| /* |
| * vdso setup for s390 |
| * |
| * Copyright IBM Corp. 2008 |
| * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License (version 2 only) |
| * as published by the Free Software Foundation. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/errno.h> |
| #include <linux/sched.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/smp.h> |
| #include <linux/stddef.h> |
| #include <linux/unistd.h> |
| #include <linux/slab.h> |
| #include <linux/user.h> |
| #include <linux/elf.h> |
| #include <linux/security.h> |
| #include <linux/bootmem.h> |
| |
| #include <asm/pgtable.h> |
| #include <asm/system.h> |
| #include <asm/processor.h> |
| #include <asm/mmu.h> |
| #include <asm/mmu_context.h> |
| #include <asm/sections.h> |
| #include <asm/vdso.h> |
| |
| #if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT) |
| extern char vdso32_start, vdso32_end; |
| static void *vdso32_kbase = &vdso32_start; |
| static unsigned int vdso32_pages; |
| static struct page **vdso32_pagelist; |
| #endif |
| |
| #ifdef CONFIG_64BIT |
| extern char vdso64_start, vdso64_end; |
| static void *vdso64_kbase = &vdso64_start; |
| static unsigned int vdso64_pages; |
| static struct page **vdso64_pagelist; |
| #endif /* CONFIG_64BIT */ |
| |
| /* |
| * Should the kernel map a VDSO page into processes and pass its |
| * address down to glibc upon exec()? |
| */ |
| unsigned int __read_mostly vdso_enabled = 1; |
| |
| static int __init vdso_setup(char *s) |
| { |
| vdso_enabled = simple_strtoul(s, NULL, 0); |
| return 1; |
| } |
| __setup("vdso=", vdso_setup); |
| |
| /* |
| * The vdso data page |
| */ |
| static union { |
| struct vdso_data data; |
| u8 page[PAGE_SIZE]; |
| } vdso_data_store __attribute__((__section__(".data.page_aligned"))); |
| struct vdso_data *vdso_data = &vdso_data_store.data; |
| |
| /* |
| * Setup vdso data page. |
| */ |
| static void vdso_init_data(struct vdso_data *vd) |
| { |
| unsigned int facility_list; |
| |
| facility_list = stfl(); |
| vd->ectg_available = switch_amode && (facility_list & 1); |
| } |
| |
| #ifdef CONFIG_64BIT |
| /* |
| * Setup per cpu vdso data page. |
| */ |
| static void vdso_init_per_cpu_data(int cpu, struct vdso_per_cpu_data *vpcd) |
| { |
| } |
| |
| /* |
| * Allocate/free per cpu vdso data. |
| */ |
| #ifdef CONFIG_64BIT |
| #define SEGMENT_ORDER 2 |
| #else |
| #define SEGMENT_ORDER 1 |
| #endif |
| |
| int vdso_alloc_per_cpu(int cpu, struct _lowcore *lowcore) |
| { |
| unsigned long segment_table, page_table, page_frame; |
| u32 *psal, *aste; |
| int i; |
| |
| lowcore->vdso_per_cpu_data = __LC_PASTE; |
| |
| if (!switch_amode || !vdso_enabled) |
| return 0; |
| |
| segment_table = __get_free_pages(GFP_KERNEL, SEGMENT_ORDER); |
| page_table = get_zeroed_page(GFP_KERNEL | GFP_DMA); |
| page_frame = get_zeroed_page(GFP_KERNEL); |
| if (!segment_table || !page_table || !page_frame) |
| goto out; |
| |
| clear_table((unsigned long *) segment_table, _SEGMENT_ENTRY_EMPTY, |
| PAGE_SIZE << SEGMENT_ORDER); |
| clear_table((unsigned long *) page_table, _PAGE_TYPE_EMPTY, |
| 256*sizeof(unsigned long)); |
| |
| *(unsigned long *) segment_table = _SEGMENT_ENTRY + page_table; |
| *(unsigned long *) page_table = _PAGE_RO + page_frame; |
