[-next,V10,10/10] riscv: stack: Add config of thread stack size

Commit Message

Guo Ren Dec. 8, 2022, 2:58 a.m. UTC

From: Guo Ren <[e-mail]>

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/[e-mail]/
Suggested-by: Arnd Bergmann <[e-mail]>
Tested-by: Jisheng Zhang <[e-mail]>
Signed-off-by: Guo Ren <[e-mail]>
Signed-off-by: Guo Ren <[e-mail]>
---
 arch/riscv/Kconfig                   | 10 ++++++++++
 arch/riscv/include/asm/thread_info.h | 12 +-----------
 2 files changed, 11 insertions(+), 11 deletions(-)

Comments

Björn Töpel Dec. 8, 2022, 10:12 a.m. UTC | #1

[e-mail] writes:

> From: Guo Ren <[e-mail]>
>
> 0cac21b02ba5 ("risc v: use 16KB kernel stack on 64-bit") increase the

checkpatch complains here: Use "commit SHA...".

> 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.

...and again, my "why is this in the generic entry" series rant. :-)


Björn

Guo Ren Dec. 9, 2022, 2:11 a.m. UTC | #2

On Thu, Dec 8, 2022 at 6:12 PM Björn Töpel <[e-mail]> wrote:
>
> [e-mail] writes:
>
> > From: Guo Ren <[e-mail]>
> >
> > 0cac21b02ba5 ("risc v: use 16KB kernel stack on 64-bit") increase the
>
> checkpatch complains here: Use "commit SHA...".
Okay, I would check that.

>
> > 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.
>
> ...and again, my "why is this in the generic entry" series rant. :-)
I would remove it from the generic entry series.

>
>
> Björn

Patch

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index bd4c4ae4cdc9..60202cd5c5ae 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -455,6 +455,16 @@  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)
 
 /*