diff options
author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2016-10-27 12:41:39 +0200 |
---|---|---|
committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2017-07-26 08:25:14 +0200 |
commit | 6e2ef5e4f6cc57344762932d70d38ba4ec65fa8b (patch) | |
tree | 51e148a3b1e6991260af2ac51e6b1a6d5eb0f83a /arch | |
parent | 45be0a02f8110a13502fac6167a893c7c0eff432 (diff) | |
download | linux-6e2ef5e4f6cc57344762932d70d38ba4ec65fa8b.tar.bz2 |
s390/time: add support for the TOD clock epoch extension
The TOD epoch extension adds 8 epoch bits to the TOD clock to provide
a continuous clock after 2042/09/17. The store-clock-extended (STCKE)
instruction will store the epoch index in the first byte of the
16 bytes stored by the instruction. The read_boot_clock64 and the
read_presistent_clock64 functions need to take the additional bits
into account to give the correct result after 2042/09/17.
The clock-comparator register will stay 64 bit wide. The comparison
of the clock-comparator with the TOD clock is limited to bytes
1 to 8 of the extended TOD format. To deal with the overflow problem
due to an epoch change the clock-comparator sign control in CR0 can
be used to switch the comparison of the 64-bit TOD clock with the
clock-comparator to a signed comparison.
The decision between the signed vs. unsigned clock-comparator
comparisons is done at boot time. Only if the TOD clock is in the
second half of a 142 year epoch the signed comparison is used.
This solves the epoch overflow issue as long as the machine is
booted at least once in an epoch.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/s390/include/asm/lowcore.h | 48 | ||||
-rw-r--r-- | arch/s390/include/asm/setup.h | 2 | ||||
-rw-r--r-- | arch/s390/include/asm/timex.h | 38 | ||||
-rw-r--r-- | arch/s390/kernel/asm-offsets.c | 1 | ||||
-rw-r--r-- | arch/s390/kernel/debug.c | 9 | ||||
-rw-r--r-- | arch/s390/kernel/early.c | 15 | ||||
-rw-r--r-- | arch/s390/kernel/head.S | 3 | ||||
-rw-r--r-- | arch/s390/kernel/head64.S | 4 | ||||
-rw-r--r-- | arch/s390/kernel/irq.c | 3 | ||||
-rw-r--r-- | arch/s390/kernel/setup.c | 2 | ||||
-rw-r--r-- | arch/s390/kernel/time.c | 65 | ||||
-rw-r--r-- | arch/s390/lib/delay.c | 2 |
12 files changed, 130 insertions, 62 deletions
diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h index 8a5b082797f8..a6870ea6ea8b 100644 --- a/arch/s390/include/asm/lowcore.h +++ b/arch/s390/include/asm/lowcore.h @@ -95,46 +95,46 @@ struct lowcore { __u64 int_clock; /* 0x0310 */ __u64 mcck_clock; /* 0x0318 */ __u64 clock_comparator; /* 0x0320 */ + __u64 boot_clock[2]; /* 0x0328 */ /* Current process. */ - __u64 current_task; /* 0x0328 */ - __u8 pad_0x318[0x320-0x318]; /* 0x0330 */ - __u64 kernel_stack; /* 0x0338 */ + __u64 current_task; /* 0x0338 */ + __u64 kernel_stack; /* 0x0340 */ /* Interrupt, panic and restart stack. */ - __u64 async_stack; /* 0x0340 */ - __u64 panic_stack; /* 0x0348 */ - __u64 restart_stack; /* 0x0350 */ + __u64 async_stack; /* 0x0348 */ + __u64 panic_stack; /* 0x0350 */ + __u64 restart_stack; /* 0x0358 */ /* Restart function and parameter. */ - __u64 restart_fn; /* 0x0358 */ - __u64 restart_data; /* 0x0360 */ - __u64 restart_source; /* 0x0368 */ + __u64 restart_fn; /* 0x0360 */ + __u64 restart_data; /* 0x0368 */ + __u64 restart_source; /* 0x0370 */ /* Address space pointer. */ - __u64 kernel_asce; /* 0x0370 */ - __u64 user_asce; /* 0x0378 */ + __u64 kernel_asce; /* 0x0378 */ + __u64 user_asce; /* 0x0380 */ /* * The lpp and current_pid fields form a * 64-bit value that is set as program * parameter with the