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Commit e344e52c authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
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s390/bitops: make use of interlocked-access facility 1 instructions 



Make use of the interlocked-access facility 1 that got added with the
z196 architecure.
This facilility added new instructions which can atomically update a
storage location without a compare-and-swap loop. E.g. setting a bit
within a "long" can be done with a single instruction.

The size of the kernel image gets ~30kb smaller. Considering that there
are appr. 1900 bitops call sites this means that each one saves about
15-16 bytes per call site which is expected.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent e6036c0b

arch/s390/include/asm/bitops.h

+49 −17
Original line number Diff line number Diff line
@@ -65,7 +65,10 @@ extern const char _sb_findmap[]; 
#define __BITOPS_AND		"nr"

#define __BITOPS_XOR		"xr"



#define __BITOPS_LOOP(__old, __new, __addr, __val, __op_string)	\

#define __BITOPS_LOOP(__addr, __val, __op_string)		\

({								\

	unsigned long __old, __new;				\

								\

	asm volatile(						\

		"	l	%0,%2\n"			\

		"0:	lr	%1,%0\n"			\
@@ -75,15 +78,40 @@ extern const char _sb_findmap[]; 
		: "=&d" (__old), "=&d" (__new),			\

		  "=Q" (*(unsigned long *) __addr)		\

		: "d" (__val), "Q" (*(unsigned long *) __addr)	\

		: "cc");

		: "cc");					\

	__old;							\

})



#else /* CONFIG_64BIT */



#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES



#define __BITOPS_OR		"laog"

#define __BITOPS_AND		"lang"

#define __BITOPS_XOR		"laxg"



#define __BITOPS_LOOP(__addr, __val, __op_string)		\

({								\

	unsigned long __old;					\

								\

	asm volatile(						\

		__op_string "	%0,%2,%1\n"			\

		: "=d" (__old),	"+Q" (*(unsigned long *)__addr)	\

		: "d" (__val)					\

		: "cc");					\

	__old;							\

})



#else /* CONFIG_HAVE_MARCH_Z196_FEATURES */



#define __BITOPS_OR		"ogr"

#define __BITOPS_AND		"ngr"

#define __BITOPS_XOR		"xgr"



#define __BITOPS_LOOP(__old, __new, __addr, __val, __op_string)	\

#define __BITOPS_LOOP(__addr, __val, __op_string)		\

({								\

	unsigned long __old, __new;				\

								\

	asm volatile(						\

		"	lg	%0,%2\n"			\

		"0:	lgr	%1,%0\n"			\
@@ -93,7 +121,11 @@ extern const char _sb_findmap[]; 
		: "=&d" (__old), "=&d" (__new),			\

		  "=Q" (*(unsigned long *) __addr)		\

		: "d" (__val), "Q" (*(unsigned long *) __addr)	\

		: "cc");

		: "cc");					\

	__old;							\

})



#endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */



#endif /* CONFIG_64BIT */
@@ -105,7 +137,7 @@ extern const char _sb_findmap[]; 
 */

static inline void set_bit_cs(unsigned long nr, volatile unsigned long *ptr)

{

        unsigned long addr, old, new, mask;

	unsigned long addr, mask;



	addr = (unsigned long) ptr;

	/* calculate address for CS */
@@ -113,7 +145,7 @@ static inline void set_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
	/* make OR mask */

	mask = 1UL << (nr & (BITS_PER_LONG - 1));

	/* Do the atomic update. */

	__BITOPS_LOOP(old, new, addr, mask, __BITOPS_OR);

	__BITOPS_LOOP(addr, mask, __BITOPS_OR);

}



/*
@@ -121,7 +153,7 @@ static inline void set_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
 */

static inline void clear_bit_cs(unsigned long nr, volatile unsigned long *ptr)

{

        unsigned long addr, old, new, mask;

	unsigned long addr, mask;



	addr = (unsigned long) ptr;

	/* calculate address for CS */
@@ -129,7 +161,7 @@ static inline void clear_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
	/* make AND mask */

	mask = ~(1UL << (nr & (BITS_PER_LONG - 1)));

	/* Do the atomic update. */

	__BITOPS_LOOP(old, new, addr, mask, __BITOPS_AND);

	__BITOPS_LOOP(addr, mask, __BITOPS_AND);

}



/*
@@ -137,7 +169,7 @@ static inline void clear_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
 */

static inline void change_bit_cs(unsigned long nr, volatile unsigned long *ptr)

{

        unsigned long addr, old, new, mask;

	unsigned long addr, mask;



	addr = (unsigned long) ptr;

	/* calculate address for CS */
@@ -145,7 +177,7 @@ static inline void change_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
	/* make XOR mask */

	mask = 1UL << (nr & (BITS_PER_LONG - 1));

	/* Do the atomic update. */

	__BITOPS_LOOP(old, new, addr, mask, __BITOPS_XOR);

	__BITOPS_LOOP(addr, mask, __BITOPS_XOR);

}



/*
@@ -154,7 +186,7 @@ static inline void change_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
static inline int

test_and_set_bit_cs(unsigned long nr, volatile unsigned long *ptr)

{

        unsigned long addr, old, new, mask;

	unsigned long addr, old, mask;



	addr = (unsigned long) ptr;

	/* calculate address for CS */
@@ -162,7 +194,7 @@ test_and_set_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
	/* make OR/test mask */

	mask = 1UL << (nr & (BITS_PER_LONG - 1));

	/* Do the atomic update. */

	__BITOPS_LOOP(old, new, addr, mask, __BITOPS_OR);

	old = __BITOPS_LOOP(addr, mask, __BITOPS_OR);

	barrier();

	return (old & mask) != 0;

}
@@ -173,7 +205,7 @@ test_and_set_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
static inline int

test_and_clear_bit_cs(unsigned long nr, volatile unsigned long *ptr)

{

        unsigned long addr, old, new, mask;

	unsigned long addr, old, mask;



	addr = (unsigned long) ptr;

	/* calculate address for CS */
@@ -181,9 +213,9 @@ test_and_clear_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
	/* make AND/test mask */

	mask = ~(1UL << (nr & (BITS_PER_LONG - 1)));

	/* Do the atomic update. */

	__BITOPS_LOOP(old, new, addr, mask, __BITOPS_AND);

	old = __BITOPS_LOOP(addr, mask, __BITOPS_AND);

	barrier();

	return (old ^ new) != 0;

	return (old & ~mask) != 0;

}



/*
@@ -192,7 +224,7 @@ test_and_clear_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
static inline int

test_and_change_bit_cs(unsigned long nr, volatile unsigned long *ptr)

{

        unsigned long addr, old, new, mask;

	unsigned long addr, old, mask;



	addr = (unsigned long) ptr;

	/* calculate address for CS */
@@ -200,7 +232,7 @@ test_and_change_bit_cs(unsigned long nr, volatile unsigned long *ptr) 
	/* make XOR/test mask */

	mask = 1UL << (nr & (BITS_PER_LONG - 1));

	/* Do the atomic update. */

	__BITOPS_LOOP(old, new, addr, mask, __BITOPS_XOR);

	old = __BITOPS_LOOP(addr, mask, __BITOPS_XOR);

	barrier();

	return (old & mask) != 0;

}