[PATCH 13/17] riscv: Add vector extension XOR implementation

[Chris Stillson]

This patch adds support for vector optimized XOR and it is tested in
qemu.

Co-developed-by: Han-Kuan Chen <hankuan.chen at sifive.com>
Signed-off-by: Han-Kuan Chen <hankuan.chen at sifive.com>
Signed-off-by: Greentime Hu <greentime.hu at sifive.com>
---
 arch/riscv/include/asm/xor.h | 82 ++++++++++++++++++++++++++++++++++++
 arch/riscv/lib/Makefile      |  1 +
 arch/riscv/lib/xor.S         | 81 +++++++++++++++++++++++++++++++++++
 3 files changed, 164 insertions(+)
 create mode 100644 arch/riscv/include/asm/xor.h
 create mode 100644 arch/riscv/lib/xor.S

diff --git a/arch/riscv/include/asm/xor.h b/arch/riscv/include/asm/xor.h
new file mode 100644
index 000000000000..d1f2eeb14afb
--- /dev/null
+++ b/arch/riscv/include/asm/xor.h
@@ -0,0 +1,82 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2021 SiFive
+ */
+
+#include <linux/hardirq.h>
+#include <asm-generic/xor.h>
+#ifdef CONFIG_VECTOR
+#include <asm/vector.h>
+#include <asm/switch_to.h>
+
+void xor_regs_2_(unsigned long bytes, unsigned long * __restrict p1,
+                const unsigned long * __restrict p2);
+void xor_regs_3_(unsigned long bytes, unsigned long * __restrict p1,
+                const unsigned long * __restrict p2,
+                const unsigned long * __restrict p3);
+void xor_regs_4_(unsigned long bytes, unsigned long * __restrict p1,
+                const unsigned long * __restrict p2,
+                const unsigned long * __restrict p3,
+                const unsigned long * __restrict p4);
+void xor_regs_5_(unsigned long bytes, unsigned long * __restrict p1,
+                const unsigned long * __restrict p2,
+                const unsigned long * __restrict p3,
+                const unsigned long * __restrict p4,
+                const unsigned long * __restrict p5);
+
+static void xor_rvv_2(unsigned long bytes, unsigned long * __restrict p1,
+                     const unsigned long * __restrict p2)
+{
+       kernel_rvv_begin();
+       xor_regs_2_(bytes, p1, p2);
+       kernel_rvv_end();
+}
+
+static void xor_rvv_3(unsigned long bytes, unsigned long * __restrict p1,
+                     const unsigned long * __restrict p2,
+                     const unsigned long * __restrict p3)
+{
+       kernel_rvv_begin();
+       xor_regs_3_(bytes, p1, p2, p3);
+       kernel_rvv_end();
+}
+
+static void xor_rvv_4(unsigned long bytes, unsigned long * __restrict p1,
+                     const unsigned long * __restrict p2,
+                     const unsigned long * __restrict p3,
+                     const unsigned long * __restrict p4)
+{
+       kernel_rvv_begin();
+       xor_regs_4_(bytes, p1, p2, p3, p4);
+       kernel_rvv_end();
+}
+
+static void xor_rvv_5(unsigned long bytes, unsigned long * __restrict p1,
+                     const unsigned long * __restrict p2,
+                     const unsigned long * __restrict p3,
+                     const unsigned long * __restrict p4,
+                     const unsigned long * __restrict p5)
+{
+       kernel_rvv_begin();
+       xor_regs_5_(bytes, p1, p2, p3, p4, p5);
+       kernel_rvv_end();
+}
+
+static struct xor_block_template xor_block_rvv = {
+       .name = "rvv",
+       .do_2 = xor_rvv_2,
+       .do_3 = xor_rvv_3,
+       .do_4 = xor_rvv_4,
+       .do_5 = xor_rvv_5
+};
+
+#undef XOR_TRY_TEMPLATES
+#define XOR_TRY_TEMPLATES           \
+       do {        \
+               xor_speed(&xor_block_8regs);    \
+               xor_speed(&xor_block_32regs);    \
+               if (has_vector()) { \
+                       xor_speed(&xor_block_rvv);\
+               } \
+       } while (0)
+#endif
diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 25d5c9664e57..acd87ac86d24 100644
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -7,3 +7,4 @@ lib-$(CONFIG_MMU)       += uaccess.o
 lib-$(CONFIG_64BIT)    += tishift.o

 obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
+lib-$(CONFIG_VECTOR)   += xor.o
diff --git a/arch/riscv/lib/xor.S b/arch/riscv/lib/xor.S
new file mode 100644
index 000000000000..3bc059e18171
--- /dev/null
+++ b/arch/riscv/lib/xor.S
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2021 SiFive
+ */
+#include <linux/linkage.h>
+#include <asm-generic/export.h>
+#include <asm/asm.h>
+
+ENTRY(xor_regs_2_)
+       vsetvli a3, a0, e8, m8, ta, ma
+       vle8.v v0, (a1)
+       vle8.v v8, (a2)
+       sub a0, a0, a3
+       vxor.vv v16, v0, v8
+       add a2, a2, a3
+       vse8.v v16, (a1)
+       add a1, a1, a3
+       bnez a0, xor_regs_2_
+       ret
+END(xor_regs_2_)
+EXPORT_SYMBOL(xor_regs_2_)
+
+ENTRY(xor_regs_3_)
+       vsetvli a4, a0, e8, m8, ta, ma
+       vle8.v v0, (a1)
+       vle8.v v8, (a2)
+       sub a0, a0, a4
+       vxor.vv v0, v0, v8
+       vle8.v v16, (a3)
+       add a2, a2, a4
+       vxor.vv v16, v0, v16
+       add a3, a3, a4
+       vse8.v v16, (a1)
+       add a1, a1, a4
+       bnez a0, xor_regs_3_
+       ret
+END(xor_regs_3_)
+EXPORT_SYMBOL(xor_regs_3_)
+
+ENTRY(xor_regs_4_)
+       vsetvli a5, a0, e8, m8, ta, ma
+       vle8.v v0, (a1)
+       vle8.v v8, (a2)
+       sub a0, a0, a5
+       vxor.vv v0, v0, v8
+       vle8.v v16, (a3)
+       add a2, a2, a5
+       vxor.vv v0, v0, v16
+       vle8.v v24, (a4)
+       add a3, a3, a5
+       vxor.vv v16, v0, v24
+       add a4, a4, a5
+       vse8.v v16, (a1)
+       add a1, a1, a5
+       bnez a0, xor_regs_4_
+       ret
+END(xor_regs_4_)
+EXPORT_SYMBOL(xor_regs_4_)
+
+ENTRY(xor_regs_5_)
+       vsetvli a6, a0, e8, m8, ta, ma
+       vle8.v v0, (a1)
+       vle8.v v8, (a2)
+       sub a0, a0, a6
+       vxor.vv v0, v0, v8
+       vle8.v v16, (a3)
+       add a2, a2, a6
+       vxor.vv v0, v0, v16
+       vle8.v v24, (a4)
+       add a3, a3, a6
+       vxor.vv v0, v0, v24
+       vle8.v v8, (a5)
+       add a4, a4, a6
+       vxor.vv v16, v0, v8
+       add a5, a5, a6
+       vse8.v v16, (a1)
+       add a1, a1, a6
+       bnez a0, xor_regs_5_
+       ret
+END(xor_regs_5_)
+EXPORT_SYMBOL(xor_regs_5_)
--
2.25.1