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    SubjectRe: [PATCH 1/4] panic: Allow warnings to set different taint flags
    On 04/03/2010 08:34 PM, 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 flag for TAINT_WARN. To allow for this,
    > add WARN_TAINT() and WARN_TAINT_ONCE() macros that take a taint number
    > as argument.
    >
    > Architectures that implement warnings using trap instructions instead
    > of calls to warn_slowpath_*() now implement __WARN_TAINT(taint)
    > instead of __WARN().
    >
    > Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

    Builds and works on the parisc architecture.
    Acked-by: Helge Deller <deller@gmx.de>


    > ---
    > Changes since the previous version:
    > - Added note to Documentation/oops-tracing.txt
    > - Changed the commit message to distinguish taint numbers from taint
    > flags
    > - Removed 'must' from last sentence of commit message; this patch
    > converts all mainline architectures
    >
    > Ben.
    >
    > Documentation/oops-tracing.txt | 1 +
    > 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 +-
    > 8 files changed, 67 insertions(+), 20 deletions(-)
    >
    > diff --git a/Documentation/oops-tracing.txt b/Documentation/oops-tracing.txt
    > index c10c022..069fab3 100644
    > --- a/Documentation/oops-tracing.txt
    > +++ b/Documentation/oops-tracing.txt
    > @@ -256,6 +256,7 @@ characters, each representing a particular tainted value.
    > 9: 'A' if the ACPI table has been overridden.
    >
    > 10: 'W' if a warning has previously been issued by the kernel.
    > + (Though some warnings may set more specific taint flags.)
    >
    > 11: 'C' if a staging driver has been loaded.
    >
    > 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); \
    > if (__builtin_constant_p(__ret_warn_on)) { \
    > if (__ret_warn_on) \
    > - __EMIT_BUG(BUGFLAG_WARNING); \
    > + __WARN(); \
    > } else { \
    > if (unlikely(__ret_warn_on)) \
    > - __EMIT_BUG(BUGFLAG_WARNING); \
    > + __WARN(); \
    > } \
    > unlikely(__ret_warn_on); \
    > })
    > diff --git a/arch/sh/include/asm/bug.h b/arch/sh/include/asm/bug.h
    > index d02c01b..6323f86 100644
    > --- a/arch/sh/include/asm/bug.h
    > +++ b/arch/sh/include/asm/bug.h
    > @@ -48,7 +48,7 @@ do { \
    > "i" (sizeof(struct bug_entry))); \
    > } while (0)
    >
    > -#define __WARN() \
    > +#define __WARN_TAINT(taint) \
    > do { \
    > __asm__ __volatile__ ( \
    > "1:\t.short %O0\n" \
    > @@ -57,7 +57,7 @@ do { \
    > : "n" (TRAPA_BUG_OPCODE), \
    > "i" (__FILE__), \
    > "i" (__LINE__), \
    > - "i" (BUGFLAG_WARNING), \
    > + "i" (BUGFLAG_TAINT(taint)), \
    > "i" (sizeof(struct bug_entry))); \
    > } while (0)
    >
    > diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
    > index 18c435d..c2c9ba0 100644
    > --- a/include/asm-generic/bug.h
    > +++ b/include/asm-generic/bug.h
    > @@ -25,7 +25,10 @@ struct bug_entry {
    > };
    > #endif /* __ASSEMBLY__ */
    >
    > -#define BUGFLAG_WARNING (1<<0)
    > +#define BUGFLAG_WARNING (1 << 0)
    > +#define BUGFLAG_TAINT(taint) (BUGFLAG_WARNING | ((taint) << 8))
    > +#define BUG_GET_TAINT(bug) ((bug)->flags >> 8)
    > +
    > #endif /* CONFIG_GENERIC_BUG */
    >
    > /*
    > @@ -56,17 +59,25 @@ struct bug_entry {
    > * appear at runtime. Use the versions with printk format strings
    > * to provide better diagnostics.
    > */
    > -#ifndef __WARN
    > +#ifndef __WARN_TAINT
    > #ifndef __ASSEMBLY__
    > extern void warn_slowpath_fmt(const char *file, const int line,
    > const char *fmt, ...) __attribute__((format(printf, 3, 4)));
    > +extern void warn_slowpath_fmt_taint(const char *file, const int line,
    > + unsigned taint, const char *fmt, ...)
    > + __attribute__((format(printf, 4, 5)));
    > extern void warn_slowpath_null(const char *file, const int line);
    > #define WANT_WARN_ON_SLOWPATH
    > #endif
    > #define __WARN() warn_slowpath_null(__FILE__, __LINE__)
    > #define __WARN_printf(arg...) warn_slowpath_fmt(__FILE__, __LINE__, arg)
