cb3444cfdb
There is already a generic union definition for vdso_data_store in the vdso datapage header. Use this definition to prevent code duplication. Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Heiko Carstens <hca@linux.ibm.com> Link: https://lore.kernel.org/r/20240219153939.75719-8-anna-maria@linutronix.de
256 lines
6.4 KiB
C
256 lines
6.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* vdso setup for s390
|
|
*
|
|
* Copyright IBM Corp. 2008
|
|
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
|
|
*/
|
|
|
|
#include <linux/binfmts.h>
|
|
#include <linux/compat.h>
|
|
#include <linux/elf.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/smp.h>
|
|
#include <linux/time_namespace.h>
|
|
#include <linux/random.h>
|
|
#include <vdso/datapage.h>
|
|
#include <asm/vdso.h>
|
|
|
|
extern char vdso64_start[], vdso64_end[];
|
|
extern char vdso32_start[], vdso32_end[];
|
|
|
|
static struct vm_special_mapping vvar_mapping;
|
|
|
|
static union vdso_data_store vdso_data_store __page_aligned_data;
|
|
|
|
struct vdso_data *vdso_data = vdso_data_store.data;
|
|
|
|
enum vvar_pages {
|
|
VVAR_DATA_PAGE_OFFSET,
|
|
VVAR_TIMENS_PAGE_OFFSET,
|
|
VVAR_NR_PAGES,
|
|
};
|
|
|
|
#ifdef CONFIG_TIME_NS
|
|
struct vdso_data *arch_get_vdso_data(void *vvar_page)
|
|
{
|
|
return (struct vdso_data *)(vvar_page);
|
|
}
|
|
|
|
/*
|
|
* The VVAR page layout depends on whether a task belongs to the root or
|
|
* non-root time namespace. Whenever a task changes its namespace, the VVAR
|
|
* page tables are cleared and then they will be re-faulted with a
|
|
* corresponding layout.
|
|
* See also the comment near timens_setup_vdso_data() for details.
|
|
*/
|
|
int vdso_join_timens(struct task_struct *task, struct time_namespace *ns)
|
|
{
|
|
struct mm_struct *mm = task->mm;
|
|
VMA_ITERATOR(vmi, mm, 0);
|
|
struct vm_area_struct *vma;
|
|
|
|
mmap_read_lock(mm);
|
|
for_each_vma(vmi, vma) {
|
|
if (!vma_is_special_mapping(vma, &vvar_mapping))
|
|
continue;
|
|
zap_vma_pages(vma);
|
|
break;
|
|
}
|
|
mmap_read_unlock(mm);
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
|
|
struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
struct page *timens_page = find_timens_vvar_page(vma);
|
|
unsigned long addr, pfn;
|
|
vm_fault_t err;
|
|
|
|
switch (vmf->pgoff) {
|
|
case VVAR_DATA_PAGE_OFFSET:
|
|
pfn = virt_to_pfn(vdso_data);
|
|
if (timens_page) {
|
|
/*
|
|
* Fault in VVAR page too, since it will be accessed
|
|
* to get clock data anyway.
|
|
*/
|
|
addr = vmf->address + VVAR_TIMENS_PAGE_OFFSET * PAGE_SIZE;
|
|
err = vmf_insert_pfn(vma, addr, pfn);
|
|
if (unlikely(err & VM_FAULT_ERROR))
|
|
return err;
|
|
pfn = page_to_pfn(timens_page);
|
|
}
|
|
break;
|
|
#ifdef CONFIG_TIME_NS
|
|
case VVAR_TIMENS_PAGE_OFFSET:
|
|
/*
|
|
* If a task belongs to a time namespace then a namespace
|
|
* specific VVAR is mapped with the VVAR_DATA_PAGE_OFFSET and
|
|
* the real VVAR page is mapped with the VVAR_TIMENS_PAGE_OFFSET
|
|
* offset.
|
|
* See also the comment near timens_setup_vdso_data().