| |
| psal = (u32 *) (page_table + 256*sizeof(unsigned long)); |
| aste = psal + 32; |
| |
| for (i = 4; i < 32; i += 4) |
| psal[i] = 0x80000000; |
| |
| lowcore->paste[4] = (u32)(addr_t) psal; |
| psal[0] = 0x20000000; |
| psal[2] = (u32)(addr_t) aste; |
| *(unsigned long *) (aste + 2) = segment_table + |
| _ASCE_TABLE_LENGTH + _ASCE_USER_BITS + _ASCE_TYPE_SEGMENT; |
| aste[4] = (u32)(addr_t) psal; |
| lowcore->vdso_per_cpu_data = page_frame; |
| |
| vdso_init_per_cpu_data(cpu, (struct vdso_per_cpu_data *) page_frame); |
| return 0; |
| |
| out: |
| free_page(page_frame); |
| free_page(page_table); |
| free_pages(segment_table, SEGMENT_ORDER); |
| return -ENOMEM; |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| void vdso_free_per_cpu(int cpu, struct _lowcore *lowcore) |
| { |
| unsigned long segment_table, page_table, page_frame; |
| u32 *psal, *aste; |
| |
| if (!switch_amode || !vdso_enabled) |
| return; |
| |
| psal = (u32 *)(addr_t) lowcore->paste[4]; |
| aste = (u32 *)(addr_t) psal[2]; |
| segment_table = *(unsigned long *)(aste + 2) & PAGE_MASK; |
| page_table = *(unsigned long *) segment_table; |
| page_frame = *(unsigned long *) page_table; |
| |
| free_page(page_frame); |
| free_page(page_table); |
| free_pages(segment_table, SEGMENT_ORDER); |
| } |
| #endif /* CONFIG_HOTPLUG_CPU */ |
| |
| static void __vdso_init_cr5(void *dummy) |
| { |
| unsigned long cr5; |
| |
| cr5 = offsetof(struct _lowcore, paste); |
| __ctl_load(cr5, 5, 5); |
| } |
| |
| static void vdso_init_cr5(void) |
| { |
| if (switch_amode && vdso_enabled) |
| on_each_cpu(__vdso_init_cr5, NULL, 1); |
| } |
| #endif /* CONFIG_64BIT */ |
| |
| /* |
| * This is called from binfmt_elf, we create the special vma for the |
| * vDSO and insert it into the mm struct tree |
| */ |
| int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) |
| { |
| struct mm_struct *mm = current->mm; |
| struct page **vdso_pagelist; |
| unsigned long vdso_pages; |
| unsigned long vdso_base; |
| int rc; |
| |
| if (!vdso_enabled) |
| return 0; |
| /* |
| * Only map the vdso for dynamically linked elf binaries. |
| */ |
| if (!uses_interp) |
| return 0; |
| |
| vdso_base = mm->mmap_base; |
| #ifdef CONFIG_64BIT |
| vdso_pagelist = vdso64_pagelist; |
| vdso_pages = vdso64_pages; |
| #ifdef CONFIG_COMPAT |
| if (test_thread_flag(TIF_31BIT)) { |
| vdso_pagelist = vdso32_pagelist; |
| vdso_pages = vdso32_pages; |
| } |
| #endif |
| #else |
| vdso_pagelist = vdso32_pagelist; |
| vdso_pages = vdso32_pages; |
| #endif |
| |
| /* |
| * vDSO has a problem and was disabled, just don't "enable" it for |
| * the process |
| */ |
| if (vdso_pages == 0) |
| return 0; |
| |
| current->mm->context.vdso_base = 0; |
| |
| /* |
| * pick a base address for the vDSO in process space. We try to put |
| * it at vdso_base which is the "natural" base for it, but we might |
| * fail and end up putting it elsewhere. |
| */ |
| down_write(&mm->mmap_sem); |
| vdso_base = get_unmapped_area(NULL, vdso_base, |
| vdso_pages << PAGE_SHIFT, 0, 0); |
| if (IS_ERR_VALUE(vdso_base)) { |
| rc = vdso_base; |
| goto out_up; |
| } |
| |
| /* |
| * our vma flags don't have VM_WRITE so by default, the process |
| * isn't allowed to write those pages. |
