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From: Andy Chiu <andy.chiu@sifive.com>
Date: Fri, 12 Apr 2024 14:48:57 +0800
Subject: [PATCH v4 1/9] riscv: vector: add a comment when calling
 riscv_setup_vsize()
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Message-Id: <20240412-zve-detection-v4-1-e0c45bb6b253@sifive.com>
References: <20240412-zve-detection-v4-0-e0c45bb6b253@sifive.com>
In-Reply-To: <20240412-zve-detection-v4-0-e0c45bb6b253@sifive.com>
To: Paul Walmsley <paul.walmsley@sifive.com>, 
 Palmer Dabbelt <palmer@dabbelt.com>, Albert Ou <aou@eecs.berkeley.edu>, 
 Conor Dooley <conor.dooley@microchip.com>, Heiko Stuebner <heiko@sntech.de>, 
 Andy Chiu <andy.chiu@sifive.com>, Guo Ren <guoren@kernel.org>, 
 Conor Dooley <conor@kernel.org>, Rob Herring <robh@kernel.org>, 
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, 
 Jonathan Corbet <corbet@lwn.net>, Evan Green <evan@rivosinc.com>, 
 =?utf-8?q?Cl=C3=A9ment_L=C3=A9ger?= <cleger@rivosinc.com>, 
 Shuah Khan <shuah@kernel.org>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, 
 Palmer Dabbelt <palmer@rivosinc.com>, 
 Vincent Chen <vincent.chen@sifive.com>, 
 Greentime Hu <greentime.hu@sifive.com>, devicetree@vger.kernel.org, 
 linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org

The function would fail when it detects the calling hart's vlen doesn't
match the first one's. The boot hart is the first hart calling this
function during riscv_fill_hwcap, so it is impossible to fail here. Add
a comment about this behavior.

Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
---
Changelog v2:
 - update the comment (Conor)
---
 arch/riscv/kernel/cpufeature.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/kernel/cpufeature.c b/arch/riscv/kernel/cpufeature.c
index 3ed2359eae35..d22b12072579 100644
--- a/arch/riscv/kernel/cpufeature.c
+++ b/arch/riscv/kernel/cpufeature.c
@@ -683,6 +683,10 @@ void __init riscv_fill_hwcap(void)
 	}
 
 	if (elf_hwcap & COMPAT_HWCAP_ISA_V) {
+		/*
+		 * This callsite can't fail here. It cannot fail when called on
+		 * the boot hart.
+		 */
 		riscv_v_setup_vsize();
 		/*
 		 * ISA string in device tree might have 'v' flag, but

-- 
2.44.0.rc2