* [PATCH] csky: uaccess.h: Coding convention with asm generic
@ 2021-04-21 8:54 guoren
2021-04-21 14:48 ` Christoph Hellwig
2021-04-28 3:18 ` Guenter Roeck
0 siblings, 2 replies; 9+ messages in thread
From: guoren @ 2021-04-21 8:54 UTC (permalink / raw)
To: guoren, arnd; +Cc: linux-kernel, linux-csky, linux-arch, Guo Ren
From: Guo Ren <guoren@linux.alibaba.com>
Using asm-generic/uaccess.h to prevent duplicated code:
- Add user_addr_max which mentioned in generic uaccess.h
- Remove custom definitions of KERNEL/USER_DS, get/set_fs,
uaccess_kerenl
- Using generic extable.h instead of custom definitions in
uaccess.h
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
---
arch/csky/include/asm/Kbuild | 1 +
arch/csky/include/asm/segment.h | 7 -
arch/csky/include/asm/uaccess.h | 362 ++++++++-------------------------------
arch/csky/lib/usercopy.c | 364 +++++++++++++++++++++++-----------------
arch/csky/mm/fault.c | 2 +-
5 files changed, 287 insertions(+), 449 deletions(-)
diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild
index cc24bb8..904a18a 100644
--- a/arch/csky/include/asm/Kbuild
+++ b/arch/csky/include/asm/Kbuild
@@ -1,5 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
generic-y += asm-offsets.h
+generic-y += extable.h
generic-y += gpio.h
generic-y += kvm_para.h
generic-y += qrwlock.h
diff --git a/arch/csky/include/asm/segment.h b/arch/csky/include/asm/segment.h
index 589e832..5bc1cc62 100644
--- a/arch/csky/include/asm/segment.h
+++ b/arch/csky/include/asm/segment.h
@@ -7,11 +7,4 @@ typedef struct {
unsigned long seg;
} mm_segment_t;
-#define KERNEL_DS ((mm_segment_t) { 0xFFFFFFFF })
-
-#define USER_DS ((mm_segment_t) { PAGE_OFFSET })
-#define get_fs() (current_thread_info()->addr_limit)
-#define set_fs(x) (current_thread_info()->addr_limit = (x))
-#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
-
#endif /* __ASM_CSKY_SEGMENT_H */
diff --git a/arch/csky/include/asm/uaccess.h b/arch/csky/include/asm/uaccess.h
index 3dec272..c33077e 100644
--- a/arch/csky/include/asm/uaccess.h
+++ b/arch/csky/include/asm/uaccess.h
@@ -3,118 +3,22 @@
#ifndef __ASM_CSKY_UACCESS_H
#define __ASM_CSKY_UACCESS_H
-/*
- * User space memory access functions
- */
-#include <linux/compiler.h>
-#include <linux/errno.h>
-#include <linux/types.h>
-#include <linux/sched.h>
-#include <linux/string.h>
-#include <linux/version.h>
-#include <asm/segment.h>
+#define user_addr_max() \
+ (uaccess_kernel() ? KERNEL_DS.seg : get_fs().seg)
-static inline int access_ok(const void *addr, unsigned long size)
+static inline int __access_ok(unsigned long addr, unsigned long size)
{
unsigned long limit = current_thread_info()->addr_limit.seg;
- return (((unsigned long)addr < limit) &&
- ((unsigned long)(addr + size) < limit));
+ return ((addr < limit) && ((addr + size) < limit));
}
-
-#define __addr_ok(addr) (access_ok(addr, 0))
-
-extern int __put_user_bad(void);
+#define __access_ok __access_ok
/*
- * Tell gcc we read from memory instead of writing: this is because
- * we do not write to any memory gcc knows about, so there are no
- * aliasing issues.
+ * __put_user_fn
*/
+extern int __put_user_bad(void);
-/*
- * These are the main single-value transfer routines. They automatically
- * use the right size if we just have the right pointer type.
- *
- * This gets kind of ugly. We want to return _two_ values in "get_user()"
- * and yet we don't want to do any pointers, because that is too much
- * of a performance impact. Thus we have a few rather ugly macros here,
- * and hide all the ugliness from the user.
- *
- * The "__xxx" versions of the user access functions are versions that
- * do not verify the address space, that must have been done previously
- * with a separate "access_ok()" call (this is used when we do multiple
- * accesses to the same area of user memory).
- *
- * As we use the same address space for kernel and user data on
- * Ckcore, we can just do these as direct assignments. (Of course, the
- * exception handling means that it's no longer "just"...)
- */
-
-#define put_user(x, ptr) \
- __put_user_check((x), (ptr), sizeof(*(ptr)))
-
-#define __put_user(x, ptr) \
- __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
-
-#define __ptr(x) ((unsigned long *)(x))
-
-#define get_user(x, ptr) \
- __get_user_check((x), (ptr), sizeof(*(ptr)))
-
-#define __get_user(x, ptr) \
- __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
-
-#define __put_user_nocheck(x, ptr, size) \
-({ \
- long __pu_err = 0; \
- typeof(*(ptr)) *__pu_addr = (ptr); \
- typeof(*(ptr)) __pu_val = (typeof(*(ptr)))(x); \
- if (__pu_addr) \
- __put_user_size(__pu_val, (__pu_addr), (size), \
- __pu_err); \
- __pu_err; \
-})
-
-#define __put_user_check(x, ptr, size) \
-({ \
- long __pu_err = -EFAULT; \
- typeof(*(ptr)) *__pu_addr = (ptr); \
- typeof(*(ptr)) __pu_val = (typeof(*(ptr)))(x); \
- if (access_ok(__pu_addr, size) && __pu_addr) \
- __put_user_size(__pu_val, __pu_addr, (size), __pu_err); \
- __pu_err; \
-})
-
-#define __put_user_size(x, ptr, size, retval) \
-do { \
- retval = 0; \
- switch (size) { \
- case 1: \
- __put_user_asm_b(x, ptr, retval); \
- break; \
- case 2: \
- __put_user_asm_h(x, ptr, retval); \
- break; \
- case 4: \
- __put_user_asm_w(x, ptr, retval); \
- break; \
- case 8: \
- __put_user_asm_64(x, ptr, retval); \
- break; \
- default: \
- __put_user_bad(); \
- } \
-} while (0)
-
-/*
- * We don't tell gcc that we are accessing memory, but this is OK
- * because we do not write to any memory gcc knows about, so there
- * are no aliasing issues.
- *
- * Note that PC at a fault is the address *after* the faulting
- * instruction.
