2022-02-14 18:53:47

by Christophe Leroy

Subject: [PATCH] powerpc: Don't allow the use of EMIT_BUG_ENTRY with BUGFLAG_WARNING

Warnings in assembly must use EMIT_WARN_ENTRY in order to generate
the necessary entry in exception table.

Check in EMIT_BUG_ENTRY that flags don't include BUGFLAG_WARNING.

This change avoids problems like the one fixed by
commit fd1eaaaaa686 ("powerpc/64s: Use EMIT_WARN_ENTRY for SRR debug
warnings").

Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/include/asm/bug.h | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 02c08d1492f8..ecbae1832de3 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -11,7 +11,7 @@
#ifdef __ASSEMBLY__
#include <asm/asm-offsets.h>
#ifdef CONFIG_DEBUG_BUGVERBOSE
-.macro EMIT_BUG_ENTRY addr,file,line,flags
+.macro __EMIT_BUG_ENTRY addr,file,line,flags
.section __bug_table,"aw"
5001: .4byte \addr - 5001b, 5002f - 5001b
.short \line, \flags
@@ -22,7 +22,7 @@
.previous
.endm
#else
-.macro EMIT_BUG_ENTRY addr,file,line,flags
+.macro __EMIT_BUG_ENTRY addr,file,line,flags
.section __bug_table,"aw"
5001: .4byte \addr - 5001b
.short \flags
@@ -33,7 +33,14 @@

.macro EMIT_WARN_ENTRY addr,file,line,flags
EX_TABLE(\addr,\addr+4)
- EMIT_BUG_ENTRY \addr,\file,\line,\flags
+ __EMIT_BUG_ENTRY \addr,\file,\line,\flags
+.endm
+
+.macro EMIT_BUG_ENTRY addr,file,line,flags
+ .if \flags & 1 /* BUGFLAG_WARNING */
+ .err /* Use EMIT_WARN_ENTRY for warnings */
+ .endif
+ __EMIT_BUG_ENTRY \addr,\file,\line,\flags
.endm

#else /* !__ASSEMBLY__ */
--
2.34.1

2022-03-02 13:53:14

by Michael Ellerman

Subject: Re: [PATCH] powerpc: Don't allow the use of EMIT_BUG_ENTRY with BUGFLAG_WARNING

On Sun, 13 Feb 2022 10:02:41 +0100, Christophe Leroy wrote:
> Warnings in assembly must use EMIT_WARN_ENTRY in order to generate
> the necessary entry in exception table.
>
> Check in EMIT_BUG_ENTRY that flags don't include BUGFLAG_WARNING.
>
> This change avoids problems like the one fixed by
> commit fd1eaaaaa686 ("powerpc/64s: Use EMIT_WARN_ENTRY for SRR debug
> warnings").
>
> [...]

Applied to powerpc/next.

[1/1] powerpc: Don't allow the use of EMIT_BUG_ENTRY with BUGFLAG_WARNING
https://git.kernel.org/powerpc/c/38a1756861b8fc2ea9afb93e231194c642a4e261

cheers