linux_dsm_epyc7002/arch/um/kernel/skas/uaccess.c
Jeff Dike 9157f90f08 uml: move um_virt_to_phys
This patchset makes UML build and run with three-level page tables on
32-bit hosts.  This is an uncommon use case, but the code here needed
fixing and cleaning up, so 32-bit three-level pages tables were tested
to make sure the changes are good.

Patch 1 - code movement
Patch 2 - header untangling
Patch 3 - style fixups in files affected so far
Patch 4 - clean up use of current.h
Patch 5 - fix sizes of types that are different between 2 and 3-level
	page tables - three-level page table support should build at
	this point
Patch 6 - tidy (i.e. eliminate much of) the code that figures out how
	big the address space is
Patch 7 - change um_virt_to_phys into virt_to_pte, clean its
	interface, and clean its (so far) one caller
Patch 8 - the stub pages are covered with a VMA, allowing some nasty
	code to be thrown out - three-level page tables now work

This patch:

um_virt_to_phys only has one user, so it can be moved to the same file
and made static.  Its declarations in pgtable.h and ksyms.c are also
gone.

current_cmd was another apparent user, but it itself isn't used, so it
is deleted.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-05 09:44:28 -08:00

282 lines
5.8 KiB
C

/*
* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include "linux/err.h"
#include "linux/highmem.h"
#include "linux/mm.h"
#include "asm/current.h"
#include "asm/page.h"
#include "asm/pgtable.h"
#include "kern_util.h"
#include "os.h"
static void *um_virt_to_phys(struct task_struct *task, unsigned long addr,
pte_t *pte_out)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pte_t ptent;
if (task->mm == NULL)
return ERR_PTR(-EINVAL);
pgd = pgd_offset(task->mm, addr);
if (!pgd_present(*pgd))
return ERR_PTR(-EINVAL);
pud = pud_offset(pgd, addr);
if (!pud_present(*pud))
return ERR_PTR(-EINVAL);
pmd = pmd_offset(pud, addr);
if (!pmd_present(*pmd))
return ERR_PTR(-EINVAL);
pte = pte_offset_kernel(pmd, addr);
ptent = *pte;
if (!pte_present(ptent))
return ERR_PTR(-EINVAL);
if (pte_out != NULL)
*pte_out = ptent;
return (void *) (pte_val(ptent) & PAGE_MASK) + (addr & ~PAGE_MASK);
}
static unsigned long maybe_map(unsigned long virt, int is_write)
{
pte_t pte;
int err;
void *phys = um_virt_to_phys(current, virt, &pte);
int dummy_code;
if (IS_ERR(phys) || (is_write && !pte_write(pte))) {
err = handle_page_fault(virt, 0, is_write, 1, &dummy_code);
if (err)
return -1UL;
phys = um_virt_to_phys(current, virt, NULL);
}
if (IS_ERR(phys))
phys = (void *) -1;
return (unsigned long) phys;
}
static int do_op_one_page(unsigned long addr, int len, int is_write,
int (*op)(unsigned long addr, int len, void *arg), void *arg)
{
struct page *page;
int n;
addr = maybe_map(addr, is_write);
if (addr == -1UL)
return -1;
page = phys_to_page(addr);
addr = (unsigned long) kmap_atomic(page, KM_UML_USERCOPY) +
(addr & ~PAGE_MASK);
n = (*op)(addr, len, arg);
kunmap_atomic(page, KM_UML_USERCOPY);
return n;
}
static void do_buffer_op(void *jmpbuf, void *arg_ptr)
{
va_list args;
unsigned long addr;
int len, is_write, size, remain, n;
int (*op)(unsigned long, int, void *);
void *arg;
int *res;
va_copy(args, *(va_list *)arg_ptr);
addr = va_arg(args, unsigned long);
len = va_arg(args, int);
is_write = va_arg(args, int);
op = va_arg(args, void *);
arg = va_arg(args, void *);
res = va_arg(args, int *);