- */
#define __put_user_asm_b(x, ptr, err) \
do { \
int errcode; \
@@ -173,8 +77,6 @@ do { \
do { \
int tmp; \
int errcode; \
- typeof(*(ptr))src = (typeof(*(ptr)))x; \
- typeof(*(ptr))*psrc = &src; \
\
asm volatile( \
" ldw %3, (%1, 0) \n" \
@@ -190,53 +92,52 @@ do { \
".long 2b, 3b \n" \
".previous \n" \
"4: \n" \
- : "=r"(err), "=r"(psrc), "=r"(ptr), \
+ : "=r"(err), "=r"(x), "=r"(ptr), \
"=r"(tmp), "=r"(errcode) \
- : "0"(err), "1"(psrc), "2"(ptr), "3"(0), "4"(-EFAULT) \
+ : "0"(err), "1"(x), "2"(ptr), "3"(0), "4"(-EFAULT) \
: "memory"); \
} while (0)
-#define __get_user_nocheck(x, ptr, size) \
-({ \
- long __gu_err; \
- __get_user_size(x, (ptr), (size), __gu_err); \
- __gu_err; \
-})
-
-#define __get_user_check(x, ptr, size) \
-({ \
- int __gu_err = -EFAULT; \
- const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
- if (access_ok(__gu_ptr, size) && __gu_ptr) \
- __get_user_size(x, __gu_ptr, size, __gu_err); \
- __gu_err; \
-})
+static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
+{
+ int retval = 0;
+ u32 tmp;
+
+ switch (size) {
+ case 1:
+ tmp = *(u8 *)x;
+ __put_user_asm_b(tmp, ptr, retval);
+ break;
+ case 2:
+ tmp = *(u16 *)x;
+ __put_user_asm_h(tmp, ptr, retval);
+ break;
+ case 4:
+ tmp = *(u32 *)x;
+ __put_user_asm_w(tmp, ptr, retval);
+ break;
+ case 8:
+ __put_user_asm_64(x, (u64 *)ptr, retval);
+ break;
+ default:
+ __put_user_bad();
+ }
+
+ return retval;
+}
+#define __put_user_fn __put_user_fn
-#define __get_user_size(x, ptr, size, retval) \
-do { \
- switch (size) { \
- case 1: \
- __get_user_asm_common((x), ptr, "ldb", retval); \
- break; \
- case 2: \
- __get_user_asm_common((x), ptr, "ldh", retval); \
- break; \
- case 4: \
- __get_user_asm_common((x), ptr, "ldw", retval); \
- break; \
- default: \
- x = 0; \
- (retval) = __get_user_bad(); \
- } \
-} while (0)
+/*
+ * __get_user_fn
+ */
+extern int __get_user_bad(void);
#define __get_user_asm_common(x, ptr, ins, err) \
do { \
int errcode; \
- asm volatile( \
- "1: " ins " %1, (%4,0) \n" \
+ __asm__ __volatile__( \
+ "1: " ins " %1, (%4, 0) \n" \
" br 3f \n" \
- /* Fix up codes */ \
"2: mov %0, %2 \n" \
" movi %1, 0 \n" \
" br 3f \n" \
@@ -250,160 +151,45 @@ do { \
: "memory"); \
} while (0)
-extern int __get_user_bad(void);
-
-#define ___copy_to_user(to, from, n) \
-do { \
- int w0, w1, w2, w3; \
- asm volatile( \
- "0: cmpnei %1, 0 \n" \
- " bf 8f \n" \
- " mov %3, %1 \n" \
- " or %3, %2 \n" \
- " andi %3, 3 \n" \
- " cmpnei %3, 0 \n" \
- " bf 1f \n" \
- " br 5f \n" \
- "1: cmplti %0, 16 \n" /* 4W */ \
- " bt 3f \n" \
- " ldw %3, (%2, 0) \n" \
- " ldw %4, (%2, 4) \n" \
- " ldw %5, (%2, 8) \n" \
- " ldw %6, (%2, 12) \n" \
- "2: stw %3, (%1, 0) \n" \
- "9: stw %4, (%1, 4) \n" \
- "10: stw %5, (%1, 8) \n" \
- "11: stw %6, (%1, 12) \n" \
- " addi %2, 16 \n" \
- " addi %1, 16 \n" \
- " subi %0, 16 \n" \
- " br 1b \n" \
- "3: cmplti %0, 4 \n" /* 1W */ \
- " bt 5f \n" \
- " ldw %3, (%2, 0) \n" \
- "4: stw %3, (%1, 0) \n" \
- " addi %2, 4 \n" \
- " addi %1, 4 \n" \
- " subi %0, 4 \n" \
- " br 3b \n" \
- "5: cmpnei %0, 0 \n" /* 1B */ \
- " bf 13f \n" \
- " ldb %3, (%2, 0) \n" \
- "6: stb %3, (%1, 0) \n" \
- " addi %2, 1 \n" \
- " addi %1, 1 \n" \
- " subi %0, 1 \n" \
- " br 5b \n" \
- "7: subi %0, 4 \n" \
- "8: subi %0, 4 \n" \
- "12: subi %0, 4 \n" \
- " br 13f \n" \
- ".section __ex_table, \"a\" \n" \
- ".align 2 \n" \
- ".long 2b, 13f \n" \
- ".long 4b, 13f \n" \
- ".long 6b, 13f \n" \
- ".long 9b, 12b \n" \
- ".long 10b, 8b \n" \
- ".long 11b, 7b \n" \
- ".previous \n" \
- "13: \n" \
- : "=r"(n), "=r"(to), "=r"(from), "=r"(w0), \
- "=r"(w1), "=r"(w2), "=r"(w3) \
- : "0"(n), "1"(to), "2"(from) \
- : "memory"); \
-} while (0)
-
-#define ___copy_from_user(to, from, n) \
-do { \
- int tmp; \
- int nsave; \
- asm volatile( \
- "0: cmpnei %1, 0 \n" \
- " bf 7f \n" \
- " mov %3, %1 \n" \
- " or %3, %2 \n" \
- " andi %3, 3 \n" \
- " cmpnei %3, 0 \n" \
- " bf 1f \n" \
- " br 5f \n" \
- "1: cmplti %0, 16 \n" \
- " bt 3f \n" \
- "2: ldw %3, (%2, 0) \n" \
- "10: ldw %4, (%2, 4) \n" \
- " stw %3, (%1, 0) \n" \
- " stw %4, (%1, 4) \n" \
- "11: ldw %3, (%2, 8) \n" \
- "12: ldw %4, (%2, 12) \n" \
- " stw %3, (%1, 8) \n" \
- " stw %4, (%1, 12) \n" \
- " addi %2, 16 \n" \
- " addi %1, 16 \n" \
- " subi %0, 16 \n" \
- " br 1b \n" \
- "3: cmplti %0, 4 \n" \
- " bt 5f \n" \
- "4: ldw %3, (%2, 0) \n" \
- " stw %3, (%1, 0) \n" \
- " addi %2, 4 \n" \
- " addi %1, 4 \n" \
- " subi %0, 4 \n" \
- " br 3b \n" \
- "5: cmpnei %0, 0 \n" \
- " bf 7f \n" \
- "6: ldb %3, (%2, 0) \n" \
- " stb %3, (%1, 0) \n" \
- " addi %2, 1 \n" \
- " addi %1, 1 \n" \
- " subi %0, 1 \n" \
- " br 5b \n" \
- "8: stw %3, (%1, 0) \n" \
- " subi %0, 4 \n" \
- " bf 7f \n" \
- "9: subi %0, 8 \n" \
- " bf 7f \n" \
- "13: stw %3, (%1, 8) \n" \
- " subi %0, 12 \n" \
- " bf 7f \n" \
- ".section __ex_table, \"a\" \n" \
- ".align 2 \n" \
- ".long 2b, 7f \n" \
- ".long 4b, 7f \n" \
