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m68k: Provide __{get,put}_kernel_nofault

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Allow non-faulting access to kernel addresses without overriding the
address space.  Implemented by passing the instruction name to the
low-level assembly macros as an argument, and force the use of the
normal move instructions for kernel access.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Link: https://lore.kernel.org/r/20210916070405.52750-6-hch@lst.de
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
This commit is contained in:
Christoph Hellwig
2021-09-16 09:04:04 +02:00
committed by Geert Uytterhoeven
parent 01eec1af5e
commit 8ade833909
1 changed files with 84 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

105
arch/m68k/include/asm/uaccess.h
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@@ -39,9 +39,9 @@ static inline int access_ok(const void __user *addr,
#define MOVES "move" #define MOVES "move"
#endif #endif
#define __put_user_asm(res, x, ptr, bwl, reg, err) \ #define __put_user_asm(inst, res, x, ptr, bwl, reg, err) \
asm volatile ("\n" \ asm volatile ("\n" \
"1: "MOVES"."#bwl" %2,%1\n" \ "1: "inst"."#bwl" %2,%1\n" \
"2:\n" \ "2:\n" \
" .section .fixup,\"ax\"\n" \ " .section .fixup,\"ax\"\n" \
" .even\n" \ " .even\n" \
@@ -57,13 +57,13 @@ asm volatile ("\n" \
: "+d" (res), "=m" (*(ptr)) \ : "+d" (res), "=m" (*(ptr)) \
: #reg (x), "i" (err)) : #reg (x), "i" (err))
#define __put_user_asm8(res, x, ptr) \ #define __put_user_asm8(inst, res, x, ptr) \
do { \ do { \
const void *__pu_ptr = (const void __force *)(ptr); \ const void *__pu_ptr = (const void __force *)(ptr); \
\ \
asm volatile ("\n" \ asm volatile ("\n" \
"1: "MOVES".l %2,(%1)+\n" \ "1: "inst".l %2,(%1)+\n" \
"2: "MOVES".l %R2,(%1)\n" \ "2: "inst".l %R2,(%1)\n" \
"3:\n" \ "3:\n" \
" .section .fixup,\"ax\"\n" \ " .section .fixup,\"ax\"\n" \
" .even\n" \ " .even\n" \
@@ -94,16 +94,16 @@ do { \
__chk_user_ptr(ptr); \ __chk_user_ptr(ptr); \
switch (sizeof (*(ptr))) { \ switch (sizeof (*(ptr))) { \
case 1: \ case 1: \
__put_user_asm(__pu_err, __pu_val, ptr, b, d, -EFAULT); \ __put_user_asm(MOVES, __pu_err, __pu_val, ptr, b, d, -EFAULT); \
break; \ break; \
case 2: \ case 2: \
__put_user_asm(__pu_err, __pu_val, ptr, w, r, -EFAULT); \ __put_user_asm(MOVES, __pu_err, __pu_val, ptr, w, r, -EFAULT); \
break; \ break; \
case 4: \ case 4: \
__put_user_asm(__pu_err, __pu_val, ptr, l, r, -EFAULT); \ __put_user_asm(MOVES, __pu_err, __pu_val, ptr, l, r, -EFAULT); \
break; \ break; \
case 8: \ case 8: \
__put_user_asm8(__pu_err, __pu_val, ptr); \ __put_user_asm8(MOVES, __pu_err, __pu_val, ptr); \
break; \ break; \
default: \ default: \
BUILD_BUG(); \ BUILD_BUG(); \
@@ -113,10 +113,10 @@ do { \
#define put_user(x, ptr) __put_user(x, ptr) #define put_user(x, ptr) __put_user(x, ptr)
#define __get_user_asm(res, x, ptr, type, bwl, reg, err) ({ \ #define __get_user_asm(inst, res, x, ptr, type, bwl, reg, err) ({ \
type __gu_val; \ type __gu_val; \
asm volatile ("\n" \ asm volatile ("\n" \
"1: "MOVES"."#bwl" %2,%1\n" \ "1: "inst"."#bwl" %2,%1\n" \
"2:\n" \ "2:\n" \
" .section .fixup,\"ax\"\n" \ " .section .fixup,\"ax\"\n" \
" .even\n" \ " .even\n" \
@@ -134,7 +134,7 @@ do { \
(x) = (__force typeof(*(ptr)))(__force unsigned long)__gu_val; \ (x) = (__force typeof(*(ptr)))(__force unsigned long)__gu_val; \
}) })
#define __get_user_asm8(res, x, ptr) \ #define __get_user_asm8(inst, res, x, ptr) \
do { \ do { \
const void *__gu_ptr = (const void __force *)(ptr); \ const void *__gu_ptr = (const void __force *)(ptr); \
