This patch simplifies the code for get_user() and put_user() a lot.
Instead of accessing kernel memory (%sr0) and userspace memory (%sr3)
hard-coded in the assembler instruction, we now preload %sr2 with either
%sr0 (for accessing KERNEL_DS) or with sr3 (to access USER_DS) and
use %sr2 in the load directly.
The generated code avoids a branch and speeds up execution by generating
less assembler instructions.
Signed-off-by: Helge Deller <deller@xxxxxx>
diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h
index fbd2e79..48070f2 100644
--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -40,14 +40,10 @@ static inline long access_ok(int type, const void __user * addr,
#define get_user __get_user
#if !defined(CONFIG_64BIT)
-#define LDD_KERNEL(ptr) BUILD_BUG()
#define LDD_USER(ptr) BUILD_BUG()
-#define STD_KERNEL(x, ptr) __put_kernel_asm64(x, ptr)
#define STD_USER(x, ptr) __put_user_asm64(x, ptr)
#else
-#define LDD_KERNEL(ptr) __get_kernel_asm("ldd", ptr)
#define LDD_USER(ptr) __get_user_asm("ldd", ptr)
-#define STD_KERNEL(x, ptr) __put_kernel_asm("std", x, ptr)
#define STD_USER(x, ptr) __put_user_asm("std", x, ptr)
#endif
@@ -79,43 +75,39 @@ struct exception_data {
unsigned long fault_addr;
};
+/*
+ * load_sr2() preloads the space register %%sr2 - based on the value of
+ * get_fs() - with either a value of 0 to access kernel space (KERNEL_DS which
+ * is 0), or with the current value of %%sr3 to access user space (USER_DS)
+ * memory. The following __get_user_asm() and __put_user_asm() functions have
+ * %%sr2 hard-coded to access the requested memory.
+ */
+#define load_sr2() \
+ __asm__(" or,= %0,%%r0,%%r0\n\t" \
+ " mfsp %%sr3,%0\n\t" \
+ " mtsp %0,%%sr2\n\t" \
+ : : "r"(get_fs()) : )
+
#define __get_user(x, ptr) \
({ \
register long __gu_err __asm__ ("r8") = 0; \
register long __gu_val __asm__ ("r9") = 0; \
\
- if (segment_eq(get_fs(), KERNEL_DS)) { \
- switch (sizeof(*(ptr))) { \
- case 1: __get_kernel_asm("ldb", ptr); break; \
- case 2: __get_kernel_asm("ldh", ptr); break; \
- case 4: __get_kernel_asm("ldw", ptr); break; \
- case 8: LDD_KERNEL(ptr); break; \
- default: BUILD_BUG(); break; \
- } \
- } \
- else { \
- switch (sizeof(*(ptr))) { \
+ load_sr2(); \
+ switch (sizeof(*(ptr))) { \
case 1: __get_user_asm("ldb", ptr); break; \
case 2: __get_user_asm("ldh", ptr); break; \
case 4: __get_user_asm("ldw", ptr); break; \
case 8: LDD_USER(ptr); break; \
default: BUILD_BUG(); break; \
- } \
} \
\
(x) = (__force __typeof__(*(ptr))) __gu_val; \
__gu_err; \
})
-#define __get_kernel_asm(ldx, ptr) \
- __asm__("\n1:\t" ldx "\t0(%2),%0\n\t" \
- ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_1)\
- : "=r"(__gu_val), "=r"(__gu_err) \
- : "r"(ptr), "1"(__gu_err) \
- : "r1");
-
#define __get_user_asm(ldx, ptr) \
- __asm__("\n1:\t" ldx "\t0(%%sr3,%2),%0\n\t" \
+ __asm__("\n1:\t" ldx "\t0(%%sr2,%2),%0\n\t" \
ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_get_user_skip_1)\
: "=r"(__gu_val), "=r"(__gu_err) \
: "r"(ptr), "1"(__gu_err) \
@@ -126,23 +118,13 @@ struct exception_data {
register long __pu_err __asm__ ("r8") = 0; \
__typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x); \
\
- if (segment_eq(get_fs(), KERNEL_DS)) { \
- switch (sizeof(*(ptr))) { \
- case 1: __put_kernel_asm("stb", __x, ptr); break; \
- case 2: __put_kernel_asm("sth", __x, ptr); break; \
- case 4: __put_kernel_asm("stw", __x, ptr); break; \
- case 8: STD_KERNEL(__x, ptr); break; \
- default: BUILD_BUG(); break; \
- } \
- } \
- else { \
- switch (sizeof(*(ptr))) { \
+ load_sr2(); \
+ switch (sizeof(*(ptr))) { \
case 1: __put_user_asm("stb", __x, ptr); break; \
case 2: __put_user_asm("sth", __x, ptr); break; \
case 4: __put_user_asm("stw", __x, ptr); break; \
case 8: STD_USER(__x, ptr); break; \
default: BUILD_BUG(); break; \
- } \
} \
\
__pu_err; \
@@ -158,17 +140,9 @@ struct exception_data {
* r8/r9 are already listed as err/val.
*/
-#define __put_kernel_asm(stx, x, ptr) \
- __asm__ __volatile__ ( \
- "\n1:\t" stx "\t%2,0(%1)\n\t" \
- ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_1)\
- : "=r"(__pu_err) \
- : "r"(ptr), "r"(x), "0"(__pu_err) \
- : "r1")
-
#define __put_user_asm(stx, x, ptr) \
__asm__ __volatile__ ( \
- "\n1:\t" stx "\t%2,0(%%sr3,%1)\n\t" \
+ "\n1:\t" stx "\t%2,0(%%sr2,%1)\n\t" \
ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_1)\
: "=r"(__pu_err) \
: "r"(ptr), "r"(x), "0"(__pu_err) \
@@ -177,21 +151,10 @@ struct exception_data {
#if !defined(CONFIG_64BIT)
-#define __put_kernel_asm64(__val, ptr) do { \
- __asm__ __volatile__ ( \
- "\n1:\tstw %2,0(%1)" \
- "\n2:\tstw %R2,4(%1)\n\t" \
- ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_2)\
- ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_put_user_skip_1)\
- : "=r"(__pu_err) \
- : "r"(ptr), "r"(__val), "0"(__pu_err) \
- : "r1"); \
-} while (0)
-
#define __put_user_asm64(__val, ptr) do { \
__asm__ __volatile__ ( \
- "\n1:\tstw %2,0(%%sr3,%1)" \
- "\n2:\tstw %R2,4(%%sr3,%1)\n\t" \
+ "\n1:\tstw %2,0(%%sr2,%1)" \
+ "\n2:\tstw %R2,4(%%sr2,%1)\n\t" \
ASM_EXCEPTIONTABLE_ENTRY(1b, fixup_put_user_skip_2)\
ASM_EXCEPTIONTABLE_ENTRY(2b, fixup_put_user_skip_1)\
: "=r"(__pu_err) \
--
To unsubscribe from this list: send the line "unsubscribe linux-parisc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
