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authorLinus Torvalds <torvalds@linux-foundation.org>2020-10-24 10:57:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-24 10:57:57 -0700
commit0593c1b4598a77b5f835b278cde0ab71e2578588 (patch)
tree337c391b0a9b44dc84d3d4ef90d78ed409877e48 /arch
parent45fe605832c8c0c962bfaf2581c6489b39abfe10 (diff)
parente8d444d3e98c255f91d228984abc46cfdfaf48b4 (diff)
downloadlwn-0593c1b4598a77b5f835b278cde0ab71e2578588.tar.gz
lwn-0593c1b4598a77b5f835b278cde0ab71e2578588.zip
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
Diffstat (limited to 'arch')
-rw-r--r--arch/riscv/Kconfig2
-rw-r--r--arch/riscv/include/asm/thread_info.h6
-rw-r--r--arch/riscv/include/asm/uaccess.h177
-rw-r--r--arch/riscv/kernel/process.c1
-rw-r--r--arch/riscv/lib/Makefile2
5 files changed, 93 insertions, 95 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index d5e7ca08f22c..44377fd7860e 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -88,7 +88,7 @@ config RISCV
select SPARSE_IRQ
select SYSCTL_EXCEPTION_TRACE
select THREAD_INFO_IN_TASK
- select SET_FS
+ select UACCESS_MEMCPY if !MMU
config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
index 464a2bbc97ea..a390711129de 100644
--- a/arch/riscv/include/asm/thread_info.h
+++ b/arch/riscv/include/asm/thread_info.h
@@ -24,10 +24,6 @@
#include <asm/processor.h>
#include <asm/csr.h>
-typedef struct {
- unsigned long seg;
-} mm_segment_t;
-
/*
* low level task data that entry.S needs immediate access to
* - this struct should fit entirely inside of one cache line
@@ -39,7 +35,6 @@ typedef struct {
struct thread_info {
unsigned long flags; /* low level flags */
int preempt_count; /* 0=>preemptible, <0=>BUG */
- mm_segment_t addr_limit;
/*
* These stack pointers are overwritten on every system call or
* exception. SP is also saved to the stack it can be recovered when
@@ -59,7 +54,6 @@ struct thread_info {
{ \
.flags = 0, \
.preempt_count = INIT_PREEMPT_COUNT, \
- .addr_limit = KERNEL_DS, \
}
#endif /* !__ASSEMBLY__ */
diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
index f56c66b3f5fe..c47e6b35c551 100644
--- a/arch/riscv/include/asm/uaccess.h
+++ b/arch/riscv/include/asm/uaccess.h
@@ -13,24 +13,6 @@
/*
* User space memory access functions
*/
-
-extern unsigned long __must_check __asm_copy_to_user(void __user *to,
- const void *from, unsigned long n);
-extern unsigned long __must_check __asm_copy_from_user(void *to,
- const void __user *from, unsigned long n);
-
-static inline unsigned long
-raw_copy_from_user(void *to, const void __user *from, unsigned long n)
-{
- return __asm_copy_from_user(to, from, n);
-}
-
-static inline unsigned long
-raw_copy_to_user(void __user *to, const void *from, unsigned long n)
-{
- return __asm_copy_to_user(to, from, n);
-}
-
#ifdef CONFIG_MMU
#include <linux/errno.h>
#include <linux/compiler.h>
@@ -44,29 +26,6 @@ raw_copy_to_user(void __user *to, const void *from, unsigned long n)
#define __disable_user_access() \
__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")
-/*
- * The fs value determines whether argument validity checking should be
- * performed or not. If get_fs() == USER_DS, checking is performed, with
- * get_fs() == KERNEL_DS, checking is bypassed.
- *
- * For historical reasons, these macros are grossly misnamed.
