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Subject[tip:locking/core] x86/asm: 'Simplify' GEN_*_RMWcc() macros
Commit-ID:  288e4521f0f6717909933116563e66bb894ae2af
Gitweb: https://git.kernel.org/tip/288e4521f0f6717909933116563e66bb894ae2af
Author: Peter Zijlstra <peterz@infradead.org>
AuthorDate: Wed, 3 Oct 2018 12:34:10 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 16 Oct 2018 17:33:54 +0200

x86/asm: 'Simplify' GEN_*_RMWcc() macros

Currently the GEN_*_RMWcc() macros include a return statement, which
pretty much mandates we directly wrap them in a (inline) function.

Macros with return statements are tricky and, as per the above, limit
use, so remove the return statement and make them
statement-expressions. This allows them to be used more widely.

Also, shuffle the arguments a bit. Place the @cc argument as 3rd, this
makes it consistent between UNARY and BINARY, but more importantly, it
makes the @arg0 argument last.

Since the @arg0 argument is now last, we can do CPP trickery and make
it an optional argument, simplifying the users; 17 out of 18
occurences do not need this argument.

Finally, change to asm symbolic names, instead of the numeric ordering
of operands, which allows us to get rid of __BINARY_RMWcc_ARG and get
cleaner code overall.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: JBeulich@suse.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@alien8.de
Cc: hpa@linux.intel.com
Link: https://lkml.kernel.org/r/20181003130957.108960094@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/atomic.h | 8 ++---
arch/x86/include/asm/atomic64_64.h | 8 ++---
arch/x86/include/asm/bitops.h | 9 ++---
arch/x86/include/asm/local.h | 8 ++---
arch/x86/include/asm/preempt.h | 2 +-
arch/x86/include/asm/refcount.h | 13 +++----
arch/x86/include/asm/rmwcc.h | 69 ++++++++++++++++++++++----------------
7 files changed, 64 insertions(+), 53 deletions(-)

diff --git a/arch/x86/include/asm/atomic.h b/arch/x86/include/asm/atomic.h
index ce84388e540c..ea3d95275b43 100644
--- a/arch/x86/include/asm/atomic.h
+++ b/arch/x86/include/asm/atomic.h
@@ -82,7 +82,7 @@ static __always_inline void arch_atomic_sub(int i, atomic_t *v)
*/
static __always_inline bool arch_atomic_sub_and_test(int i, atomic_t *v)
{
- GEN_BINARY_RMWcc(LOCK_PREFIX "subl", v->counter, "er", i, "%0", e);
+ return GEN_BINARY_RMWcc(LOCK_PREFIX "subl", v->counter, e, "er", i);
}
#define arch_atomic_sub_and_test arch_atomic_sub_and_test

@@ -122,7 +122,7 @@ static __always_inline void arch_atomic_dec(atomic_t *v)
*/
static __always_inline bool arch_atomic_dec_and_test(atomic_t *v)
{
- GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, "%0", e);
+ return GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, e);
}
#define arch_atomic_dec_and_test arch_atomic_dec_and_test

@@ -136,7 +136,7 @@ static __always_inline bool arch_atomic_dec_and_test(atomic_t *v)
*/
static __always_inline bool arch_atomic_inc_and_test(atomic_t *v)
{
- GEN_UNARY_RMWcc(LOCK_PREFIX "incl", v->counter, "%0", e);
+ return GEN_UNARY_RMWcc(LOCK_PREFIX "incl", v->counter, e);
}
#define arch_atomic_inc_and_test arch_atomic_inc_and_test

