diff options
Diffstat (limited to 'arch/nds32/kernel/vdso.c')
| -rw-r--r-- | arch/nds32/kernel/vdso.c | 230 |
1 files changed, 230 insertions, 0 deletions
diff --git a/arch/nds32/kernel/vdso.c b/arch/nds32/kernel/vdso.c new file mode 100644 index 000000000000..f1198d7a5654 --- /dev/null +++ b/arch/nds32/kernel/vdso.c @@ -0,0 +1,230 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2012 ARM Limited +// Copyright (C) 2005-2017 Andes Technology Corporation + +#include <linux/cache.h> +#include <linux/clocksource.h> +#include <linux/elf.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/gfp.h> +#include <linux/kernel.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/signal.h> +#include <linux/slab.h> +#include <linux/timekeeper_internal.h> +#include <linux/vmalloc.h> +#include <linux/random.h> + +#include <asm/cacheflush.h> +#include <asm/vdso.h> +#include <asm/vdso_datapage.h> +#include <asm/vdso_timer_info.h> +#include <asm/cache_info.h> +extern struct cache_info L1_cache_info[2]; +extern char vdso_start, vdso_end; +static unsigned long vdso_pages __ro_after_init; +static unsigned long timer_mapping_base; + +struct timer_info_t timer_info = { + .cycle_count_down = true, + .mapping_base = EMPTY_TIMER_MAPPING, + .cycle_count_reg_offset = EMPTY_REG_OFFSET +}; +/* + * The vDSO data page. + */ +static struct page *no_pages[] = { NULL }; + +static union { + struct vdso_data data; + u8 page[PAGE_SIZE]; +} vdso_data_store __page_aligned_data; +struct vdso_data *vdso_data = &vdso_data_store.data; +static struct vm_special_mapping vdso_spec[2] __ro_after_init = { + { + .name = "[vvar]", + .pages = no_pages, + }, + { + .name = "[vdso]", + }, +}; + +static void get_timer_node_info(void) +{ + timer_mapping_base = timer_info.mapping_base; + vdso_data->cycle_count_offset = + timer_info.cycle_count_reg_offset; + vdso_data->cycle_count_down = + timer_info.cycle_count_down; +} + +static int __init vdso_init(void) +{ + int i; + struct page **vdso_pagelist; + + if (memcmp(&vdso_start, "\177ELF", 4)) { + pr_err("vDSO is not a valid ELF object!\n"); + return -EINVAL; + } + /* Creat a timer io mapping to get clock cycles counter */ + get_timer_node_info(); + + vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT; + pr_info("vdso: %ld pages (%ld code @ %p, %ld data @ %p)\n", + vdso_pages + 1, vdso_pages, &vdso_start, 1L, vdso_data); + + /* Allocate the vDSO pagelist */ + vdso_pagelist = kcalloc(vdso_pages, sizeof(struct page *), GFP_KERNEL); + if (vdso_pagelist == NULL) + return -ENOMEM; + + for (i = 0; i < vdso_pages; i++) + vdso_pagelist[i] = virt_to_page(&vdso_start + i * PAGE_SIZE); + vdso_spec[1].pages = &vdso_pagelist[0]; + + return 0; +} + +arch_initcall(vdso_init); + +unsigned long inline vdso_random_addr(unsigned long vdso_mapping_len) +{ + unsigned long start = current->mm->mmap_base, end, offset, addr; + start = PAGE_ALIGN(start); + + /* Round the lowest possible end address up to a PMD boundary. */ + end = (start + vdso_mapping_len + PMD_SIZE - 1) & PMD_MASK; + if (end >= TASK_SIZE) + end = TASK_SIZE; + end -= vdso_mapping_len; + + if (end > start) { + offset = get_random_int() % (((end - start) >> PAGE_SHIFT) + 1); + addr = start + (offset << PAGE_SHIFT); + } else { + addr = start; + } + return