select SYSCTL_EXCEPTION_TRACE
select HAVE_VIRT_CPU_ACCOUNTING_GEN
select HAVE_IRQ_TIME_ACCOUNTING
+ select GENERIC_TIME_VSYSCALL
+ select ARCH_CLOCKSOURCE_DATA
menu "Machine selection"
config CSRC_SB1250
bool
+config MIPS_CLOCK_VSYSCALL
+ def_bool CSRC_R4K || CLKSRC_MIPS_GIC
+
config GPIO_TXX9
select ARCH_REQUIRE_GPIOLIB
bool
--- /dev/null
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#ifndef __ASM_CLOCKSOURCE_H
+#define __ASM_CLOCKSOURCE_H
+
+#include <linux/types.h>
+
+/* VDSO clocksources. */
+#define VDSO_CLOCK_NONE 0 /* No suitable clocksource. */
+#define VDSO_CLOCK_R4K 1 /* Use the coprocessor 0 count. */
+#define VDSO_CLOCK_GIC 2 /* Use the GIC. */
+
+/**
+ * struct arch_clocksource_data - Architecture-specific clocksource information.
+ * @vdso_clock_mode: Method the VDSO should use to access the clocksource.
+ */
+struct arch_clocksource_data {
+ u8 vdso_clock_mode;
+};
+
+#endif /* __ASM_CLOCKSOURCE_H */
#include <linux/mm_types.h>
+#include <asm/barrier.h>
+
/**
* struct mips_vdso_image - Details of a VDSO image.
* @data: Pointer to VDSO image data (page-aligned).
/**
* union mips_vdso_data - Data provided by the kernel for the VDSO.
+ * @xtime_sec: Current real time (seconds part).
+ * @xtime_nsec: Current real time (nanoseconds part, shifted).
+ * @wall_to_mono_sec: Wall-to-monotonic offset (seconds part).
+ * @wall_to_mono_nsec: Wall-to-monotonic offset (nanoseconds part).
+ * @seq_count: Counter to synchronise updates (odd = updating).
+ * @cs_shift: Clocksource shift value.
+ * @clock_mode: Clocksource to use for time functions.
+ * @cs_mult: Clocksource multiplier value.
+ * @cs_cycle_last: Clock cycle value at last update.
+ * @cs_mask: Clocksource mask value.
+ * @tz_minuteswest: Minutes west of Greenwich (from timezone).
+ * @tz_dsttime: Type of DST correction (from timezone).
*
* This structure contains data needed by functions within the VDSO. It is
- * populated by the kernel and mapped read-only into user memory.
+ * populated by the kernel and mapped read-only into user memory. The time
+ * fields are mirrors of internal data from the timekeeping infrastructure.
*
* Note: Care should be taken when modifying as the layout must remain the same
* for both 64- and 32-bit (for 32-bit userland on 64-bit kernel).
*/
union mips_vdso_data {
struct {
+ u64 xtime_sec;
+ u64 xtime_nsec;
+ u32 wall_to_mono_sec;
+ u32 wall_to_mono_nsec;
+ u32 seq_count;
+ u32 cs_shift;
+ u8 clock_mode;
+ u32 cs_mult;
+ u64 cs_cycle_last;
+ u64 cs_mask;
+ s32 tz_minuteswest;
+ s32 tz_dsttime;
};
u8 page[PAGE_SIZE];
};
+static inline u32 vdso_data_read_begin(const union mips_vdso_data *data)
+{
+ u32 seq;
+
+ while (true) {
+ seq = ACCESS_ONCE(data->seq_count);
+ if (likely(!(seq & 1))) {
+ /* Paired with smp_wmb() in vdso_data_write_*(). */
+ smp_rmb();
+ return seq;
+ }
+
+ cpu_relax();
+ }
+}
+
+static inline bool vdso_data_read_retry(const union mips_vdso_data *data,
+ u32 start_seq)
+{
+ /* Paired with smp_wmb() in vdso_data_write_*(). */
+ smp_rmb();
+ return unlikely(data->seq_count != start_seq);
+}
+
+static inline void vdso_data_write_begin(union mips_vdso_data *data)
+{
+ ++data->seq_count;
+
+ /* Ensure sequence update is written before other data page values. */
+ smp_wmb();
+}
+
+static inline void vdso_data_write_end(union mips_vdso_data *data)
+{
+ /* Ensure data values are written before updating sequence again. */
+ smp_wmb();
+ ++data->seq_count;
+}
+
#endif /* __ASM_VDSO_H */
return read_c0_count();
}
+static inline unsigned int rdhwr_count(void)
+{
+ unsigned int count;
+
+ __asm__ __volatile__(
+ " .set push\n"
+ " .set mips32r2\n"
+ " rdhwr %0, $2\n"
+ " .set pop\n"
+ : "=r" (count));
+
+ return count;
+}
+
+static bool rdhwr_count_usable(void)
+{
+ unsigned int prev, curr, i;
+
+ /*
+ * Older QEMUs have a broken implementation of RDHWR for the CP0 count
+ * which always returns a constant value. Try to identify this and don't
+ * use it in the VDSO if it is broken. This workaround can be removed
+ * once the fix has been in QEMU stable for a reasonable amount of time.
