nsec = xt.tv_nsec;
- vdso_data->stamp_sec_fraction = frac_sec;
- vdso_data->hrtimer_res = hrtimer_resolution;
- smp_wmb();
- ++(vdso_data->tb_update_count);
-}
-
-void update_vsyscall_tz(void)
-{
- vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
- vdso_data->tz_dsttime = sys_tz.tz_dsttime;
-}
-
static void __init clocksource_init(void)
{
struct clocksource *clock;
@@ -1140,8 +1051,7 @@ void __init time_init(void)
sys_tz.tz_dsttime = 0;
}

- vdso_data->tb_update_count = 0;
- vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
+ vdso_arch_data->tb_ticks_per_sec = tb_ticks_per_sec;

/* initialise and enable the large decrementer (if we have one) */
set_decrementer_max();
diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c
index eae9ddaecbcf..d1e4f3a3a781 100644
--- a/arch/powerpc/kernel/vdso.c
+++ b/arch/powerpc/kernel/vdso.c
@@ -17,6 +17,7 @@
#include <linux/elf.h>
#include <linux/security.h>
#include <linux/memblock.h>
+#include <vdso/datapage.h>

#include <asm/pgtable.h>
#include <asm/processor.h>
@@ -71,10 +72,10 @@ static int vdso_ready;
* with it, it will become dynamically allocated
*/
static union {
- struct vdso_data data;
+ struct vdso_arch_data arch_data;
u8 page[PAGE_SIZE];
} vdso_data_store __page_aligned_data;
-struct vdso_data *vdso_data = &vdso_data_store.data;
+struct vdso_arch_data *vdso_arch_data = &vdso_data_store.arch_data;

/* Format of the patch table */
struct vdso_patch_def
@@ -661,7 +662,7 @@ static void __init vdso_setup_syscall_map(void)
0x80000000UL >> (i & 0x1f);
#else /* CONFIG_PPC64 */
if (sys_call_table[i] != sys_ni_syscall)
- vdso_data->syscall_map_32[i >> 5] |=
+ vdso_arch_data->syscall_map_32[i >> 5] |=
0x80000000UL >> (i & 0x1f);
#endif /* CONFIG_PPC64 */
}
@@ -729,10 +730,10 @@ static int __init vdso_init(void)
vdso64_pages = (&vdso64_end - &vdso64_start) >> PAGE_SHIFT;
DBG("vdso64_kbase: %p, 0x%x pages\n", vdso64_kbase, vdso64_pages);
#else
- vdso_data->dcache_block_size = L1_CACHE_BYTES;
- vdso_data->dcache_log_block_size = L1_CACHE_SHIFT;
- vdso_data->icache_block_size = L1_CACHE_BYTES;
- vdso_data->icache_log_block_size = L1_CACHE_SHIFT;
+ vdso_arch_data->dcache_block_size = L1_CACHE_BYTES;
+ vdso_arch_data->dcache_log_block_size = L1_CACHE_SHIFT;
+ vdso_arch_data->icache_block_size = L1_CACHE_BYTES;
+ vdso_arch_data->icache_log_block_size = L1_CACHE_SHIFT;
#endif /* CONFIG_PPC64 */


@@ -775,7 +776,7 @@ static int __init vdso_init(void)
get_page(pg);
vdso32_pagelist[i] = pg;
}
- vdso32_pagelist[i++] = virt_to_page(vdso_data);
+ vdso32_pagelist[i++] = virt_to_page(vdso_arch_data);
vdso32_pagelist[i] = NULL;
#endif

@@ -792,7 +793,7 @@ static int __init vdso_init(void)
vdso64_pagelist[i] = NULL;
#endif /* CONFIG_PPC64 */

- get_page(virt_to_page(vdso_data));
+ get_page(virt_to_page(vdso_arch_data));

smp_wmb();
vdso_ready = 1;
diff --git a/arch/powerpc/kernel/vdso32/Makefile b/arch/powerpc/kernel/vdso32/Makefile
index 06f54d947057..09edcd1a2dc7 100644
--- a/arch/powerpc/kernel/vdso32/Makefile
+++ b/arch/powerpc/kernel/vdso32/Makefile
@@ -2,10 +2,17 @@

# List of files in the vdso, has to be asm only for now

+ARCH_REL_TYPE_ABS := R_PPC_JUMP_SLOT|R_PPC_GLOB_DAT|R_PPC_ADDR32|R_PPC_ADDR24|R_PPC_ADDR16|R_PPC_ADDR16_LO|R_PPC_ADDR16_HI|R_PPC_ADDR16_HA|R_PPC_ADDR14|R_PPC_ADDR14_BRTAKEN|R_PPC_ADDR14_BRNTAKEN
+include $(srctree)/lib/vdso/Makefile
+
obj-vdso32-$(CONFIG_PPC64) = getcpu.o
obj-vdso32 = sigtramp.o gettimeofday.o datapage.o cacheflush.o note.o \
$(obj-vdso32-y)