LPP instruction. */ - __u32 lpp; /* 0x0380 */ - __u32 current_pid; /* 0x0384 */ + __u32 lpp; /* 0x0388 */ + __u32 current_pid; /* 0x038c */ /* SMP info area */ - __u32 cpu_nr; /* 0x0388 */ - __u32 softirq_pending; /* 0x038c */ - __u64 percpu_offset; /* 0x0390 */ - __u64 vdso_per_cpu_data; /* 0x0398 */ - __u64 machine_flags; /* 0x03a0 */ - __u32 preempt_count; /* 0x03a8 */ - __u8 pad_0x03ac[0x03b0-0x03ac]; /* 0x03ac */ - __u64 gmap; /* 0x03b0 */ - __u32 spinlock_lockval; /* 0x03b8 */ - __u32 fpu_flags; /* 0x03bc */ - __u8 pad_0x03c0[0x0400-0x03c0]; /* 0x03c0 */ + __u32 cpu_nr; /* 0x0390 */ + __u32 softirq_pending; /* 0x0394 */ + __u64 percpu_offset; /* 0x0398 */ + __u64 vdso_per_cpu_data; /* 0x03a0 */ + __u64 machine_flags; /* 0x03a8 */ + __u32 preempt_count; /* 0x03b0 */ + __u8 pad_0x03b4[0x03b8-0x03b4]; /* 0x03b4 */ + __u64 gmap; /* 0x03b8 */ + __u32 spinlock_lockval; /* 0x03c0 */ + __u32 fpu_flags; /* 0x03c4 */ + __u8 pad_0x03c8[0x0400-0x03c8]; /* 0x03c8 */ /* Per cpu primary space access list */ __u32 paste[16]; /* 0x0400 */ diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h index 49c425903894..61da4bd6edad 100644 --- a/arch/s390/include/asm/setup.h +++ b/arch/s390/include/asm/setup.h @@ -32,6 +32,7 @@ #define MACHINE_FLAG_TLB_GUEST _BITUL(14) #define MACHINE_FLAG_NX _BITUL(15) #define MACHINE_FLAG_GS _BITUL(16) +#define MACHINE_FLAG_SCC _BITUL(17) #define LPP_MAGIC _BITUL(31) #define LPP_PFAULT_PID_MASK _AC(0xffffffff, UL) @@ -72,6 +73,7 @@ extern void detect_memory_memblock(void); #define MACHINE_HAS_TLB_GUEST (S390_lowcore.machine_flags & MACHINE_FLAG_TLB_GUEST) #define MACHINE_HAS_NX (S390_lowcore.machine_flags & MACHINE_FLAG_NX) #define MACHINE_HAS_GS (S390_lowcore.machine_flags & MACHINE_FLAG_GS) +#define MACHINE_HAS_SCC (S390_lowcore.machine_flags & MACHINE_FLAG_SCC) /* * Console mode. Override with conmode= diff --git a/arch/s390/include/asm/timex.h b/arch/s390/include/asm/timex.h index 118535123f34..0ea03c11458d 100644 --- a/arch/s390/include/asm/timex.h +++ b/arch/s390/include/asm/timex.h @@ -15,6 +15,8 @@ /* The value of the TOD clock for 1.1.1970. */ #define TOD_UNIX_EPOCH 0x7d91048bca000000ULL +extern u64 clock_comparator_max; + /* Inline functions for clock register access. */ static inline int set_tod_clock(__u64 time) { @@ -126,7 +128,7 @@ static inline unsigned long long local_tick_disable(void) unsigned long long old; old = S390_lowcore.clock_comparator; - S390_lowcore.clock_comparator = -1ULL; + S390_lowcore.clock_comparator = clock_comparator_max; set_clock_comparator(S390_lowcore.clock_comparator); return old; } @@ -178,20 +180,20 @@ int get_phys_clock(unsigned long long *clock); void init_cpu_timer(void); unsigned long long monotonic_clock(void); -extern u64 sched_clock_base_cc; +extern unsigned char tod_clock_base[16] __aligned(8); /** * get_clock_monotonic - returns current time in clock rate units * * The caller must ensure that preemption is disabled. - * The clock and sched_clock_base get changed via stop_machine. + * The clock and tod_clock_base get changed via stop_machine. * Therefore preemption must be disabled when calling this * function, otherwise the returned value is not guaranteed to * be monotonic. */ static inline unsigned long long get_tod_clock_monotonic(void) { - return get_tod_clock() - sched_clock_base_cc; + return get_tod_clock() - *(unsigned long long *) &tod_clock_base[1]; } /** @@ -218,4 +220,32 @@ static inline unsigned long long tod_to_ns(unsigned long long todval) return ((todval >> 9) * 125) + (((todval & 0x1ff) * 125) >> 9); } +/** + * tod_after - compare two 64 bit TOD values + * @a: first 64 bit TOD timestamp + * @b: second 64 bit TOD timestamp + * + * Returns: true if a is later than b + */ +static inline int tod_after(unsigned long long a, unsigned long long b) +{ + if (MACHINE_HAS_SCC) + return (long long) a > (long long) b; + return a > b; +} + +/** + * tod_after_eq - compare two 64 bit TOD values + * @a: first 64 bit TOD timestamp + * @b: second 64 bit TOD timestamp + * + * Returns: true if a is later than b + */ +static inline int tod_after_eq(unsigned long long a, unsigned long long b) +{ + if (MACHINE_HAS_SCC) + return (long long) a >= (long long) b; + return a >= b; +} + #endif diff --git a/arch/s390/kernel/asm-offsets.c b/arch/s390/kernel/asm-offsets.c index b65c414b6c0e..3d42f91c95fd 100644 --- a/arch/s390/kernel/asm-offsets.c +++ b/arch/s390/kernel/asm-offsets.c @@ -158,6 +158,7 @@ int main(void) OFFSET(__LC_LAST_UPDATE_CLOCK, lowcore, last_update_clock); OFFSET(__LC_INT_CLOCK, lowcore, int_clock); OFFSET(__LC_MCCK_CLOCK, lowcore, mcck_clock); + OFFSET(__LC_BOOT_CLOCK, lowcore, boot_clock); OFFSET(__LC_CURRENT, lowcore, current_task); OFFSET(__LC_KERNEL_STACK, lowcore, kernel_stack); OFFSET(__LC_ASYNC_STACK, lowcore, async_stack); diff --git a/arch/s390/kernel/debug.c b/arch/s390/kernel/debug.c index 86b3e74f569e..1d9e83c401fc 100644 --- a/arch/s390/kernel/debug.c +++ b/arch/s390/kernel/debug.c @@ -866,7 +866,8 @@ static inline void debug_finish_entry(debug_info_t * id, debug_entry_t* active, int level, int exception) { - active->id.stck = get_tod_clock_fast() - sched_clock_base_cc; + active->id.stck = get_tod_clock_fast() - + *(unsigned long long *) &tod_clock_base[1]; active->id.fields.cpuid = smp_processor_id(); active->caller = __builtin_return_address(0); active->id.fields.exception = exception; @@ -1455,15 +1456,15 @@ int debug_dflt_header_fn(debug_info_t * id, struct debug_view *view, int area, debug_entry_t * entry, char *out_buf) { - unsigned long sec, usec; + unsigned long base, sec, usec; char *except_str; unsigned long caller; int rc = 0; unsigned int level; level = entry->id.fields.level; - sec = (entry->id.stck >> 12) + (sched_clock_base_cc >> 12); - sec = sec - (TOD_UNIX_EPOCH >> 12); + base = (*(unsigned long *) &tod_clock_base[0]) >> 4; + sec = (entry->id.stck >> 12) + base - (TOD_UNIX_EPOCH >> 12); usec = do_div(sec, USEC_PER_SEC); if (entry->id.fields.exception) diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c index 5d20182ee8ae..added6790460 100644 --- a/arch/s390/kernel/early.c +++ b/arch/s390/kernel/early.c @@ -53,8 +53,9 @@ static void __init reset_tod_clock(void) if (set_tod_clock(TOD_UNIX_EPOCH) != 0 || store_tod_clock(&time) != 0) disabled_wait(0); - sched_clock_base_cc = TOD_UNIX_EPOCH; - S390_lowcore.last_update_clock = sched_clock_base_cc; + memset(tod_clock_base, 0, 16); + *(__u64 *) &tod_clock_base[1] = TOD_UNIX_EPOCH; + S390_lowcore.last_update_clock = TOD_UNIX_EPOCH; } #ifdef CONFIG_SHARED_KERNEL @@ -165,8 +166,8 @@ static noinline __init void create_kernel_nss(void) } /* re-initialize cputime accounting. */ - sched_clock_base_cc = get_tod_clock(); - S390_lowcore.last_update_clock = sched_clock_base_cc; + get_tod_clock_ext(tod_clock_base); + S390_lowcore.last_update_clock = *(__u64 *) &tod_clock_base[1]; S390_lowcore.last_update_timer = 0x7fffffffffffffffULL; S390_lowcore.user_timer = 0; S390_lowcore.system_timer = 0; @@ -387,6 +388,12 @@ static __init void detect_machine_facilities(void) } if (test_facility(133)) S390_lowcore.machine_flags |= MACHINE_FLAG_GS; + if (test_facility(139) && (tod_clock_base[1] & 0x80)) { + /* Enabled signed clock comparator comparisons */ + S390_lowcore.machine_flags |= MACHINE_FLAG_SCC; + clock_comparator_max = -1ULL >> 1; + __ctl_set_bit(0, 53); + } } static inline void save_vector_registers(void) diff --git a/arch/s390/kernel/head.S b/arch/s390/kernel/head.S index eff5b31671d4..8ed753c72d9b 100644 --- a/arch/s390/kernel/head.S +++ b/arch/s390/kernel/head.S @@ -302,7 +302,8 @@ ENTRY(startup_kdump) xc 0xe00(256),0xe00 xc 0xf00(256),0xf00 lctlg %c0,%c15,0x200(%r0) # initialize control registers - stck __LC_LAST_UPDATE_CLOCK + stcke __LC_BOOT_CLOCK + mvc __LC_LAST_UPDATE_CLOCK(8),__LC_BOOT_CLOCK+1 spt 6f-.LPG0(%r13) mvc __LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13) l %r15,.Lstack-.LPG0(%r13) diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S index 31c91f24e562..0d8f2a858ced 100644 --- a/arch/s390/kernel/head64.S +++ b/arch/s390/kernel/head64.S @@ -21,8 +21,8 @@ ENTRY(startup_continue) xc __LC_LPP+1(7,0),__LC_LPP+1 # clear lpp and current_pid mvi __LC_LPP,0x80 # and set LPP_MAGIC .insn s,0xb2800000,__LC_LPP # load program parameter -0: larl %r1,sched_clock_base_cc - mvc 0(8,%r1),__LC_LAST_UPDATE_CLOCK +0: larl %r1,tod_clock_base + mvc 0(16,%r1),__LC_BOOT_CLOCK larl %r13,.LPG1 # get base lctlg %c0,%c15,.Lctl-.LPG1(%r13) # load control registers lg %r12,.Lparmaddr-.LPG1(%r13) # pointer to parameter area diff --git a/arch/s390/kernel/irq.c b/arch/s390/kernel/irq.c index 6dca93b29bed..a2fdff0e730b 100644 --- a/arch/s390/kernel/irq.c +++ b/arch/s390/kernel/irq.c @@ -105,7 +105,8 @@ void do_IRQ(struct pt_regs *regs, int irq) old_regs = set_irq_regs(regs); irq_enter(); - if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator) + if (tod_after_eq(S390_lowcore.int_clock, + S390_lowcore.clock_comparator)) /* Serve timer interrupts first. */ clock_comparator_work(); generic_handle_irq(irq); diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c index bc1c95b7a4bd..e8b84894b650 100644 --- a/arch/s390/kernel/setup.c +++ b/arch/s390/kernel/setup.c @@ -323,7 +323,7 @@ static void __init setup_lowcore(void) lc->io_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT | PSW_MASK_MCHECK; lc->io_new_psw.addr = (unsigned long) io_int_handler; - lc->clock_comparator = -1ULL; + lc->clock_comparator = clock_comparator_max; lc->kernel_stack = ((unsigned long) &init_thread_union) + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs); lc->async_stack = (unsigned long) diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index 192efdfac918..15abecba068e 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -51,8 +51,15 @@ #include <asm/cio.h> #include "entry.h" -u64 sched_clock_base_cc = -1; /* Force to data section. */ -EXPORT_SYMBOL_GPL(sched_clock_base_cc); +unsigned char tod_clock_base[16] __aligned(8) = { + /* Force to data section. */ + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff +}; +EXPORT_SYMBOL_GPL(tod_clock_base); + +u64 clock_comparator_max = -1ULL; +EXPORT_SYMBOL_GPL(clock_comparator_max); static DEFINE_PER_CPU(struct clock_event_device, comparators); @@ -75,7 +82,7 @@ void __init time_early_init(void) struct ptff_qui qui; /* Initialize TOD steering parameters */ - tod_steering_end = sched_clock_base_cc; + tod_steering_end = *(unsigned long long *) &tod_clock_base[1]; vdso_data->ts_end = tod_steering_end; if (!test_facility(28)) @@ -111,22 +118,27 @@ unsigned long long monotonic_clock(void) } EXPORT_SYMBOL(monotonic_clock); -static void tod_to_timeval(__u64 todval, struct timespec64 *xt) +static void