v4.19.13 snapshot.
diff --git a/arch/arm/lib/bitops.h b/arch/arm/lib/bitops.h
new file mode 100644
index 0000000..93cddab
--- /dev/null
+++ b/arch/arm/lib/bitops.h
@@ -0,0 +1,107 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <asm/assembler.h>
+#include <asm/unwind.h>
+
+#if __LINUX_ARM_ARCH__ >= 6
+ .macro bitop, name, instr
+ENTRY( \name )
+UNWIND( .fnstart )
+ ands ip, r1, #3
+ strneb r1, [ip] @ assert word-aligned
+ mov r2, #1
+ and r3, r0, #31 @ Get bit offset
+ mov r0, r0, lsr #5
+ add r1, r1, r0, lsl #2 @ Get word offset
+#if __LINUX_ARM_ARCH__ >= 7 && defined(CONFIG_SMP)
+ .arch_extension mp
+ ALT_SMP(W(pldw) [r1])
+ ALT_UP(W(nop))
+#endif
+ mov r3, r2, lsl r3
+1: ldrex r2, [r1]
+ \instr r2, r2, r3
+ strex r0, r2, [r1]
+ cmp r0, #0
+ bne 1b
+ bx lr
+UNWIND( .fnend )
+ENDPROC(\name )
+ .endm
+
+ .macro testop, name, instr, store
+ENTRY( \name )
+UNWIND( .fnstart )
+ ands ip, r1, #3
+ strneb r1, [ip] @ assert word-aligned
+ mov r2, #1
+ and r3, r0, #31 @ Get bit offset
+ mov r0, r0, lsr #5
+ add r1, r1, r0, lsl #2 @ Get word offset
+ mov r3, r2, lsl r3 @ create mask
+ smp_dmb
+#if __LINUX_ARM_ARCH__ >= 7 && defined(CONFIG_SMP)
+ .arch_extension mp
+ ALT_SMP(W(pldw) [r1])
+ ALT_UP(W(nop))
+#endif
+1: ldrex r2, [r1]
+ ands r0, r2, r3 @ save old value of bit
+ \instr r2, r2, r3 @ toggle bit
+ strex ip, r2, [r1]
+ cmp ip, #0
+ bne 1b
+ smp_dmb
+ cmp r0, #0
+ movne r0, #1
+2: bx lr
+UNWIND( .fnend )
+ENDPROC(\name )
+ .endm
+#else
+ .macro bitop, name, instr
+ENTRY( \name )
+UNWIND( .fnstart )
+ ands ip, r1, #3
+ strneb r1, [ip] @ assert word-aligned
+ and r2, r0, #31
+ mov r0, r0, lsr #5
+ mov r3, #1
+ mov r3, r3, lsl r2
+ save_and_disable_irqs ip
+ ldr r2, [r1, r0, lsl #2]
+ \instr r2, r2, r3
+ str r2, [r1, r0, lsl #2]
+ restore_irqs ip
+ ret lr
+UNWIND( .fnend )
+ENDPROC(\name )
+ .endm
+
+/**
+ * testop - implement a test_and_xxx_bit operation.
+ * @instr: operational instruction
+ * @store: store instruction
+ *
+ * Note: we can trivially conditionalise the store instruction
+ * to avoid dirtying the data cache.
+ */
+ .macro testop, name, instr, store
+ENTRY( \name )
+UNWIND( .fnstart )
+ ands ip, r1, #3
+ strneb r1, [ip] @ assert word-aligned
+ and r3, r0, #31
+ mov r0, r0, lsr #5
+ save_and_disable_irqs ip
+ ldr r2, [r1, r0, lsl #2]!
+ mov r0, #1
+ tst r2, r0, lsl r3
+ \instr r2, r2, r0, lsl r3
+ \store r2, [r1]
+ moveq r0, #0
+ restore_irqs ip
+ ret lr
+UNWIND( .fnend )
+ENDPROC(\name )
+ .endm
+#endif