+ifneq ($(c-gettimeofday-y),)
+ CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
+endif
+
# Build rules

ifdef CROSS32_COMPILE
@@ -38,8 +45,8 @@ CPPFLAGS_vdso32.lds += -P -C -Upowerpc
$(obj)/vdso32_wrapper.o : $(obj)/vdso32.so

# link rule for the .so file, .lds has to be first
-$(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32) FORCE
- $(call if_changed,vdso32ld)
+$(obj)/vdso32.so.dbg: $(src)/vdso32.lds $(obj-vdso32) $(obj)/vgettimeofday.o FORCE
+ $(call if_changed,vdso32ld_and_check)

# strip rule for the .so file
$(obj)/%.so: OBJCOPYFLAGS := -S
@@ -49,12 +56,16 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE
# assembly rules for the .S files
$(obj-vdso32): %.o: %.S FORCE
$(call if_changed_dep,vdso32as)
+$(obj)/vgettimeofday.o: %.o: %.c FORCE
+ $(call if_changed_dep,vdso32cc)

# actual build commands
-quiet_cmd_vdso32ld = VDSO32L $@
- cmd_vdso32ld = $(VDSOCC) $(c_flags) $(CC32FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^)
+quiet_cmd_vdso32ld_and_check = VDSO32L $@
+ cmd_vdso32ld_and_check = $(VDSOCC) $(c_flags) $(CC32FLAGS) -o $@ -Wl,-T$(filter %.lds,$^) $(filter %.o,$^) ; $(cmd_vdso_check)
quiet_cmd_vdso32as = VDSO32A $@
cmd_vdso32as = $(VDSOCC) $(a_flags) $(CC32FLAGS) -c -o $@ $<
+quiet_cmd_vdso32cc = VDSO32A $@
+ cmd_vdso32cc = $(VDSOCC) $(c_flags) $(CC32FLAGS) -c -o $@ $<

# install commands for the unstripped file
quiet_cmd_vdso_install = INSTALL $@
diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index d6c1d331e8cb..d767d0089ad0 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -13,14 +13,32 @@
#include <asm/asm-offsets.h>
#include <asm/unistd.h>

-/* Offset for the low 32-bit part of a field of long type */
-#ifdef CONFIG_PPC64
-#define LOPART 4
-#else
-#define LOPART 0
-#endif
-
.text
+
+.macro cvdso_call_with_fallback funct, syscall
+ stwu r1, -16(r1)
+ mflr r0
+ stw r0, 20(r1)
+ stw r3, 8(r1)
+ stw r4, 12(r1)
+ get_datapage r5, r0
+ bl \funct
+ lwz r0, 20(r1)
+ cmpwi r3, 0
+ mtlr r0
+ bne- 99f
+ addi r1, r1, 16
+ crclr so
+ blr
+99:
+ lwz r3, 8(r1)
+ lwz r4, 12(r1)
+ li r0, \syscall
+ addi r1, r1, 16
+ sc
+ blr
+.endm
+
/*
* Exact prototype of gettimeofday
*
@@ -29,31 +47,7 @@
*/
V_FUNCTION_BEGIN(__kernel_gettimeofday)
.cfi_startproc
- mflr r12
- .cfi_register lr,r12
-
- mr r10,r3 /* r10 saves tv */
- mr r11,r4 /* r11 saves tz */
- get_datapage r9, r0
- cmplwi r10,0 /* check if tv is NULL */
- beq 3f
- lis r7,1000000@ha /* load up USEC_PER_SEC */
- addi r7,r7,1000000@l /* so we get microseconds in r4 */
- bl __do_get_tspec@local /* get sec/usec from tb & kernel */
- stw r3,TVAL32_TV_SEC(r10)
- stw r4,TVAL32_TV_USEC(r10)
-
-3: cmplwi r11,0 /* check if tz is NULL */
- beq 1f
- lwz r4,CFG_TZ_MINUTEWEST(r9)/* fill tz */
- lwz r5,CFG_TZ_DSTTIME(r9)
- stw r4,TZONE_TZ_MINWEST(r11)
- stw r5,TZONE_TZ_DSTTIME(r11)
-
-1: mtlr r12
- crclr cr0*4+so
- li r3,0
- blr
+ cvdso_call_with_fallback __c_kernel_gettimeofday, __NR_gettimeofday
.cfi_endproc
V_FUNCTION_END(__kernel_gettimeofday)

