352 lines
8.5 KiB
C
352 lines
8.5 KiB
C
/*
|
|
* 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;
|
|
}
|