--- /dev/null
- if (strcmp(tk->tkr.clock->name, "arch_sys_counter") != 0)
+ /*
+ * Adapted from arm64 version.
+ *
+ * Copyright (C) 2012 ARM Limited
+ * Copyright (C) 2015 Mentor Graphics Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+ #include <linux/elf.h>
+ #include <linux/err.h>
+ #include <linux/kernel.h>
+ #include <linux/mm.h>
+ #include <linux/of.h>
+ #include <linux/printk.h>
+ #include <linux/slab.h>
+ #include <linux/timekeeper_internal.h>
+ #include <linux/vmalloc.h>
+ #include <asm/arch_timer.h>
+ #include <asm/barrier.h>
+ #include <asm/cacheflush.h>
+ #include <asm/page.h>
+ #include <asm/vdso.h>
+ #include <asm/vdso_datapage.h>
+ #include <clocksource/arm_arch_timer.h>
+
+ #define MAX_SYMNAME 64
+
+ static struct page **vdso_text_pagelist;
+
+ /* Total number of pages needed for the data and text portions of the VDSO. */
+ unsigned int vdso_total_pages __read_mostly;
+
+ /*
+ * The VDSO data page.
+ */
+ static union vdso_data_store vdso_data_store __page_aligned_data;
+ static struct vdso_data *vdso_data = &vdso_data_store.data;
+
+ static struct page *vdso_data_page;
+ static struct vm_special_mapping vdso_data_mapping = {
+ .name = "[vvar]",
+ .pages = &vdso_data_page,
+ };
+
+ static struct vm_special_mapping vdso_text_mapping = {
+ .name = "[vdso]",
+ };
+
+ struct elfinfo {
+ Elf32_Ehdr *hdr; /* ptr to ELF */
+ Elf32_Sym *dynsym; /* ptr to .dynsym section */
+ unsigned long dynsymsize; /* size of .dynsym section */
+ char *dynstr; /* ptr to .dynstr section */
+ };
+
+ /* Cached result of boot-time check for whether the arch timer exists,
+ * and if so, whether the virtual counter is useable.
+ */
+ static bool cntvct_ok __read_mostly;
+
+ static bool __init cntvct_functional(void)
+ {
+ struct device_node *np;
+ bool ret = false;
+
+ if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
+ goto out;
+
+ /* The arm_arch_timer core should export
+ * arch_timer_use_virtual or similar so we don't have to do
+ * this.
+ */
+ np = of_find_compatible_node(NULL, NULL, "arm,armv7-timer");
+ if (!np)
+ goto out_put;
+
+ if (of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
+ goto out_put;
+
+ ret = true;
+
+ out_put:
+ of_node_put(np);
+ out:
+ return ret;
+ }
+
+ static void * __init find_section(Elf32_Ehdr *ehdr, const char *name,
+ unsigned long *size)
+ {
+ Elf32_Shdr *sechdrs;
+ unsigned int i;
+ char *secnames;
+
+ /* Grab section headers and strings so we can tell who is who */
+ sechdrs = (void *)ehdr + ehdr->e_shoff;
+ secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
+
+ /* Find the section they want */
+ for (i = 1; i < ehdr->e_shnum; i++) {
+ if (strcmp(secnames + sechdrs[i].sh_name, name) == 0) {
+ if (size)
+ *size = sechdrs[i].sh_size;
+ return (void *)ehdr + sechdrs[i].sh_offset;
+ }
+ }
+
+ if (size)
+ *size = 0;
+ return NULL;
+ }
+
+ static Elf32_Sym * __init find_symbol(struct elfinfo *lib, const char *symname)
+ {
+ unsigned int i;
+
+ for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
+ char name[MAX_SYMNAME], *c;
+
+ if (lib->dynsym[i].st_name == 0)
+ continue;
+ strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
+ MAX_SYMNAME);
+ c = strchr(name, '@');
+ if (c)
+ *c = 0;
+ if (strcmp(symname, name) == 0)
+ return &lib->dynsym[i];
+ }
+ return NULL;
+ }
+
+ static void __init vdso_nullpatch_one(struct elfinfo *lib, const char *symname)
+ {
+ Elf32_Sym *sym;
+
+ sym = find_symbol(lib, symname);
+ if (!sym)
+ return;
+
+ sym->st_name = 0;
+ }
+
+ static void __init patch_vdso(void *ehdr)
+ {
+ struct elfinfo einfo;
+
+ einfo = (struct elfinfo) {
+ .hdr = ehdr,
+ };
+
+ einfo.dynsym = find_section(einfo.hdr, ".dynsym", &einfo.dynsymsize);
+ einfo.dynstr = find_section(einfo.hdr, ".dynstr", NULL);
+
+ /* If the virtual counter is absent or non-functional we don't
+ * want programs to incur the slight additional overhead of
+ * dispatching through the VDSO only to fall back to syscalls.