    > +#define __WARN_printf_taint(taint, arg...) \
    > + warn_slowpath_fmt_taint(__FILE__, __LINE__, taint, arg)
    > #else
    > +#define __WARN() __WARN_TAINT(TAINT_WARN)
    > #define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
    > +#define __WARN_printf_taint(taint, arg...) \
    > + do { printk(arg); __WARN_TAINT(taint); } while (0)
    > #endif
    >
    > #ifndef WARN_ON
    > @@ -87,6 +98,13 @@ extern void warn_slowpath_null(const char *file, const int line);
    > })
    > #endif
    >
    > +#define WARN_TAINT(condition, taint, format...) ({ \
    > + int __ret_warn_on = !!(condition); \
    > + if (unlikely(__ret_warn_on)) \
    > + __WARN_printf_taint(taint, format); \
    > + unlikely(__ret_warn_on); \
    > +})
    > +
    > #else /* !CONFIG_BUG */
    > #ifndef HAVE_ARCH_BUG
    > #define BUG() do {} while(0)
    > @@ -110,6 +128,8 @@ extern void warn_slowpath_null(const char *file, const int line);
    > })
    > #endif
    >
    > +#define WARN_TAINT(condition, taint, format...) WARN_ON(condition)
    > +
    > #endif
    >
    > #define WARN_ON_ONCE(condition) ({ \
    > @@ -132,6 +152,16 @@ extern void warn_slowpath_null(const char *file, const int line);
    > unlikely(__ret_warn_once); \
    > })
    >
    > +#define WARN_TAINT_ONCE(condition, taint, format...) ({ \
    > + static bool __warned; \
    > + int __ret_warn_once = !!(condition); \
    > + \
    > + if (unlikely(__ret_warn_once)) \
    > + if (WARN_TAINT(!__warned, taint, format)) \
    > + __warned = true; \
    > + unlikely(__ret_warn_once); \
    > +})
    > +
    > #define WARN_ON_RATELIMIT(condition, state) \
    > WARN_ON((condition) && __ratelimit(state))
    >
    > diff --git a/kernel/panic.c b/kernel/panic.c
    > index 13d966b..8b821bc 100644
    > --- a/kernel/panic.c
    > +++ b/kernel/panic.c
    > @@ -365,7 +365,8 @@ struct slowpath_args {
    > va_list args;
    > };
    >
    > -static void warn_slowpath_common(const char *file, int line, void *caller, struct slowpath_args *args)
    > +static void warn_slowpath_common(const char *file, int line, void *caller,
    > + unsigned taint, struct slowpath_args *args)
    > {
    > const char *board;
    >
    > @@ -381,7 +382,7 @@ static void warn_slowpath_common(const char *file, int line, void *caller, struc
    > print_modules();
    > dump_stack();
    > print_oops_end_marker();
    > - add_taint(TAINT_WARN);
    > + add_taint(taint);
    > }
    >
    > void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
    > @@ -390,14 +391,29 @@ void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
    >
    > args.fmt = fmt;
    > va_start(args.args, fmt);
    > - warn_slowpath_common(file, line, __builtin_return_address(0), &args);
    > + warn_slowpath_common(file, line, __builtin_return_address(0),
    > + TAINT_WARN, &args);
    > va_end(args.args);
    > }
    > EXPORT_SYMBOL(warn_slowpath_fmt);
    >
    > +void warn_slowpath_fmt_taint(const char *file, int line,
    > + unsigned taint, const char *fmt, ...)
    > +{
    > + struct slowpath_args args;
    > +
    > + args.fmt = fmt;
    > + va_start(args.args, fmt);
    > + warn_slowpath_common(file, line, __builtin_return_address(0),
    > + taint, &args);
    > + va_end(args.args);
    > +}
    > +EXPORT_SYMBOL(warn_slowpath_fmt_taint);
    > +
    > void warn_slowpath_null(const char *file, int line)
    > {
    > - warn_slowpath_common(file, line, __builtin_return_address(0), NULL);
    > + warn_slowpath_common(file, line, __builtin_return_address(0),
    > + TAINT_WARN, NULL);
    > }
    > EXPORT_SYMBOL(warn_slowpath_null);
    > #endif
    > diff --git a/lib/bug.c b/lib/bug.c
    > index 300e41a..f13daf4 100644
    > --- a/lib/bug.c
    > +++ b/lib/bug.c
    > @@ -165,7 +165,7 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs)
    > (void *)bugaddr);
    >
    > show_regs(regs);
    > - add_taint(TAINT_WARN);
    > + add_taint(BUG_GET_TAINT(bug));
    > return BUG_TRAP_TYPE_WARN;
    > }
    >



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