9 Aug
2020
9 Aug
'20
6:28 a.m.
Add XCHAL definitions for S32C1I and EXCLUSIVE options to
xtensa-config.h, include it in places that implement atomic operations
and add implementations with exclusive access option opcodes.
Signed-off-by: Max Filippov <jcmvbkbc(a)gmail.com>
---
libc/sysdeps/linux/xtensa/bits/atomic.h | 128 ++++++++++++++++++
.../sysdeps/linux/xtensa/bits/xtensa-config.h | 6 +
.../linuxthreads/sysdeps/xtensa/pt-machine.h | 56 ++++++++
.../nptl/sysdeps/xtensa/pthread_spin_lock.S | 16 +++
.../sysdeps/xtensa/pthread_spin_trylock.S | 17 +++
5 files changed, 223 insertions(+)
diff --git a/libc/sysdeps/linux/xtensa/bits/atomic.h
b/libc/sysdeps/linux/xtensa/bits/atomic.h
index efc027d1ac25..18b809998054 100644
--- a/libc/sysdeps/linux/xtensa/bits/atomic.h
+++ b/libc/sysdeps/linux/xtensa/bits/atomic.h
@@ -18,6 +18,7 @@
#ifndef _BITS_ATOMIC_H
#define _BITS_ATOMIC_H 1
+#include <bits/xtensa-config.h>
#include <inttypes.h>
typedef int32_t atomic32_t;
@@ -50,6 +51,128 @@ typedef uintmax_t uatomic_max_t;
#define __arch_compare_and_exchange_bool_16_rel(mem, newval, oldval) \
(abort (), 0)
+#if XCHAL_HAVE_EXCLUSIVE
+
+/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
+ Return the old *MEM value. */
+
+#define __arch_compare_and_exchange_val_32_acq(mem, newval, oldval) \
+ ({__typeof__(*(mem)) __tmp, __value; \
+ __asm__ __volatile__( \
+ " memw \n" \
+ "1: l32ex %0, %2 \n" \
+ " bne %0, %4, 2f \n" \
+ " mov %1, %3 \n" \
+ " s32ex %1, %2 \n" \
+ " getex %1 \n" \
+ " beqz %1, 1b \n" \
+ " memw \n" \
+ "2: \n" \
+ : "=&a" (__value), "=&a" (__tmp)
\
+ : "a" (mem), "a" (newval), "a" (oldval)
\
+ : "memory" ); \
+ __value; \
+ })
+
+/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
+ Return zero if *MEM was changed or non-zero if no exchange happened. */
+
+#define __arch_compare_and_exchange_bool_32_acq(mem, newval, oldval) \
+ ({__typeof__(*(mem)) __tmp, __value; \
+ __asm__ __volatile__( \
+ " memw \n" \
+ "1: l32ex %0, %2 \n" \
+ " sub %0, %4, %0 \n" \
+ " bnez %0, 2f \n" \
+ " mov %1, %3 \n" \
+ " s32ex %1, %2 \n" \
+ " getex %1 \n" \
+ " beqz %1, 1b \n" \
+ " movi %0, 0 \n" \
+ " memw \n" \
+ "2: \n" \
+ : "=&a" (__value), "=&a" (__tmp)
\
+ : "a" (mem), "a" (newval), "a" (oldval)
\
+ : "memory" ); \
+ __value != 0; \
+ })
+
+/* Store NEWVALUE in *MEM and return the old value. */
+
+#define __arch_exchange_32_acq(mem, newval) \
+ ({__typeof__(*(mem)) __tmp, __value; \
+ __asm__ __volatile__( \
+ " memw \n" \
+ "1: l32ex %0, %2 \n" \
+ " mov %1, %3 \n" \
+ " s32ex %1, %2 \n" \
+ " getex %1 \n" \
+ " beqz %1, 1b \n" \
+ " memw \n" \
+ : "=&a" (__value), "=&a" (__tmp)
\
+ : "a" (mem), "a" (newval)
\
+ : "memory" ); \
+ __value; \
+ })
+
