From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 1/3] powerpc/irq: don't use current_stack_pointer() in check_stack_overflow()
Date: Fri, 24 Jan 2020 07:07:52 +0000 (UTC) [thread overview]
Message-ID: <435e0030e942507766cbef5bc95f906262d2ccf2.1579849665.git.christophe.leroy@c-s.fr> (raw)
current_stack_pointer() doesn't return the stack pointer, but the
caller's stack frame. See commit bfe9a2cfe91a ("powerpc: Reimplement
__get_SP() as a function not a define") and commit acf620ecf56c
("powerpc: Rename __get_SP() to current_stack_pointer()") for details.
The purpose of check_stack_overflow() is to verify that the stack has
not overflowed.
To really know whether the stack pointer is still within boundaries,
the check must be done directly on the value of r1.
Define a get_sp() macro to get the value of r1 directly. (Adapted from
arch/powerpc/boot/reg.h)
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
v2: Define a get_sp() macro instead of using asm("r1") locally.
---
arch/powerpc/include/asm/reg.h | 3 +++
arch/powerpc/kernel/irq.c | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 1aa46dff0957..d585f2566338 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1450,6 +1450,9 @@ static inline void mtsrin(u32 val, u32 idx)
extern unsigned long current_stack_pointer(void);
+register unsigned long __stack_pointer asm("r1");
+#define get_sp() (__stack_pointer)
+
extern unsigned long scom970_read(unsigned int address);
extern void scom970_write(unsigned int address, unsigned long value);
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index add67498c126..cd29c2eb2d8e 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -601,7 +601,7 @@ static inline void check_stack_overflow(void)
#ifdef CONFIG_DEBUG_STACKOVERFLOW
long sp;
- sp = current_stack_pointer() & (THREAD_SIZE-1);
+ sp = get_sp() & (THREAD_SIZE - 1);
/* check for stack overflow: is there less than 2KB free? */
if (unlikely(sp < 2048)) {
--
2.25.0
next reply other threads:[~2020-01-24 7:07 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-24 7:07 Christophe Leroy [this message]
2020-01-24 7:07 ` [PATCH v2 2/3] powerpc/irq: use IS_ENABLED() in check_stack_overflow() Christophe Leroy
2020-01-24 7:07 ` [PATCH v2 3/3] powerpc/irq: don't use current_stack_pointer() in do_IRQ() Christophe Leroy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=435e0030e942507766cbef5bc95f906262d2ccf2.1579849665.git.christophe.leroy@c-s.fr \
--to=christophe.leroy@c-s.fr \
--cc=benh@kernel.crashing.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).