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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-10-20 00:10:27 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2016-10-20 00:10:27 -0300
commitd0b2f91bede3bd5e3d24dd6803e56eee959c1797 (patch)
tree7fee4ab0509879c373c4f2cbd5b8a5be5b4041ee /arch/arm64/kernel/vdso
parente914f8eb445e8f74b00303c19c2ffceaedd16a05 (diff)
Linux-libre 4.8.2-gnupck-4.8.2-gnu
Diffstat (limited to 'arch/arm64/kernel/vdso')
-rw-r--r--arch/arm64/kernel/vdso/Makefile7
-rw-r--r--arch/arm64/kernel/vdso/gettimeofday.S331
2 files changed, 209 insertions, 129 deletions
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index b467fd0a3..62c84f7cb 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -23,7 +23,7 @@ GCOV_PROFILE := n
ccflags-y += -Wl,-shared
obj-y += vdso.o
-extra-y += vdso.lds vdso-offsets.h
+extra-y += vdso.lds
CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
# Force dependency (incbin is bad)
@@ -42,11 +42,10 @@ $(obj)/%.so: $(obj)/%.so.dbg FORCE
gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh
quiet_cmd_vdsosym = VDSOSYM $@
define cmd_vdsosym
- $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ && \
- cp $@ include/generated/
+ $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@
endef
-$(obj)/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
+include/generated/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE
$(call if_changed,vdsosym)
# Assembly rules for the .S files
diff --git a/arch/arm64/kernel/vdso/gettimeofday.S b/arch/arm64/kernel/vdso/gettimeofday.S
index efa79e8d4..e00b4671b 100644
--- a/arch/arm64/kernel/vdso/gettimeofday.S
+++ b/arch/arm64/kernel/vdso/gettimeofday.S
@@ -26,24 +26,109 @@
#define NSEC_PER_SEC_HI16 0x3b9a
vdso_data .req x6
-use_syscall .req w7
-seqcnt .req w8
+seqcnt .req w7
+w_tmp .req w8
+x_tmp .req x8
+
+/*
+ * Conventions for macro arguments:
+ * - An argument is write-only if its name starts with "res".
+ * - All other arguments are read-only, unless otherwise specified.
+ */
.macro seqcnt_acquire
9999: ldr seqcnt, [vdso_data, #VDSO_TB_SEQ_COUNT]
tbnz seqcnt, #0, 9999b
dmb ishld
- ldr use_syscall, [vdso_data, #VDSO_USE_SYSCALL]
.endm
- .macro seqcnt_read, cnt
+ .macro seqcnt_check fail
dmb ishld
- ldr \cnt, [vdso_data, #VDSO_TB_SEQ_COUNT]
+ ldr w_tmp, [vdso_data, #VDSO_TB_SEQ_COUNT]
+ cmp w_tmp, seqcnt
+ b.ne \fail
.endm
- .macro seqcnt_check, cnt, fail
- cmp \cnt, seqcnt
- b.ne \fail
+ .macro syscall_check fail
+ ldr w_tmp, [vdso_data, #VDSO_USE_SYSCALL]
+ cbnz w_tmp, \fail
+ .endm
+
+ .macro get_nsec_per_sec res
+ mov \res, #NSEC_PER_SEC_LO16
+ movk \res, #NSEC_PER_SEC_HI16, lsl #16
+ .endm
+
+ /*
+ * Returns the clock delta, in nanoseconds left-shifted by the clock
+ * shift.
+ */
+ .macro get_clock_shifted_nsec res, cycle_last, mult
+ /* Read the virtual counter. */
+ isb
+ mrs x_tmp, cntvct_el0
+ /* Calculate cycle delta and convert to ns. */
+ sub \res, x_tmp, \cycle_last
+ /* We can only guarantee 56 bits of precision. */
+ movn x_tmp, #0xff00, lsl #48
+ and \res, x_tmp, \res
+ mul \res, \res, \mult
+ .endm
+
+ /*
+ * Returns in res_{sec,nsec} the REALTIME timespec, based on the
+ * "wall time" (xtime) and the clock_mono delta.
