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torvaldstorvalds
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Merge tag 'riscv-for-linus-5.10-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull more RISC-V updates from Palmer Dabbelt: "Just a single patch set: the remainder of Christoph's work to remove set_fs, including the RISC-V portion" * tag 'riscv-for-linus-5.10-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: riscv: remove address space overrides using set_fs() riscv: implement __get_kernel_nofault and __put_user_nofault riscv: refactor __get_user and __put_user riscv: use memcpy based uaccess for nommu again asm-generic: make the set_fs implementation optional asm-generic: add nommu implementations of __{get,put}_kernel_nofault asm-generic: improve the nommu {get,put}_user handling uaccess: provide a generic TASK_SIZE_MAX definition
2 parents 45fe605 + e8d444d commit 0593c1b

7 files changed

Lines changed: 166 additions & 135 deletions

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‎arch/riscv/Kconfig‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -88,7 +88,7 @@ config RISCV
8888
select SPARSE_IRQ
8989
select SYSCTL_EXCEPTION_TRACE
9090
select THREAD_INFO_IN_TASK
91-
select SET_FS
91+
select UACCESS_MEMCPY if !MMU
9292

9393
config ARCH_MMAP_RND_BITS_MIN
9494
default 18 if 64BIT

‎arch/riscv/include/asm/thread_info.h‎

Lines changed: 0 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -24,10 +24,6 @@
2424
#include <asm/processor.h>
2525
#include <asm/csr.h>
2626

27-
typedef struct {
28-
unsigned long seg;
29-
} mm_segment_t;
30-
3127
/*
3228
* low level task data that entry.S needs immediate access to
3329
* - this struct should fit entirely inside of one cache line
@@ -39,7 +35,6 @@ typedef struct {
3935
struct thread_info {
4036
unsigned long flags; /* low level flags */
4137
int preempt_count; /* 0=>preemptible, <0=>BUG */
42-
mm_segment_t addr_limit;
4338
/*
4439
* These stack pointers are overwritten on every system call or
4540
* exception. SP is also saved to the stack it can be recovered when
@@ -59,7 +54,6 @@ struct thread_info {
5954
{ \
6055
.flags = 0, \
6156
.preempt_count = INIT_PREEMPT_COUNT, \
62-
.addr_limit = KERNEL_DS, \
6357
}
6458

6559
#endif /* !__ASSEMBLY__ */

‎arch/riscv/include/asm/uaccess.h‎

Lines changed: 91 additions & 86 deletions
Original file line numberDiff line numberDiff line change
@@ -13,24 +13,6 @@
1313
/*
1414
* User space memory access functions
1515
*/
16-
17-
extern unsigned long __must_check __asm_copy_to_user(void __user *to,
18-
const void *from, unsigned long n);
19-
extern unsigned long __must_check __asm_copy_from_user(void *to,
20-
const void __user *from, unsigned long n);
21-
22-
static inline unsigned long
23-
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
24-
{
25-
return __asm_copy_from_user(to, from, n);
26-
}
27-
28-
static inline unsigned long
29-
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
30-
{
31-
return __asm_copy_to_user(to, from, n);
32-
}
33-
3416
#ifdef CONFIG_MMU
3517
#include <linux/errno.h>
3618
#include <linux/compiler.h>
@@ -44,29 +26,6 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
4426
#define __disable_user_access() \
4527
__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")
4628

47-
/*
48-
* The fs value determines whether argument validity checking should be
49-
* performed or not. If get_fs() == USER_DS, checking is performed, with
50-
* get_fs() == KERNEL_DS, checking is bypassed.
51-
*
52-
* For historical reasons, these macros are grossly misnamed.
53-
*/
54-
55-
#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
56-
57-
#define KERNEL_DS MAKE_MM_SEG(~0UL)
58-
#define USER_DS MAKE_MM_SEG(TASK_SIZE)
59-
60-
#define get_fs() (current_thread_info()->addr_limit)
61-
62-
static inline void set_fs(mm_segment_t fs)
63-
{
64-
current_thread_info()->addr_limit = fs;
65-
}
66-
67-
#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
68-
#define user_addr_max() (get_fs().seg)
69-
7029
/**
7130
* access_ok: - Checks if a user space pointer is valid
7231
* @addr: User space pointer to start of block to check
@@ -94,9 +53,7 @@ static inline void set_fs(mm_segment_t fs)
9453
*/
9554
static inline int __access_ok(unsigned long addr, unsigned long size)
9655
{
97-
const mm_segment_t fs = get_fs();
98-
99-
return size <= fs.seg && addr <= fs.seg - size;
56+
return size <= TASK_SIZE && addr <= TASK_SIZE - size;
10057
}
10158