- ".long 6b, 7f \n" \
- ".long 10b, 8b \n" \
- ".long 11b, 9b \n" \
- ".long 12b,13b \n" \
- ".previous \n" \
- "7: \n" \
- : "=r"(n), "=r"(to), "=r"(from), "=r"(nsave), \
- "=r"(tmp) \
- : "0"(n), "1"(to), "2"(from) \
- : "memory"); \
-} while (0)
+static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
+{
+ int retval;
+ u32 tmp;
+
+ switch (size) {
+ case 1:
+ __get_user_asm_common(tmp, ptr, "ldb", retval);
+ *(u8 *)x = (u8)tmp;
+ break;
+ case 2:
+ __get_user_asm_common(tmp, ptr, "ldh", retval);
+ *(u16 *)x = (u16)tmp;
+ break;
+ case 4:
+ __get_user_asm_common(tmp, ptr, "ldw", retval);
+ *(u32 *)x = (u32)tmp;
+ break;
+ default:
+ retval = __get_user_bad();
+ }
+
+ return retval;
+}
+#define __get_user_fn __get_user_fn
unsigned long raw_copy_from_user(void *to, const void *from, unsigned long n);
unsigned long raw_copy_to_user(void *to, const void *from, unsigned long n);
-unsigned long clear_user(void *to, unsigned long n);
unsigned long __clear_user(void __user *to, unsigned long n);
+#define __clear_user __clear_user
-long strncpy_from_user(char *dst, const char *src, long count);
long __strncpy_from_user(char *dst, const char *src, long count);
+#define __strncpy_from_user __strncpy_from_user
-/*
- * Return the size of a string (including the ending 0)
- *
- * Return 0 on exception, a value greater than N if too long
- */
-long strnlen_user(const char *src, long n);
-
-#define strlen_user(str) strnlen_user(str, 32767)
-
-struct exception_table_entry {
- unsigned long insn;
- unsigned long nextinsn;
-};
+long __strnlen_user(const char *s, long n);
+#define __strnlen_user __strnlen_user
-extern int fixup_exception(struct pt_regs *regs);
+#include <asm/segment.h>
+#include <asm-generic/uaccess.h>
#endif /* __ASM_CSKY_UACCESS_H */
diff --git a/arch/csky/lib/usercopy.c b/arch/csky/lib/usercopy.c
index 3c9bd64..a718360 100644
--- a/arch/csky/lib/usercopy.c
+++ b/arch/csky/lib/usercopy.c
@@ -7,7 +7,70 @@
unsigned long raw_copy_from_user(void *to, const void *from,
unsigned long n)
{
- ___copy_from_user(to, from, n);
+ int tmp, nsave;
+
+ __asm__ __volatile__(
+ "0: cmpnei %1, 0 \n"
+ " bf 7f \n"
+ " mov %3, %1 \n"
+ " or %3, %2 \n"
+ " andi %3, 3 \n"
+ " cmpnei %3, 0 \n"
+ " bf 1f \n"
+ " br 5f \n"
+ "1: cmplti %0, 16 \n"
+ " bt 3f \n"
+ "2: ldw %3, (%2, 0) \n"
+ "10: ldw %4, (%2, 4) \n"
+ " stw %3, (%1, 0) \n"
+ " stw %4, (%1, 4) \n"
+ "11: ldw %3, (%2, 8) \n"
+ "12: ldw %4, (%2, 12) \n"
+ " stw %3, (%1, 8) \n"
+ " stw %4, (%1, 12) \n"
+ " addi %2, 16 \n"
+ " addi %1, 16 \n"
+ " subi %0, 16 \n"
+ " br 1b \n"
+ "3: cmplti %0, 4 \n"
+ " bt 5f \n"
+ "4: ldw %3, (%2, 0) \n"
+ " stw %3, (%1, 0) \n"
+ " addi %2, 4 \n"
+ " addi %1, 4 \n"
+ " subi %0, 4 \n"
+ " br 3b \n"
+ "5: cmpnei %0, 0 \n"
+ " bf 7f \n"
+ "6: ldb %3, (%2, 0) \n"
+ " stb %3, (%1, 0) \n"
+ " addi %2, 1 \n"
+ " addi %1, 1 \n"
+ " subi %0, 1 \n"
+ " br 5b \n"
+ "8: stw %3, (%1, 0) \n"
+ " subi %0, 4 \n"
+ " bf 7f \n"
+ "9: subi %0, 8 \n"
+ " bf 7f \n"
+ "13: stw %3, (%1, 8) \n"
+ " subi %0, 12 \n"
+ " bf 7f \n"
+ ".section __ex_table, \"a\" \n"
+ ".align 2 \n"
+ ".long 2b, 7f \n"
+ ".long 4b, 7f \n"
+ ".long 6b, 7f \n"
+ ".long 10b, 8b \n"
+ ".long 11b, 9b \n"
+ ".long 12b,13b \n"
+ ".previous \n"
+ "7: \n"
+ : "=r"(n), "=r"(to), "=r"(from), "=r"(nsave),
+ "=r"(tmp)
+ : "0"(n), "1"(to), "2"(from)
+ : "memory");
+
return n;
}
EXPORT_SYMBOL(raw_copy_from_user);
@@ -15,48 +78,70 @@ EXPORT_SYMBOL(raw_copy_from_user);
unsigned long raw_copy_to_user(void *to, const void *from,
unsigned long n)
{
- ___copy_to_user(to, from, n);
+ int w0, w1, w2, w3;
+
+ __asm__ __volatile__(
+ "0: cmpnei %1, 0 \n"
+ " bf 8f \n"
+ " mov %3, %1 \n"
+ " or %3, %2 \n"
+ " andi %3, 3 \n"
+ " cmpnei %3, 0 \n"
+ " bf 1f \n"
+ " br 5f \n"
+ "1: cmplti %0, 16 \n" /* 4W */
+ " bt 3f \n"
+ " ldw %3, (%2, 0) \n"
+ " ldw %4, (%2, 4) \n"
+ " ldw %5, (%2, 8) \n"
+ " ldw %6, (%2, 12) \n"
+ "2: stw %3, (%1, 0) \n"
+ "9: stw %4, (%1, 4) \n"
+ "10: stw %5, (%1, 8) \n"
+ "11: stw %6, (%1, 12) \n"
+ " addi %2, 16 \n"
+ " addi %1, 16 \n"
+ " subi %0, 16 \n"
+ " br 1b \n"
+ "3: cmplti %0, 4 \n" /* 1W */
+ " bt 5f \n"
+ " ldw %3, (%2, 0) \n"
+ "4: stw %3, (%1, 0) \n"
+ " addi %2, 4 \n"
+ " addi %1, 4 \n"
+ " subi %0, 4 \n"
+ " br 3b \n"
+ "5: cmpnei %0, 0 \n" /* 1B */
+ " bf 13f \n"
+ " ldb %3, (%2, 0) \n"
+ "6: stb %3, (%1, 0) \n"
+ " addi %2, 1 \n"
+ " addi %1, 1 \n"
+ " subi %0, 1 \n"
+ " br 5b \n"
+ "7: subi %0, 4 \n"
+ "8: subi %0, 4 \n"
+ "12: subi %0, 4 \n"
+ " br 13f \n"
+ ".section __ex_table, \"a\" \n"
+ ".align 2 \n"
+ ".long 2b, 13f \n"
+ ".long 4b, 13f \n"
+ ".long 6b, 13f \n"
+ ".long 9b, 12b \n"
+ ".long 10b, 8b \n"
+ ".long 11b, 7b \n"
+ ".previous \n"
+ "13: \n"
+ : "=r"(n), "=r"(to), "=r"(from), "=r"(w0),
+ "=r"(w1), "=r"(w2), "=r"(w3)
+ : "0"(n), "1"(to), "2"(from)
+ : "memory");
+
return n;
}
EXPORT_SYMBOL(raw_copy_to_user);
-
-/*
- * copy a null terminated string from userspace.
