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1d8f51d41f
Instead of comparing the name to a magic string, use archdata to explicitly communicate whether the arch timer is suitable for direct vdso access. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Russell King <rmk+kernel@armlinux.org.uk> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Scott Wood <oss@buserror.net> Signed-off-by: Will Deacon <will.deacon@arm.com>
239 lines
6.2 KiB
C
239 lines
6.2 KiB
C
/*
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* VDSO implementation for AArch64 and vector page setup for AArch32.
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*
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* Copyright (C) 2012 ARM Limited
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* Author: Will Deacon <will.deacon@arm.com>
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*/
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#include <linux/cache.h>
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#include <linux/clocksource.h>
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#include <linux/elf.h>
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/gfp.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/signal.h>
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#include <linux/slab.h>
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#include <linux/timekeeper_internal.h>
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#include <linux/vmalloc.h>
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#include <asm/cacheflush.h>
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#include <asm/signal32.h>
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#include <asm/vdso.h>
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#include <asm/vdso_datapage.h>
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extern char vdso_start, vdso_end;
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static unsigned long vdso_pages __ro_after_init;
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/*
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* The vDSO data page.
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*/
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static union {
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struct vdso_data data;
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u8 page[PAGE_SIZE];
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} vdso_data_store __page_aligned_data;
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struct vdso_data *vdso_data = &vdso_data_store.data;
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#ifdef CONFIG_COMPAT
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/*
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* Create and map the vectors page for AArch32 tasks.
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*/
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static struct page *vectors_page[1] __ro_after_init;
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static int __init alloc_vectors_page(void)
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{
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extern char __kuser_helper_start[], __kuser_helper_end[];
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extern char __aarch32_sigret_code_start[], __aarch32_sigret_code_end[];
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int kuser_sz = __kuser_helper_end - __kuser_helper_start;
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int sigret_sz = __aarch32_sigret_code_end - __aarch32_sigret_code_start;
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unsigned long vpage;
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vpage = get_zeroed_page(GFP_ATOMIC);
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if (!vpage)
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return -ENOMEM;
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/* kuser helpers */
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memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start,
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kuser_sz);
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/* sigreturn code */
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memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET,
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__aarch32_sigret_code_start, sigret_sz);
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flush_icache_range(vpage, vpage + PAGE_SIZE);
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vectors_page[0] = virt_to_page(vpage);
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return 0;
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}
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arch_initcall(alloc_vectors_page);
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int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp)
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{
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struct mm_struct *mm = current->mm;
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unsigned long addr = AARCH32_VECTORS_BASE;
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static const struct vm_special_mapping spec = {
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.name = "[vectors]",
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.pages = vectors_page,
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};
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void *ret;
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if (down_write_killable(&mm->mmap_sem))
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return -EINTR;
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current->mm->context.vdso = (void *)addr;
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/* Map vectors page at the high address. */
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ret = _install_special_mapping(mm, addr, PAGE_SIZE,
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VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC,
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&spec);
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up_write(&mm->mmap_sem);
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return PTR_ERR_OR_ZERO(ret);
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}
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#endif /* CONFIG_COMPAT */
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static struct vm_special_mapping vdso_spec[2] __ro_after_init = {
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{
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.name = "[vvar]",
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},
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{
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.name = "[vdso]",
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},
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};
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static int __init vdso_init(void)
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{
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int i;
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struct page **vdso_pagelist;
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if (memcmp(&vdso_start, "\177ELF", 4)) {
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pr_err("vDSO is not a valid ELF object!\n");
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return -EINVAL;
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}
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vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
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pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n",
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vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data);
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/* Allocate the vDSO pagelist, plus a page for the data. */
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vdso_pagelist = kcalloc(vdso_pages + 1, sizeof(struct page *),
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GFP_KERNEL);
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if (vdso_pagelist == NULL)
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return -ENOMEM;
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/* Grab the vDSO data page. */
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vdso_pagelist[0] = pfn_to_page(PHYS_PFN(__pa(vdso_data)));
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/* Grab the vDSO code pages. */
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for (i = 0; i < vdso_pages; i++)
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vdso_pagelist[i + 1] = pfn_to_page(PHYS_PFN(__pa(&vdso_start)) + i);
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vdso_spec[0].pages = &vdso_pagelist[0];
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vdso_spec[1].pages = &vdso_pagelist[1];
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return 0;
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}
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arch_initcall(vdso_init);
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int arch_setup_additional_pages(struct linux_binprm *bprm,
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int uses_interp)
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{
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struct mm_struct *mm = current->mm;
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unsigned long vdso_base, vdso_text_len, vdso_mapping_len;
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void *ret;
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vdso_text_len = vdso_pages << PAGE_SHIFT;
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/* Be sure to map the data page */
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vdso_mapping_len = vdso_text_len + PAGE_SIZE;
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if (down_write_killable(&mm->mmap_sem))
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return -EINTR;
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vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0);
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if (IS_ERR_VALUE(vdso_base)) {
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ret = ERR_PTR(vdso_base);
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goto up_fail;
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}
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ret = _install_special_mapping(mm, vdso_base, PAGE_SIZE,
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VM_READ|VM_MAYREAD,
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&vdso_spec[0]);
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if (IS_ERR(ret))
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goto up_fail;
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vdso_base += PAGE_SIZE;
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mm->context.vdso = (void *)vdso_base;
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ret = _install_special_mapping(mm, vdso_base, vdso_text_len,
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
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&vdso_spec[1]);
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if (IS_ERR(ret))
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goto up_fail;
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up_write(&mm->mmap_sem);
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return 0;
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up_fail:
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mm->context.vdso = NULL;
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up_write(&mm->mmap_sem);
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return PTR_ERR(ret);
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}
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/*
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* Update the vDSO data page to keep in sync with kernel timekeeping.
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*/
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void update_vsyscall(struct timekeeper *tk)
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{
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u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct;
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++vdso_data->tb_seq_count;
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smp_wmb();
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vdso_data->use_syscall = use_syscall;
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vdso_data->xtime_coarse_sec = tk->xtime_sec;
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vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >>
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tk->tkr_mono.shift;
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vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec;
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vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec;
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if (!use_syscall) {
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/* tkr_mono.cycle_last == tkr_raw.cycle_last */
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vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last;
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vdso_data->raw_time_sec = tk->raw_time.tv_sec;
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vdso_data->raw_time_nsec = tk->raw_time.tv_nsec;
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vdso_data->xtime_clock_sec = tk->xtime_sec;
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vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec;
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/* tkr_raw.xtime_nsec == 0 */
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vdso_data->cs_mono_mult = tk->tkr_mono.mult;
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vdso_data->cs_raw_mult = tk->tkr_raw.mult;
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/* tkr_mono.shift == tkr_raw.shift */
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vdso_data->cs_shift = tk->tkr_mono.shift;
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}
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smp_wmb();
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++vdso_data->tb_seq_count;
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}
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void update_vsyscall_tz(void)
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{
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vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
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vdso_data->tz_dsttime = sys_tz.tz_dsttime;
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}
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