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![Florian Fainelli](/assets/img/avatar_default.png)
Provide hooks to intercept bad usages of virt_to_phys() and __pa_symbol() throughout the kernel. To make this possible, we need to rename the current implement of virt_to_phys() into __virt_to_phys_nodebug() and wrap it around depending on CONFIG_DEBUG_VIRTUAL. A similar thing is needed for __pa_symbol() which is now aliased to __phys_addr_symbol() whose implementation is either the direct return of RELOC_HIDE or goes through the debug version. Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
193 lines
4.8 KiB
C
193 lines
4.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2015 Imagination Technologies
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* Author: Alex Smith <alex.smith@imgtec.com>
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*/
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#include <linux/binfmts.h>
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#include <linux/elf.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/random.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/timekeeper_internal.h>
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#include <asm/abi.h>
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#include <asm/mips-cps.h>
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#include <asm/page.h>
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#include <asm/vdso.h>
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#include <vdso/helpers.h>
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#include <vdso/vsyscall.h>
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/* Kernel-provided data used by the VDSO. */
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static union mips_vdso_data mips_vdso_data __page_aligned_data;
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struct vdso_data *vdso_data = mips_vdso_data.data;
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/*
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* Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as
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* what we map and where within the area they are mapped is determined at
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* runtime.
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*/
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static struct page *no_pages[] = { NULL };
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static struct vm_special_mapping vdso_vvar_mapping = {
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.name = "[vvar]",
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.pages = no_pages,
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};
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static void __init init_vdso_image(struct mips_vdso_image *image)
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{
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unsigned long num_pages, i;
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unsigned long data_pfn;
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BUG_ON(!PAGE_ALIGNED(image->data));
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BUG_ON(!PAGE_ALIGNED(image->size));
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num_pages = image->size / PAGE_SIZE;
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data_pfn = __phys_to_pfn(__pa_symbol(image->data));
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for (i = 0; i < num_pages; i++)
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image->mapping.pages[i] = pfn_to_page(data_pfn + i);
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}
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static int __init init_vdso(void)
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{
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init_vdso_image(&vdso_image);
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#ifdef CONFIG_MIPS32_O32
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init_vdso_image(&vdso_image_o32);
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#endif
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#ifdef CONFIG_MIPS32_N32
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init_vdso_image(&vdso_image_n32);
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#endif
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return 0;
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}
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subsys_initcall(init_vdso);
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static unsigned long vdso_base(void)
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{
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unsigned long base = STACK_TOP;
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if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
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/* Skip the delay slot emulation page */
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base += PAGE_SIZE;
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}
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if (current->flags & PF_RANDOMIZE) {
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base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1);
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base = PAGE_ALIGN(base);
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}
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return base;
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}
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int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
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{
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struct mips_vdso_image *image = current->thread.abi->vdso;
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struct mm_struct *mm = current->mm;
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unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn, gic_base;
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struct vm_area_struct *vma;
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int ret;
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if (mmap_write_lock_killable(mm))
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return -EINTR;
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if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) {
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/* Map delay slot emulation page */
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base = mmap_region(NULL, STACK_TOP, PAGE_SIZE,
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VM_READ | VM_EXEC |
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
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0, NULL);
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if (IS_ERR_VALUE(base)) {
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ret = base;
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goto out;
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}
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}
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/*
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* Determine total area size. This includes the VDSO data itself, the
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* data page, and the GIC user page if present. Always create a mapping
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* for the GIC user area if the GIC is present regardless of whether it
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* is the current clocksource, in case it comes into use later on. We
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* only map a page even though the total area is 64K, as we only need
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* the counter registers at the start.
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*/
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gic_size = mips_gic_present() ? PAGE_SIZE : 0;
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vvar_size = gic_size + PAGE_SIZE;
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size = vvar_size + image->size;
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/*
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* Find a region that's large enough for us to perform the
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* colour-matching alignment below.
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*/
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if (cpu_has_dc_aliases)
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size += shm_align_mask + 1;
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base = get_unmapped_area(NULL, vdso_base(), size, 0, 0);
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if (IS_ERR_VALUE(base)) {
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ret = base;
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goto out;
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}
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/*
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* If we suffer from dcache aliasing, ensure that the VDSO data page
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* mapping is coloured the same as the kernel's mapping of that memory.
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* This ensures that when the kernel updates the VDSO data userland
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* will observe it without requiring cache invalidations.
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*/
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if (cpu_has_dc_aliases) {
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base = __ALIGN_MASK(base, shm_align_mask);
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base += ((unsigned long)vdso_data - gic_size) & shm_align_mask;
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}
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data_addr = base + gic_size;
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vdso_addr = data_addr + PAGE_SIZE;
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vma = _install_special_mapping(mm, base, vvar_size,
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VM_READ | VM_MAYREAD,
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&vdso_vvar_mapping);
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if (IS_ERR(vma)) {
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ret = PTR_ERR(vma);
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goto out;
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}
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/* Map GIC user page. */
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if (gic_size) {
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gic_base = (unsigned long)mips_gic_base + MIPS_GIC_USER_OFS;
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gic_pfn = virt_to_phys((void *)gic_base) >> PAGE_SHIFT;
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ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size,
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pgprot_noncached(vma->vm_page_prot));
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if (ret)
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goto out;
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}
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/* Map data page. */
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ret = remap_pfn_range(vma, data_addr,
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virt_to_phys(vdso_data) >> PAGE_SHIFT,
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PAGE_SIZE, vma->vm_page_prot);
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if (ret)
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goto out;
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/* Map VDSO image. */
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vma = _install_special_mapping(mm, vdso_addr, image->size,
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VM_READ | VM_EXEC |
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VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
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&image->mapping);
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if (IS_ERR(vma)) {
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ret = PTR_ERR(vma);
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goto out;
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}
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mm->context.vdso = (void *)vdso_addr;
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ret = 0;
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out:
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mmap_write_unlock(mm);
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return ret;
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}
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