1 // SPDX-License-Identifier: GPL-2.0-or-later
3 * Copyright (C) 2015 Imagination Technologies
4 * Author: Alex Smith <alex.smith@imgtec.com>
7 #include <linux/binfmts.h>
10 #include <linux/init.h>
11 #include <linux/ioport.h>
12 #include <linux/kernel.h>
14 #include <linux/random.h>
15 #include <linux/sched.h>
16 #include <linux/slab.h>
17 #include <linux/timekeeper_internal.h>
20 #include <asm/mips-cps.h>
24 /* Kernel-provided data used by the VDSO. */
25 static union mips_vdso_data vdso_data __page_aligned_data
;
28 * Mapping for the VDSO data/GIC pages. The real pages are mapped manually, as
29 * what we map and where within the area they are mapped is determined at
32 static struct page
*no_pages
[] = { NULL
};
33 static struct vm_special_mapping vdso_vvar_mapping
= {
38 static void __init
init_vdso_image(struct mips_vdso_image
*image
)
40 unsigned long num_pages
, i
;
41 unsigned long data_pfn
;
43 BUG_ON(!PAGE_ALIGNED(image
->data
));
44 BUG_ON(!PAGE_ALIGNED(image
->size
));
46 num_pages
= image
->size
/ PAGE_SIZE
;
48 data_pfn
= __phys_to_pfn(__pa_symbol(image
->data
));
49 for (i
= 0; i
< num_pages
; i
++)
50 image
->mapping
.pages
[i
] = pfn_to_page(data_pfn
+ i
);
53 static int __init
init_vdso(void)
55 init_vdso_image(&vdso_image
);
57 #ifdef CONFIG_MIPS32_O32
58 init_vdso_image(&vdso_image_o32
);
61 #ifdef CONFIG_MIPS32_N32
62 init_vdso_image(&vdso_image_n32
);
67 subsys_initcall(init_vdso
);
69 void update_vsyscall(struct timekeeper
*tk
)
71 vdso_data_write_begin(&vdso_data
);
73 vdso_data
.xtime_sec
= tk
->xtime_sec
;
74 vdso_data
.xtime_nsec
= tk
->tkr_mono
.xtime_nsec
;
75 vdso_data
.wall_to_mono_sec
= tk
->wall_to_monotonic
.tv_sec
;
76 vdso_data
.wall_to_mono_nsec
= tk
->wall_to_monotonic
.tv_nsec
;
77 vdso_data
.cs_shift
= tk
->tkr_mono
.shift
;
79 vdso_data
.clock_mode
= tk
->tkr_mono
.clock
->archdata
.vdso_clock_mode
;
80 if (vdso_data
.clock_mode
!= VDSO_CLOCK_NONE
) {
81 vdso_data
.cs_mult
= tk
->tkr_mono
.mult
;
82 vdso_data
.cs_cycle_last
= tk
->tkr_mono
.cycle_last
;
83 vdso_data
.cs_mask
= tk
->tkr_mono
.mask
;
86 vdso_data_write_end(&vdso_data
);
89 void update_vsyscall_tz(void)
91 if (vdso_data
.clock_mode
!= VDSO_CLOCK_NONE
) {
92 vdso_data
.tz_minuteswest
= sys_tz
.tz_minuteswest
;
93 vdso_data
.tz_dsttime
= sys_tz
.tz_dsttime
;
97 static unsigned long vdso_base(void)
101 /* Skip the delay slot emulation page */
102 base
= STACK_TOP
+ PAGE_SIZE
;
104 if (current
->flags
& PF_RANDOMIZE
) {
105 base
+= get_random_int() & (VDSO_RANDOMIZE_SIZE
- 1);
106 base
= PAGE_ALIGN(base
);
112 int arch_setup_additional_pages(struct linux_binprm
*bprm
, int uses_interp
)
114 struct mips_vdso_image
*image
= current
->thread
.abi
->vdso
;
115 struct mm_struct
*mm
= current
->mm
;
116 unsigned long gic_size
, vvar_size
, size
, base
, data_addr
, vdso_addr
, gic_pfn
;
117 struct vm_area_struct
*vma
;
120 if (down_write_killable(&mm
->mmap_sem
))
123 /* Map delay slot emulation page */
124 base
= mmap_region(NULL
, STACK_TOP
, PAGE_SIZE
,
126 VM_MAYREAD
| VM_MAYWRITE
| VM_MAYEXEC
,
128 if (IS_ERR_VALUE(base
)) {
134 * Determine total area size. This includes the VDSO data itself, the
135 * data page, and the GIC user page if present. Always create a mapping
136 * for the GIC user area if the GIC is present regardless of whether it
137 * is the current clocksource, in case it comes into use later on. We
138 * only map a page even though the total area is 64K, as we only need
139 * the counter registers at the start.
141 gic_size
= mips_gic_present() ? PAGE_SIZE
: 0;
142 vvar_size
= gic_size
+ PAGE_SIZE
;
143 size
= vvar_size
+ image
->size
;
146 * Find a region that's large enough for us to perform the
147 * colour-matching alignment below.
149 if (cpu_has_dc_aliases
)
150 size
+= shm_align_mask
+ 1;
152 base
= get_unmapped_area(NULL
, vdso_base(), size
, 0, 0);
153 if (IS_ERR_VALUE(base
)) {
159 * If we suffer from dcache aliasing, ensure that the VDSO data page
160 * mapping is coloured the same as the kernel's mapping of that memory.
161 * This ensures that when the kernel updates the VDSO data userland
162 * will observe it without requiring cache invalidations.
164 if (cpu_has_dc_aliases
) {
165 base
= __ALIGN_MASK(base
, shm_align_mask
);
166 base
+= ((unsigned long)&vdso_data
- gic_size
) & shm_align_mask
;
169 data_addr
= base
+ gic_size
;
170 vdso_addr
= data_addr
+ PAGE_SIZE
;
172 vma
= _install_special_mapping(mm
, base
, vvar_size
,
173 VM_READ
| VM_MAYREAD
,
180 /* Map GIC user page. */
182 gic_pfn
= virt_to_phys(mips_gic_base
+ MIPS_GIC_USER_OFS
) >> PAGE_SHIFT
;
184 ret
= io_remap_pfn_range(vma
, base
, gic_pfn
, gic_size
,
185 pgprot_noncached(PAGE_READONLY
));
191 ret
= remap_pfn_range(vma
, data_addr
,
192 virt_to_phys(&vdso_data
) >> PAGE_SHIFT
,
193 PAGE_SIZE
, PAGE_READONLY
);
197 /* Map VDSO image. */
198 vma
= _install_special_mapping(mm
, vdso_addr
, image
->size
,
200 VM_MAYREAD
| VM_MAYWRITE
| VM_MAYEXEC
,
207 mm
->context
.vdso
= (void *)vdso_addr
;
211 up_write(&mm
->mmap_sem
);