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>,
segher@kernel.crashing.org,
Drew Davenport <ddavenport@chromium.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 1/3] powerpc: don't use __WARN() for WARN_ON()
Date: Mon, 19 Aug 2019 13:06:28 +0000 (UTC) [thread overview]
Message-ID: <a6781075192afe0c909ce7d091de7931183a5d93.1566219503.git.christophe.leroy@c-s.fr> (raw)
__WARN() used to just call __WARN_TAINT(TAINT_WARN)
But a call to printk() has been added in the commit identified below
to print a "---- cut here ----" line.
This change only applies to warnings using __WARN(), which means
WARN_ON() where the condition is constant at compile time.
For WARN_ON() with a non constant condition, the additional line is
not printed.
In addition, adding a call to printk() forces GCC to add a stack frame
and save volatile registers. Powerpc has been using traps to implement
warnings in order to avoid that.
So, call __WARN_TAINT(TAINT_WARN) directly instead of using __WARN()
in order to restore the previous behaviour.
If one day powerpc wants the decorative "---- cut here ----" line, it
has to be done in the trap handler, not in the WARN_ON() macro.
Fixes: 6b15f678fb7d ("include/asm-generic/bug.h: fix "cut here" for WARN_ON for __WARN_TAINT architectures")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/include/asm/bug.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index fed7e6241349..3928fdaebb71 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -99,7 +99,7 @@
int __ret_warn_on = !!(x); \
if (__builtin_constant_p(__ret_warn_on)) { \
if (__ret_warn_on) \
- __WARN(); \
+ __WARN_TAINT(TAINT_WARN); \
} else { \
__asm__ __volatile__( \
"1: "PPC_TLNEI" %4,0\n" \
--
2.13.3
next reply other threads:[~2019-08-19 13:06 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-19 13:06 Christophe Leroy [this message]
2019-08-19 13:06 ` [PATCH 2/3] powerpc: refactoring BUG/WARN macros Christophe Leroy
2019-11-25 10:46 ` Michael Ellerman
2019-08-19 13:06 ` [PATCH 3/3] powerpc: use __builtin_trap() in " Christophe Leroy
2019-08-19 13:23 ` Segher Boessenkool
2019-08-19 14:08 ` Christophe Leroy
2019-08-19 14:37 ` Segher Boessenkool
2019-08-19 15:05 ` Christophe Leroy
2019-08-19 15:45 ` Segher Boessenkool
2019-08-23 15:35 ` Christophe Leroy
2019-08-19 16:28 ` [PATCH 1/3] powerpc: don't use __WARN() for WARN_ON() Kees Cook
2019-08-19 17:29 ` Clean up cut-here even harder (was Re: [PATCH 1/3] powerpc: don't use __WARN() for WARN_ON()) Kees Cook
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