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

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.orgSigned-off-by: default avatarPalmer Dabbelt <palmer@rivosinc.com>
parent dd69d07a
......@@ -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"
......
......@@ -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)
/*
......
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