va_end(args);
size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
remain = len;
current->thread.fault_catcher = jmpbuf;
n = do_op_one_page(addr, size, is_write, op, arg);
if (n != 0) {
*res = (n < 0 ? remain : 0);
goto out;
}
addr += size;
remain -= size;
if (remain == 0) {
*res = 0;
goto out;
}
while(addr < ((addr + remain) & PAGE_MASK)) {
n = do_op_one_page(addr, PAGE_SIZE, is_write, op, arg);
if (n != 0) {
*res = (n < 0 ? remain : 0);
goto out;
}
addr += PAGE_SIZE;
remain -= PAGE_SIZE;
}
if (remain == 0) {
*res = 0;
goto out;
}
n = do_op_one_page(addr, remain, is_write, op, arg);
if (n != 0)
*res = (n < 0 ? remain : 0);
else *res = 0;
out:
current->thread.fault_catcher = NULL;
}
static int buffer_op(unsigned long addr, int len, int is_write,
int (*op)(unsigned long addr, int len, void *arg),
void *arg)
{
int faulted, res;
faulted = setjmp_wrapper(do_buffer_op, addr, len, is_write, op, arg,
&res);
if (!faulted)
return res;
return addr + len - (unsigned long) current->thread.fault_addr;
}
static int copy_chunk_from_user(unsigned long from, int len, void *arg)
{
unsigned long *to_ptr = arg, to = *to_ptr;
memcpy((void *) to, (void *) from, len);
*to_ptr += len;
return 0;
}
int copy_from_user(void *to, const void __user *from, int n)
{
if (segment_eq(get_fs(), KERNEL_DS)) {
memcpy(to, (__force void*)from, n);
return 0;
}
return access_ok(VERIFY_READ, from, n) ?
buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to):
n;
}
static int copy_chunk_to_user(unsigned long to, int len, void *arg)
{
unsigned long *from_ptr = arg, from = *from_ptr;
memcpy((void *) to, (void *) from, len);
*from_ptr += len;
return 0;
}
int copy_to_user(void __user *to, const void *from, int n)
{
if (segment_eq(get_fs(), KERNEL_DS)) {
memcpy((__force void *) to, from, n);
return 0;
}
return access_ok(VERIFY_WRITE, to, n) ?
buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) :
n;
}
static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
{
char **to_ptr = arg, *to = *to_ptr;
int n;
strncpy(to, (void *) from, len);
n = strnlen(to, len);
*to_ptr += n;
if (n < len)
return 1;
return 0;
}
int strncpy_from_user(char *dst, const char __user *src, int count)
{
int n;
char *ptr = dst;
if (segment_eq(get_fs(), KERNEL_DS)) {
strncpy(dst, (__force void *) src, count);
return strnlen(dst, count);
}
if (!access_ok(VERIFY_READ, src, 1))
return -EFAULT;
n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
&ptr);
if (n != 0)
return -EFAULT;
return strnlen(dst, count);
}
static int clear_chunk(unsigned long addr, int len, void *unused)
{
memset((void *) addr, 0, len);
return 0;
}
int __clear_user(void __user *mem, int len)
{
return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
}
int clear_user(void __user *mem, int len)
{
if (segment_eq(get_fs(), KERNEL_DS)) {
memset((__force void*)mem, 0, len);
return 0;
}
return access_ok(VERIFY_WRITE, mem, len) ?
buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len;
}
static int strnlen_chunk(unsigned long str, int len, void *arg)
{
int *len_ptr = arg, n;
n = strnlen((void *) str, len);
*len_ptr += n;
if (n < len)
return 1;
return 0;
}
int strnlen_user(const void __user *str, int len)
{
int count = 0, n;
if (segment_eq(get_fs(), KERNEL_DS))
return strnlen((__force char*)str, len) + 1;
n = buffer_op((unsigned long) str, len, 0, strnlen_chunk, &count);
if (n == 0)
return count + 1;
return -EFAULT;
}