+/* Add VALUE to *MEM and return the old value of *MEM. */
+
+#define __arch_atomic_exchange_and_add_32(mem, value) \
+ ({__typeof__(*(mem)) __tmp, __value; \
+ __asm__ __volatile__( \
+ " memw \n" \
+ "1: l32ex %0, %2 \n" \
+ " add %1, %0, %3 \n" \
+ " s32ex %1, %2 \n" \
+ " getex %1 \n" \
+ " beqz %1, 1b \n" \
+ " memw \n" \
+ : "=&a" (__value), "=&a" (__tmp)
\
+ : "a" (mem), "a" (value)
\
+ : "memory" ); \
+ __value; \
+ })
+
+/* Subtract VALUE from *MEM and return the old value of *MEM. */
+
+#define __arch_atomic_exchange_and_sub_32(mem, value) \
+ ({__typeof__(*(mem)) __tmp, __value; \
+ __asm__ __volatile__( \
+ " memw \n" \
+ "1: l32ex %0, %2 \n" \
+ " sub %1, %0, %3 \n" \
+ " s32ex %1, %2 \n" \
+ " getex %1 \n" \
+ " beqz %1, 1b \n" \
+ " memw \n" \
+ : "=&a" (__value), "=&a" (__tmp)
\
+ : "a" (mem), "a" (value)
\
+ : "memory" ); \
+ __tmp; \
+ })
+
+/* Decrement *MEM if it is > 0, and return the old value. */
+
+#define __arch_atomic_decrement_if_positive_32(mem) \
+ ({__typeof__(*(mem)) __tmp, __value; \
+ __asm__ __volatile__( \
+ " memw \n" \
+ "1: l32ex %0, %2 \n" \
+ " blti %0, 1, 2f \n" \
+ " addi %1, %0, -1 \n" \
+ " s32ex %1, %2 \n" \
+ " getex %1 \n" \
+ " beqz %1, 1b \n" \
+ " memw \n" \
+ "2: \n" \
+ : "=&a" (__value), "=&a" (__tmp)
\
+ : "a" (mem) \
+ : "memory" ); \
+ __value; \
+ })
+
+#elif XCHAL_HAVE_S32C1I
+
/* Atomically store NEWVAL in *MEM if *MEM is equal to OLDVAL.
Return the old *MEM value. */
@@ -156,6 +279,11 @@ typedef uintmax_t uatomic_max_t;
__value; \
})
+#else
+
+#error No hardware atomic operations
+
+#endif
/* These are the preferred public interfaces: */
diff --git a/libc/sysdeps/linux/xtensa/bits/xtensa-config.h
b/libc/sysdeps/linux/xtensa/bits/xtensa-config.h
index 2e60af936e6e..b99928b1e058 100644
--- a/libc/sysdeps/linux/xtensa/bits/xtensa-config.h
+++ b/libc/sysdeps/linux/xtensa/bits/xtensa-config.h
@@ -43,4 +43,10 @@
#undef XCHAL_NUM_AREGS
#define XCHAL_NUM_AREGS 64
+#undef XCHAL_HAVE_S32C1I
+#define XCHAL_HAVE_S32C1I 1
+
+#undef XCHAL_HAVE_EXCLUSIVE
+#define XCHAL_HAVE_EXCLUSIVE 0
+
#endif /* !XTENSA_CONFIG_H */
diff --git a/libpthread/linuxthreads/sysdeps/xtensa/pt-machine.h
b/libpthread/linuxthreads/sysdeps/xtensa/pt-machine.h
index 82d9b540c611..0b7f58b635f3 100644
--- a/libpthread/linuxthreads/sysdeps/xtensa/pt-machine.h
+++ b/libpthread/linuxthreads/sysdeps/xtensa/pt-machine.h
@@ -21,6 +21,7 @@
#ifndef _PT_MACHINE_H
#define _PT_MACHINE_H 1
+#include <bits/xtensa-config.h>
#include <sys/syscall.h>
#include <asm/unistd.h>
@@ -34,6 +35,55 @@
extern long int testandset (int *spinlock);
extern int __compare_and_swap (long int *p, long int oldval, long int newval);
+#if XCHAL_HAVE_EXCLUSIVE
+
+/* Spinlock implementation; required. */
