Unverified Commit a7555f6b authored by Guo Ren's avatar Guo Ren Committed by Palmer Dabbelt
Browse files

riscv: stack: Add config of thread stack size 

The commit 0cac21b0 ("riscv: use 16KB kernel stack on 64-bit")
increases 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: default avatarArnd Bergmann <arnd@arndb.de>
Tested-by: default avatarJisheng Zhang <jszhang@kernel.org>
Signed-off-by: default avatarGuo Ren <guoren@linux.alibaba.com>
Signed-off-by: default avatarGuo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20230614013018.2168426-4-guoren@kernel.org


Signed-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent dd69d07a

arch/riscv/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -599,6 +599,16 @@ 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"

arch/riscv/include/asm/thread_info.h

+1 −11
Original line number Diff line number Diff line
@@ -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)



/*