| * gdb can break that with ptrace interface, and thus trigger COW |
| * on those pages but it's then your responsibility to never do that |
| * on the "data" page of the vDSO or you'll stop getting kernel |
| * updates and your nice userland gettimeofday will be totally dead. |
| * It's fine to use that for setting breakpoints in the vDSO code |
| * pages though |
| * |
| * Make sure the vDSO gets into every core dump. |
| * Dumping its contents makes post-mortem fully interpretable later |
| * without matching up the same kernel and hardware config to see |
| * what PC values meant. |
| */ |
| rc = install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT, |
| VM_READ|VM_EXEC| |
| VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC| |
| VM_ALWAYSDUMP, |
| vdso_pagelist); |
| if (rc) |
| goto out_up; |
| |
| /* Put vDSO base into mm struct */ |
| current->mm->context.vdso_base = vdso_base; |
| |
| up_write(&mm->mmap_sem); |
| return 0; |
| |
| out_up: |
| up_write(&mm->mmap_sem); |
| return rc; |
| } |
| |
| const char *arch_vma_name(struct vm_area_struct *vma) |
| { |
| if (vma->vm_mm && vma->vm_start == vma->vm_mm->context.vdso_base) |
| return "[vdso]"; |
| return NULL; |
| } |
| |
| static int __init vdso_init(void) |
| { |
| int i; |
| |
| if (!vdso_enabled) |
| return 0; |
| vdso_init_data(vdso_data); |
| #if defined(CONFIG_32BIT) || defined(CONFIG_COMPAT) |
| /* Calculate the size of the 32 bit vDSO */ |
| vdso32_pages = ((&vdso32_end - &vdso32_start |
| + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1; |
| |
| /* Make sure pages are in the correct state */ |
| vdso32_pagelist = kzalloc(sizeof(struct page *) * (vdso32_pages + 1), |
| GFP_KERNEL); |
| BUG_ON(vdso32_pagelist == NULL); |
| for (i = 0; i < vdso32_pages - 1; i++) { |
| struct page *pg = virt_to_page(vdso32_kbase + i*PAGE_SIZE); |
| ClearPageReserved(pg); |
| get_page(pg); |
| vdso32_pagelist[i] = pg; |
| } |
| vdso32_pagelist[vdso32_pages - 1] = virt_to_page(vdso_data); |
| vdso32_pagelist[vdso32_pages] = NULL; |
| #endif |
| |
| #ifdef CONFIG_64BIT |
| /* Calculate the size of the 64 bit vDSO */ |
| vdso64_pages = ((&vdso64_end - &vdso64_start |
| + PAGE_SIZE - 1) >> PAGE_SHIFT) + 1; |
| |
| /* Make sure pages are in the correct state */ |
| vdso64_pagelist = kzalloc(sizeof(struct page *) * (vdso64_pages + 1), |
| GFP_KERNEL); |
| BUG_ON(vdso64_pagelist == NULL); |
| for (i = 0; i < vdso64_pages - 1; i++) { |
| struct page *pg = virt_to_page(vdso64_kbase + i*PAGE_SIZE); |
| ClearPageReserved(pg); |
| get_page(pg); |
| vdso64_pagelist[i] = pg; |
| } |
| vdso64_pagelist[vdso64_pages - 1] = virt_to_page(vdso_data); |
| vdso64_pagelist[vdso64_pages] = NULL; |
| #ifndef CONFIG_SMP |
| BUG_ON(vdso_alloc_per_cpu(0, S390_lowcore)); |
| #endif |
| vdso_init_cr5(); |
| #endif /* CONFIG_64BIT */ |
| |
| get_page(virt_to_page(vdso_data)); |
| |
| smp_wmb(); |
| |
| return 0; |
| } |
| arch_initcall(vdso_init); |
| |
| int in_gate_area_no_task(unsigned long addr) |
| { |
| return 0; |
| } |
| |
| int in_gate_area(struct task_struct *task, unsigned long addr) |
| { |
| return 0; |
| } |
| |
| struct vm_area_struct *get_gate_vma(struct task_struct *tsk) |
| { |
| return NULL; |
| } |