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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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9031fefde6
This patch adds VDSO support for 64-bit applications. The VDSO code is currently used for sys_rt_sigreturn() and optimised gettimeofday() (using the user-accessible generic counter). Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Tony Lindgren <tony@atomide.com> Acked-by: Nicolas Pitre <nico@linaro.org> Acked-by: Olof Johansson <olof@lixom.net> Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Acked-by: Arnd Bergmann <arnd@arndb.de>
262 lines
6.3 KiB
C
262 lines
6.3 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/kernel.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/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/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;
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static struct page **vdso_pagelist;
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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];
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static int alloc_vectors_page(void)
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{
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extern char __kuser_helper_start[], __kuser_helper_end[];
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int kuser_sz = __kuser_helper_end - __kuser_helper_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, sizeof(aarch32_sigret_code));
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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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int ret;
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down_write(&mm->mmap_sem);
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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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vectors_page);
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up_write(&mm->mmap_sem);
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return ret;
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}
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#endif /* CONFIG_COMPAT */
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static int __init vdso_init(void)
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{
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struct page *pg;
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char *vbase;
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int i, ret = 0;
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vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
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pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n",
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vdso_pages + 1, vdso_pages, 1L, &vdso_start);
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/* Allocate the vDSO pagelist, plus a page for the data. */
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vdso_pagelist = kzalloc(sizeof(struct page *) * (vdso_pages + 1),
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GFP_KERNEL);
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if (vdso_pagelist == NULL) {
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pr_err("Failed to allocate vDSO pagelist!\n");
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return -ENOMEM;
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}
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/* Grab the vDSO code pages. */
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for (i = 0; i < vdso_pages; i++) {
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pg = virt_to_page(&vdso_start + i*PAGE_SIZE);
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ClearPageReserved(pg);
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get_page(pg);
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vdso_pagelist[i] = pg;
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}
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/* Sanity check the shared object header. */
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vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL);
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if (vbase == NULL) {
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pr_err("Failed to map vDSO pagelist!\n");
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return -ENOMEM;
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} else if (memcmp(vbase, "\177ELF", 4)) {
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pr_err("vDSO is not a valid ELF object!\n");
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ret = -EINVAL;
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goto unmap;
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}
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/* Grab the vDSO data page. */
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pg = virt_to_page(vdso_data);
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get_page(pg);
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vdso_pagelist[i] = pg;
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unmap:
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vunmap(vbase);
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return ret;
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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_mapping_len;
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int ret;
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/* Be sure to map the data page */
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vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT;
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down_write(&mm->mmap_sem);
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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 = vdso_base;
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goto up_fail;
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}
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mm->context.vdso = (void *)vdso_base;
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ret = install_special_mapping(mm, vdso_base, vdso_mapping_len,
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
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vdso_pagelist);
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if (ret) {
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mm->context.vdso = NULL;
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goto up_fail;
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}
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up_fail:
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up_write(&mm->mmap_sem);
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return ret;
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}
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const char *arch_vma_name(struct vm_area_struct *vma)
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{
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/*
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* We can re-use the vdso pointer in mm_context_t for identifying
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* the vectors page for compat applications. The vDSO will always
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* sit above TASK_UNMAPPED_BASE and so we don't need to worry about
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* it conflicting with the vectors base.
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*/
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if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) {
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#ifdef CONFIG_COMPAT
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if (vma->vm_start == AARCH32_VECTORS_BASE)
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return "[vectors]";
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#endif
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return "[vdso]";
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}
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return NULL;
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}
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/*
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* We define AT_SYSINFO_EHDR, so we need these function stubs to keep
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* Linux happy.
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*/
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int in_gate_area_no_mm(unsigned long addr)
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{
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return 0;
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}
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int in_gate_area(struct mm_struct *mm, unsigned long addr)
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{
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return 0;
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}
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struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
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{
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return NULL;
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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 timespec *ts, struct timespec *wtm,
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struct clocksource *clock, u32 mult)
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{
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struct timespec xtime_coarse;
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u32 use_syscall = strcmp(clock->name, "arch_sys_counter");
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++vdso_data->tb_seq_count;
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smp_wmb();
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xtime_coarse = __current_kernel_time();
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vdso_data->use_syscall = use_syscall;
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vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec;
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vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec;
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if (!use_syscall) {
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vdso_data->cs_cycle_last = clock->cycle_last;
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vdso_data->xtime_clock_sec = ts->tv_sec;
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vdso_data->xtime_clock_nsec = ts->tv_nsec;
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vdso_data->cs_mult = mult;
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vdso_data->cs_shift = clock->shift;
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vdso_data->wtm_clock_sec = wtm->tv_sec;
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vdso_data->wtm_clock_nsec = wtm->tv_nsec;
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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->tb_seq_count;
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smp_wmb();
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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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smp_wmb();
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++vdso_data->tb_seq_count;
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}
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