- */
-#define __do_strncpy_from_user(dst, src, count, res) \
-do { \
- int tmp; \
- long faultres; \
- asm volatile( \
- " cmpnei %3, 0 \n" \
- " bf 4f \n" \
- "1: cmpnei %1, 0 \n" \
- " bf 5f \n" \
- "2: ldb %4, (%3, 0) \n" \
- " stb %4, (%2, 0) \n" \
- " cmpnei %4, 0 \n" \
- " bf 3f \n" \
- " addi %3, 1 \n" \
- " addi %2, 1 \n" \
- " subi %1, 1 \n" \
- " br 1b \n" \
- "3: subu %0, %1 \n" \
- " br 5f \n" \
- "4: mov %0, %5 \n" \
- " br 5f \n" \
- ".section __ex_table, \"a\" \n" \
- ".align 2 \n" \
- ".long 2b, 4b \n" \
- ".previous \n" \
- "5: \n" \
- : "=r"(res), "=r"(count), "=r"(dst), \
- "=r"(src), "=r"(tmp), "=r"(faultres) \
- : "5"(-EFAULT), "0"(count), "1"(count), \
- "2"(dst), "3"(src) \
- : "memory", "cc"); \
-} while (0)
-
/*
* __strncpy_from_user: - Copy a NUL terminated string from userspace,
* with less checking.
@@ -80,40 +165,40 @@ do { \
*/
long __strncpy_from_user(char *dst, const char *src, long count)
{
- long res;
+ long res, faultres;
+ int tmp;
- __do_strncpy_from_user(dst, src, count, res);
- return res;
-}
-EXPORT_SYMBOL(__strncpy_from_user);
-
-/*
- * strncpy_from_user: - Copy a NUL terminated string from userspace.
- * @dst: Destination address, in kernel space. This buffer must be at
- * least @count bytes long.
- * @src: Source address, in user space.
- * @count: Maximum number of bytes to copy, including the trailing NUL.
- *
- * Copies a NUL-terminated string from userspace to kernel space.
- *
- * On success, returns the length of the string (not including the trailing
- * NUL).
- *
- * If access to userspace fails, returns -EFAULT (some data may have been
- * copied).
- *
- * If @count is smaller than the length of the string, copies @count bytes
- * and returns @count.
- */
-long strncpy_from_user(char *dst, const char *src, long count)
-{
- long res = -EFAULT;
+ __asm__ __volatile__(
+ " cmpnei %3, 0 \n"
+ " bf 4f \n"
+ "1: cmpnei %1, 0 \n"
+ " bf 5f \n"
+ "2: ldb %4, (%3, 0) \n"
+ " stb %4, (%2, 0) \n"
+ " cmpnei %4, 0 \n"
+ " bf 3f \n"
+ " addi %3, 1 \n"
+ " addi %2, 1 \n"
+ " subi %1, 1 \n"
+ " br 1b \n"
+ "3: subu %0, %1 \n"
+ " br 5f \n"
+ "4: mov %0, %5 \n"
+ " br 5f \n"
+ ".section __ex_table, \"a\" \n"
+ ".align 2 \n"
+ ".long 2b, 4b \n"
+ ".previous \n"
+ "5: \n"
+ : "=r"(res), "=r"(count), "=r"(dst),
+ "=r"(src), "=r"(tmp), "=r"(faultres)
+ : "5"(-EFAULT), "0"(count), "1"(count),
+ "2"(dst), "3"(src)
+ : "memory");
- if (access_ok(src, 1))
- __do_strncpy_from_user(dst, src, count, res);
return res;
}
-EXPORT_SYMBOL(strncpy_from_user);
+EXPORT_SYMBOL(__strncpy_from_user);
/*
* strlen_user: - Get the size of a string in user space.
@@ -126,14 +211,11 @@ EXPORT_SYMBOL(strncpy_from_user);
* On exception, returns 0.
* If the string is too long, returns a value greater than @n.
*/
-long strnlen_user(const char *s, long n)
+long __strnlen_user(const char *s, long n)
{
unsigned long res, tmp;
- if (s == NULL)
- return 0;
-
- asm volatile(
+ __asm__ __volatile__(
" cmpnei %1, 0 \n"
" bf 3f \n"
"1: cmpnei %0, 0 \n"
@@ -156,87 +238,11 @@ long strnlen_user(const char *s, long n)
"5: \n"
: "=r"(n), "=r"(s), "=r"(res), "=r"(tmp)
: "0"(n), "1"(s), "2"(n)
- : "memory", "cc");
+ : "memory");
return res;
}
-EXPORT_SYMBOL(strnlen_user);
-
-#define __do_clear_user(addr, size) \
-do { \
- int __d0, zvalue, tmp; \
- \
- asm volatile( \
- "0: cmpnei %1, 0 \n" \
- " bf 7f \n" \
- " mov %3, %1 \n" \
- " andi %3, 3 \n" \
- " cmpnei %3, 0 \n" \
- " bf 1f \n" \
- " br 5f \n" \
- "1: cmplti %0, 32 \n" /* 4W */ \
- " bt 3f \n" \
- "8: stw %2, (%1, 0) \n" \
- "10: stw %2, (%1, 4) \n" \
- "11: stw %2, (%1, 8) \n" \
- "12: stw %2, (%1, 12) \n" \
- "13: stw %2, (%1, 16) \n" \
- "14: stw %2, (%1, 20) \n" \
- "15: stw %2, (%1, 24) \n" \
- "16: stw %2, (%1, 28) \n" \
- " addi %1, 32 \n" \
- " subi %0, 32 \n" \
- " br 1b \n" \
- "3: cmplti %0, 4 \n" /* 1W */ \
- " bt 5f \n" \
- "4: stw %2, (%1, 0) \n" \
- " addi %1, 4 \n" \
- " subi %0, 4 \n" \
- " br 3b \n" \
- "5: cmpnei %0, 0 \n" /* 1B */ \
- "9: bf 7f \n" \
- "6: stb %2, (%1, 0) \n" \
- " addi %1, 1 \n" \
- " subi %0, 1 \n" \
- " br 5b \n" \
- ".section __ex_table,\"a\" \n" \
- ".align 2 \n" \
- ".long 8b, 9b \n" \
- ".long 10b, 9b \n" \
- ".long 11b, 9b \n" \
- ".long 12b, 9b \n" \
- ".long 13b, 9b \n" \
- ".long 14b, 9b \n" \
- ".long 15b, 9b \n" \
- ".long 16b, 9b \n" \
- ".long 4b, 9b \n" \
- ".long 6b, 9b \n" \
- ".previous \n" \
- "7: \n" \
- : "=r"(size), "=r" (__d0), \
- "=r"(zvalue), "=r"(tmp) \
- : "0"(size), "1"(addr), "2"(0) \
- : "memory", "cc"); \
-} while (0)
-
-/*
- * clear_user: - Zero a block of memory in user space.
- * @to: Destination address, in user space.
- * @n: Number of bytes to zero.
- *
- * Zero a block of memory in user space.
- *
- * Returns number of bytes that could not be cleared.
- * On success, this will be zero.
- */
-unsigned long
-clear_user(void __user *to, unsigned long n)
-{
- if (access_ok(to, n))
- __do_clear_user(to, n);
- return n;
-}
-EXPORT_SYMBOL(clear_user);
+EXPORT_SYMBOL(__strnlen_user);
/*
* __clear_user: - Zero a block of memory in user space, with less checking.