ext_to_timespec64(unsigned char *clk, struct timespec64 *xt) { - unsigned long long sec; + unsigned long long high, low, rem, sec, nsec; + + /* Split extendnd TOD clock to micro-seconds and sub-micro-seconds */ + high = (*(unsigned long long *) clk) >> 4; + low = (*(unsigned long long *)&clk[7]) << 4; + /* Calculate seconds and nano-seconds */ + sec = high; + rem = do_div(sec, 1000000); + nsec = (((low >> 32) + (rem << 32)) * 1000) >> 32; - sec = todval >> 12; - do_div(sec, 1000000); xt->tv_sec = sec; - todval -= (sec * 1000000) << 12; - xt->tv_nsec = ((todval * 1000) >> 12); + xt->tv_nsec = nsec; } void clock_comparator_work(void) { struct clock_event_device *cd; - S390_lowcore.clock_comparator = -1ULL; + S390_lowcore.clock_comparator = clock_comparator_max; cd = this_cpu_ptr(&comparators); cd->event_handler(cd); } @@ -148,7 +160,7 @@ void init_cpu_timer(void) struct clock_event_device *cd; int cpu; - S390_lowcore.clock_comparator = -1ULL; + S390_lowcore.clock_comparator = clock_comparator_max; set_clock_comparator(S390_lowcore.clock_comparator); cpu = smp_processor_id(); @@ -179,7 +191,7 @@ static void clock_comparator_interrupt(struct ext_code ext_code, unsigned long param64) { inc_irq_stat(IRQEXT_CLK); - if (S390_lowcore.clock_comparator == -1ULL) + if (S390_lowcore.clock_comparator == clock_comparator_max) set_clock_comparator(S390_lowcore.clock_comparator); } @@ -197,18 +209,28 @@ static void stp_reset(void); void read_persistent_clock64(struct timespec64 *ts) { - __u64 clock; + unsigned char clk[STORE_CLOCK_EXT_SIZE]; + __u64 delta; - clock = get_tod_clock() - initial_leap_seconds; - tod_to_timeval(clock - TOD_UNIX_EPOCH, ts); + delta = initial_leap_seconds + TOD_UNIX_EPOCH; + get_tod_clock_ext(clk); + *(__u64 *) &clk[1] -= delta; + if (*(__u64 *) &clk[1] > delta) + clk[0]--; + ext_to_timespec64(clk, ts); } void read_boot_clock64(struct timespec64 *ts) { - __u64 clock; + unsigned char clk[STORE_CLOCK_EXT_SIZE]; + __u64 delta; - clock = sched_clock_base_cc - initial_leap_seconds; - tod_to_timeval(clock - TOD_UNIX_EPOCH, ts); + delta = initial_leap_seconds + TOD_UNIX_EPOCH; + memcpy(clk, tod_clock_base, 16); + *(__u64 *) &clk[1] -= delta; + if (*(__u64 *) &clk[1] > delta) + clk[0]--; + ext_to_timespec64(clk, ts); } static u64 read_tod_clock(struct clocksource *cs) @@ -406,7 +428,10 @@ static void clock_sync_global(unsigned long long delta) struct ptff_qto qto; /* Fixup the monotonic sched clock. */ - sched_clock_base_cc += delta; + *(unsigned long long *) &tod_clock_base[1] += delta; + if (*(unsigned long long *) &tod_clock_base[1] < delta) + /* Epoch overflow */ + tod_clock_base[0]++; /* Adjust TOD steering parameters. */ vdso_data->tb_update_count++; now = get_tod_clock(); @@ -437,7 +462,7 @@ static void clock_sync_global(unsigned long long delta) static void clock_sync_local(unsigned long long delta) { /* Add the delta to the clock comparator. */ - if (S390_lowcore.clock_comparator != -1ULL) { + if (S390_lowcore.clock_comparator != clock_comparator_max) { S390_lowcore.clock_comparator += delta; set_clock_comparator(S390_lowcore.clock_comparator); } diff --git a/arch/s390/lib/delay.c b/arch/s390/lib/delay.c index 92e90e40b6fb..7f17555ad4d5 100644 --- a/arch/s390/lib/delay.c +++ b/arch/s390/lib/delay.c @@ -57,7 +57,7 @@ static void __udelay_enabled(unsigned long long usecs) end = get_tod_clock_fast() + (usecs << 12); do { clock_saved = 0; - if (end < S390_lowcore.clock_comparator) { + if (tod_after(S390_lowcore.clock_comparator, end)) { clock_saved = local_tick_disable(); set_clock_comparator(end); } |