12874c5fdSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 2c52d0d30SDavid Daney /* 3ebb5e78cSAlex Smith * Copyright (C) 2015 Imagination Technologies 4ebb5e78cSAlex Smith * Author: Alex Smith <alex.smith@imgtec.com> 5c52d0d30SDavid Daney */ 6c52d0d30SDavid Daney 7c52d0d30SDavid Daney #include <linux/binfmts.h> 8c52d0d30SDavid Daney #include <linux/elf.h> 9ebb5e78cSAlex Smith #include <linux/err.h> 10ebb5e78cSAlex Smith #include <linux/init.h> 11a7f4df4eSAlex Smith #include <linux/ioport.h> 120f02cfbcSPaul Burton #include <linux/kernel.h> 13ebb5e78cSAlex Smith #include <linux/mm.h> 14ea7e0480SPaul Burton #include <linux/random.h> 15ebb5e78cSAlex Smith #include <linux/sched.h> 16ebb5e78cSAlex Smith #include <linux/slab.h> 17a7f4df4eSAlex Smith #include <linux/timekeeper_internal.h> 18c52d0d30SDavid Daney 19ebb5e78cSAlex Smith #include <asm/abi.h> 2000578cd8SPaul Burton #include <asm/mips-cps.h> 210f02cfbcSPaul Burton #include <asm/page.h> 22c52d0d30SDavid Daney #include <asm/vdso.h> 2324640f23SVincenzo Frascino #include <vdso/helpers.h> 2424640f23SVincenzo Frascino #include <vdso/vsyscall.h> 25ebb5e78cSAlex Smith 26ebb5e78cSAlex Smith /* Kernel-provided data used by the VDSO. */ 2724640f23SVincenzo Frascino static union mips_vdso_data mips_vdso_data __page_aligned_data; 2824640f23SVincenzo Frascino struct vdso_data *vdso_data = mips_vdso_data.data; 29c52d0d30SDavid Daney 30c52d0d30SDavid Daney /* 31a7f4df4eSAlex Smith * Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as 32ebb5e78cSAlex Smith * what we map and where within the area they are mapped is determined at 33ebb5e78cSAlex Smith * runtime. 34c52d0d30SDavid Daney */ 35ebb5e78cSAlex Smith static struct page *no_pages[] = { NULL }; 36ebb5e78cSAlex Smith static struct vm_special_mapping vdso_vvar_mapping = { 37ebb5e78cSAlex Smith .name = "[vvar]", 38ebb5e78cSAlex Smith .pages = no_pages, 39ebb5e78cSAlex Smith }; 40c52d0d30SDavid Daney 41ebb5e78cSAlex Smith static void __init init_vdso_image(struct mips_vdso_image *image) 42c52d0d30SDavid Daney { 43ebb5e78cSAlex Smith unsigned long num_pages, i; 44554af0c3SJames Hogan unsigned long data_pfn; 45ebb5e78cSAlex Smith 46ebb5e78cSAlex Smith BUG_ON(!PAGE_ALIGNED(image->data)); 47ebb5e78cSAlex Smith BUG_ON(!PAGE_ALIGNED(image->size)); 48ebb5e78cSAlex Smith 49ebb5e78cSAlex Smith num_pages = image->size / PAGE_SIZE; 50ebb5e78cSAlex Smith 51554af0c3SJames Hogan data_pfn = __phys_to_pfn(__pa_symbol(image->data)); 52554af0c3SJames Hogan for (i = 0; i < num_pages; i++) 53554af0c3SJames Hogan image->mapping.pages[i] = pfn_to_page(data_pfn + i); 54c52d0d30SDavid Daney } 55c52d0d30SDavid Daney 56c52d0d30SDavid Daney static int __init init_vdso(void) 57c52d0d30SDavid Daney { 58ebb5e78cSAlex Smith init_vdso_image(&vdso_image); 59c52d0d30SDavid Daney 60ebb5e78cSAlex Smith #ifdef CONFIG_MIPS32_O32 61ebb5e78cSAlex Smith init_vdso_image(&vdso_image_o32); 62c52d0d30SDavid Daney #endif 63c52d0d30SDavid Daney 64ebb5e78cSAlex Smith #ifdef CONFIG_MIPS32_N32 65ebb5e78cSAlex Smith