@@ -252,7 +258,59 @@ EXPORT_SYMBOL(clear_user);
unsigned long
__clear_user(void __user *to, unsigned long n)
{
- __do_clear_user(to, n);
+ int data, value, tmp;
+
+ __asm__ __volatile__(
+ "0: cmpnei %1, 0 \n"
+ " bf 7f \n"
+ " mov %3, %1 \n"
+ " andi %3, 3 \n"
+ " cmpnei %3, 0 \n"
+ " bf 1f \n"
+ " br 5f \n"
+ "1: cmplti %0, 32 \n" /* 4W */
+ " bt 3f \n"
+ "8: stw %2, (%1, 0) \n"
+ "10: stw %2, (%1, 4) \n"
+ "11: stw %2, (%1, 8) \n"
+ "12: stw %2, (%1, 12) \n"
+ "13: stw %2, (%1, 16) \n"
+ "14: stw %2, (%1, 20) \n"
+ "15: stw %2, (%1, 24) \n"
+ "16: stw %2, (%1, 28) \n"
+ " addi %1, 32 \n"
+ " subi %0, 32 \n"
+ " br 1b \n"
+ "3: cmplti %0, 4 \n" /* 1W */
+ " bt 5f \n"
+ "4: stw %2, (%1, 0) \n"
+ " addi %1, 4 \n"
+ " subi %0, 4 \n"
+ " br 3b \n"
+ "5: cmpnei %0, 0 \n" /* 1B */
+ "9: bf 7f \n"
+ "6: stb %2, (%1, 0) \n"
+ " addi %1, 1 \n"
+ " subi %0, 1 \n"
+ " br 5b \n"
+ ".section __ex_table,\"a\" \n"
+ ".align 2 \n"
+ ".long 8b, 9b \n"
+ ".long 10b, 9b \n"
+ ".long 11b, 9b \n"
+ ".long 12b, 9b \n"
+ ".long 13b, 9b \n"
+ ".long 14b, 9b \n"
+ ".long 15b, 9b \n"
+ ".long 16b, 9b \n"
+ ".long 4b, 9b \n"
+ ".long 6b, 9b \n"
+ ".previous \n"
+ "7: \n"
+ : "=r"(n), "=r" (data), "=r"(value), "=r"(tmp)
+ : "0"(n), "1"(to), "2"(0)
+ : "memory");
+
return n;
}
EXPORT_SYMBOL(__clear_user);
diff --git a/arch/csky/mm/fault.c b/arch/csky/mm/fault.c
index 1482de5..466ad94 100644
--- a/arch/csky/mm/fault.c
+++ b/arch/csky/mm/fault.c
@@ -12,7 +12,7 @@ int fixup_exception(struct pt_regs *regs)
fixup = search_exception_tables(instruction_pointer(regs));
if (fixup) {
- regs->pc = fixup->nextinsn;
+ regs->pc = fixup->fixup;
return 1;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH] csky: uaccess.h: Coding convention with asm generic
2021-04-21 8:54 [PATCH] csky: uaccess.h: Coding convention with asm generic guoren
@ 2021-04-21 14:48 ` Christoph Hellwig
2021-04-28 3:18 ` Guenter Roeck
1 sibling, 0 replies; 9+ messages in thread
From: Christoph Hellwig @ 2021-04-21 14:48 UTC (permalink / raw)
To: guoren; +Cc: arnd, linux-kernel, linux-csky, linux-arch, Guo Ren
On Wed, Apr 21, 2021 at 08:54:15AM +0000, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Using asm-generic/uaccess.h to prevent duplicated code:
> - Add user_addr_max which mentioned in generic uaccess.h
> - Remove custom definitions of KERNEL/USER_DS, get/set_fs,
> uaccess_kerenl
Instead of using the generic definitions removing support for set_fs
entirely would be much preferred. The series in linux-next for mips,
or the riscv version that landed in 5.10 might be good examples.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] csky: uaccess.h: Coding convention with asm generic
2021-04-21 8:54 [PATCH] csky: uaccess.h: Coding convention with asm generic guoren
2021-04-21 14:48 ` Christoph Hellwig
@ 2021-04-28 3:18 ` Guenter Roeck
2021-04-28 8:29 ` Guo Ren
1 sibling, 1 reply; 9+ messages in thread
From: Guenter Roeck @ 2021-04-28 3:18 UTC (permalink / raw)
To: guoren; +Cc: arnd, linux-kernel, linux-csky, linux-arch, Guo Ren
On Wed, Apr 21, 2021 at 08:54:15AM +0000, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Using asm-generic/uaccess.h to prevent duplicated code:
> - Add user_addr_max which mentioned in generic uaccess.h
> - Remove custom definitions of KERNEL/USER_DS, get/set_fs,
> uaccess_kerenl
> - Using generic extable.h instead of custom definitions in
> uaccess.h
>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
Building csky:tinyconfig ... failed
--------------
Error log:
csky-linux-ld: fs/readdir.o: in function `__put_user_fn':
readdir.c:(.text+0x7c): undefined reference to `__put_user_bad'
csky-linux-ld: fs/readdir.o: in function `$d':
readdir.c:(.text+0x1bc): undefined reference to `__put_user_bad'
make[1]: *** [Makefile:1277: vmlinux] Error 1
make: *** [Makefile:222: __sub-make] Error 2
Bisect log attached.
Guenter
---
# bad: [3f1fee3e7237347f09a2c7fa538119e6d9ea4b84] Add linux-next specific files for 20210426
# good: [9f4ad9e425a1d3b6a34617b8ea226d56a119a717] Linux 5.12
git bisect start 'HEAD' 'v5.12'
# bad: [bb8f486776983897309645c98705670c3d2a16e5] Merge remote-tracking branch 'crypto/master'
git bisect bad bb8f486776983897309645c98705670c3d2a16e5
# bad: [6ab4f4364c450991a476eef5bc57bef3586354ed] Merge remote-tracking branch 'jc_docs/docs-next'
git bisect bad 6ab4f4364c450991a476eef5bc57bef3586354ed
# bad: [fd73cab0b2a046136842b23f027dae3686588ba5] Merge remote-tracking branch 'parisc-hd/for-next'
git bisect bad fd73cab0b2a046136842b23f027dae3686588ba5
# good: [f0e6103e023e0ede67848ddcd6b07044574f4fd3] soc: document merges
git bisect good f0e6103e023e0ede67848ddcd6b07044574f4fd3
# good: [70361dc0add47d3818acf9c33718ce7395f8aaa5] Merge remote-tracking branch 'arm-soc/for-next'
git bisect good 70361dc0add47d3818acf9c33718ce7395f8aaa5
# good: [f62ad9f6e1100e3a1b6ca7a004fd5a972ff768df] Merge remote-tracking branch 'ti-k3/ti-k3-next'
git bisect good f62ad9f6e1100e3a1b6ca7a004fd5a972ff768df
# bad: [b3b33dda4fd25e201c77f0ce9277dd34f31e86ce] Merge remote-tracking branch 'h8300/h8300-next'
git bisect bad b3b33dda4fd25e201c77f0ce9277dd34f31e86ce
# good: [6a861bd8cf3c96f5825d031732e365b7721a84a5] Merge branch 'clk-qcom' into clk-next
git bisect good 6a861bd8cf3c96f5825d031732e365b7721a84a5
# good: [1dd129f1deec0606fb70992521a7e5bcd2f85c69] Merge branch 'clk-qcom' into clk-next
git bisect good 1dd129f1deec0606fb70992521a7e5bcd2f85c69
# good: [8808515be0ed4e33de9bfdc65f4c1b547ee11065] h8300: Replace <linux/clk-provider.h> by <linux/of_clk.h>
git bisect good 8808515be0ed4e33de9bfdc65f4c1b547ee11065
# good: [e27d3ecdeb8923f35cb856fd20be14256aaa7575] Merge remote-tracking branch 'clk/clk-next'
git bisect good e27d3ecdeb8923f35cb856fd20be14256aaa7575
# bad: [d3900e8d918f8fbd1366b9c2998e2830e66a0081] csky: uaccess.h: Coding convention with asm generic
git bisect bad d3900e8d918f8fbd1366b9c2998e2830e66a0081
# good: [0b1f557a1fa02174a982f557581e348d91987ec6] csky: Fixup typos
git bisect good 0b1f557a1fa02174a982f557581e348d91987ec6
# good: [8bfe70e696584deeed1de1bcbfcde405aa1a1344] csky: fix syscache.c fallthrough warning
git bisect good 8bfe70e696584deeed1de1bcbfcde405aa1a1344
# first bad commit: [d3900e8d918f8fbd1366b9c2998e2830e66a0081] csky: uaccess.h: Coding convention with asm generic
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] csky: uaccess.h: Coding convention with asm generic
