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-rw-r--r--arch/x86/lib/atomic64_cx8_32.S180
1 files changed, 180 insertions, 0 deletions
diff --git a/arch/x86/lib/atomic64_cx8_32.S b/arch/x86/lib/atomic64_cx8_32.S
new file mode 100644
index 000000000..90afb488b
--- /dev/null
+++ b/arch/x86/lib/atomic64_cx8_32.S
@@ -0,0 +1,180 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * atomic64_t for 586+
+ *
+ * Copyright © 2010 Luca Barbieri
+ */
+
+#include <linux/linkage.h>
+#include <asm/alternative.h>
+
+.macro read64 reg
+ movl %ebx, %eax
+ movl %ecx, %edx
+/* we need LOCK_PREFIX since otherwise cmpxchg8b always does the write */
+ LOCK_PREFIX
+ cmpxchg8b (\reg)
+.endm
+
+SYM_FUNC_START(atomic64_read_cx8)
+ read64 %ecx
+ RET
+SYM_FUNC_END(atomic64_read_cx8)
+
+SYM_FUNC_START(atomic64_set_cx8)
+1:
+/* we don't need LOCK_PREFIX since aligned 64-bit writes
+ * are atomic on 586 and newer */
+ cmpxchg8b (%esi)
+ jne 1b
+
+ RET
+SYM_FUNC_END(atomic64_set_cx8)
+
+SYM_FUNC_START(atomic64_xchg_cx8)
+1:
+ LOCK_PREFIX
+ cmpxchg8b (%esi)
+ jne 1b
+
+ RET
+SYM_FUNC_END(atomic64_xchg_cx8)
+
+.macro addsub_return func ins insc
+SYM_FUNC_START(atomic64_\func\()_return_cx8)
+ pushl %ebp
+ pushl %ebx
+ pushl %esi
+ pushl %edi
+
+ movl %eax, %esi
+ movl %edx, %edi
+ movl %ecx, %ebp
+
+ read64 %ecx
+1:
+ movl %eax, %ebx
+ movl %edx, %ecx
+ \ins\()l %esi, %ebx
+ \insc\()l %edi, %ecx
+ LOCK_PREFIX
+ cmpxchg8b (%ebp)
+ jne 1b
+
+10:
+ movl %ebx, %eax
+ movl %ecx, %edx
+ popl %edi
+ popl %esi
+ popl %ebx
+ popl %ebp
+ RET
+SYM_FUNC_END(atomic64_\func\()_return_cx8)
+.endm
+
+addsub_return add add adc
+addsub_return sub sub sbb
+
+.macro incdec_return func ins insc
+SYM_FUNC_START(atomic64_\func\()_return_cx8)
+ pushl %ebx
+
+ read64 %esi
+1:
+ movl %eax, %ebx
+ movl %edx, %ecx
+ \ins\()l $1, %ebx
+ \insc\()l $0, %ecx
+ LOCK_PREFIX
+ cmpxchg8b (%esi)
+ jne 1b
+
+10:
+ movl %ebx, %eax
+ movl %ecx, %edx
+ popl %ebx
+ RET
+SYM_FUNC_END(atomic64_\func\()_return_cx8)
+.endm
+
+incdec_return inc add adc
+incdec_return dec sub sbb
+
+SYM_FUNC_START(atomic64_dec_if_positive_cx8)
+ pushl %ebx
+
+ read64 %esi
+1:
+ movl %eax, %ebx
+ movl %edx, %ecx
+ subl $1, %ebx
+ sbb $0, %ecx
+ js 2f
+ LOCK_PREFIX
+ cmpxchg8b (%esi)
+ jne 1b
+
+2:
+ movl %ebx, %eax
+ movl %ecx, %edx
+ popl %ebx
+ RET
+SYM_FUNC_END(atomic64_dec_if_positive_cx8)
+
+SYM_FUNC_START(atomic64_add_unless_cx8)
+ pushl %ebp
+ pushl %ebx
+/* these just push these two parameters on the stack */
+ pushl %edi
+ pushl %ecx
+
+ movl %eax, %ebp
+ movl %edx, %edi
+
+ read64 %esi
+1:
+ cmpl %eax, 0(%esp)
+ je 4f
+2:
+ movl %eax, %ebx
+ movl %edx, %ecx
+ addl %ebp, %ebx
+ adcl %edi, %ecx
+ LOCK_PREFIX
+ cmpxchg8b (%esi)
+ jne 1b
+
+ movl $1, %eax
+3:
+ addl $8, %esp
+ popl %ebx
+ popl %ebp
+ RET
+4:
+ cmpl %edx, 4(%esp)
+ jne 2b
+ xorl %eax, %eax
+ jmp 3b
+SYM_FUNC_END(atomic64_add_unless_cx8)
+
+SYM_FUNC_START(atomic64_inc_not_zero_cx8)
+ pushl %ebx
+
+ read64 %esi
+1:
+ movl %eax, %ecx
+ orl %edx, %ecx
+ jz 3f
+ movl %eax, %ebx
+ xorl %ecx, %ecx
+ addl $1, %ebx
+ adcl %edx, %ecx
+ LOCK_PREFIX
+ cmpxchg8b (%esi)
+ jne 1b
+
+ movl $1, %eax
+3:
+ popl %ebx
+ RET
+SYM_FUNC_END(atomic64_inc_not_zero_cx8)