--- /dev/null
+/*
+ * VDSO implementation for AArch64 and vector page setup for AArch32.
+ *
+ * Copyright (C) 2012 ARM Limited
+ *
+ * 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/>.
+ *
+ * Author: Will Deacon <will.deacon@arm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/clocksource.h>
+#include <linux/elf.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/gfp.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/signal.h>
+#include <linux/slab.h>
+#include <linux/timekeeper_internal.h>
+#include <linux/vmalloc.h>
+
+#include <asm/cacheflush.h>
+#include <asm/signal32.h>
+#include <asm/vdso.h>
+#include <asm/vdso_datapage.h>
+
+extern char vdso_start, vdso_end;
+static unsigned long vdso_pages;
+static struct page **vdso_pagelist;
+
+/*
+ * The vDSO data page.
+ */
+static union {
+ struct vdso_data data;
+ u8 page[PAGE_SIZE];
+} vdso_data_store __page_aligned_data;
+struct vdso_data *vdso_data = &vdso_data_store.data;
+
+#ifdef CONFIG_COMPAT
+/*
+ * Create and map the vectors page for AArch32 tasks.
+ */
+static struct page *vectors_page[1];
+
+static int alloc_vectors_page(void)
+{
+ extern char __kuser_helper_start[], __kuser_helper_end[];
+ extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
+
+ int kuser_sz = __kuser_helper_end - __kuser_helper_start;
+ int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
+ unsigned long vpage;
+
+ vpage = get_zeroed_page(GFP_ATOMIC);
+
+ if (!vpage)
+ return -ENOMEM;
+
+ /* kuser helpers */
+ memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start,
+ kuser_sz);
+
+ /* sigreturn code */
+ memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET,
+ __aarch32_sigret_code_start, sigret_sz);
+
+ flush_icache_range(vpage, vpage + PAGE_SIZE);
+ vectors_page[0] = virt_to_page(vpage);
+
+ return 0;
+}
+arch_initcall(alloc_vectors_page);
+
+int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long addr = AARCH32_VECTORS_BASE;
+ static struct vm_special_mapping spec = {
+ .name = "[vectors]",
+ .pages = vectors_page,
+
+ };
+ void *ret;
+
+ down_write(&mm->mmap_sem);
+ current->mm->context.vdso = (void *)addr;
+
+ /* Map vectors page at the high address. */
+ ret = _install_special_mapping(mm, addr, PAGE_SIZE,
+ VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC,
+ &spec);
+
+ up_write(&mm->mmap_sem);
+
+ return PTR_ERR_OR_ZERO(ret);
+}
+#endif /* CONFIG_COMPAT */
+
+static struct vm_special_mapping vdso_spec[2];
+
+static int __init vdso_init(void)
+{
+ int i;
+
+ if (memcmp(&vdso_start, "\177ELF", 4)) {
+ pr_err("vDSO is not a valid ELF object!\n");
+ return -EINVAL;
+ }
+
+ vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
+ pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
+ vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data);
+
+ /* Allocate the vDSO pagelist, plus a page for the data. */
+ vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
+ GFP_KERNEL);
+ if (vdso_pagelist == NULL)
+ return -ENOMEM;
+
+ /* Grab the vDSO data page. */
+ vdso_pagelist[0] = virt_to_page(vdso_data);
+
+ /* Grab the vDSO code pages. */
+ for (i = 0; i < vdso_pages; i++)
+ vdso_pagelist[i + 1] = virt_to_page(&vdso_start + i * PAGE_SIZE);
+
+ /* Populate the special mapping structures */
+ vdso_spec[0] = (struct vm_special_mapping) {
+ .name = "[vvar]",
+ .pages = vdso_pagelist,
+ };
+
+ vdso_spec[1] = (struct vm_special_mapping) {
+ .name = "[vdso]",
+ .pages = &vdso_pagelist[1],
+ };
+
+ return 0;
+}
+arch_initcall(vdso_init);
+
+int arch_setup_additional_pages(struct linux_binprm *bprm,
+ int uses_interp)
+{
+ struct mm_struct *mm = current->mm;
+ unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
+ void *ret;
+
+ vdso_text_len = vdso_pages << PAGE_SHIFT;
+ /* Be sure to map the data page */
+ vdso_mapping_len = vdso_text_len + PAGE_SIZE;
+
+ down_write(&mm->mmap_sem);
+ vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
+ if (IS_ERR_VALUE(vdso_base)) {
+ ret = ERR_PTR(vdso_base);
+ goto up_fail;
+ }
+ ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
+ VM_READ|VM_MAYREAD,
+ &vdso_spec[0]);
+ if (IS_ERR(ret))
+ goto up_fail;
+
+ vdso_base += PAGE_SIZE;
+ mm->context.vdso = (void *)vdso_base;
+ ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
+ VM_READ|VM_EXEC|
+ VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
+ &vdso_spec[1]);
+ if (IS_ERR(ret))
+ goto up_fail;
+
+
+ up_write(&mm->mmap_sem);
+ return 0;
+
+up_fail:
+ mm->context.vdso = NULL;
+ up_write(&mm->mmap_sem);
+ return PTR_ERR(ret);
+}
+
+/*
+ * Update the vDSO data page to keep in sync with kernel timekeeping.
+ */
+void update_vsyscall(struct timekeeper *tk)
+{
+ struct timespec xtime_coarse;
+ u32 use_syscall = strcmp(tk->tkr_mono.clock->name, "arch_sys_counter");
+
+ ++vdso_data->tb_seq_count;
+ smp_wmb();
+
+ xtime_coarse = __current_kernel_time();
+ vdso_data->use_syscall = use_syscall;
+ vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec;
+ vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec;
+ vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
+ vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
+
+ if (!use_syscall) {
+ vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
+ vdso_data->xtime_clock_sec = tk->xtime_sec;
+ vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
+ vdso_data->cs_mult = tk->tkr_mono.mult;
+ vdso_data->cs_shift = tk->tkr_mono.shift;
+ }
+
+ smp_wmb();
+ ++vdso_data->tb_seq_count;
+}
+
+void update_vsyscall_tz(void)
+{
+ vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
+ vdso_data->tz_dsttime = sys_tz.tz_dsttime;
+}
Code Review / kvmfornfv.git / blobdiff