[PATCH 2/4] panic: Allow taint flag for warnings to be changed from TAINT_WARN

Ben Hutchings
2010-03-20T23:05:40Z

[-- Attachment #1: Type: text/plain, Size: 9299 bytes --]

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 <ben@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); \
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;
}

--
1.7.0