init_vdso_image(&vdso_image_n32); 66ebb5e78cSAlex Smith #endif 67c52d0d30SDavid Daney 68c52d0d30SDavid Daney return 0; 69c52d0d30SDavid Daney } 701ed84537SDavid Daney subsys_initcall(init_vdso); 71c52d0d30SDavid Daney 72ea7e0480SPaul Burton static unsigned long vdso_base(void) 73ea7e0480SPaul Burton { 74aebdc6ffSYousong Zhou unsigned long base = STACK_TOP; 75ea7e0480SPaul Burton 76aebdc6ffSYousong Zhou if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) { 77ea7e0480SPaul Burton /* Skip the delay slot emulation page */ 78aebdc6ffSYousong Zhou base += PAGE_SIZE; 79aebdc6ffSYousong Zhou } 80ea7e0480SPaul Burton 81ea7e0480SPaul Burton if (current->flags & PF_RANDOMIZE) { 82ea7e0480SPaul Burton base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1); 83ea7e0480SPaul Burton base = PAGE_ALIGN(base); 84ea7e0480SPaul Burton } 85ea7e0480SPaul Burton 86ea7e0480SPaul Burton return base; 87ea7e0480SPaul Burton } 88ea7e0480SPaul Burton 89c52d0d30SDavid Daney int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 90c52d0d30SDavid Daney { 91ebb5e78cSAlex Smith struct mips_vdso_image *image = current->thread.abi->vdso; 92c52d0d30SDavid Daney struct mm_struct *mm = current->mm; 9300578cd8SPaul Burton unsigned long gic_size, vvar_size, size, base, data_addr, vdso_addr, gic_pfn; 94ebb5e78cSAlex Smith struct vm_area_struct *vma; 95ebb5e78cSAlex Smith int ret; 96c52d0d30SDavid Daney 9769048176SMichal Hocko if (down_write_killable(&mm->mmap_sem)) 9869048176SMichal Hocko return -EINTR; 99c52d0d30SDavid Daney 100aebdc6ffSYousong Zhou if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT)) { 101432c6bacSPaul Burton /* Map delay slot emulation page */ 102432c6bacSPaul Burton base = mmap_region(NULL, STACK_TOP, PAGE_SIZE, 103adcc81f1SPaul Burton VM_READ | VM_EXEC | 104432c6bacSPaul Burton VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 105897ab3e0SMike Rapoport 0, NULL); 106432c6bacSPaul Burton if (IS_ERR_VALUE(base)) { 107432c6bacSPaul Burton ret = base; 108432c6bacSPaul Burton goto out; 109432c6bacSPaul Burton } 110aebdc6ffSYousong Zhou } 111432c6bacSPaul Burton 112a7f4df4eSAlex Smith /* 113a7f4df4eSAlex Smith * Determine total area size. This includes the VDSO data itself, the 114a7f4df4eSAlex Smith * data page, and the GIC user page if present. Always create a mapping 115a7f4df4eSAlex Smith * for the GIC user area if the GIC is present regardless of whether it 116a7f4df4eSAlex Smith * is the current clocksource, in case it comes into use later on. We 117a7f4df4eSAlex Smith * only map a page even though the total area is 64K, as we only need 118a7f4df4eSAlex Smith * the counter registers at the start. 119a7f4df4eSAlex Smith */ 12000578cd8SPaul Burton gic_size = mips_gic_present() ? PAGE_SIZE : 0; 121a7f4df4eSAlex Smith vvar_size = gic_size + PAGE_SIZE; 122a7f4df4eSAlex Smith size = vvar_size + image->size; 123a7f4df4eSAlex Smith 1240f02cfbcSPaul Burton /* 1250f02cfbcSPaul Burton * Find a region that's large enough for us to perform the 1260f02cfbcSPaul Burton * colour-matching alignment below. 