+ */
+ for (i = 0, prev = rdhwr_count(); i < 100; i++) {
+ curr = rdhwr_count();
+
+ if (curr != prev)
+ return true;
+
+ prev = curr;
+ }
+
+ pr_warn("Not using R4K clocksource in VDSO due to broken RDHWR\n");
+ return false;
+}
+
int __init init_r4k_clocksource(void)
{
if (!cpu_has_counter || !mips_hpt_frequency)
/* Calculate a somewhat reasonable rating value */
clocksource_mips.rating = 200 + mips_hpt_frequency / 10000000;
+ /*
+ * R2 onwards makes the count accessible to user mode so it can be used
+ * by the VDSO (HWREna is configured by configure_hwrena()).
+ */
+ if (cpu_has_mips_r2_r6 && rdhwr_count_usable())
+ clocksource_mips.archdata.vdso_clock_mode = VDSO_CLOCK_R4K;
+
clocksource_register_hz(&clocksource_mips, mips_hpt_frequency);
sched_clock_register(r4k_read_sched_clock, 32, mips_hpt_frequency);
#include <linux/elf.h>
#include <linux/err.h>
#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/irqchip/mips-gic.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/slab.h>
+#include <linux/timekeeper_internal.h>
#include <asm/abi.h>
#include <asm/vdso.h>
static union mips_vdso_data vdso_data __page_aligned_data;
/*
- * Mapping for the VDSO data pages. The real pages are mapped manually, as
+ * Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as
* what we map and where within the area they are mapped is determined at
* runtime.
*/
}
subsys_initcall(init_vdso);
+void update_vsyscall(struct timekeeper *tk)
+{
+ vdso_data_write_begin(&vdso_data);
+
+ vdso_data.xtime_sec = tk->xtime_sec;
+ vdso_data.xtime_nsec = tk->tkr_mono.xtime_nsec;
+ vdso_data.wall_to_mono_sec = tk->wall_to_monotonic.tv_sec;
+ vdso_data.wall_to_mono_nsec = tk->wall_to_monotonic.tv_nsec;
+ vdso_data.cs_shift = tk->tkr_mono.shift;
+
+ vdso_data.clock_mode = tk->tkr_mono.clock->archdata.vdso_clock_mode;
+ if (vdso_data.clock_mode != VDSO_CLOCK_NONE) {
+ vdso_data.cs_mult = tk->tkr_mono.mult;
+ vdso_data.cs_cycle_last = tk->tkr_mono.cycle_last;
+ vdso_data.cs_mask = tk->tkr_mono.mask;
+ }
+
+ vdso_data_write_end(&vdso_data);
+}
+
+void update_vsyscall_tz(void)
+{
+ if (vdso_data.clock_mode != VDSO_CLOCK_NONE) {
+ vdso_data.tz_minuteswest = sys_tz.tz_minuteswest;
+ vdso_data.tz_dsttime = sys_tz.tz_dsttime;
+ }
+}
+
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct mips_vdso_image *image = current->thread.abi->vdso;
struct mm_struct *mm = current->mm;
- unsigned long base, vdso_addr;
+ unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr;
struct vm_area_struct *vma;
+ struct resource gic_res;
int ret;
down_write(&mm->mmap_sem);
- base = get_unmapped_area(NULL, 0, PAGE_SIZE + image->size, 0, 0);
+ /*
+ * Determine total area size. This includes the VDSO data itself, the
+ * data page, and the GIC user page if present. Always create a mapping
+ * for the GIC user area if the GIC is present regardless of whether it
+ * is the current clocksource, in case it comes into use later on. We
+ * only map a page even though the total area is 64K, as we only need
+ * the counter registers at the start.