@@ -65,76 +59,7 @@ V_FUNCTION_END(__kernel_gettimeofday)
*/
V_FUNCTION_BEGIN(__kernel_clock_gettime)
.cfi_startproc
- /* Check for supported clock IDs */
- cmpli cr0,r3,CLOCK_REALTIME
- cmpli cr1,r3,CLOCK_MONOTONIC
- cror cr0*4+eq,cr0*4+eq,cr1*4+eq
- bne cr0,99f
-
- mflr r12 /* r12 saves lr */
- .cfi_register lr,r12
- mr r11,r4 /* r11 saves tp */
- get_datapage r9, r0
- lis r7,NSEC_PER_SEC@h /* want nanoseconds */
- ori r7,r7,NSEC_PER_SEC@l
-50: bl __do_get_tspec@local /* get sec/nsec from tb & kernel */
- bne cr1,80f /* not monotonic -> all done */
-
- /*
- * CLOCK_MONOTONIC
- */
-
- /* now we must fixup using wall to monotonic. We need to snapshot
- * that value and do the counter trick again. Fortunately, we still
- * have the counter value in r8 that was returned by __do_get_xsec.
- * At this point, r3,r4 contain our sec/nsec values, r5 and r6
- * can be used, r7 contains NSEC_PER_SEC.
- */
-
- lwz r5,(WTOM_CLOCK_SEC+LOPART)(r9)
- lwz r6,WTOM_CLOCK_NSEC(r9)
-
- /* We now have our offset in r5,r6. We create a fake dependency
- * on that value and re-check the counter
- */
- or r0,r6,r5
- xor r0,r0,r0
- add r9,r9,r0
- lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
- cmpl cr0,r8,r0 /* check if updated */
- bne- 50b
-
- /* Calculate and store result. Note that this mimics the C code,
- * which may cause funny results if nsec goes negative... is that
- * possible at all ?
- */
- add r3,r3,r5
- add r4,r4,r6
- cmpw cr0,r4,r7
- cmpwi cr1,r4,0
- blt 1f
- subf r4,r7,r4
- addi r3,r3,1
-1: bge cr1,80f
- addi r3,r3,-1
- add r4,r4,r7
-
-80: stw r3,TSPC32_TV_SEC(r11)
- stw r4,TSPC32_TV_NSEC(r11)
-
- mtlr r12
- crclr cr0*4+so
- li r3,0
- blr
-
- /*
- * syscall fallback
- */
-99:
- li r0,__NR_clock_gettime
- .cfi_restore lr
- sc
- blr
+ cvdso_call_with_fallback __c_kernel_clock_gettime, __NR_clock_gettime
.cfi_endproc
V_FUNCTION_END(__kernel_clock_gettime)

@@ -147,32 +72,7 @@ V_FUNCTION_END(__kernel_clock_gettime)
*/
V_FUNCTION_BEGIN(__kernel_clock_getres)
.cfi_startproc
- /* Check for supported clock IDs */
- cmpwi cr0,r3,CLOCK_REALTIME
- cmpwi cr1,r3,CLOCK_MONOTONIC
- cror cr0*4+eq,cr0*4+eq,cr1*4+eq
- bne cr0,99f
-
- mflr r12
- .cfi_register lr,r12
- get_datapage r3, r0
- lwz r5, CLOCK_HRTIMER_RES(r3)
- mtlr r12
- li r3,0
- cmpli cr0,r4,0
- crclr cr0*4+so
- beqlr
- stw r3,TSPC32_TV_SEC(r4)
- stw r5,TSPC32_TV_NSEC(r4)
- blr
-
- /*
- * syscall fallback
- */
-99:
- li r0,__NR_clock_getres
- sc
- blr
+ cvdso_call_with_fallback __c_kernel_clock_getres, __NR_clock_getres
.cfi_endproc
V_FUNCTION_END(__kernel_clock_getres)

