[PATCH -next V9 09/14] riscv: Add config of thread stack size

From: guoren@kernel.org
To: arnd@arndb.de, guoren@kernel.org, palmer@rivosinc.com,
	tglx@linutronix.de, peterz@infradead.org, luto@kernel.org,
	conor.dooley@microchip.com, heiko@sntech.de, jszhang@kernel.org,
	lazyparser@gmail.com, falcon@tinylab.org, chenhuacai@kernel.org,
	apatel@ventanamicro.com, atishp@atishpatra.org,
	palmer@dabbelt.com, paul.walmsley@sifive.com,
	mark.rutland@arm.com, zouyipeng@huawei.com,
	bigeasy@linutronix.de, David.Laight@aculab.com,
	chenzhongjin@huawei.com, greentime.hu@sifive.com,
	andy.chiu@sifive.com, ben@decadent.org.uk
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-riscv@lists.infradead.org,
	Guo Ren <guoren@linux.alibaba.com>
Subject: [PATCH -next V9 09/14] riscv: Add config of thread stack size
Date: Tue, 29 Nov 2022 22:40:54 -0500	[thread overview]
Message-ID: <20221130034059.826599-10-guoren@kernel.org> (raw)
In-Reply-To: <20221130034059.826599-1-guoren@kernel.org>

From: Guo Ren <guoren@linux.alibaba.com>

0cac21b02ba5 ("risc v: use 16KB kernel stack on 64-bit") increase the
thread size mandatory, but some scenarios, such as D1 with a small
memory footprint, would suffer from that. After independent irq stack
support, let's give users a choice to determine their custom stack size.

Link: https://lore.kernel.org/linux-riscv/5f6e6c39-b846-4392-b468-02202404de28@www.fastmail.com/
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
---
 arch/riscv/Kconfig                   | 10 ++++++++++
 arch/riscv/include/asm/thread_info.h | 12 +-----------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 85241415a935..df067b225757 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -454,6 +454,16 @@ config IRQ_STACKS
 	  Add independent irq & softirq stacks for percpu to prevent kernel stack
 	  overflows. We may save some memory footprint by disabling IRQ_STACKS.
 
+config THREAD_SIZE_ORDER
+	int "Kernel stack size (in power-of-two numbers of page size)" if VMAP_STACK && EXPERT
+	range 0 4
+	default 1 if 32BIT && !KASAN
+	default 3 if 64BIT && KASAN
+	default 2
+	help
+	  Specify the Pages of thread stack size (from 4KB to 64KB), which also
+	  affects irq stack size, which is equal to thread stack size.
+
 endmenu # "Platform type"
 
 menu "Kernel features"
diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h
index 043da8ccc7e6..c970d41dc4c6 100644
--- a/arch/riscv/include/asm/thread_info.h
+++ b/arch/riscv/include/asm/thread_info.h
@@ -11,18 +11,8 @@
 #include <asm/page.h>
 #include <linux/const.h>
 
-#ifdef CONFIG_KASAN
-#define KASAN_STACK_ORDER 1
-#else
-#define KASAN_STACK_ORDER 0
-#endif
-
 /* thread information allocation */
-#ifdef CONFIG_64BIT
-#define THREAD_SIZE_ORDER	(2 + KASAN_STACK_ORDER)
-#else
-#define THREAD_SIZE_ORDER	(1 + KASAN_STACK_ORDER)
-#endif
+#define THREAD_SIZE_ORDER	CONFIG_THREAD_SIZE_ORDER
 #define THREAD_SIZE		(PAGE_SIZE << THREAD_SIZE_ORDER)
 
 /*
-- 
2.36.1


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