2021-04-28 3:18 ` Guenter Roeck
@ 2021-04-28 8:29 ` Guo Ren
2021-04-28 9:25 ` Arnd Bergmann
0 siblings, 1 reply; 9+ messages in thread
From: Guo Ren @ 2021-04-28 8:29 UTC (permalink / raw)
To: Guenter Roeck
Cc: Arnd Bergmann, Linux Kernel Mailing List, linux-csky, linux-arch,
Guo Ren
Thx, Guenter
On Wed, Apr 28, 2021 at 11:18 AM Guenter Roeck <linux@roeck-us.net> wrote:
>
> On Wed, Apr 21, 2021 at 08:54:15AM +0000, guoren@kernel.org wrote:
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > Using asm-generic/uaccess.h to prevent duplicated code:
> > - Add user_addr_max which mentioned in generic uaccess.h
> > - Remove custom definitions of KERNEL/USER_DS, get/set_fs,
> > uaccess_kerenl
> > - Using generic extable.h instead of custom definitions in
> > uaccess.h
> >
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > Cc: Arnd Bergmann <arnd@arndb.de>
>
> Building csky:tinyconfig ... failed
> --------------
> Error log:
> csky-linux-ld: fs/readdir.o: in function `__put_user_fn':
> readdir.c:(.text+0x7c): undefined reference to `__put_user_bad'
> csky-linux-ld: fs/readdir.o: in function `$d':
> readdir.c:(.text+0x1bc): undefined reference to `__put_user_bad'
> make[1]: *** [Makefile:1277: vmlinux] Error 1
> make: *** [Makefile:222: __sub-make] Error 2
It's a bug, I can't put __put_user_bad in __put_user_fn, and
__put_user has done that:
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
* This version just falls back to copy_{from,to}_user, which should
* provide a fast-path for small values.
*/
#define __put_user(x, ptr) \
({ \
__typeof__(*(ptr)) __x = (x); \
int __pu_err = -EFAULT; \
__chk_user_ptr(ptr); \
switch (sizeof (*(ptr))) { \
case 1: \
case 2: \
case 4: \
case 8: \
__pu_err = __put_user_fn(sizeof (*(ptr)), \
ptr, &__x); \
break; \
default: \
__put_user_bad(); \
break; \
} \
__pu_err; \
})
Also, the same problem in __get_user, and I didn't implement "case 8:".
I'll fix up it in another patch and implement __get_user_case_8
(similar with arch/arc.)
>
> Bisect log attached.
>
> Guenter
>
> ---
> # bad: [3f1fee3e7237347f09a2c7fa538119e6d9ea4b84] Add linux-next specific files for 20210426
> # good: [9f4ad9e425a1d3b6a34617b8ea226d56a119a717] Linux 5.12
> git bisect start 'HEAD' 'v5.12'
> # bad: [bb8f486776983897309645c98705670c3d2a16e5] Merge remote-tracking branch 'crypto/master'
> git bisect bad bb8f486776983897309645c98705670c3d2a16e5
> # bad: [6ab4f4364c450991a476eef5bc57bef3586354ed] Merge remote-tracking branch 'jc_docs/docs-next'
> git bisect bad 6ab4f4364c450991a476eef5bc57bef3586354ed
> # bad: [fd73cab0b2a046136842b23f027dae3686588ba5] Merge remote-tracking branch 'parisc-hd/for-next'
> git bisect bad fd73cab0b2a046136842b23f027dae3686588ba5
> # good: [f0e6103e023e0ede67848ddcd6b07044574f4fd3] soc: document merges
> git bisect good f0e6103e023e0ede67848ddcd6b07044574f4fd3
> # good: [70361dc0add47d3818acf9c33718ce7395f8aaa5] Merge remote-tracking branch 'arm-soc/for-next'
> git bisect good 70361dc0add47d3818acf9c33718ce7395f8aaa5
> # good: [f62ad9f6e1100e3a1b6ca7a004fd5a972ff768df] Merge remote-tracking branch 'ti-k3/ti-k3-next'
> git bisect good f62ad9f6e1100e3a1b6ca7a004fd5a972ff768df
> # bad: [b3b33dda4fd25e201c77f0ce9277dd34f31e86ce] Merge remote-tracking branch 'h8300/h8300-next'
> git bisect bad b3b33dda4fd25e201c77f0ce9277dd34f31e86ce
> # good: [6a861bd8cf3c96f5825d031732e365b7721a84a5] Merge branch 'clk-qcom' into clk-next
> git bisect good 6a861bd8cf3c96f5825d031732e365b7721a84a5
> # good: [1dd129f1deec0606fb70992521a7e5bcd2f85c69] Merge branch 'clk-qcom' into clk-next
> git bisect good 1dd129f1deec0606fb70992521a7e5bcd2f85c69
> # good: [8808515be0ed4e33de9bfdc65f4c1b547ee11065] h8300: Replace <linux/clk-provider.h> by <linux/of_clk.h>
> git bisect good 8808515be0ed4e33de9bfdc65f4c1b547ee11065
> # good: [e27d3ecdeb8923f35cb856fd20be14256aaa7575] Merge remote-tracking branch 'clk/clk-next'
> git bisect good e27d3ecdeb8923f35cb856fd20be14256aaa7575
> # bad: [d3900e8d918f8fbd1366b9c2998e2830e66a0081] csky: uaccess.h: Coding convention with asm generic
> git bisect bad d3900e8d918f8fbd1366b9c2998e2830e66a0081
> # good: [0b1f557a1fa02174a982f557581e348d91987ec6] csky: Fixup typos
> git bisect good 0b1f557a1fa02174a982f557581e348d91987ec6
> # good: [8bfe70e696584deeed1de1bcbfcde405aa1a1344] csky: fix syscache.c fallthrough warning
> git bisect good 8bfe70e696584deeed1de1bcbfcde405aa1a1344
> # first bad commit: [d3900e8d918f8fbd1366b9c2998e2830e66a0081] csky: uaccess.h: Coding convention with asm generic
--
Best Regards
Guo Ren
ML: https://lore.kernel.org/linux-csky/
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] csky: uaccess.h: Coding convention with asm generic
2021-04-28 8:29 ` Guo Ren
@ 2021-04-28 9:25 ` Arnd Bergmann
2021-04-28 12:49 ` Christoph Hellwig
2021-04-28 13:03 ` Guo Ren
0 siblings, 2 replies; 9+ messages in thread
From: Arnd Bergmann @ 2021-04-28 9:25 UTC (permalink / raw)
To: Guo Ren
Cc: Guenter Roeck, Linux Kernel Mailing List, linux-csky, linux-arch,
Guo Ren, Christoph Hellwig
On Wed, Apr 28, 2021 at 10:30 AM Guo Ren <guoren@kernel.org> wrote:
> On Wed, Apr 28, 2021 at 11:18 AM Guenter Roeck <linux@roeck-us.net> wrote:
> >
> > On Wed, Apr 21, 2021 at 08:54:15AM +0000, guoren@kernel.org wrote:
> > > From: Guo Ren <guoren@linux.alibaba.com>
> > >
> > > Using asm-generic/uaccess.h to prevent duplicated code:
> > > - Add user_addr_max which mentioned in generic uaccess.h
> > > - Remove custom definitions of KERNEL/USER_DS, get/set_fs,
> > > uaccess_kerenl
> > > - Using generic extable.h instead of custom definitions in
> > > uaccess.h
> > >
> > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > > Cc: Arnd Bergmann <arnd@arndb.de>
> >
> > Building csky:tinyconfig ... failed
> > --------------
> > Error log:
> > csky-linux-ld: fs/readdir.o: in function `__put_user_fn':
> > readdir.c:(.text+0x7c): undefined reference to `__put_user_bad'
> > csky-linux-ld: fs/readdir.o: in function `$d':
> > readdir.c:(.text+0x1bc): undefined reference to `__put_user_bad'
> > make[1]: *** [Makefile:1277: vmlinux] Error 1
> > make: *** [Makefile:222: __sub-make] Error 2
> It's a bug, I can't put __put_user_bad in __put_user_fn, and
> __put_user has done that:
>
> /*
> * These are the main single-value transfer routines. They automatically
> * use the right size if we just have the right pointer type.