+ */
+ .macro get_ts_realtime res_sec, res_nsec, \
+ clock_nsec, xtime_sec, xtime_nsec, nsec_to_sec
+ add \res_nsec, \clock_nsec, \xtime_nsec
+ udiv x_tmp, \res_nsec, \nsec_to_sec
+ add \res_sec, \xtime_sec, x_tmp
+ msub \res_nsec, x_tmp, \nsec_to_sec, \res_nsec
+ .endm
+
+ /*
+ * Returns in res_{sec,nsec} the timespec based on the clock_raw delta,
+ * used for CLOCK_MONOTONIC_RAW.
+ */
+ .macro get_ts_clock_raw res_sec, res_nsec, clock_nsec, nsec_to_sec
+ udiv \res_sec, \clock_nsec, \nsec_to_sec
+ msub \res_nsec, \res_sec, \nsec_to_sec, \clock_nsec
+ .endm
+
+ /* sec and nsec are modified in place. */
+ .macro add_ts sec, nsec, ts_sec, ts_nsec, nsec_to_sec
+ /* Add timespec. */
+ add \sec, \sec, \ts_sec
+ add \nsec, \nsec, \ts_nsec
+
+ /* Normalise the new timespec. */
+ cmp \nsec, \nsec_to_sec
+ b.lt 9999f
+ sub \nsec, \nsec, \nsec_to_sec
+ add \sec, \sec, #1
+9999:
+ cmp \nsec, #0
+ b.ge 9998f
+ add \nsec, \nsec, \nsec_to_sec
+ sub \sec, \sec, #1
+9998:
+ .endm
+
+ .macro clock_gettime_return, shift=0
+ .if \shift == 1
+ lsr x11, x11, x12
+ .endif
+ stp x10, x11, [x1, #TSPEC_TV_SEC]
+ mov x0, xzr
+ ret
+ .endm
+
+ .macro jump_slot jumptable, index, label
+ .if (. - \jumptable) != 4 * (\index)
+ .error "Jump slot index mismatch"
+ .endif
+ b \label
.endm
.text
@@ -51,18 +136,25 @@ seqcnt .req w8
/* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); */
ENTRY(__kernel_gettimeofday)
.cfi_startproc
- mov x2, x30
- .cfi_register x30, x2
-
- /* Acquire the sequence counter and get the timespec. */
adr vdso_data, _vdso_data
-1: seqcnt_acquire
- cbnz use_syscall, 4f
-
/* If tv is NULL, skip to the timezone code. */
cbz x0, 2f
- bl __do_get_tspec
- seqcnt_check w9, 1b
+
+ /* Compute the time of day. */
+1: seqcnt_acquire
+ syscall_check fail=4f
+ ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
+ /* w11 = cs_mono_mult, w12 = cs_shift */
+ ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
+ ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
+ seqcnt_check fail=1b
+
+ get_nsec_per_sec res=x9
+ lsl x9, x9, x12
+
+ get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
+ get_ts_realtime res_sec=x10, res_nsec=x11, \
+ clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
/* Convert ns to us. */
mov x13, #1000
@@ -76,95 +168,126 @@ ENTRY(__kernel_gettimeofday)
stp w4, w5, [x1, #TZ_MINWEST]
3:
mov x0, xzr
- ret x2
+ ret
4:
/* Syscall fallback. */
mov x8, #__NR_gettimeofday
svc #0
- ret x2
+ ret
.cfi_endproc
ENDPROC(__kernel_gettimeofday)
+#define JUMPSLOT_MAX CLOCK_MONOTONIC_COARSE
+
/* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); */
ENTRY(__kernel_clock_gettime)
.cfi_startproc
- cmp w0, #CLOCK_REALTIME
- ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
- b.ne 2f
+ cmp w0, #JUMPSLOT_MAX
+ b.hi syscall
+ adr vdso_data, _vdso_data
+ adr x_tmp, jumptable
+ add x_tmp, x_tmp, w0, uxtw #2
