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From: Charlie Jenkins <charlie@rivosinc.com>
Date: Mon, 10 Jun 2024 15:56:45 -0700
Subject: [PATCH v2 08/13] riscv: Add xtheadvector instruction definitions
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Message-Id: <20240610-xtheadvector-v2-8-97a48613ad64@rivosinc.com>
References: <20240610-xtheadvector-v2-0-97a48613ad64@rivosinc.com>
In-Reply-To: <20240610-xtheadvector-v2-0-97a48613ad64@rivosinc.com>
To: Conor Dooley <conor@kernel.org>, Rob Herring <robh@kernel.org>, 
 Krzysztof Kozlowski <krzk+dt@kernel.org>, 
 Paul Walmsley <paul.walmsley@sifive.com>, 
 Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, 
 Jisheng Zhang <jszhang@kernel.org>, Chen-Yu Tsai <wens@csie.org>, 
 Jernej Skrabec <jernej.skrabec@gmail.com>, 
 Samuel Holland <samuel@sholland.org>, Jonathan Corbet <corbet@lwn.net>, 
 Shuah Khan <shuah@kernel.org>, Guo Ren <guoren@kernel.org>, 
 Evan Green <evan@rivosinc.com>, Andy Chiu <andy.chiu@sifive.com>, 
 Jessica Clarke <jrtc27@jrtc27.com>
Cc: linux-riscv@lists.infradead.org, devicetree@vger.kernel.org, 
 linux-kernel@vger.kernel.org, linux-sunxi@lists.linux.dev, 
 linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, 
 Charlie Jenkins <charlie@rivosinc.com>, Heiko Stuebner <heiko@sntech.de>

xtheadvector uses different encodings than standard vector for
vsetvli and vector loads/stores. Write the instruction formats to be
used in assembly code.

Co-developed-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Charlie Jenkins <charlie@rivosinc.com>
---
 arch/riscv/include/asm/vendor_extensions/thead.h | 26 ++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/arch/riscv/include/asm/vendor_extensions/thead.h b/arch/riscv/include/asm/vendor_extensions/thead.h
index 48421d1553ad..27a253a20ab8 100644
--- a/arch/riscv/include/asm/vendor_extensions/thead.h
+++ b/arch/riscv/include/asm/vendor_extensions/thead.h
@@ -13,4 +13,30 @@
 
 extern struct riscv_isa_vendor_ext_data_list riscv_isa_vendor_ext_list_thead;
 
+/* Extension specific helpers */
+
+/*
+ * Vector 0.7.1 as used for example on T-Head Xuantie cores, uses an older
+ * encoding for vsetvli (ta, ma vs. d1), so provide an instruction for
+ * vsetvli	t4, x0, e8, m8, d1
+ */
+#define THEAD_VSETVLI_T4X0E8M8D1	".long	0x00307ed7\n\t"
+#define THEAD_VSETVLI_X0X0E8M8D1	".long	0x00307057\n\t"
+
+/*
+ * While in theory, the vector-0.7.1 vsb.v and vlb.v result in the same
+ * encoding as the standard vse8.v and vle8.v, compilers seem to optimize
+ * the call resulting in a different encoding and then using a value for
+ * the "mop" field that is not part of vector-0.7.1
+ * So encode specific variants for vstate_save and _restore.
+ */
+#define THEAD_VSB_V_V0T0		".long	0x02028027\n\t"
+#define THEAD_VSB_V_V8T0		".long	0x02028427\n\t"
+#define THEAD_VSB_V_V16T0		".long	0x02028827\n\t"
+#define THEAD_VSB_V_V24T0		".long	0x02028c27\n\t"
+#define THEAD_VLB_V_V0T0		".long	0x012028007\n\t"
+#define THEAD_VLB_V_V8T0		".long	0x012028407\n\t"
+#define THEAD_VLB_V_V16T0		".long	0x012028807\n\t"
+#define THEAD_VLB_V_V24T0		".long	0x012028c07\n\t"
+
 #endif

-- 
2.44.0