@@ -151,7 +151,7 @@ static __always_inline bool arch_atomic_inc_and_test(atomic_t *v)
*/
static __always_inline bool arch_atomic_add_negative(int i, atomic_t *v)
{
- GEN_BINARY_RMWcc(LOCK_PREFIX "addl", v->counter, "er", i, "%0", s);
+ return GEN_BINARY_RMWcc(LOCK_PREFIX "addl", v->counter, s, "er", i);
}
#define arch_atomic_add_negative arch_atomic_add_negative

diff --git a/arch/x86/include/asm/atomic64_64.h b/arch/x86/include/asm/atomic64_64.h
index 5f851d92eecd..dadc20adba21 100644
--- a/arch/x86/include/asm/atomic64_64.h
+++ b/arch/x86/include/asm/atomic64_64.h
@@ -73,7 +73,7 @@ static inline void arch_atomic64_sub(long i, atomic64_t *v)
*/
static inline bool arch_atomic64_sub_and_test(long i, atomic64_t *v)
{
- GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, "er", i, "%0", e);
+ return GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, e, "er", i);
}
#define arch_atomic64_sub_and_test arch_atomic64_sub_and_test

@@ -115,7 +115,7 @@ static __always_inline void arch_atomic64_dec(atomic64_t *v)
*/
static inline bool arch_atomic64_dec_and_test(atomic64_t *v)
{
- GEN_UNARY_RMWcc(LOCK_PREFIX "decq", v->counter, "%0", e);
+ return GEN_UNARY_RMWcc(LOCK_PREFIX "decq", v->counter, e);
}
#define arch_atomic64_dec_and_test arch_atomic64_dec_and_test

@@ -129,7 +129,7 @@ static inline bool arch_atomic64_dec_and_test(atomic64_t *v)
*/
static inline bool arch_atomic64_inc_and_test(atomic64_t *v)
{
- GEN_UNARY_RMWcc(LOCK_PREFIX "incq", v->counter, "%0", e);
+ return GEN_UNARY_RMWcc(LOCK_PREFIX "incq", v->counter, e);
}
#define arch_atomic64_inc_and_test arch_atomic64_inc_and_test

@@ -144,7 +144,7 @@ static inline bool arch_atomic64_inc_and_test(atomic64_t *v)
*/
static inline bool arch_atomic64_add_negative(long i, atomic64_t *v)
{
- GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, "er", i, "%0", s);
+ return GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, s, "er", i);
}
#define arch_atomic64_add_negative arch_atomic64_add_negative

diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index 9f645ba57dbb..124f9195eb3e 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -217,8 +217,7 @@ static __always_inline void change_bit(long nr, volatile unsigned long *addr)
*/
static __always_inline bool test_and_set_bit(long nr, volatile unsigned long *addr)
{
- GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts),
- *addr, "Ir", nr, "%0", c);
+ return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(bts), *addr, c, "Ir", nr);
}

/**
@@ -264,8 +263,7 @@ static __always_inline bool __test_and_set_bit(long nr, volatile unsigned long *
*/
static __always_inline bool test_and_clear_bit(long nr, volatile unsigned long *addr)
{
- GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btr),
- *addr, "Ir", nr, "%0", c);
+ return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btr), *addr, c, "Ir", nr);
}

/**
@@ -318,8 +316,7 @@ static __always_inline bool __test_and_change_bit(long nr, volatile unsigned lon
*/
static __always_inline bool test_and_change_bit(long nr, volatile unsigned long *addr)
{
- GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc),
- *addr, "Ir", nr, "%0", c);
+ return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc), *addr, c, "Ir", nr);
}

static __always_inline bool constant_test_bit(long nr, const volatile unsigned long *addr)
diff --git a/arch/x86/include/asm/local.h b/arch/x86/include/asm/local.h
index c91083c59845..349a47acaa4a 100644
--- a/arch/x86/include/asm/local.h
+++ b/arch/x86/include/asm/local.h
@@ -53,7 +53,7 @@ static inline void local_sub(long i, local_t *l)
*/
static inline bool local_sub_and_test(long i, local_t *l)
{
- GEN_BINARY_RMWcc(_ASM_SUB, l->a.counter, "er", i, "%0", e);
+ return GEN_BINARY_RMWcc(_ASM_SUB, l->a.counter, e, "er", i);
}

/**
@@ -66,7 +66,7 @@ static inline bool local_sub_and_test(long i, local_t *l)
*/
static inline bool local_dec_and_test(local_t *l)
{
- GEN_UNARY_RMWcc(_ASM_DEC, l->a.counter, "%0", e);
+ return GEN_UNARY_RMWcc(_ASM_DEC, l->a.counter, e);
}

