diff options
Diffstat (limited to 'arch/x86/entry/vdso/vma.c')
| -rw-r--r-- | arch/x86/entry/vdso/vma.c | 127 |
1 files changed, 79 insertions, 48 deletions
diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index b8f69e264ac4..10f704584922 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -20,6 +20,7 @@ #include <asm/page.h> #include <asm/hpet.h> #include <asm/desc.h> +#include <asm/cpufeature.h> #if defined(CONFIG_X86_64) unsigned int __read_mostly vdso64_enabled = 1; @@ -27,13 +28,7 @@ unsigned int __read_mostly vdso64_enabled = 1; void __init init_vdso_image(const struct vdso_image *image) { - int i; - int npages = (image->size) / PAGE_SIZE; - BUG_ON(image->size % PAGE_SIZE != 0); - for (i = 0; i < npages; i++) - image->text_mapping.pages[i] = - virt_to_page(image->data + i*PAGE_SIZE); apply_alternatives((struct alt_instr *)(image->data + image->alt), (struct alt_instr *)(image->data + image->alt + @@ -90,18 +85,87 @@ static unsigned long vdso_addr(unsigned long start, unsigned len) #endif } +static int vdso_fault(const struct vm_special_mapping *sm, + struct vm_area_struct *vma, struct vm_fault *vmf) +{ + const struct vdso_image *image = vma->vm_mm->context.vdso_image; + + if (!image || (vmf->pgoff << PAGE_SHIFT) >= image->size) + return VM_FAULT_SIGBUS; + + vmf->page = virt_to_page(image->data + (vmf->pgoff << PAGE_SHIFT)); + get_page(vmf->page); + return 0; +} + +static const struct vm_special_mapping text_mapping = { + .name = "[vdso]", + .fault = vdso_fault, +}; + +static int vvar_fault(const struct vm_special_mapping *sm, + struct vm_area_struct *vma, struct vm_fault *vmf) +{ + const struct vdso_image *image = vma->vm_mm->context.vdso_image; + long sym_offset; + int ret = -EFAULT; + + if (!image) + return VM_FAULT_SIGBUS; + + sym_offset = (long)(vmf->pgoff << PAGE_SHIFT) + + image->sym_vvar_start; + + /* + * Sanity check: a symbol offset of zero means that the page + * does not exist for this vdso image, not that the page is at + * offset zero relative to the text mapping. This should be + * impossible here, because sym_offset should only be zero for + * the page past the end of the vvar mapping. + */ + if (sym_offset == 0) + return VM_FAULT_SIGBUS; + + if (sym_offset == image->sym_vvar_page) { + ret = vm_insert_pfn(vma, (unsigned long)vmf->virtual_address, + __pa_symbol(&__vvar_page) >> PAGE_SHIFT); + } else if (sym_offset == image->sym_hpet_page) { +#ifdef CONFIG_HPET_TIMER + if (hpet_address && vclock_was_used(VCLOCK_HPET)) { + ret = vm_insert_pfn_prot( + vma, + (unsigned long)vmf->virtual_address, + hpet_address >> PAGE_SHIFT, + pgprot_noncached(PAGE_READONLY)); + } +#endif + } else if (sym_offset == image->sym_pvclock_page) { + struct pvclock_vsyscall_time_info *pvti = + pvclock_pvti_cpu0_va(); + if (pvti && vclock_was_used(VCLOCK_PVCLOCK)) { + ret = vm_insert_pfn( + vma, + (unsigned long)vmf->virtual_address, + __pa(pvti) >> PAGE_SHIFT); + } + } + + if (ret == 0 || ret == -EBUSY) + return VM_FAULT_NOPAGE; + + return VM_FAULT_SIGBUS; +} + static int map_vdso(const struct vdso_image *image, bool calculate_addr) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; unsigned long addr, text_start; int ret = 0; - static struct page *no_pages[] = {NULL}; - static struct vm_special_mapping vvar_mapping = { + static const struct vm_special_mapping vvar_mapping = { .name = "[vvar]", - .pages = no_pages, + .fault = vvar_fault, }; - struct pvclock_vsyscall_time_info *pvti; if (calculate_addr) { addr = vdso_addr(current->mm->start_stack, @@ -121,6 +185,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) text_start = addr - image->sym_vvar_start; current->mm->context.vdso = (void __user *)text_start; + current->mm->context.vdso_image = image; /* * MAYWRITE to allow gdb to COW and set breakpoints @@ -130,7 +195,7 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) image->size, VM_READ|VM_EXEC| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, - &image->text_mapping); + &text_mapping); if (IS_ERR(vma)) { ret = PTR_ERR(vma); @@ -140,7 +205,8 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) vma = _install_special_mapping(mm, addr, -image->sym_vvar_start, - VM_READ|VM_MAYREAD, + VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP| + VM_PFNMAP, &vvar_mapping); if (IS_ERR(vma)) { @@ -148,41 +214,6 @@ static int map_vdso(const struct vdso_image *image, bool calculate_addr) goto up_fail; } - if (image->sym_vvar_page) - ret = remap_pfn_range(vma, - text_start + image->sym_vvar_page, - __pa_symbol(&__vvar_page) >> PAGE_SHIFT, - PAGE_SIZE, - PAGE_READONLY); - - if (ret) - goto up_fail; - -#ifdef CONFIG_HPET_TIMER - if (hpet_address && image->sym_hpet_page) { - ret = io_remap_pfn_range(vma, - text_start + image->sym_hpet_page, - hpet_address >> PAGE_SHIFT, - PAGE_SIZE, - pgprot_noncached(PAGE_READONLY)); - - if (ret) - goto up_fail; - } -#endif - - pvti = pvclock_pvti_cpu0_va(); - if (pvti && image->sym_pvclock_page) { - ret = remap_pfn_range(vma, - text_start + image->sym_pvclock_page, - __pa(pvti) >> PAGE_SHIFT, - PAGE_SIZE, - PAGE_READONLY); - - if (ret) - goto up_fail; - } - up_fail: if (ret) current->mm->context.vdso = NULL; @@ -254,7 +285,7 @@ static void vgetcpu_cpu_init(void *arg) #ifdef CONFIG_NUMA node = cpu_to_node(cpu); #endif - if (cpu_has(&cpu_data(cpu), X86_FEATURE_RDTSCP)) + if (static_cpu_has(X86_FEATURE_RDTSCP)) write_rdtscp_aux((node << 12) | cpu); /* |