From: Ralf Baechle <ralf@linux-mips.org>
To: David Daney <ddaney.cavm@gmail.com>
Cc: "Steven J. Hill" <sjhill@mips.com>, linux-mips@linux-mips.org
Subject: Re: [PATCH] MIPS: microMIPS: Redefine value of BRK_BUG.
Date: Thu, 17 Jan 2013 23:54:10 +0100 [thread overview]
Message-ID: <20130117225410.GB19406@linux-mips.org> (raw)
In-Reply-To: <50F83FD5.2060908@gmail.com>
On Thu, Jan 17, 2013 at 10:15:49AM -0800, David Daney wrote:
> >diff --git a/arch/mips/include/asm/break.h b/arch/mips/include/asm/break.h
> >index 9161e68..df9d090 100644
> >--- a/arch/mips/include/asm/break.h
> >+++ b/arch/mips/include/asm/break.h
> >@@ -27,6 +27,7 @@
> > #define BRK_STACKOVERFLOW 9 /* For Ada stackchecking */
> > #define BRK_NORLD 10 /* No rld found - not used by Linux/MIPS */
> > #define _BRK_THREADBP 11 /* For threads, user bp (used by debuggers) */
> >+#define BRK_BUG_MM 12 /* Used by BUG() in microMIPS mode */
> > #define BRK_BUG 512 /* Used by BUG() */
>
> Can we move the CONFIG_CPU_MICROMIPS to here and just call the thing
> BRK_BUG?
>
> Or perhaps redefining it unconditionally. I am not sure what the
> implications of doing that would be.
>
> That way...
The kernel decodes break and trap instruction in traps.c. For a microMIPS-
enabled kernel it needs to be able to decode both classic and microMIPS
encoded instructions so we want separate symbols.
Or we do something like
#define BRK_MM_BUG 12 /* Used by BUG() in microMIPS mode */
#define BRK_CM_BUG 512 /* Used by BUG() */
#ifdef __mips_micromips
#define BRK_BUG BRK_MM_BUG
#else
#define BRK_BUG BRK_CM_BUG
#endif
This makes the BRK_MM_* / BRK_CM_* macros available for decoding instructions
and the microMIPS-agnostic BRK_BUG for code such as BUG().
> > #define BRK_KDB 513 /* Used in KDB_ENTER() */
> > #define BRK_MEMU 514 /* Used by FPU emulator */
> >diff --git a/arch/mips/include/asm/bug.h b/arch/mips/include/asm/bug.h
> >index 540c98a..b716fb9 100644
> >--- a/arch/mips/include/asm/bug.h
> >+++ b/arch/mips/include/asm/bug.h
> >@@ -7,6 +7,10 @@
> > #ifdef CONFIG_BUG
> >
> > #include <asm/break.h>
> >+#ifdef CONFIG_CPU_MICROMIPS
> >+#undef BRK_BUG
> >+#define BRK_BUG BRK_BUG_MM
> >+#endif
> >
>
> ...We don't need this bit. Doing an #undef risks using different
> values for BRK_BUG depending on whether or not asm/bug.h is
> included.
And generally is not very elegant.
Ralf
next prev parent reply other threads:[~2013-01-17 22:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-17 17:36 [PATCH] MIPS: microMIPS: Redefine value of BRK_BUG Steven J. Hill
2013-01-17 18:15 ` David Daney
2013-01-17 19:07 ` Hill, Steven
2013-01-17 22:54 ` Ralf Baechle [this message]
2013-01-18 0:42 ` David Daney
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