+PT_EI long int
+testandset (int *spinlock)
+{
+ unsigned long tmp;
+ __asm__ volatile (
+" memw \n"
+"1: l32ex %0, %1 \n"
+" bnez %0, 2f \n"
+" movi %0, 1 \n"
+" s32ex %0, %1 \n"
+" getex %0 \n"
+" beqz %0, 1b \n"
+" movi %0, 0 \n"
+" memw \n"
+"2: \n"
+ : "=&a" (tmp)
+ : "a" (spinlock)
+ : "memory"
+ );
+ return tmp;
+}
+
+PT_EI int
+__compare_and_swap (long int *p, long int oldval, long int newval)
+{
+ unsigned long tmp;
+ unsigned long value;
+ __asm__ volatile (
+" memw \n"
+"1: l32ex %0, %2 \n"
+" bne %0, %4, 2f \n"
+" mov %1, %3 \n"
+" s32ex %1, %2 \n"
+" getex %1 \n"
+" beqz %1, 1b \n"
+" memw \n"
+"2: \n"
+ : "=&a" (tmp), "=&a" (value)
+ : "a" (p), "a" (newval), "a" (oldval)
+ : "memory" );
+
+ return tmp == oldval;
+}
+
+#elif XCHAL_HAVE_S32C1I
+
/* Spinlock implementation; required. */
PT_EI long int
testandset (int *spinlock)
@@ -71,6 +121,12 @@ __compare_and_swap (long int *p, long int oldval, long int newval)
return tmp == oldval;
}
+#else
+
+#error No hardware atomic operations
+
+#endif
+
/* Get some notion of the current stack. Need not be exactly the top
of the stack, just something somewhere in the current frame. */
#define CURRENT_STACK_FRAME __builtin_frame_address (0)
diff --git a/libpthread/nptl/sysdeps/xtensa/pthread_spin_lock.S
b/libpthread/nptl/sysdeps/xtensa/pthread_spin_lock.S
index 3386afae9e58..3faac36da12b 100644
--- a/libpthread/nptl/sysdeps/xtensa/pthread_spin_lock.S
+++ b/libpthread/nptl/sysdeps/xtensa/pthread_spin_lock.S
@@ -15,16 +15,32 @@
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <http://www.gnu.org/licenses/>. */
+#include <bits/xtensa-config.h>
#include <sysdep.h>
.text
ENTRY (pthread_spin_lock)
+#if XCHAL_HAVE_EXCLUSIVE
+ memw
+1: l32ex a3, a2
+ bnez a3, 1b
+ movi a3, 1
+ s32ex a3, a2
+ getex a3
+ beqz a3, 1b
+ memw
+#elif XCHAL_HAVE_S32C1I
movi a3, 0
wsr a3, scompare1
movi a3, 1
1: s32c1i a3, a2, 0
bnez a3, 1b
+#else
+
+#error No hardware atomic operations
+
+#endif
movi a2, 0
abi_ret
diff --git a/libpthread/nptl/sysdeps/xtensa/pthread_spin_trylock.S
b/libpthread/nptl/sysdeps/xtensa/pthread_spin_trylock.S
index 72b2dda92310..0669682ec9bd 100644
--- a/libpthread/nptl/sysdeps/xtensa/pthread_spin_trylock.S
+++ b/libpthread/nptl/sysdeps/xtensa/pthread_spin_trylock.S
@@ -17,15 +17,32 @@
#define _ERRNO_H 1
#include <bits/errno.h>
+#include <bits/xtensa-config.h>
#include <sysdep.h>
.text
ENTRY (pthread_spin_trylock)
+#if XCHAL_HAVE_EXCLUSIVE
+ memw
+ l32ex a3, a2
+ bnez a3, 1f
+ movi a3, 1
+ s32ex a3, a2
+ getex a3
+ addi a3, a3, -1
+ memw
+1:
+#elif XCHAL_HAVE_S32C1I
movi a3, 0
wsr a3, scompare1
movi a3, 1
s32c1i a3, a2, 0
+#else
+
+#error No hardware atomic operations
+
+#endif
movi a2, EBUSY
moveqz a2, a3, a3
--
2.20.1