+ */
+ gic_size = gic_present ? PAGE_SIZE : 0;
+ vvar_size = gic_size + PAGE_SIZE;
+ size = vvar_size + image->size;
+
+ base = get_unmapped_area(NULL, 0, size, 0, 0);
if (IS_ERR_VALUE(base)) {
ret = base;
goto out;
}
- vdso_addr = base + PAGE_SIZE;
+ data_addr = base + gic_size;
+ vdso_addr = data_addr + PAGE_SIZE;
- vma = _install_special_mapping(mm, base, PAGE_SIZE,
+ vma = _install_special_mapping(mm, base, vvar_size,
VM_READ | VM_MAYREAD,
&vdso_vvar_mapping);
if (IS_ERR(vma)) {
goto out;
}
+ /* Map GIC user page. */
+ if (gic_size) {
+ ret = gic_get_usm_range(&gic_res);
+ if (ret)
+ goto out;
+
+ ret = io_remap_pfn_range(vma, base,
+ gic_res.start >> PAGE_SHIFT,
+ gic_size,
+ pgprot_noncached(PAGE_READONLY));
+ if (ret)
+ goto out;
+ }
+
/* Map data page. */
- ret = remap_pfn_range(vma, base,
+ ret = remap_pfn_range(vma, data_addr,
virt_to_phys(&vdso_data) >> PAGE_SHIFT,
PAGE_SIZE, PAGE_READONLY);
if (ret)
--- /dev/null
+/*
+ * Copyright (C) 2015 Imagination Technologies
+ * Author: Alex Smith <alex.smith@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include "vdso.h"
+
+#include <linux/compiler.h>
+#include <linux/irqchip/mips-gic.h>
+#include <linux/time.h>
+
+#include <asm/clocksource.h>
+#include <asm/io.h>
+#include <asm/mips-cm.h>
+#include <asm/unistd.h>
+#include <asm/vdso.h>
+
+static __always_inline int do_realtime_coarse(struct timespec *ts,
+ const union mips_vdso_data *data)
+{
+ u32 start_seq;
+
+ do {
+ start_seq = vdso_data_read_begin(data);
+
+ ts->tv_sec = data->xtime_sec;
+ ts->tv_nsec = data->xtime_nsec >> data->cs_shift;
+ } while (vdso_data_read_retry(data, start_seq));
+
+ return 0;
+}
+
+static __always_inline int do_monotonic_coarse(struct timespec *ts,
+ const union mips_vdso_data *data)
+{
+ u32 start_seq;
+ u32 to_mono_sec;
+ u32 to_mono_nsec;
+
+ do {
+ start_seq = vdso_data_read_begin(data);
+
+ ts->tv_sec = data->xtime_sec;
+ ts->tv_nsec = data->xtime_nsec >> data->cs_shift;
+
+ to_mono_sec = data->wall_to_mono_sec;
+ to_mono_nsec = data->wall_to_mono_nsec;
+ } while (vdso_data_read_retry(data, start_seq));
+
+ ts->tv_sec += to_mono_sec;
+ timespec_add_ns(ts, to_mono_nsec);
+
+ return 0;
+}
+
+#ifdef CONFIG_CSRC_R4K
+
+static __always_inline u64 read_r4k_count(void)
+{
+ unsigned int count;
+
+ __asm__ __volatile__(
+ " .set push\n"
+ " .set mips32r2\n"
+ " rdhwr %0, $2\n"
+ " .set pop\n"
+ : "=r" (count));
+
+ return count;
+}
+
+#endif
+
+#ifdef CONFIG_CLKSRC_MIPS_GIC
+
+static __always_inline u64 read_gic_count(const union mips_vdso_data *data)
+{
+ void __iomem *gic = get_gic(data);
+ u32 hi, hi2, lo;
+
+ do {
+ hi = __raw_readl(gic + GIC_UMV_SH_COUNTER_63_32_OFS);
+ lo = __raw_readl(gic + GIC_UMV_SH_COUNTER_31_00_OFS);
+ hi2 = __raw_readl(gic + GIC_UMV_SH_COUNTER_63_32_OFS);
+ } while (hi2 != hi);
+
+ return (((u64)hi) << 32) + lo;
+}
+
+#endif
+
+static __always_inline u64 get_ns(const union mips_vdso_data *data)
+{
+ u64 cycle_now, delta, nsec;
+
+ switch (data->clock_mode) {
+#ifdef CONFIG_CSRC_R4K
+ case VDSO_CLOCK_R4K:
+ cycle_now = read_r4k_count();
+ break;
+#endif
+#ifdef CONFIG_CLKSRC_MIPS_GIC
+ case VDSO_CLOCK_GIC:
+ cycle_now = read_gic_count(data);
+ break;
+#endif
+ default:
+ return 0;
+ }
+
+ delta = (cycle_now - data->cs_cycle_last) & data->cs_mask;
