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From: Yangyu Chen <cyy@cyyself.name>
To: linux-riscv@lists.infradead.org
Cc: "Elliott Hughes" <enh@google.com>,
	"Charlie Jenkins" <charlie@rivosinc.com>,
	"Jonathan Corbet" <corbet@lwn.net>,
	"Paul Walmsley" <paul.walmsley@sifive.com>,
	"Palmer Dabbelt" <palmer@dabbelt.com>,
	"Evan Green" <evan@rivosinc.com>,
	"Clément Léger" <cleger@rivosinc.com>,
	"Conor Dooley" <conor.dooley@microchip.com>,
	"Andrew Jones" <ajones@ventanamicro.com>,
	linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
	"Yangyu Chen" <cyy@cyyself.name>
Subject: [PATCH v2 2/3] docs: riscv: hwprobe: Clarify misaligned keys are values not bitmasks
Date: Fri, 24 May 2024 11:35:58 +0800	[thread overview]
Message-ID: <tencent_AC4A216B8D1B7C7882DCDA648E1AB8653108@qq.com> (raw)
In-Reply-To: <tencent_1E3506F09D08066B8F3BAEE136C4F887540A@qq.com>

The original documentation says hwprobe keys are bitmasks, but actually,
they are values. This patch clarifies this to avoid confusion.

Signed-off-by: Yangyu Chen <cyy@cyyself.name>
---
 Documentation/arch/riscv/hwprobe.rst | 31 ++++++++++++++++------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/Documentation/arch/riscv/hwprobe.rst b/Documentation/arch/riscv/hwprobe.rst
index d720712e9734..2e212956185d 100644
--- a/Documentation/arch/riscv/hwprobe.rst
+++ b/Documentation/arch/riscv/hwprobe.rst
@@ -192,25 +192,30 @@ The following keys are defined:
        supported as defined in the RISC-V ISA manual starting from commit
        d8ab5c78c207 ("Zihintpause is ratified").
 
-* :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: A bitmask that contains performance
+* :c:macro:`RISCV_HWPROBE_KEY_CPUPERF_0`: A value that contains performance
   information about the selected set of processors.
 
-  * :c:macro:`RISCV_HWPROBE_MISALIGNED_UNKNOWN`: The performance of misaligned
-    scalar accesses is unknown.
+  * :c:macro:`RISCV_HWPROBE_MISALIGNED_MASK`: The bitmask of the misaligned
+    access performance field in the value of key `RISCV_HWPROBE_KEY_CPUPERF_0`.
 
-  * :c:macro:`RISCV_HWPROBE_MISALIGNED_EMULATED`: Misaligned scalar accesses are
-    emulated via software, either in or below the kernel.  These accesses are
-    always extremely slow.
+    The following values (not bitmasks) in this field are defined:
 
-  * :c:macro:`RISCV_HWPROBE_MISALIGNED_SLOW`: Misaligned scalar accesses are
-    slower than equivalent byte accesses.  Misaligned accesses may be supported
-    directly in hardware, or trapped and emulated by software.
+    * :c:macro:`RISCV_HWPROBE_MISALIGNED_UNKNOWN`: The performance of misaligned
+      scalar accesses is unknown.
 
-  * :c:macro:`RISCV_HWPROBE_MISALIGNED_FAST`: Misaligned scalar accesses are
-    faster than equivalent byte accesses.
+    * :c:macro:`RISCV_HWPROBE_MISALIGNED_EMULATED`: Misaligned scalar accesses are
+      emulated via software, either in or below the kernel.  These accesses are
+      always extremely slow.
 
-  * :c:macro:`RISCV_HWPROBE_MISALIGNED_UNSUPPORTED`: Misaligned scalar accesses
-    are not supported at all and will generate a misaligned address fault.
+    * :c:macro:`RISCV_HWPROBE_MISALIGNED_SLOW`: Misaligned scalar accesses are
+      slower than equivalent byte accesses.  Misaligned accesses may be supported
+      directly in hardware, or trapped and emulated by software.
+
+    * :c:macro:`RISCV_HWPROBE_MISALIGNED_FAST`: Misaligned scalar accesses are
+      faster than equivalent byte accesses.
+
+    * :c:macro:`RISCV_HWPROBE_MISALIGNED_UNSUPPORTED`: Misaligned scalar accesses
+      are not supported at all and will generate a misaligned address fault.
 
 * :c:macro:`RISCV_HWPROBE_KEY_ZICBOZ_BLOCK_SIZE`: An unsigned int which
   represents the size of the Zicboz block in bytes.
-- 
2.45.1


  parent reply	other threads:[~2024-05-24  3:36 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-24  3:34 [PATCH v2 0/3] docs: riscv: Some clarifies on hwprobe misaligned performance Yangyu Chen
2024-05-24  3:35 ` [PATCH v2 1/3] docs: riscv: Clarify risc-v hwprobe RISCV_HWPROBE_MISALIGNED_* docs Yangyu Chen
2024-05-24  3:35 ` Yangyu Chen [this message]
2024-05-24  3:35 ` [PATCH v2 3/3] RISC-V: hwprobe: not treat KEY_CPUPERF_0 as bitmask Yangyu Chen
2024-05-29 18:33   ` Evan Green
2024-06-26 14:43     ` Palmer Dabbelt

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