> * This version just falls back to copy_{from,to}_user, which should
> * provide a fast-path for small values.
> */
> #define __put_user(x, ptr) \
> ({ \
> __typeof__(*(ptr)) __x = (x); \
> int __pu_err = -EFAULT; \
> __chk_user_ptr(ptr); \
> switch (sizeof (*(ptr))) { \
> case 1: \
> case 2: \
> case 4: \
> case 8: \
> __pu_err = __put_user_fn(sizeof (*(ptr)), \
> ptr, &__x); \
> break; \
> default: \
> __put_user_bad(); \
> break; \
> } \
> __pu_err; \
> })
Actually, please don't use the asm-generic __put_user version based
on copy_to_user, we probably have killed it off long ago.
We might want to come up with a new version of asm-generic/uaccess.h
that actually makes it easier to have a sane per-architecture
implementation of the low-level accessors without set_fs().
I've added Christoph to Cc here, he probably has some ideas
on where we should be heading.
One noteworthy aspect is that almost nothing users the low-level
__get_user()/__put_user() helpers any more outside of architecture
specific code, so we may not need to have separate versions
for much longer.
Arnd
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] csky: uaccess.h: Coding convention with asm generic
2021-04-28 9:25 ` Arnd Bergmann
@ 2021-04-28 12:49 ` Christoph Hellwig
2021-04-28 13:07 ` Guo Ren
2021-04-28 13:48 ` Arnd Bergmann
2021-04-28 13:03 ` Guo Ren
1 sibling, 2 replies; 9+ messages in thread
From: Christoph Hellwig @ 2021-04-28 12:49 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Guo Ren, Guenter Roeck, Linux Kernel Mailing List, linux-csky,
linux-arch, Guo Ren, Christoph Hellwig
On Wed, Apr 28, 2021 at 11:25:29AM +0200, Arnd Bergmann wrote:
> Actually, please don't use the asm-generic __put_user version based
> on copy_to_user, we probably have killed it off long ago.
Yes, they are horrible.
> We might want to come up with a new version of asm-generic/uaccess.h
> that actually makes it easier to have a sane per-architecture
> implementation of the low-level accessors without set_fs().
>
> I've added Christoph to Cc here, he probably has some ideas
> on where we should be heading.
I think asm-generic/uaccess.h pretty much only makes sense for
nommu. For that case we can just kill the __{get,put}_user_fn
indirection. I actually have work for that in an old branch.
Trying to use any of asm-generic/uaccess.h for MMU based kernel is
just asking for trouble.
> One noteworthy aspect is that almost nothing users the low-level
> __get_user()/__put_user() helpers any more outside of architecture
> specific code, so we may not need to have separate versions
> for much longer.
Al has been trying to kill them off entirely for a while, and I hope
he'll eventually succeed. That being said the difference should be
that the __ versions just skip the access_ok, so having both is
fairly trivial to implement.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] csky: uaccess.h: Coding convention with asm generic
2021-04-28 9:25 ` Arnd Bergmann
2021-04-28 12:49 ` Christoph Hellwig
@ 2021-04-28 13:03 ` Guo Ren
1 sibling, 0 replies; 9+ messages in thread
From: Guo Ren @ 2021-04-28 13:03 UTC (permalink / raw)
To: Arnd Bergmann
Cc: Guenter Roeck, Linux Kernel Mailing List, linux-csky, linux-arch,
Guo Ren, Christoph Hellwig
On Wed, Apr 28, 2021 at 5:26 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Wed, Apr 28, 2021 at 10:30 AM Guo Ren <guoren@kernel.org> wrote:
> > On Wed, Apr 28, 2021 at 11:18 AM Guenter Roeck <linux@roeck-us.net> wrote:
> > >
> > > On Wed, Apr 21, 2021 at 08:54:15AM +0000, guoren@kernel.org wrote:
> > > > From: Guo Ren <guoren@linux.alibaba.com>
> > > >
> > > > Using asm-generic/uaccess.h to prevent duplicated code:
> > > > - Add user_addr_max which mentioned in generic uaccess.h
> > > > - Remove custom definitions of KERNEL/USER_DS, get/set_fs,
> > > > uaccess_kerenl
> > > > - Using generic extable.h instead of custom definitions in
> > > > uaccess.h
> > > >
> > > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> > > > Cc: Arnd Bergmann <arnd@arndb.de>
> > >
> > > Building csky:tinyconfig ... failed
> > > --------------
> > > Error log:
> > > csky-linux-ld: fs/readdir.o: in function `__put_user_fn':
> > > readdir.c:(.text+0x7c): undefined reference to `__put_user_bad'
> > > csky-linux-ld: fs/readdir.o: in function `$d':
> > > readdir.c:(.text+0x1bc): undefined reference to `__put_user_bad'
> > > make[1]: *** [Makefile:1277: vmlinux] Error 1
> > > make: *** [Makefile:222: __sub-make] Error 2
> > It's a bug, I can't put __put_user_bad in __put_user_fn, and
> > __put_user has done that:
> >
> > /*
> > * These are the main single-value transfer routines. They automatically
> > * use the right size if we just have the right pointer type.
> > * This version just falls back to copy_{from,to}_user, which should
> > * provide a fast-path for small values.
> > */
> > #define __put_user(x, ptr) \
> > ({ \
> > __typeof__(*(ptr)) __x = (x); \
> > int __pu_err = -EFAULT; \
> > __chk_user_ptr(ptr); \
> > switch (sizeof (*(ptr))) { \
> > case 1: \
> > case 2: \
> > case 4: \
> > case 8: \
> > __pu_err = __put_user_fn(sizeof (*(ptr)), \
> > ptr, &__x); \
> > break; \
> > default: \
> > __put_user_bad(); \
> > break; \
> > } \
> > __pu_err; \
> > })
>
> Actually, please don't use the asm-generic __put_user version based
> on copy_to_user, we probably have killed it off long ago.