+ */
+ if (!cntvct_ok) {
+ vdso_nullpatch_one(&einfo, "__vdso_gettimeofday");
+ vdso_nullpatch_one(&einfo, "__vdso_clock_gettime");
+ }
+ }
+
+ static int __init vdso_init(void)
+ {
+ unsigned int text_pages;
+ int i;
+
+ if (memcmp(&vdso_start, "\177ELF", 4)) {
+ pr_err("VDSO is not a valid ELF object!\n");
+ return -ENOEXEC;
+ }
+
+ text_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
+ pr_debug("vdso: %i text pages at base %p\n", text_pages, &vdso_start);
+
+ /* Allocate the VDSO text pagelist */
+ vdso_text_pagelist = kcalloc(text_pages, sizeof(struct page *),
+ GFP_KERNEL);
+ if (vdso_text_pagelist == NULL)
+ return -ENOMEM;
+
+ /* Grab the VDSO data page. */
+ vdso_data_page = virt_to_page(vdso_data);
+
+ /* Grab the VDSO text pages. */
+ for (i = 0; i < text_pages; i++) {
+ struct page *page;
+
+ page = virt_to_page(&vdso_start + i * PAGE_SIZE);
+ vdso_text_pagelist[i] = page;
+ }
+
+ vdso_text_mapping.pages = vdso_text_pagelist;
+
+ vdso_total_pages = 1; /* for the data/vvar page */
+ vdso_total_pages += text_pages;
+
+ cntvct_ok = cntvct_functional();
+
+ patch_vdso(&vdso_start);
+
+ return 0;
+ }
+ arch_initcall(vdso_init);
+
+ static int install_vvar(struct mm_struct *mm, unsigned long addr)
+ {
+ struct vm_area_struct *vma;
+
+ vma = _install_special_mapping(mm, addr, PAGE_SIZE,
+ VM_READ | VM_MAYREAD,
+ &vdso_data_mapping);
+
+ return IS_ERR(vma) ? PTR_ERR(vma) : 0;
+ }
+
+ /* assumes mmap_sem is write-locked */
+ void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
+ {
+ struct vm_area_struct *vma;
+ unsigned long len;
+
+ mm->context.vdso = 0;
+
+ if (vdso_text_pagelist == NULL)
+ return;
+
+ if (install_vvar(mm, addr))
+ return;
+
+ /* Account for vvar page. */
+ addr += PAGE_SIZE;
+ len = (vdso_total_pages - 1) << PAGE_SHIFT;
+
+ vma = _install_special_mapping(mm, addr, len,
+ VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
+ &vdso_text_mapping);
+
+ if (!IS_ERR(vma))
+ mm->context.vdso = addr;
+ }
+
+ static void vdso_write_begin(struct vdso_data *vdata)
+ {
+ ++vdso_data->seq_count;
+ smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */
+ }
+
+ static void vdso_write_end(struct vdso_data *vdata)
+ {
+ smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */
+ ++vdso_data->seq_count;
+ }
+
+ static bool tk_is_cntvct(const struct timekeeper *tk)
+ {
+ if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
+ return false;
+
- vdso_data->cs_cycle_last = tk->tkr.cycle_last;
++ if (strcmp(tk->tkr_mono.clock->name, "arch_sys_counter") != 0)
+ return false;
+
+ return true;
+ }
+
+ /**
+ * update_vsyscall - update the vdso data page
+ *
+ * Increment the sequence counter, making it odd, indicating to
+ * userspace that an update is in progress. Update the fields used
+ * for coarse clocks and, if the architected system timer is in use,
+ * the fields used for high precision clocks. Increment the sequence
+ * counter again, making it even, indicating to userspace that the
+ * update is finished.
+ *
+ * Userspace is expected to sample seq_count before reading any other
+ * fields from the data page. If seq_count is odd, userspace is
+ * expected to wait until it becomes even. After copying data from
+ * the page, userspace must sample seq_count again; if it has changed
+ * from its previous value, userspace must retry the whole sequence.
+ *
+ * Calls to update_vsyscall are serialized by the timekeeping core.
+ */
+ void update_vsyscall(struct timekeeper *tk)
+ {
+ struct timespec xtime_coarse;
+ struct timespec64 *wtm = &tk->wall_to_monotonic;
+
+ if (!cntvct_ok) {
+ /* The entry points have been zeroed, so there is no
+ * point in updating the data page.
+ */
+ return;
+ }
+
+ vdso_write_begin(vdso_data);
+
+ xtime_coarse = __current_kernel_time();
+ vdso_data->tk_is_cntvct = tk_is_cntvct(tk);
+ vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec;
+ vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec;
+ vdso_data->wtm_clock_sec = wtm->tv_sec;
+ vdso_data->wtm_clock_nsec = wtm->tv_nsec;
+
+ if (vdso_data->tk_is_cntvct) {
- vdso_data->xtime_clock_snsec = tk->tkr.xtime_nsec;
- vdso_data->cs_mult = tk->tkr.mult;
- vdso_data->cs_shift = tk->tkr.shift;
- vdso_data->cs_mask = tk->tkr.mask;
++ vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
+ vdso_data->xtime_clock_sec = tk->xtime_sec;
++ vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec;
++ vdso_data->cs_mult = tk->tkr_mono.mult;
++ vdso_data->cs_shift = tk->tkr_mono.shift;
++ vdso_data->cs_mask = tk->tkr_mono.mask;
+ }
+
+ vdso_write_end(vdso_data);
+
+ flush_dcache_page(virt_to_page(vdso_data));
+ }
+
+ void update_vsyscall_tz(void)
+ {
+ vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
+ vdso_data->tz_dsttime = sys_tz.tz_dsttime;
+ flush_dcache_page(virt_to_page(vdso_data));
+ }
projects / openwrt / staging / blogic.git / commitdiff