diff options
Diffstat (limited to 'arch/csky/kernel/vdso.c')
-rw-r--r-- | arch/csky/kernel/vdso.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/arch/csky/kernel/vdso.c b/arch/csky/kernel/vdso.c new file mode 100644 index 0000000000..16c20d64d1 --- /dev/null +++ b/arch/csky/kernel/vdso.c @@ -0,0 +1,107 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. + +#include <linux/binfmts.h> +#include <linux/elf.h> +#include <linux/err.h> +#include <linux/mm.h> +#include <linux/slab.h> + +#include <asm/page.h> +#ifdef GENERIC_TIME_VSYSCALL +#include <vdso/datapage.h> +#else +#include <asm/vdso.h> +#endif + +extern char vdso_start[], vdso_end[]; + +static unsigned int vdso_pages; +static struct page **vdso_pagelist; + +/* + * The vDSO data page. + */ +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 int __init vdso_init(void) +{ + unsigned int i; + + vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT; + vdso_pagelist = + kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL); + if (unlikely(vdso_pagelist == NULL)) { + pr_err("vdso: pagelist allocation failed\n"); + return -ENOMEM; + } + + for (i = 0; i < vdso_pages; i++) { + struct page *pg; + + pg = virt_to_page(vdso_start + (i << PAGE_SHIFT)); + vdso_pagelist[i] = pg; + } + vdso_pagelist[i] = virt_to_page(vdso_data); + + return 0; +} +arch_initcall(vdso_init); + +int arch_setup_additional_pages(struct linux_binprm *bprm, + int uses_interp) +{ + struct mm_struct *mm = current->mm; + unsigned long vdso_base, vdso_len; + int ret; + + vdso_len = (vdso_pages + 1) << PAGE_SHIFT; + + mmap_write_lock(mm); + vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0); + if (IS_ERR_VALUE(vdso_base)) { + ret = vdso_base; + goto end; + } + + /* + * Put vDSO base into mm struct. We need to do this before calling + * install_special_mapping or the perf counter mmap tracking code + * will fail to recognise it as a vDSO (since arch_vma_name fails). + */ + mm->context.vdso = (void *)vdso_base; + + ret = + install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT, + (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC), + vdso_pagelist); + + if (unlikely(ret)) { + mm->context.vdso = NULL; + goto end; + } + + vdso_base += (vdso_pages << PAGE_SHIFT); + ret = install_special_mapping(mm, vdso_base, PAGE_SIZE, + (VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]); + + if (unlikely(ret)) + mm->context.vdso = NULL; +end: + mmap_write_unlock(mm); + return ret; +} + +const char *arch_vma_name(struct vm_area_struct *vma) +{ + if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso)) + return "[vdso]"; + if (vma->vm_mm && (vma->vm_start == + (long)vma->vm_mm->context.vdso + PAGE_SIZE)) + return "[vdso_data]"; + return NULL; +} |