/**
@@ -79,7 +79,7 @@ static inline bool local_dec_and_test(local_t *l)
*/
static inline bool local_inc_and_test(local_t *l)
{
- GEN_UNARY_RMWcc(_ASM_INC, l->a.counter, "%0", e);
+ return GEN_UNARY_RMWcc(_ASM_INC, l->a.counter, e);
}

/**
@@ -93,7 +93,7 @@ static inline bool local_inc_and_test(local_t *l)
*/
static inline bool local_add_negative(long i, local_t *l)
{
- GEN_BINARY_RMWcc(_ASM_ADD, l->a.counter, "er", i, "%0", s);
+ return GEN_BINARY_RMWcc(_ASM_ADD, l->a.counter, s, "er", i);
}

/**
diff --git a/arch/x86/include/asm/preempt.h b/arch/x86/include/asm/preempt.h
index 7f2dbd91fc74..90cb2f36c042 100644
--- a/arch/x86/include/asm/preempt.h
+++ b/arch/x86/include/asm/preempt.h
@@ -88,7 +88,7 @@ static __always_inline void __preempt_count_sub(int val)
*/
static __always_inline bool __preempt_count_dec_and_test(void)
{
- GEN_UNARY_RMWcc("decl", __preempt_count, __percpu_arg(0), e);
+ return GEN_UNARY_RMWcc("decl", __preempt_count, e, __percpu_arg([var]));
}

/*
diff --git a/arch/x86/include/asm/refcount.h b/arch/x86/include/asm/refcount.h
index c92909da0686..a8b5e1e13319 100644
--- a/arch/x86/include/asm/refcount.h
+++ b/arch/x86/include/asm/refcount.h
@@ -79,16 +79,17 @@ static __always_inline void refcount_dec(refcount_t *r)
static __always_inline __must_check
bool refcount_sub_and_test(unsigned int i, refcount_t *r)
{
- GEN_BINARY_SUFFIXED_RMWcc(LOCK_PREFIX "subl",
- "REFCOUNT_CHECK_LT_ZERO counter=\"%0\"",
- r->refs.counter, "er", i, "%0", e, "cx");
+
+ return GEN_BINARY_SUFFIXED_RMWcc(LOCK_PREFIX "subl",
+ "REFCOUNT_CHECK_LT_ZERO counter=\"%[var]\"",
+ r->refs.counter, e, "er", i, "cx");
}

static __always_inline __must_check bool refcount_dec_and_test(refcount_t *r)
{
- GEN_UNARY_SUFFIXED_RMWcc(LOCK_PREFIX "decl",
- "REFCOUNT_CHECK_LT_ZERO counter=\"%0\"",
- r->refs.counter, "%0", e, "cx");
+ return GEN_UNARY_SUFFIXED_RMWcc(LOCK_PREFIX "decl",
+ "REFCOUNT_CHECK_LT_ZERO counter=\"%[var]\"",
+ r->refs.counter, e, "cx");
}

static __always_inline __must_check
diff --git a/arch/x86/include/asm/rmwcc.h b/arch/x86/include/asm/rmwcc.h
index 4914a3e7c803..46ac84b506f5 100644
--- a/arch/x86/include/asm/rmwcc.h
+++ b/arch/x86/include/asm/rmwcc.h
@@ -2,56 +2,69 @@
#ifndef _ASM_X86_RMWcc
#define _ASM_X86_RMWcc

+/* This counts to 12. Any more, it will return 13th argument. */
+#define __RMWcc_ARGS(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _n, X...) _n
+#define RMWcc_ARGS(X...) __RMWcc_ARGS(, ##X, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0)
+
+#define __RMWcc_CONCAT(a, b) a ## b
+#define RMWcc_CONCAT(a, b) __RMWcc_CONCAT(a, b)
+
#define __CLOBBERS_MEM(clb...) "memory", ## clb

#if !defined(__GCC_ASM_FLAG_OUTPUTS__) && defined(CC_HAVE_ASM_GOTO)

