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Commit 06bff6b9 authored by Helge Deller's avatar Helge Deller
Browse files

parisc: Simplify and speed up get_user() and put_user() 



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: default avatarHelge Deller <deller@gmx.de>
Tested-by: default avatarRolf Eike Beer <eike-kernel@sf-tec.de>
parent fc79168a

arch/parisc/include/asm/uaccess.h

+21 −58
Original line number Diff line number Diff line
@@ -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
@@ -80,43 +76,39 @@ 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 {                                           \

	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)		\
@@ -127,23 +119,13 @@ 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 {                                                  \

	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;						\
@@ -159,17 +141,9 @@ 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)	    \
@@ -178,21 +152,10 @@ 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)                            \