Re: [PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN
On Sat, 2010-03-20 at 23:05 +, Ben Hutchings wrote: WARN() is used in some places to report firmware or hardware bugs that are then worked-around. These bugs do not affect the stability of the kernel and should not set the usual TAINT_WARN flag. To allow for this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint flag as argument. .. The architecture-specific changes here are untested and need to be reviewed by architecture maintainers. I'm not one of them, but this at least builds on powerpc FWIW. cheers signature.asc Description: This is a digitally signed message part ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN
On Sat, Mar 20, 2010 at 11:05:40PM +, Ben Hutchings wrote: WARN() is used in some places to report firmware or hardware bugs that are then worked-around. These bugs do not affect the stability of the kernel and should not set the usual TAINT_WARN flag. To allow for this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint flag as argument. Architectures that implement warnings using trap instructions instead of calls to warn_slowpath_*() must now implement __WARN_TAINT(taint) instead of __WARN(). Signed-off-by: Ben Hutchings b...@decadent.org.uk --- The architecture-specific changes here are untested and need to be reviewed by architecture maintainers. I'm a bit confused about how this is supposed to work, the TAINT_xxx values are bit positions presently from 0 to 10, while BUGFLAG_xxx are ranged from 0 up. You've set up BUGFLAG_TAINT() to that the TAINT_xxx value is shifted up 8 bits but neglected the fact that the trap type is 16-bits on most (all?) of the platforms using trap-based BUG handling. If the 'taint' in question is just the TAINT_xxx value by itself and will never be a bitmap then that's fine, but there's certainly not enough room to pass the bitmap in on top of the bugflag otherwise (I don't know if this is your intention or not though). Also note that some platforms (like SH) implement additional bugflags, so we at least want to keep the lower byte available for architecture private use. Having said that, the current patch does work for me, although I'm a bit nervous about someone thinking it's ok to pass in a taint bitmap here. Tested-by: Paul Mundt let...@linux-sh.org ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN
On Mon, 2010-03-22 at 22:47 -0400, Andrew Morton wrote: On Sat, 20 Mar 2010 23:05:40 + Ben Hutchings b...@decadent.org.uk wrote: WARN() is used in some places to report firmware or hardware bugs that are then worked-around. These bugs do not affect the stability of the kernel and should not set the usual TAINT_WARN flag. To allow for this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint flag as argument. Architectures that implement warnings using trap instructions instead of calls to warn_slowpath_*() must now implement __WARN_TAINT(taint) instead of __WARN(). When you say they must now implement, I assume that you mean that they _do_ now implement, and that no additional architecture work is needed. Right, I believe I fixed-up all the current architectures. There might be more architectures out there, unmerged as yet. Ben. -- Ben Hutchings Any smoothly functioning technology is indistinguishable from a rigged demo. signature.asc Description: This is a digitally signed message part ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN
On Tue, 2010-03-23 at 16:45 +0900, Paul Mundt wrote: On Sat, Mar 20, 2010 at 11:05:40PM +, Ben Hutchings wrote: WARN() is used in some places to report firmware or hardware bugs that are then worked-around. These bugs do not affect the stability of the kernel and should not set the usual TAINT_WARN flag. To allow for this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint flag as argument. Architectures that implement warnings using trap instructions instead of calls to warn_slowpath_*() must now implement __WARN_TAINT(taint) instead of __WARN(). Signed-off-by: Ben Hutchings b...@decadent.org.uk --- The architecture-specific changes here are untested and need to be reviewed by architecture maintainers. I'm a bit confused about how this is supposed to work, the TAINT_xxx values are bit positions presently from 0 to 10, while BUGFLAG_xxx are ranged from 0 up. You've set up BUGFLAG_TAINT() to that the TAINT_xxx value is shifted up 8 bits but neglected the fact that the trap type is 16-bits on most (all?) of the platforms using trap-based BUG handling. If the 'taint' in question is just the TAINT_xxx value by itself and will never be a bitmap then that's fine, but there's certainly not enough room to pass the bitmap in on top of the bugflag otherwise (I don't know if this is your intention or not though). Yes, the taint value must be a bit number not a flag. Sloppy wording on my part. Also note that some platforms (like SH) implement additional bugflags, so we at least want to keep the lower byte available for architecture private use. I noticed, that's why I started at 8 not 1. Having said that, the current patch does work for me, although I'm a bit nervous about someone thinking it's ok to pass in a taint bitmap here. We can maybe use BUILD_BUG_ON() here as the taint bit is already required to be a compile-time constant. Ben. Tested-by: Paul Mundt let...@linux-sh.org -- Ben Hutchings Any smoothly functioning technology is indistinguishable from a rigged demo. signature.asc Description: This is a digitally signed message part ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN
On Sat, 20 Mar 2010 23:05:40 + Ben Hutchings b...@decadent.org.uk wrote: WARN() is used in some places to report firmware or hardware bugs that are then worked-around. These bugs do not affect the stability of the kernel and should not set the usual TAINT_WARN flag. To allow for this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint flag as argument. Architectures that implement warnings using trap instructions instead of calls to warn_slowpath_*() must now implement __WARN_TAINT(taint) instead of __WARN(). When you say they must now implement, I assume that you mean that they _do_ now implement, and that no additional architecture work is needed. The architecture-specific changes here are untested and need to be reviewed by architecture maintainers. That would be nice. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN
On Sun, 2010-03-21 at 20:10 +0100, Andi Kleen wrote: Ben Hutchings b...@decadent.org.uk writes: WARN() is used in some places to report firmware or hardware bugs that are then worked-around. These bugs do not affect the stability of the kernel and should not set the usual TAINT_WARN flag. To allow for this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint flag as argument. Architectures that implement warnings using trap instructions instead of calls to warn_slowpath_*() must now implement __WARN_TAINT(taint) instead of __WARN(). I guess this should enforce that at least some taint flag is set? (e.g. with a BUILD_BUG_ON) I'm being a bit sloppy with the wording here. The TAINT_* macros are actually bit numbers, not flags. I could define a TAINT_MAX and add: BUILD_BUG_ON(taint 0 || taint TAINT_MAX); Not sure that that's really worth doing though. Ben. -- Ben Hutchings If you seem to know what you are doing, you'll be given more to do. signature.asc Description: This is a digitally signed message part ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
Re: [PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN
Ben Hutchings b...@decadent.org.uk writes: WARN() is used in some places to report firmware or hardware bugs that are then worked-around. These bugs do not affect the stability of the kernel and should not set the usual TAINT_WARN flag. To allow for this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint flag as argument. Architectures that implement warnings using trap instructions instead of calls to warn_slowpath_*() must now implement __WARN_TAINT(taint) instead of __WARN(). I guess this should enforce that at least some taint flag is set? (e.g. with a BUILD_BUG_ON) -Andi -- a...@linux.intel.com -- Speaking for myself only. ___ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
[PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN
WARN() is used in some places to report firmware or hardware bugs that
are then worked-around. These bugs do not affect the stability of the
kernel and should not set the usual TAINT_WARN flag. To allow for
this, add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint
flag as argument.
Architectures that implement warnings using trap instructions instead
of calls to warn_slowpath_*() must now implement __WARN_TAINT(taint)
instead of __WARN().
Signed-off-by: Ben Hutchings b...@decadent.org.uk
---
The architecture-specific changes here are untested and need to be
reviewed by architecture maintainers.
Ben.
arch/parisc/include/asm/bug.h |8
arch/powerpc/include/asm/bug.h |6 +++---
arch/s390/include/asm/bug.h|8
arch/sh/include/asm/bug.h |4 ++--
include/asm-generic/bug.h | 34 --
kernel/panic.c | 24
lib/bug.c |2 +-
7 files changed, 66 insertions(+), 20 deletions(-)
diff --git a/arch/parisc/include/asm/bug.h b/arch/parisc/include/asm/bug.h
index 75e46c5..72cfdb0 100644
--- a/arch/parisc/include/asm/bug.h
+++ b/arch/parisc/include/asm/bug.h
@@ -44,7 +44,7 @@
#endif
#ifdef CONFIG_DEBUG_BUGVERBOSE
-#define __WARN() \
+#define __WARN_TAINT(taint)\
do {\
asm volatile(\n \
1:\t PARISC_BUG_BREAK_ASM \n \
@@ -54,11 +54,11 @@
\t.org 2b+%c3\n \
\t.popsection\
: : i (__FILE__), i (__LINE__),\
-i (BUGFLAG_WARNING), \
+i (BUGFLAG_TAINT(taint)),\
i (sizeof(struct bug_entry)) ); \
} while(0)
#else
-#define __WARN() \
+#define __WARN_TAINT(taint)\
do {\
asm volatile(\n \
1:\t PARISC_BUG_BREAK_ASM \n \
@@ -67,7 +67,7 @@
\t.short %c0\n \
\t.org 2b+%c1\n \
\t.popsection\
-: : i (BUGFLAG_WARNING), \
+: : i (BUGFLAG_TAINT(taint)),\
i (sizeof(struct bug_entry)) ); \
} while(0)
#endif
diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
index 2c15212..065c590 100644
--- a/arch/powerpc/include/asm/bug.h
+++ b/arch/powerpc/include/asm/bug.h
@@ -85,12 +85,12 @@
} \
} while (0)
-#define __WARN() do { \
+#define __WARN_TAINT(taint) do { \
__asm__ __volatile__( \
1: twi 31,0,0\n \
_EMIT_BUG_ENTRY \
: : i (__FILE__), i (__LINE__), \
- i (BUGFLAG_WARNING),\
+ i (BUGFLAG_TAINT(taint)), \
i (sizeof(struct bug_entry))); \
} while (0)
@@ -104,7 +104,7 @@
1: PPC_TLNEI %4,0\n \
_EMIT_BUG_ENTRY \
: : i (__FILE__), i (__LINE__), \
- i (BUGFLAG_WARNING),\
+ i (BUGFLAG_TAINT(TAINT_WARN)), \
i (sizeof(struct bug_entry)), \
r (__ret_warn_on)); \
} \
diff --git a/arch/s390/include/asm/bug.h b/arch/s390/include/asm/bug.h
index 9beeb9d..bf90d1f 100644
--- a/arch/s390/include/asm/bug.h
+++ b/arch/s390/include/asm/bug.h
@@ -46,18 +46,18 @@
unreachable(); \
} while (0)
-#define __WARN() do { \
- __EMIT_BUG(BUGFLAG_WARNING);\
+#define __WARN_TAINT(taint) do { \
+ __EMIT_BUG(BUGFLAG_TAINT(taint)); \
} while (0)
#define WARN_ON(x) ({ \
int __ret_warn_on = !!(x); \