- */
-
-#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
-
-#define KERNEL_DS MAKE_MM_SEG(~0UL)
-#define USER_DS MAKE_MM_SEG(TASK_SIZE)
-
-#define get_fs() (current_thread_info()->addr_limit)
-
-static inline void set_fs(mm_segment_t fs)
-{
- current_thread_info()->addr_limit = fs;
-}
-
-#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
-#define user_addr_max() (get_fs().seg)
-
/**
* access_ok: - Checks if a user space pointer is valid
* @addr: User space pointer to start of block to check
@@ -94,9 +53,7 @@ static inline void set_fs(mm_segment_t fs)
*/
static inline int __access_ok(unsigned long addr, unsigned long size)
{
- const mm_segment_t fs = get_fs();
-
- return size <= fs.seg && addr <= fs.seg - size;
+ return size <= TASK_SIZE && addr <= TASK_SIZE - size;
}
/*
@@ -125,7 +82,6 @@ static inline int __access_ok(unsigned long addr, unsigned long size)
do { \
uintptr_t __tmp; \
__typeof__(x) __x; \
- __enable_user_access(); \
__asm__ __volatile__ ( \
"1:\n" \
" " insn " %1, %3\n" \
@@ -143,7 +99,6 @@ do { \
" .previous" \
: "+r" (err), "=&r" (__x), "=r" (__tmp) \
: "m" (*(ptr)), "i" (-EFAULT)); \
- __disable_user_access(); \
(x) = __x; \
} while (0)
@@ -156,7 +111,6 @@ do { \
u32 __user *__ptr = (u32 __user *)(ptr); \
u32 __lo, __hi; \
uintptr_t __tmp; \
- __enable_user_access(); \
__asm__ __volatile__ ( \
"1:\n" \
" lw %1, %4\n" \
@@ -180,12 +134,30 @@ do { \
"=r" (__tmp) \
: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \
"i" (-EFAULT)); \
- __disable_user_access(); \
(x) = (__typeof__(x))((__typeof__((x)-(x)))( \
(((u64)__hi << 32) | __lo))); \
} while (0)
#endif /* CONFIG_64BIT */
+#define __get_user_nocheck(x, __gu_ptr, __gu_err) \
+do { \
+ switch (sizeof(*__gu_ptr)) { \
+ case 1: \
+ __get_user_asm("lb", (x), __gu_ptr, __gu_err); \
+ break; \
+ case 2: \
+ __get_user_asm("lh", (x), __gu_ptr, __gu_err); \
+ break; \
+ case 4: \
+ __get_user_asm("lw", (x), __gu_ptr, __gu_err); \
+ break; \
+ case 8: \
+ __get_user_8((x), __gu_ptr, __gu_err); \
+ break; \
+ default: \
+ BUILD_BUG(); \
+ } \
+} while (0)
/**
* __get_user: - Get a simple variable from user space, with less checking.
@@ -209,25 +181,15 @@ do { \
*/
#define __get_user(x, ptr) \
({ \
- register long __gu_err = 0; \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
+ long __gu_err = 0; \
+ \
__chk_user_ptr(__gu_ptr); \
- switch (sizeof(*__gu_ptr)) { \
- case 1: \
- __get_user_asm("lb", (x), __gu_ptr, __gu_err); \
- break; \
- case 2: \
- __get_user_asm("lh", (x), __gu_ptr, __gu_err); \
- break; \
- case 4: \
- __get_user_asm("lw", (x), __gu_ptr, __gu_err); \
- break; \
- case 8: \
- __get_user_8((x), __gu_ptr, __gu_err); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
+ \
+ __enable_user_access(); \
+ __get_user_nocheck(x, __gu_ptr, __gu_err); \
+ __disable_user_access(); \
+ \
__gu_err; \
})
@@ -261,7 +223,6 @@ do { \
do { \
uintptr_t __tmp; \
__typeof__(*(ptr)) __x = x; \
- __enable_user_access(); \
__asm__ __volatile__ ( \
"1:\n" \
" " insn " %z3, %2\n" \
@@ -278,7 +239,6 @@ do { \
" .previous" \
: "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \
: "rJ" (__x), "i" (-EFAULT)); \
- __disable_user_access(); \
} while (0)
#ifdef CONFIG_64BIT
@@ -290,7 +250,6 @@ do { \
u32 __user *__ptr = (u32 __user *)(ptr); \
u64 __x = (__typeof__((x)-(x)))(x); \
uintptr_t __tmp; \
- __enable_user_access(); \
__asm__ __volatile__ ( \
"1:\n" \
" sw %z4, %2\n" \
@@ -312,10 +271,28 @@ do { \
"=m" (__ptr[__LSW]), \
"=m" (__ptr[__MSW]) \
: "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \
- __disable_user_access(); \
} while (0)
#endif /* CONFIG_64BIT */
+#define __put_user_nocheck(x, __gu_ptr, __pu_err) \
+do { \
+ switch (sizeof(*__gu_ptr)) { \
+ case 1: \
+ __put_user_asm("sb", (x), __gu_ptr, __pu_err); \
+ break; \
+ case 2: \
+ __put_user_asm("sh", (x), __gu_ptr, __pu_err); \
+ break; \
+ case 4: \
+ __put_user_asm("sw", (x), __gu_ptr, __pu_err); \
+ break; \
+ case 8: \
+ __put_user_8((x), __gu_ptr, __pu_err); \
+ break; \
+ default: \
+ BUILD_BUG(); \
+ } \
+} while (0)
/**
* __put_user: - Write a simple value into user space, with less checking.