>
> We might want to come up with a new version of asm-generic/uaccess.h
> that actually makes it easier to have a sane per-architecture
> implementation of the low-level accessors without set_fs().
>
> I've added Christoph to Cc here, he probably has some ideas
> on where we should be heading.
>
> One noteworthy aspect is that almost nothing users the low-level
> __get_user()/__put_user() helpers any more outside of architecture
> specific code, so we may not need to have separate versions
> for much longer.
Thx Arnd, here is my implementation:
#define __put_user_asm_64(x, ptr, err) \
do { \
int tmp; \
int errcode; \
\
__asm__ __volatile__( \
" ldw %3, (%1, 0) \n" \
"1: stw %3, (%2, 0) \n" \
" ldw %3, (%1, 4) \n" \
"2: stw %3, (%2, 4) \n" \
" br 4f \n" \
"3: mov %0, %4 \n" \
" br 4f \n" \
".section __ex_table, \"a\" \n" \
".align 2 \n" \
".long 1b, 3b \n" \
".long 2b, 3b \n" \
".previous \n" \
"4: \n" \
: "=r"(err), "=r"(x), "=r"(ptr), \
"=r"(tmp), "=r"(errcode) \
: "0"(err), "1"(x), "2"(ptr), "3"(0), \
"4"(-EFAULT) \
: "memory"); \
} while (0)
static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
{
int retval = 0;
u32 tmp;
...
case 8:
__put_user_asm_64(x, (u64 *)ptr, retval);
break;
}
return retval;
}
#define __put_user_fn __put_user_fn
#define __get_user_asm_64(x, ptr, err) \
do { \
int tmp; \
int errcode; \
\
__asm__ __volatile__( \
"1: ldw %3, (%2, 0) \n" \
" stw %3, (%1, 0) \n" \
"2: ldw %3, (%2, 4) \n" \
" stw %3, (%1, 4) \n" \
" br 4f \n" \
"3: mov %0, %4 \n" \
" br 4f \n" \
".section __ex_table, \"a\" \n" \
".align 2 \n" \
".long 1b, 3b \n" \
".long 2b, 3b \n" \
".previous \n" \
"4: \n" \
: "=r"(err), "=r"(x), "=r"(ptr), \
"=r"(tmp), "=r"(errcode) \
: "0"(err), "1"(x), "2"(ptr), "3"(0), \
"4"(-EFAULT) \
: "memory"); \
} while (0)
static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
{
int retval;
u32 tmp;
...
case 8:
__get_user_asm_64(x, ptr, retval);
break;
}
return retval;
}
#define __get_user_fn __get_user_fn
--
Best Regards
Guo Ren
ML: https://lore.kernel.org/linux-csky/
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] csky: uaccess.h: Coding convention with asm generic
2021-04-28 12:49 ` Christoph Hellwig
@ 2021-04-28 13:07 ` Guo Ren
2021-04-28 13:48 ` Arnd Bergmann
1 sibling, 0 replies; 9+ messages in thread
From: Guo Ren @ 2021-04-28 13:07 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Arnd Bergmann, Guenter Roeck, Linux Kernel Mailing List,
linux-csky, linux-arch, Guo Ren
On Wed, Apr 28, 2021 at 8:50 PM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Wed, Apr 28, 2021 at 11:25:29AM +0200, Arnd Bergmann wrote:
> > Actually, please don't use the asm-generic __put_user version based
> > on copy_to_user, we probably have killed it off long ago.
>
> Yes, they are horrible.
>
> > We might want to come up with a new version of asm-generic/uaccess.h
> > that actually makes it easier to have a sane per-architecture
> > implementation of the low-level accessors without set_fs().
> >
> > I've added Christoph to Cc here, he probably has some ideas
> > on where we should be heading.
>
> I think asm-generic/uaccess.h pretty much only makes sense for
> nommu. For that case we can just kill the __{get,put}_user_fn
> indirection. I actually have work for that in an old branch.
>
> Trying to use any of asm-generic/uaccess.h for MMU based kernel is
> just asking for trouble.
I still think the arch should base on asm-generic/uaccess.h, not abandon it.
Thx for reviewing.
>
> > One noteworthy aspect is that almost nothing users the low-level
> > __get_user()/__put_user() helpers any more outside of architecture
> > specific code, so we may not need to have separate versions
> > for much longer.
>
> Al has been trying to kill them off entirely for a while, and I hope
> he'll eventually succeed. That being said the difference should be
> that the __ versions just skip the access_ok, so having both is
> fairly trivial to implement.
--
Best Regards
Guo Ren
ML: https://lore.kernel.org/linux-csky/
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] csky: uaccess.h: Coding convention with asm generic
2021-04-28 12:49 ` Christoph Hellwig
2021-04-28 13:07 ` Guo Ren
@ 2021-04-28 13:48 ` Arnd Bergmann
1 sibling, 0 replies; 9+ messages in thread
From: Arnd Bergmann @ 2021-04-28 13:48 UTC (permalink / raw)
To: Christoph Hellwig
Cc: Guo Ren, Guenter Roeck, Linux Kernel Mailing List, linux-csky,
linux-arch, Guo Ren
On Wed, Apr 28, 2021 at 2:49 PM Christoph Hellwig <hch@infradead.org> wrote:
> On Wed, Apr 28, 2021 at 11:25:29AM +0200, Arnd Bergmann wrote:
> > We might want to come up with a new version of asm-generic/uaccess.h
> > that actually makes it easier to have a sane per-architecture
> > implementation of the low-level accessors without set_fs().
> >
> > I've added Christoph to Cc here, he probably has some ideas
> > on where we should be heading.
>
> I think asm-generic/uaccess.h pretty much only makes sense for
> nommu. For that case we can just kill the __{get,put}_user_fn
> indirection. I actually have work for that in an old branch.
>
> Trying to use any of asm-generic/uaccess.h for MMU based kernel is
> just asking for trouble.
The one thing I'd like to see is a generic implementation of the outer
bit that implements handling the variable-length arguments, there are
so many ways that people have gotten that wrong in the past, and
it would be nice if architectures only had to implement a set of fixed-size
accessors that contain the architecture specific inline asm.
There is now a new version for x86 that based on asm-goto with
output, which should in theory provide a better implementation
for any architecture when using gcc-11/clang-11 or higher.
> > One noteworthy aspect is that almost nothing users the low-level
> > __get_user()/__put_user() helpers any more outside of architecture
> > specific code, so we may not need to have separate versions
> > for much longer.
>
> Al has been trying to kill them off entirely for a while, and I hope
> he'll eventually succeed. That being said the difference should be
> that the __ versions just skip the access_ok, so having both is
> fairly trivial to implement.
That is the difference in the interface, but in some of architectures
there is another difference in that the __ version is completely
inlined while the normal version calls an external function.
I could never quite figure out the reason for this difference.
Arnd
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2021-04-28 13:49 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-21 8:54 [PATCH] csky: uaccess.h: Coding convention with asm generic guoren
2021-04-21 14:48 ` Christoph Hellwig
2021-04-28 3:18 ` Guenter Roeck
2021-04-28 8:29 ` Guo Ren
2021-04-28 9:25 ` Arnd Bergmann
2021-04-28 12:49 ` Christoph Hellwig
2021-04-28 13:07 ` Guo Ren
2021-04-28 13:48 ` Arnd Bergmann
2021-04-28 13:03 ` Guo Ren
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