1270f02cfbcSPaul Burton */ 1280f02cfbcSPaul Burton if (cpu_has_dc_aliases) 1290f02cfbcSPaul Burton size += shm_align_mask + 1; 1300f02cfbcSPaul Burton 131ea7e0480SPaul Burton base = get_unmapped_area(NULL, vdso_base(), size, 0, 0); 132ebb5e78cSAlex Smith if (IS_ERR_VALUE(base)) { 133ebb5e78cSAlex Smith ret = base; 134ebb5e78cSAlex Smith goto out; 135c52d0d30SDavid Daney } 136c52d0d30SDavid Daney 1370f02cfbcSPaul Burton /* 1380f02cfbcSPaul Burton * If we suffer from dcache aliasing, ensure that the VDSO data page 1390f02cfbcSPaul Burton * mapping is coloured the same as the kernel's mapping of that memory. 1400f02cfbcSPaul Burton * This ensures that when the kernel updates the VDSO data userland 1410f02cfbcSPaul Burton * will observe it without requiring cache invalidations. 1420f02cfbcSPaul Burton */ 1430f02cfbcSPaul Burton if (cpu_has_dc_aliases) { 1440f02cfbcSPaul Burton base = __ALIGN_MASK(base, shm_align_mask); 14524640f23SVincenzo Frascino base += ((unsigned long)vdso_data - gic_size) & shm_align_mask; 1460f02cfbcSPaul Burton } 1470f02cfbcSPaul Burton 148a7f4df4eSAlex Smith data_addr = base + gic_size; 149a7f4df4eSAlex Smith vdso_addr = data_addr + PAGE_SIZE; 150ebb5e78cSAlex Smith 151a7f4df4eSAlex Smith vma = _install_special_mapping(mm, base, vvar_size, 152ebb5e78cSAlex Smith VM_READ | VM_MAYREAD, 153ebb5e78cSAlex Smith &vdso_vvar_mapping); 154ebb5e78cSAlex Smith if (IS_ERR(vma)) { 155ebb5e78cSAlex Smith ret = PTR_ERR(vma); 156ebb5e78cSAlex Smith goto out; 157ebb5e78cSAlex Smith } 158ebb5e78cSAlex Smith 159a7f4df4eSAlex Smith /* Map GIC user page. */ 160a7f4df4eSAlex Smith if (gic_size) { 16100578cd8SPaul Burton gic_pfn = virt_to_phys(mips_gic_base + MIPS_GIC_USER_OFS) >> PAGE_SHIFT; 162a7f4df4eSAlex Smith 16300578cd8SPaul Burton ret = io_remap_pfn_range(vma, base, gic_pfn, gic_size, 164a7f4df4eSAlex Smith pgprot_noncached(PAGE_READONLY)); 165a7f4df4eSAlex Smith if (ret) 166a7f4df4eSAlex Smith goto out; 167a7f4df4eSAlex Smith } 168a7f4df4eSAlex Smith 169ebb5e78cSAlex Smith /* Map data page. */ 170a7f4df4eSAlex Smith ret = remap_pfn_range(vma, data_addr, 17124640f23SVincenzo Frascino virt_to_phys(vdso_data) >> PAGE_SHIFT, 172ebb5e78cSAlex Smith PAGE_SIZE, PAGE_READONLY); 173ebb5e78cSAlex Smith if (ret) 174ebb5e78cSAlex Smith goto out; 175ebb5e78cSAlex Smith 176ebb5e78cSAlex Smith /* Map VDSO image. */ 177ebb5e78cSAlex Smith vma = _install_special_mapping(mm, vdso_addr, image->size, 178c52d0d30SDavid Daney VM_READ | VM_EXEC | 179909af768SJason Baron VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 180ebb5e78cSAlex Smith &image->mapping); 181ebb5e78cSAlex Smith if (IS_ERR(vma)) { 182ebb5e78cSAlex Smith ret = PTR_ERR(vma); 183ebb5e78cSAlex Smith goto out; 184c52d0d30SDavid Daney } 185c52d0d30SDavid Daney 186ebb5e78cSAlex Smith mm->context.vdso = (void *)vdso_addr; 187ebb5e78cSAlex Smith ret = 0; 188ebb5e78cSAlex Smith 189ebb5e78cSAlex Smith out: 190ebb5e78cSAlex Smith up_write(&mm->mmap_sem); 191ebb5e78cSAlex Smith return ret; 192c52d0d30SDavid Daney } 193