@@ -338,25 +315,15 @@ do { \
*/
#define __put_user(x, ptr) \
({ \
- register long __pu_err = 0; \
__typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
+ long __pu_err = 0; \
+ \
__chk_user_ptr(__gu_ptr); \
- switch (sizeof(*__gu_ptr)) { \
- case 1: \
- __put_user_asm("sb", (x), __gu_ptr, __pu_err); \
- break; \
- case 2: \
- __put_user_asm("sh", (x), __gu_ptr, __pu_err); \
- break; \
- case 4: \
- __put_user_asm("sw", (x), __gu_ptr, __pu_err); \
- break; \
- case 8: \
- __put_user_8((x), __gu_ptr, __pu_err); \
- break; \
- default: \
- BUILD_BUG(); \
- } \
+ \
+ __enable_user_access(); \
+ __put_user_nocheck(x, __gu_ptr, __pu_err); \
+ __disable_user_access(); \
+ \
__pu_err; \
})
@@ -385,6 +352,24 @@ do { \
-EFAULT; \
})
+
+unsigned long __must_check __asm_copy_to_user(void __user *to,
+ const void *from, unsigned long n);
+unsigned long __must_check __asm_copy_from_user(void *to,
+ const void __user *from, unsigned long n);
+
+static inline unsigned long
+raw_copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ return __asm_copy_from_user(to, from, n);
+}
+
+static inline unsigned long
+raw_copy_to_user(void __user *to, const void *from, unsigned long n)
+{
+ return __asm_copy_to_user(to, from, n);
+}
+
extern long strncpy_from_user(char *dest, const char __user *src, long count);
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)
__ret; \
})
+#define HAVE_GET_KERNEL_NOFAULT
+
+#define __get_kernel_nofault(dst, src, type, err_label) \
+do { \
+ long __kr_err; \
+ \
+ __get_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \
+ if (unlikely(__kr_err)) \
+ goto err_label; \
+} while (0)
+
+#define __put_kernel_nofault(dst, src, type, err_label) \
+do { \
+ long __kr_err; \
+ \
+ __put_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \
+ if (unlikely(__kr_err)) \
+ goto err_label; \
+} while (0)
+
#else /* CONFIG_MMU */
#include <asm-generic/uaccess.h>
#endif /* CONFIG_MMU */
diff --git a/arch/riscv/kernel/process.c b/arch/riscv/kernel/process.c
index 2b97c493427c..19225ec65db6 100644
--- a/arch/riscv/kernel/process.c
+++ b/arch/riscv/kernel/process.c
@@ -84,7 +84,6 @@ void start_thread(struct pt_regs *regs, unsigned long pc,
}
regs->epc = pc;
regs->sp = sp;
- set_fs(USER_DS);
}
void flush_thread(void)
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 0d0db80800c4..47e7a8204460 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -2,5 +2,5 @@
lib-y += delay.o
lib-y += memcpy.o
lib-y += memset.o
-lib-y += uaccess.o
+lib-$(CONFIG_MMU) += uaccess.o
lib-$(CONFIG_64BIT) += tishift.o