|
|
*/
|
|
if (!timens_page)
|
|
return VM_FAULT_SIGBUS;
|
|
pfn = virt_to_pfn(vdso_data);
|
|
break;
|
|
#endif /* CONFIG_TIME_NS */
|
|
default:
|
|
return VM_FAULT_SIGBUS;
|
|
}
|
|
return vmf_insert_pfn(vma, vmf->address, pfn);
|
|
}
|
|
|
|
static int vdso_mremap(const struct vm_special_mapping *sm,
|
|
struct vm_area_struct *vma)
|
|
{
|
|
current->mm->context.vdso_base = vma->vm_start;
|
|
return 0;
|
|
}
|
|
|
|
static struct vm_special_mapping vvar_mapping = {
|
|
.name = "[vvar]",
|
|
.fault = vvar_fault,
|
|
};
|
|
|
|
static struct vm_special_mapping vdso64_mapping = {
|
|
.name = "[vdso]",
|
|
.mremap = vdso_mremap,
|
|
};
|
|
|
|
static struct vm_special_mapping vdso32_mapping = {
|
|
.name = "[vdso]",
|
|
.mremap = vdso_mremap,
|
|
};
|
|
|
|
int vdso_getcpu_init(void)
|
|
{
|
|
set_tod_programmable_field(smp_processor_id());
|
|
return 0;
|
|
}
|
|
early_initcall(vdso_getcpu_init); /* Must be called before SMP init */
|
|
|
|
static int map_vdso(unsigned long addr, unsigned long vdso_mapping_len)
|
|
{
|
|
unsigned long vvar_start, vdso_text_start, vdso_text_len;
|
|
struct vm_special_mapping *vdso_mapping;
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma;
|
|
int rc;
|
|
|
|
BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES);
|
|
if (mmap_write_lock_killable(mm))
|
|
return -EINTR;
|
|
|
|
if (is_compat_task()) {
|
|
vdso_text_len = vdso32_end - vdso32_start;
|
|
vdso_mapping = &vdso32_mapping;
|
|
} else {
|
|
vdso_text_len = vdso64_end - vdso64_start;
|
|
vdso_mapping = &vdso64_mapping;
|
|
}
|
|
vvar_start = get_unmapped_area(NULL, addr, vdso_mapping_len, 0, 0);
|
|
rc = vvar_start;
|
|
if (IS_ERR_VALUE(vvar_start))
|
|
goto out;
|
|
vma = _install_special_mapping(mm, vvar_start, VVAR_NR_PAGES*PAGE_SIZE,
|
|
VM_READ|VM_MAYREAD|VM_IO|VM_DONTDUMP|
|
|
VM_PFNMAP,
|
|
&vvar_mapping);
|
|
rc = PTR_ERR(vma);
|
|
if (IS_ERR(vma))
|
|
goto out;
|
|
vdso_text_start = vvar_start + VVAR_NR_PAGES * PAGE_SIZE;
|
|
/* VM_MAYWRITE for COW so gdb can set breakpoints */
|
|
vma = _install_special_mapping(mm, vdso_text_start, vdso_text_len,
|
|
VM_READ|VM_EXEC|
|
|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
|
|
vdso_mapping);
|
|
if (IS_ERR(vma)) {
|
|
do_munmap(mm, vvar_start, PAGE_SIZE, NULL);
|
|
rc = PTR_ERR(vma);
|
|
} else {
|
|
current->mm->context.vdso_base = vdso_text_start;
|
|
rc = 0;
|
|
}
|
|
out:
|
|
mmap_write_unlock(mm);
|
|
return rc;
|
|
}
|
|
|
|
static unsigned long vdso_addr(unsigned long start, unsigned long len)
|
|
{
|
|
unsigned long addr, end, offset;
|
|
|
|
/*
|
|
* Round up the start address. It can start out unaligned as a result
|
|
* of stack start randomization.
|
|
*/
|
|
start = PAGE_ALIGN(start);
|
|
|
|
/* Round the lowest possible end address up to a PMD boundary. */
|
|
end = (start + len + PMD_SIZE - 1) & PMD_MASK;
|
|
if (end >= VDSO_BASE)
|
|
end = VDSO_BASE;
|
|
end -= len;
|
|
|
|
if (end > start) {
|
|
offset = get_random_u32_below(((end - start) >> PAGE_SHIFT) + 1);
|
|
addr = start + (offset << PAGE_SHIFT);
|
|
} else {
|
|
addr = start;
|
|
}
|
|
return addr;
|
|
}
|
|
|
|
unsigned long vdso_size(void)
|
|
{
|
|
unsigned long size = VVAR_NR_PAGES * PAGE_SIZE;
|
|
|
|
if (is_compat_task())
|
|
size += vdso32_end - vdso32_start;
|
|
else
|
|
size += vdso64_end - vdso64_start;
|
|
return PAGE_ALIGN(size);
|
|
}
|
|
|
|
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
|
|
{
|
|
unsigned long addr = VDSO_BASE;
|
|
unsigned long size = vdso_size();
|
|
|
|
if (current->flags & PF_RANDOMIZE)
|
|
addr = vdso_addr(current->mm->start_stack + PAGE_SIZE, size);
|
|
return map_vdso(addr, size);
|
|
}
|
|
|
|
static struct page ** __init vdso_setup_pages(void *start, void *end)
|
|
{
|
|
int pages = (end - start) >> PAGE_SHIFT;
|
|
struct page **pagelist;
|
|
int i;
|
|
|
|
pagelist = kcalloc(pages + 1, sizeof(struct page *), GFP_KERNEL);
|
|
if (!pagelist)
|
|
panic("%s: Cannot allocate page list for VDSO", __func__);
|
|
for (i = 0; i < pages; i++)
|
|
pagelist[i] = virt_to_page(start + i * PAGE_SIZE);
|
|
return pagelist;
|
|
}
|
|
|
|
static int __init vdso_init(void)
|
|
{
|
|
vdso64_mapping.pages = vdso_setup_pages(vdso64_start, vdso64_end);
|
|
if (IS_ENABLED(CONFIG_COMPAT))
|
|
vdso32_mapping.pages = vdso_setup_pages(vdso32_start, vdso32_end);
|
|
return 0;
|
|
}
|
|
arch_initcall(vdso_init);
|