10259
/*
@@ -125,7 +82,6 @@ static inline int __access_ok(unsigned long addr, unsigned long size)
12582
do { \
12683
uintptr_t __tmp; \
12784
__typeof__(x) __x; \
128-
__enable_user_access(); \
12985
__asm__ __volatile__ ( \
13086
"1:\n" \
13187
" " insn " %1, %3\n" \
@@ -143,7 +99,6 @@ do { \
14399
" .previous" \
144100
: "+r" (err), "=&r" (__x), "=r" (__tmp) \
145101
: "m" (*(ptr)), "i" (-EFAULT)); \
146-
__disable_user_access(); \
147102
(x) = __x; \
148103
} while (0)
149104

@@ -156,7 +111,6 @@ do { \
156111
u32 __user *__ptr = (u32 __user *)(ptr); \
157112
u32 __lo, __hi; \
158113
uintptr_t __tmp; \
159-
__enable_user_access(); \
160114
__asm__ __volatile__ ( \
161115
"1:\n" \
162116
" lw %1, %4\n" \
@@ -180,12 +134,30 @@ do { \
180134
"=r" (__tmp) \
181135
: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \
182136
"i" (-EFAULT)); \
183-
__disable_user_access(); \
184137
(x) = (__typeof__(x))((__typeof__((x)-(x)))( \
185138
(((u64)__hi << 32) | __lo))); \
186139
} while (0)
187140
#endif /* CONFIG_64BIT */
188141

142+
#define __get_user_nocheck(x, __gu_ptr, __gu_err) \
143+
do { \
144+
switch (sizeof(*__gu_ptr)) { \
145+
case 1: \
146+
__get_user_asm("lb", (x), __gu_ptr, __gu_err); \
147+
break; \
148+
case 2: \
149+
__get_user_asm("lh", (x), __gu_ptr, __gu_err); \
150+
break; \
151+
case 4: \
152+
__get_user_asm("lw", (x), __gu_ptr, __gu_err); \
153+
break; \
154+
case 8: \
155+
__get_user_8((x), __gu_ptr, __gu_err); \
156+
break; \
157+
default: \
158+
BUILD_BUG(); \
159+
} \
160+
} while (0)
189161

190162
/**
191163
* __get_user: - Get a simple variable from user space, with less checking.
@@ -209,25 +181,15 @@ do { \
209181
*/
210182
#define __get_user(x, ptr) \
211183
({ \
212-
register long __gu_err = 0; \
213184
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
185+
long __gu_err = 0; \
186+
\
214187
__chk_user_ptr(__gu_ptr); \
215-
switch (sizeof(*__gu_ptr)) { \
216-
case 1: \
217-
__get_user_asm("lb", (x), __gu_ptr, __gu_err); \
218-
break; \
219-
case 2: \
220-
__get_user_asm("lh", (x), __gu_ptr, __gu_err); \
221-
break; \
222-
case 4: \
223-
__get_user_asm("lw", (x), __gu_ptr, __gu_err); \
224-
break; \
225-
case 8: \
226-
__get_user_8((x), __gu_ptr, __gu_err); \
227-
break; \
228-
default: \
229-
BUILD_BUG(); \
230-
} \
188+
\
189+
__enable_user_access(); \
190+
__get_user_nocheck(x, __gu_ptr, __gu_err); \
191+
__disable_user_access(); \
192+
\
231193
__gu_err; \
232194
})
233195

@@ -261,7 +223,6 @@ do { \
261223
do { \
262224
uintptr_t __tmp; \
263225
__typeof__(*(ptr)) __x = x; \
264-
__enable_user_access(); \
265226
__asm__ __volatile__ ( \
266227
"1:\n" \
267228
" " insn " %z3, %2\n" \
@@ -278,7 +239,6 @@ do { \
278239
" .previous" \
279240
: "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \
280241
: "rJ" (__x), "i" (-EFAULT)); \
281-
__disable_user_access(); \
282242
} while (0)
283243

284244
#ifdef CONFIG_64BIT
@@ -290,7 +250,6 @@ do { \
290250
u32 __user *__ptr = (u32 __user *)(ptr); \
291251
u64 __x = (__typeof__((x)-(x)))(x); \
292252
uintptr_t __tmp; \
293-
__enable_user_access(); \
294253
__asm__ __volatile__ ( \
295254
"1:\n" \
296255
" sw %z4, %2\n" \
@@ -312,10 +271,28 @@ do { \
312271
"=m" (__ptr[__LSW]), \
313272
"=m" (__ptr[__MSW]) \
314273
: "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \
315-
__disable_user_access(); \
316274
} while (0)
317275
#endif /* CONFIG_64BIT */
318276