@@ -185,104 +85,15 @@ V_FUNCTION_END(__kernel_clock_getres)
*/
V_FUNCTION_BEGIN(__kernel_time)
.cfi_startproc
- mflr r12
- .cfi_register lr,r12
-
- mr r11,r3 /* r11 holds t */
- get_datapage r9, r0
-
- lwz r3,STAMP_XTIME_SEC+LOPART(r9)
-
- cmplwi r11,0 /* check if t is NULL */
- beq 2f
- stw r3,0(r11) /* store result at *t */
-2: mtlr r12
+ stwu r1, -16(r1)
+ mflr r0
+ stw r0, 20(r1)
+ get_datapage r4, r0
+ bl __c_kernel_time
+ lwz r0, 20(r1)
crclr cr0*4+so
+ mtlr r0
+ addi r1, r1, 16
blr
.cfi_endproc
V_FUNCTION_END(__kernel_time)
-
-/*
- * This is the core of clock_gettime() and gettimeofday(),
- * it returns the current time in r3 (seconds) and r4.
- * On entry, r7 gives the resolution of r4, either USEC_PER_SEC
- * or NSEC_PER_SEC, giving r4 in microseconds or nanoseconds.
- * It expects the datapage ptr in r9 and doesn't clobber it.
- * It clobbers r0, r5 and r6.
- * On return, r8 contains the counter value that can be reused.
- * This clobbers cr0 but not any other cr field.
- */
-__do_get_tspec:
- .cfi_startproc
- /* Check for update count & load values. We use the low
- * order 32 bits of the update count
- */
-1: lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
- andi. r0,r8,1 /* pending update ? loop */
- bne- 1b
- xor r0,r8,r8 /* create dependency */
- add r9,r9,r0
-
- /* Load orig stamp (offset to TB) */
- lwz r5,CFG_TB_ORIG_STAMP(r9)
- lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
-
- /* Get a stable TB value */
-2: MFTBU(r3)
- MFTBL(r4)
- MFTBU(r0)
- cmplw cr0,r3,r0
- bne- 2b
-
- /* Subtract tb orig stamp and shift left 12 bits.
- */
- subfc r4,r6,r4
- subfe r0,r5,r3
- slwi r0,r0,12
- rlwimi. r0,r4,12,20,31
- slwi r4,r4,12
-
- /*
- * Load scale factor & do multiplication.
- * We only use the high 32 bits of the tb_to_xs value.
- * Even with a 1GHz timebase clock, the high 32 bits of
- * tb_to_xs will be at least 4 million, so the error from
- * ignoring the low 32 bits will be no more than 0.25ppm.
- * The error will just make the clock run very very slightly
- * slow until the next time the kernel updates the VDSO data,
- * at which point the clock will catch up to the kernel's value,
- * so there is no long-term error accumulation.
- */
- lwz r5,CFG_TB_TO_XS(r9) /* load values */
- mulhwu r4,r4,r5
- li r3,0
-
- beq+ 4f /* skip high part computation if 0 */
- mulhwu r3,r0,r5
- mullw r5,r0,r5
- addc r4,r4,r5
- addze r3,r3
-4:
- /* At this point, we have seconds since the xtime stamp
- * as a 32.32 fixed-point number in r3 and r4.
- * Load & add the xtime stamp.
- */
- lwz r5,STAMP_XTIME_SEC+LOPART(r9)
- lwz r6,STAMP_SEC_FRAC(r9)
- addc r4,r4,r6
- adde r3,r3,r5
-
- /* We create a fake dependency on the result in r3/r4
- * and re-check the counter
- */
- or r6,r4,r3
- xor r0,r6,r6
- add r9,r9,r0
- lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
- cmplw cr0,r8,r0 /* check if updated */
- bne- 1b
-
- mulhwu r4,r4,r7 /* convert to micro or nanoseconds */
-
- blr
- .cfi_endproc
diff --git a/arch/powerpc/kernel/vdso32/vgettimeofday.c b/arch/powerpc/kernel/vdso32/vgettimeofday.c
new file mode 100644
index 000000000000..290b4415bf85
--- /dev/null
+++ b/arch/powerpc/kernel/vdso32/vgettimeofday.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ARM64 userspace implementations of gettimeofday() and similar.
+ *
+ * Copyright (C) 2018 ARM Limited
+ *
+ */
+#include <linux/time.h>
+#include <linux/types.h>
+
+int __c_kernel_clock_gettime(clockid_t clock, struct old_timespec32 *ts,
+ const struct vdso_data *vd)
+{
+ return __cvdso_clock_gettime32(vd, clock, ts);
+}
+
+int __c_kernel_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz,
+ const struct vdso_data *vd)
+{
+ return __cvdso_gettimeofday(vd, tv, tz);
+}
+
+int __c_kernel_clock_getres(clockid_t clock_id, struct old_timespec32 *res,
+ const struct vdso_data *vd)
+{
+ return __cvdso_clock_getres_time32(vd, clock_id, res);
+}
+
+time_t __c_kernel_time(time_t *time, const struct vdso_data *vd)
+{
+ return __cvdso_time(vd, time);
+}
--
2.13.3
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