union { \ union { \
@@ -143,8 +143,8 @@ do { \
} __gu_val; \ } __gu_val; \
\ \
asm volatile ("\n" \ asm volatile ("\n" \
"1: "MOVES".l (%2)+,%1\n" \ "1: "inst".l (%2)+,%1\n" \
"2: "MOVES".l (%2),%R1\n" \ "2: "inst".l (%2),%R1\n" \
"3:\n" \ "3:\n" \
" .section .fixup,\"ax\"\n" \ " .section .fixup,\"ax\"\n" \
" .even\n" \ " .even\n" \
@@ -172,16 +172,16 @@ do { \
__chk_user_ptr(ptr); \ __chk_user_ptr(ptr); \
switch (sizeof(*(ptr))) { \ switch (sizeof(*(ptr))) { \
case 1: \ case 1: \
__get_user_asm(__gu_err, x, ptr, u8, b, d, -EFAULT); \ __get_user_asm(MOVES, __gu_err, x, ptr, u8, b, d, -EFAULT); \
break; \ break; \
case 2: \ case 2: \
__get_user_asm(__gu_err, x, ptr, u16, w, r, -EFAULT); \ __get_user_asm(MOVES, __gu_err, x, ptr, u16, w, r, -EFAULT); \
break; \ break; \
case 4: \ case 4: \
__get_user_asm(__gu_err, x, ptr, u32, l, r, -EFAULT); \ __get_user_asm(MOVES, __gu_err, x, ptr, u32, l, r, -EFAULT); \
break; \ break; \
case 8: \ case 8: \
__get_user_asm8(__gu_err, x, ptr); \ __get_user_asm8(MOVES, __gu_err, x, ptr); \
break; \ break; \
default: \ default: \
BUILD_BUG(); \ BUILD_BUG(); \
@@ -330,16 +330,19 @@ __constant_copy_to_user(void __user *to, const void *from, unsigned long n)
switch (n) { switch (n) {
case 1: case 1:
__put_user_asm(res, *(u8 *)from, (u8 __user *)to, b, d, 1); __put_user_asm(MOVES, res, *(u8 *)from, (u8 __user *)to,
b, d, 1);
break; break;
case 2: case 2:
__put_user_asm(res, *(u16 *)from, (u16 __user *)to, w, r, 2); __put_user_asm(MOVES, res, *(u16 *)from, (u16 __user *)to,
w, r, 2);
break; break;
case 3: case 3:
__constant_copy_to_user_asm(res, to, from, tmp, 3, w, b,); __constant_copy_to_user_asm(res, to, from, tmp, 3, w, b,);
break; break;
case 4: case 4:
__put_user_asm(res, *(u32 *)from, (u32 __user *)to, l, r, 4); __put_user_asm(MOVES, res, *(u32 *)from, (u32 __user *)to,
l, r, 4);
break; break;
case 5: case 5:
__constant_copy_to_user_asm(res, to, from, tmp, 5, l, b,); __constant_copy_to_user_asm(res, to, from, tmp, 5, l, b,);
@@ -388,6 +391,66 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
#define INLINE_COPY_FROM_USER #define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER #define INLINE_COPY_TO_USER
#define HAVE_GET_KERNEL_NOFAULT
#define __get_kernel_nofault(dst, src, type, err_label) \
do { \
type *__gk_dst = (type *)(dst); \
type *__gk_src = (type *)(src); \
int __gk_err = 0; \
\
switch (sizeof(type)) { \
case 1: \
__get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \
u8, b, d, -EFAULT); \
break; \
case 2: \
__get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \
u16, w, r, -EFAULT); \
break; \
case 4: \
__get_user_asm("move", __gk_err, *__gk_dst, __gk_src, \
u32, l, r, -EFAULT); \
break; \
case 8: \
__get_user_asm8("move", __gk_err, *__gk_dst, __gk_src); \
break; \
default: \
BUILD_BUG(); \
} \
if (unlikely(__gk_err)) \
goto err_label; \
} while (0)
#define __put_kernel_nofault(dst, src, type, err_label) \
do { \
type __pk_src = *(type *)(src); \
type *__pk_dst = (type *)(dst); \
int __pk_err = 0; \
\
switch (sizeof(type)) { \
case 1: \
__put_user_asm("move", __pk_err, __pk_src, __pk_dst, \
b, d, -EFAULT); \
break; \
case 2: \
__put_user_asm("move", __pk_err, __pk_src, __pk_dst, \
w, r, -EFAULT); \
break; \
case 4: \
__put_user_asm("move", __pk_err, __pk_src, __pk_dst, \
l, r, -EFAULT); \
break; \
case 8: \
__put_user_asm8("move", __pk_err, __pk_src, __pk_dst); \
break; \
default: \
BUILD_BUG(); \
} \
if (unlikely(__pk_err)) \
goto err_label; \
} while (0)
#define user_addr_max() \ #define user_addr_max() \
(uaccess_kernel() ? ~0UL : TASK_SIZE) (uaccess_kernel() ? ~0UL : TASK_SIZE)