277+
#define __put_user_nocheck(x, __gu_ptr, __pu_err) \
278+
do { \
279+
switch (sizeof(*__gu_ptr)) { \
280+
case 1: \
281+
__put_user_asm("sb", (x), __gu_ptr, __pu_err); \
282+
break; \
283+
case 2: \
284+
__put_user_asm("sh", (x), __gu_ptr, __pu_err); \
285+
break; \
286+
case 4: \
287+
__put_user_asm("sw", (x), __gu_ptr, __pu_err); \
288+
break; \
289+
case 8: \
290+
__put_user_8((x), __gu_ptr, __pu_err); \
291+
break; \
292+
default: \
293+
BUILD_BUG(); \
294+
} \
295+
} while (0)
319296

320297
/**
321298
* __put_user: - Write a simple value into user space, with less checking.
@@ -338,25 +315,15 @@ do { \
338315
*/
339316
#define __put_user(x, ptr) \
340317
({ \
341-
register long __pu_err = 0; \
342318
__typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
319+
long __pu_err = 0; \
320+
\
343321
__chk_user_ptr(__gu_ptr); \
344-
switch (sizeof(*__gu_ptr)) { \
345-
case 1: \
346-
__put_user_asm("sb", (x), __gu_ptr, __pu_err); \
347-
break; \
348-
case 2: \
349-
__put_user_asm("sh", (x), __gu_ptr, __pu_err); \
350-
break; \
351-
case 4: \
352-
__put_user_asm("sw", (x), __gu_ptr, __pu_err); \
353-
break; \
354-
case 8: \
355-
__put_user_8((x), __gu_ptr, __pu_err); \
356-
break; \
357-
default: \
358-
BUILD_BUG(); \
359-
} \
322+
\
323+
__enable_user_access(); \
324+
__put_user_nocheck(x, __gu_ptr, __pu_err); \
325+
__disable_user_access(); \
326+
\
360327
__pu_err; \
361328
})
362329

@@ -385,6 +352,24 @@ do { \
385352
-EFAULT; \
386353
})
387354

355+
356+
unsigned long __must_check __asm_copy_to_user(void __user *to,
357+
const void *from, unsigned long n);
358+
unsigned long __must_check __asm_copy_from_user(void *to,
359+
const void __user *from, unsigned long n);
360+
361+
static inline unsigned long
362+
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
363+
{
364+
return __asm_copy_from_user(to, from, n);
365+
}
366+
367+
static inline unsigned long
368+
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
369+
{
370+
return __asm_copy_to_user(to, from, n);
371+
}
372+
388373
extern long strncpy_from_user(char *dest, const char __user *src, long count);
389374

390375
extern long __must_check strlen_user(const char __user *str);
@@ -476,6 +461,26 @@ unsigned long __must_check clear_user(void __user *to, unsigned long n)
476461
__ret; \
477462
})
478463

464+
#define HAVE_GET_KERNEL_NOFAULT
465+
466+
#define __get_kernel_nofault(dst, src, type, err_label) \
467+
do { \
468+
long __kr_err; \
469+
\
470+
__get_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \
471+
if (unlikely(__kr_err)) \
472+
goto err_label; \
473+
} while (0)
474+
475+
#define __put_kernel_nofault(dst, src, type, err_label) \
476+
do { \
477+
long __kr_err; \
478+
\
479+
__put_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \
480+
if (unlikely(__kr_err)) \
481+
goto err_label; \
482+
} while (0)
483+
479484
#else /* CONFIG_MMU */
480485
#include <asm-generic/uaccess.h>
481486
#endif /* CONFIG_MMU */

‎arch/riscv/kernel/process.c‎

Lines changed: 0 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -84,7 +84,6 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
8484
}
8585
regs->epc = pc;
8686
regs->sp = sp;
87-
set_fs(USER_DS);
8887
}
8988

9089
void flush_thread(void)

‎arch/riscv/lib/Makefile‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2,5 +2,5 @@
22
lib-y += delay.o
33
lib-y += memcpy.o
44
lib-y += memset.o
5-
lib-y += uaccess.o
5+
lib-$(CONFIG_MMU) += uaccess.o
66
lib-$(CONFIG_64BIT) += tishift.o

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