addr; +} + +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + struct mm_struct *mm = current->mm; + unsigned long vdso_base, vdso_text_len, vdso_mapping_len; + struct vm_area_struct *vma; + unsigned long addr = 0; + pgprot_t prot; + int ret, vvar_page_num = 2; + + vdso_text_len = vdso_pages << PAGE_SHIFT; + + if(timer_mapping_base == EMPTY_VALUE) + vvar_page_num = 1; + /* Be sure to map the data page */ + vdso_mapping_len = vdso_text_len + vvar_page_num * PAGE_SIZE; +#ifdef CONFIG_CPU_CACHE_ALIASING + vdso_mapping_len += L1_cache_info[DCACHE].aliasing_num - 1; +#endif + + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + + addr = vdso_random_addr(vdso_mapping_len); + vdso_base = get_unmapped_area(NULL, addr, vdso_mapping_len, 0, 0); + if (IS_ERR_VALUE(vdso_base)) { + ret = vdso_base; + goto up_fail; + } + +#ifdef CONFIG_CPU_CACHE_ALIASING + { + unsigned int aliasing_mask = + L1_cache_info[DCACHE].aliasing_mask; + unsigned int page_colour_ofs; + page_colour_ofs = ((unsigned int)vdso_data & aliasing_mask) - + (vdso_base & aliasing_mask); + vdso_base += page_colour_ofs & aliasing_mask; + } +#endif + + vma = _install_special_mapping(mm, vdso_base, vvar_page_num * PAGE_SIZE, + VM_READ | VM_MAYREAD, &vdso_spec[0]); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + goto up_fail; + } + + /*Map vdata to user space */ + ret = io_remap_pfn_range(vma, vdso_base, + virt_to_phys(vdso_data) >> PAGE_SHIFT, + PAGE_SIZE, vma->vm_page_prot); + if (ret) + goto up_fail; + + /*Map timer to user space */ + vdso_base += PAGE_SIZE; + prot = __pgprot(_PAGE_V | _PAGE_M_UR_KR | _PAGE_D | _PAGE_C_DEV); + ret = io_remap_pfn_range(vma, vdso_base, timer_mapping_base >> PAGE_SHIFT, + PAGE_SIZE, prot); + if (ret) + goto up_fail; + + /*Map vdso to user space */ + vdso_base += PAGE_SIZE; + mm->context.vdso = (void *)vdso_base; + vma = _install_special_mapping(mm, vdso_base, vdso_text_len, + VM_READ | VM_EXEC | + VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, + &vdso_spec[1]); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + goto up_fail; + } + + up_write(&mm->mmap_sem); + return 0; + +up_fail: + mm->context.vdso = NULL; + up_write(&mm->mmap_sem); + return ret; +} + +static void vdso_write_begin(struct vdso_data *vdata) +{ + ++vdso_data->seq_count; + smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */ +} + +static void vdso_write_end(struct vdso_data *vdata) +{ + smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */ + ++vdso_data->seq_count; +} + +void update_vsyscall(struct timekeeper *tk) +{ + vdso_write_begin(vdso_data); + vdso_data->cs_mask = tk->tkr_mono.mask; + vdso_data->cs_mult = tk->tkr_mono.mult; + vdso_data->cs_shift = tk->tkr_mono.shift; + vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last; + vdso_data->wtm_clock_sec = tk->wall_to_monotonic.tv_sec; + vdso_data->wtm_clock_nsec = tk->wall_to_monotonic.tv_nsec; + vdso_data->xtime_clock_sec = tk->xtime_sec; + vdso_data->xtime_clock_nsec = tk->tkr_mono.xtime_nsec; + vdso_data->xtime_coarse_sec = tk->xtime_sec; + vdso_data->xtime_coarse_nsec = tk->tkr_mono.xtime_nsec >> + tk->tkr_mono.shift; + vdso_write_end(vdso_data); +} + +void update_vsyscall_tz(void) +{ + vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; + vdso_data->tz_dsttime = sys_tz.tz_dsttime; +} |