/* Use asm goto */

-#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \
-do { \
+#define __GEN_RMWcc(fullop, _var, cc, clobbers, ...) \
+({ \
+ bool c = false; \
asm_volatile_goto (fullop "; j" #cc " %l[cc_label]" \
- : : [counter] "m" (var), ## __VA_ARGS__ \
+ : : [var] "m" (_var), ## __VA_ARGS__ \
: clobbers : cc_label); \
- return 0; \
-cc_label: \
- return 1; \
-} while (0)
-
-#define __BINARY_RMWcc_ARG " %1, "
-
+ if (0) { \
+cc_label: c = true; \
+ } \
+ c; \
+})

#else /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */

/* Use flags output or a set instruction */

-#define __GEN_RMWcc(fullop, var, cc, clobbers, ...) \
-do { \
+#define __GEN_RMWcc(fullop, _var, cc, clobbers, ...) \
+({ \
bool c; \
asm volatile (fullop CC_SET(cc) \
- : [counter] "+m" (var), CC_OUT(cc) (c) \
+ : [var] "+m" (_var), CC_OUT(cc) (c) \
: __VA_ARGS__ : clobbers); \
- return c; \
-} while (0)
-
-#define __BINARY_RMWcc_ARG " %2, "
+ c; \
+})

#endif /* defined(__GCC_ASM_FLAG_OUTPUTS__) || !defined(CC_HAVE_ASM_GOTO) */

-#define GEN_UNARY_RMWcc(op, var, arg0, cc) \
+#define GEN_UNARY_RMWcc_4(op, var, cc, arg0) \
__GEN_RMWcc(op " " arg0, var, cc, __CLOBBERS_MEM())

-#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, arg0, cc, clobbers...)\
- __GEN_RMWcc(op " " arg0 "\n\t" suffix, var, cc, \
- __CLOBBERS_MEM(clobbers))
+#define GEN_UNARY_RMWcc_3(op, var, cc) \
+ GEN_UNARY_RMWcc_4(op, var, cc, "%[var]")

-#define GEN_BINARY_RMWcc(op, var, vcon, val, arg0, cc) \
- __GEN_RMWcc(op __BINARY_RMWcc_ARG arg0, var, cc, \
- __CLOBBERS_MEM(), vcon (val))
+#define GEN_UNARY_RMWcc(X...) RMWcc_CONCAT(GEN_UNARY_RMWcc_, RMWcc_ARGS(X))(X)
+
+#define GEN_BINARY_RMWcc_6(op, var, cc, vcon, _val, arg0) \
+ __GEN_RMWcc(op " %[val], " arg0, var, cc, \
+ __CLOBBERS_MEM(), [val] vcon (_val))
+
+#define GEN_BINARY_RMWcc_5(op, var, cc, vcon, val) \
+ GEN_BINARY_RMWcc_6(op, var, cc, vcon, val, "%[var]")
+
+#define GEN_BINARY_RMWcc(X...) RMWcc_CONCAT(GEN_BINARY_RMWcc_, RMWcc_ARGS(X))(X)
+
+#define GEN_UNARY_SUFFIXED_RMWcc(op, suffix, var, cc, clobbers...) \
+ __GEN_RMWcc(op " %[var]\n\t" suffix, var, cc, \
+ __CLOBBERS_MEM(clobbers))

-#define GEN_BINARY_SUFFIXED_RMWcc(op, suffix, var, vcon, val, arg0, cc, \
- clobbers...) \
- __GEN_RMWcc(op __BINARY_RMWcc_ARG arg0 "\n\t" suffix, var, cc, \
- __CLOBBERS_MEM(clobbers), vcon (val))
+#define GEN_BINARY_SUFFIXED_RMWcc(op, suffix, var, cc, vcon, _val, clobbers...)\
+ __GEN_RMWcc(op " %[val], %[var]\n\t" suffix, var, cc, \
+ __CLOBBERS_MEM(clobbers), [val] vcon (_val))

#endif /* _ASM_X86_RMWcc */
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