+ br x_tmp
+
+ ALIGN
+jumptable:
+ jump_slot jumptable, CLOCK_REALTIME, realtime
+ jump_slot jumptable, CLOCK_MONOTONIC, monotonic
+ b syscall
+ b syscall
+ jump_slot jumptable, CLOCK_MONOTONIC_RAW, monotonic_raw
+ jump_slot jumptable, CLOCK_REALTIME_COARSE, realtime_coarse
+ jump_slot jumptable, CLOCK_MONOTONIC_COARSE, monotonic_coarse
+
+ .if (. - jumptable) != 4 * (JUMPSLOT_MAX + 1)
+ .error "Wrong jumptable size"
+ .endif
+
+ ALIGN
+realtime:
+ seqcnt_acquire
+ syscall_check fail=syscall
+ ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
+ /* w11 = cs_mono_mult, w12 = cs_shift */
+ ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
+ ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
+ seqcnt_check fail=realtime
- mov x2, x30
- .cfi_register x30, x2
+ /* All computations are done with left-shifted nsecs. */
+ get_nsec_per_sec res=x9
+ lsl x9, x9, x12
- /* Get kernel timespec. */
- adr vdso_data, _vdso_data
-1: seqcnt_acquire
- cbnz use_syscall, 7f
+ get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
+ get_ts_realtime res_sec=x10, res_nsec=x11, \
+ clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
+ clock_gettime_return, shift=1
- bl __do_get_tspec
- seqcnt_check w9, 1b
+ ALIGN
+monotonic:
+ seqcnt_acquire
+ syscall_check fail=syscall
+ ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
+ /* w11 = cs_mono_mult, w12 = cs_shift */
+ ldp w11, w12, [vdso_data, #VDSO_CS_MONO_MULT]
+ ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
+ ldp x3, x4, [vdso_data, #VDSO_WTM_CLK_SEC]
+ seqcnt_check fail=monotonic
- mov x30, x2
+ /* All computations are done with left-shifted nsecs. */
+ lsl x4, x4, x12
+ get_nsec_per_sec res=x9
+ lsl x9, x9, x12
- cmp w0, #CLOCK_MONOTONIC
- b.ne 6f
+ get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
+ get_ts_realtime res_sec=x10, res_nsec=x11, \
+ clock_nsec=x15, xtime_sec=x13, xtime_nsec=x14, nsec_to_sec=x9
- /* Get wtm timespec. */
- ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
+ add_ts sec=x10, nsec=x11, ts_sec=x3, ts_nsec=x4, nsec_to_sec=x9
+ clock_gettime_return, shift=1
- /* Check the sequence counter. */
- seqcnt_read w9
- seqcnt_check w9, 1b
- b 4f
-2:
- cmp w0, #CLOCK_REALTIME_COARSE
- ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne
- b.ne 8f
+ ALIGN
+monotonic_raw:
+ seqcnt_acquire
+ syscall_check fail=syscall
+ ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
+ /* w11 = cs_raw_mult, w12 = cs_shift */
+ ldp w12, w11, [vdso_data, #VDSO_CS_SHIFT]
+ ldp x13, x14, [vdso_data, #VDSO_RAW_TIME_SEC]
+ seqcnt_check fail=monotonic_raw
- /* xtime_coarse_nsec is already right-shifted */
- mov x12, #0
+ /* All computations are done with left-shifted nsecs. */
+ lsl x14, x14, x12
+ get_nsec_per_sec res=x9
+ lsl x9, x9, x12
- /* Get coarse timespec. */
- adr vdso_data, _vdso_data
-3: seqcnt_acquire
