diff options
Diffstat (limited to 'arch/mips/kernel')
-rw-r--r-- | arch/mips/kernel/csrc-r4k.c | 44 | ||||
-rw-r--r-- | arch/mips/kernel/vdso.c | 71 |
2 files changed, 109 insertions, 6 deletions
diff --git a/arch/mips/kernel/csrc-r4k.c b/arch/mips/kernel/csrc-r4k.c index e5ed7ad..1f91056 100644 --- a/arch/mips/kernel/csrc-r4k.c +++ b/arch/mips/kernel/csrc-r4k.c @@ -28,6 +28,43 @@ static u64 notrace r4k_read_sched_clock(void) 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) @@ -36,6 +73,13 @@ int __init init_r4k_clocksource(void) /* 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); diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c index 56cc3c4..975e997 100644 --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -12,9 +12,12 @@ #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> @@ -23,7 +26,7 @@ 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. */ @@ -64,25 +67,67 @@ static int __init init_vdso(void) } 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)) { @@ -90,8 +135,22 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 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) |