+
+ nsec = (delta * data->cs_mult) + data->xtime_nsec;
+ nsec >>= data->cs_shift;
+
+ return nsec;
+}
+
+static __always_inline int do_realtime(struct timespec *ts,
+ const union mips_vdso_data *data)
+{
+ u32 start_seq;
+ u64 ns;
+
+ do {
+ start_seq = vdso_data_read_begin(data);
+
+ if (data->clock_mode == VDSO_CLOCK_NONE)
+ return -ENOSYS;
+
+ ts->tv_sec = data->xtime_sec;
+ ns = get_ns(data);
+ } while (vdso_data_read_retry(data, start_seq));
+
+ ts->tv_nsec = 0;
+ timespec_add_ns(ts, ns);
+
+ return 0;
+}
+
+static __always_inline int do_monotonic(struct timespec *ts,
+ const union mips_vdso_data *data)
+{
+ u32 start_seq;
+ u64 ns;
+ u32 to_mono_sec;
+ u32 to_mono_nsec;
+
+ do {
+ start_seq = vdso_data_read_begin(data);
+
+ if (data->clock_mode == VDSO_CLOCK_NONE)
+ return -ENOSYS;
+
+ ts->tv_sec = data->xtime_sec;
+ ns = get_ns(data);
+
+ to_mono_sec = data->wall_to_mono_sec;
+ to_mono_nsec = data->wall_to_mono_nsec;
+ } while (vdso_data_read_retry(data, start_seq));
+
+ ts->tv_sec += to_mono_sec;
+ ts->tv_nsec = 0;
+ timespec_add_ns(ts, ns + to_mono_nsec);
+
+ return 0;
+}
+
+#ifdef CONFIG_MIPS_CLOCK_VSYSCALL
+
+/*
+ * This is behind the ifdef so that we don't provide the symbol when there's no
+ * possibility of there being a usable clocksource, because there's nothing we
+ * can do without it. When libc fails the symbol lookup it should fall back on
+ * the standard syscall path.
+ */
+int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
+{
+ const union mips_vdso_data *data = get_vdso_data();
+ struct timespec ts;
+ int ret;
+
+ ret = do_realtime(&ts, data);
+ if (ret)
+ return ret;
+
+ if (tv) {
+ tv->tv_sec = ts.tv_sec;
+ tv->tv_usec = ts.tv_nsec / 1000;
+ }
+
+ if (tz) {
+ tz->tz_minuteswest = data->tz_minuteswest;
+ tz->tz_dsttime = data->tz_dsttime;
+ }
+
+ return 0;
+}
+
+#endif /* CONFIG_CLKSRC_MIPS_GIC */
+
+int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts)
+{
+ const union mips_vdso_data *data = get_vdso_data();
+ int ret;
+
+ switch (clkid) {
+ case CLOCK_REALTIME_COARSE:
+ ret = do_realtime_coarse(ts, data);
+ break;
+ case CLOCK_MONOTONIC_COARSE:
+ ret = do_monotonic_coarse(ts, data);
+ break;
+ case CLOCK_REALTIME:
+ ret = do_realtime(ts, data);
+ break;
+ case CLOCK_MONOTONIC:
+ ret = do_monotonic(ts, data);
+ break;
+ default:
+ ret = -ENOSYS;
+ break;
+ }
+
+ /* If we return -ENOSYS libc should fall back to a syscall. */
+ return ret;
+}
return (const union mips_vdso_data *)(get_vdso_base() - PAGE_SIZE);
}
+#ifdef CONFIG_CLKSRC_MIPS_GIC
+
+static inline void __iomem *get_gic(const union mips_vdso_data *data)
+{
+ return (void __iomem *)data - PAGE_SIZE;
+}
+
+#endif /* CONFIG_CLKSRC_MIPS_GIC */
+
#endif /* __ASSEMBLY__ */
VERSION
{
LINUX_2.6 {
+#ifndef DISABLE_MIPS_VDSO
+ global:
+ __vdso_clock_gettime;
+ __vdso_gettimeofday;
+#endif
local: *;
};
}
}
static struct clocksource gic_clocksource = {
- .name = "GIC",
- .read = gic_hpt_read,
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .name = "GIC",
+ .read = gic_hpt_read,
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .archdata = { .vdso_clock_mode = VDSO_CLOCK_GIC },
};
static void __init __gic_clocksource_init(void)
projects / linux-2.6-microblaze.git / commitdiff