+ get_clock_shifted_nsec res=x15, cycle_last=x10, mult=x11
+ get_ts_clock_raw res_sec=x10, res_nsec=x11, \
+ clock_nsec=x15, nsec_to_sec=x9
+
+ add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9
+ clock_gettime_return, shift=1
+
+ ALIGN
+realtime_coarse:
+ seqcnt_acquire
ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
+ seqcnt_check fail=realtime_coarse
+ clock_gettime_return
- /* Get wtm timespec. */
+ ALIGN
+monotonic_coarse:
+ seqcnt_acquire
+ ldp x10, x11, [vdso_data, #VDSO_XTIME_CRS_SEC]
ldp x13, x14, [vdso_data, #VDSO_WTM_CLK_SEC]
+ seqcnt_check fail=monotonic_coarse
- /* Check the sequence counter. */
- seqcnt_read w9
- seqcnt_check w9, 3b
+ /* Computations are done in (non-shifted) nsecs. */
+ get_nsec_per_sec res=x9
+ add_ts sec=x10, nsec=x11, ts_sec=x13, ts_nsec=x14, nsec_to_sec=x9
+ clock_gettime_return
- cmp w0, #CLOCK_MONOTONIC_COARSE
- b.ne 6f
-4:
- /* Add on wtm timespec. */
- add x10, x10, x13
- lsl x14, x14, x12
- add x11, x11, x14
-
- /* Normalise the new timespec. */
- mov x15, #NSEC_PER_SEC_LO16
- movk x15, #NSEC_PER_SEC_HI16, lsl #16
- lsl x15, x15, x12
- cmp x11, x15
- b.lt 5f
- sub x11, x11, x15
- add x10, x10, #1
-5:
- cmp x11, #0
- b.ge 6f
- add x11, x11, x15
- sub x10, x10, #1
-
-6: /* Store to the user timespec. */
- lsr x11, x11, x12
- stp x10, x11, [x1, #TSPEC_TV_SEC]
- mov x0, xzr
- ret
-7:
- mov x30, x2
-8: /* Syscall fallback. */
+ ALIGN
+syscall: /* Syscall fallback. */
mov x8, #__NR_clock_gettime
svc #0
ret
@@ -176,6 +299,7 @@ ENTRY(__kernel_clock_getres)
.cfi_startproc
cmp w0, #CLOCK_REALTIME
ccmp w0, #CLOCK_MONOTONIC, #0x4, ne
+ ccmp w0, #CLOCK_MONOTONIC_RAW, #0x4, ne
b.ne 1f
ldr x2, 5f
@@ -203,46 +327,3 @@ ENTRY(__kernel_clock_getres)
.quad CLOCK_COARSE_RES
.cfi_endproc
ENDPROC(__kernel_clock_getres)
-
-/*
- * Read the current time from the architected counter.
- * Expects vdso_data to be initialised.
- * Clobbers the temporary registers (x9 - x15).
- * Returns:
- * - w9 = vDSO sequence counter
- * - (x10, x11) = (ts->tv_sec, shifted ts->tv_nsec)
- * - w12 = cs_shift
- */
-ENTRY(__do_get_tspec)
- .cfi_startproc
-
- /* Read from the vDSO data page. */
- ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST]
- ldp x13, x14, [vdso_data, #VDSO_XTIME_CLK_SEC]
- ldp w11, w12, [vdso_data, #VDSO_CS_MULT]
- seqcnt_read w9
-
- /* Read the virtual counter. */
- isb
- mrs x15, cntvct_el0
-
- /* Calculate cycle delta and convert to ns. */
- sub x10, x15, x10
- /* We can only guarantee 56 bits of precision. */
- movn x15, #0xff00, lsl #48
- and x10, x15, x10
- mul x10, x10, x11
-
- /* Use the kernel time to calculate the new timespec. */
- mov x11, #NSEC_PER_SEC_LO16
- movk x11, #NSEC_PER_SEC_HI16, lsl #16
- lsl x11, x11, x12
- add x15, x10, x14
- udiv x14, x15, x11
- add x10, x13, x14
- mul x13, x14, x11
- sub x11, x15, x13
-
- ret
- .cfi_endproc
-ENDPROC(__do_get_tspec)