8d4fbcfbe0
Alexey Dobriyan noticed that the new WARN_ON() semantics that were
introduced by commit 684f978347 (to also
return the value to be warned on) didn't compile when given a bitfield,
because the typeof doesn't work for bitfields.
So instead of the typeof trick, use an "int" variable together with a
"!!(x)" expression, as suggested by Al Viro.
To make matters more interesting, Paul Mackerras points out that that is
sub-optimal on Power, but the old asm-coded comparison seems to be buggy
anyway on 32-bit Power if the conditional was 64-bit, so I think there
are more problems there.
Regardless, the new WARN_ON() semantics may have been a bad idea. But
this at least avoids the more serious complications.
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
122 lines
3 KiB
C
122 lines
3 KiB
C
#ifndef _ASM_POWERPC_BUG_H
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#define _ASM_POWERPC_BUG_H
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#ifdef __KERNEL__
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#include <asm/asm-compat.h>
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/*
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* Define an illegal instr to trap on the bug.
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* We don't use 0 because that marks the end of a function
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* in the ELF ABI. That's "Boo Boo" in case you wonder...
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*/
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#define BUG_OPCODE .long 0x00b00b00 /* For asm */
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#define BUG_ILLEGAL_INSTR "0x00b00b00" /* For BUG macro */
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#ifdef CONFIG_BUG
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#ifdef __ASSEMBLY__
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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.macro EMIT_BUG_ENTRY addr,file,line,flags
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.section __bug_table,"a"
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5001: PPC_LONG \addr, 5002f
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.short \line, \flags
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.org 5001b+BUG_ENTRY_SIZE
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.previous
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.section .rodata,"a"
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5002: .asciz "\file"
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.previous
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.endm
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#else
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.macro EMIT_BUG_ENTRY addr,file,line,flags
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.section __bug_table,"a"
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5001: PPC_LONG \addr
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.short \flags
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.org 5001b+BUG_ENTRY_SIZE
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.previous
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.endm
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#endif /* verbose */
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#else /* !__ASSEMBLY__ */
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/* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and
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sizeof(struct bug_entry), respectively */
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#ifdef CONFIG_DEBUG_BUGVERBOSE
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#define _EMIT_BUG_ENTRY \
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".section __bug_table,\"a\"\n" \
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"2:\t" PPC_LONG "1b, %0\n" \
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"\t.short %1, %2\n" \
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".org 2b+%3\n" \
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".previous\n"
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#else
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#define _EMIT_BUG_ENTRY \
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".section __bug_table,\"a\"\n" \
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"2:\t" PPC_LONG "1b\n" \
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"\t.short %2\n" \
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".org 2b+%3\n" \
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".previous\n"
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#endif
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/*
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* BUG_ON() and WARN_ON() do their best to cooperate with compile-time
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* optimisations. However depending on the complexity of the condition
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* some compiler versions may not produce optimal results.
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*/
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#define BUG() do { \
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__asm__ __volatile__( \
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"1: twi 31,0,0\n" \
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_EMIT_BUG_ENTRY \
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: : "i" (__FILE__), "i" (__LINE__), \
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"i" (0), "i" (sizeof(struct bug_entry))); \
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for(;;) ; \
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} while (0)
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#define BUG_ON(x) do { \
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if (__builtin_constant_p(x)) { \
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if (x) \
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BUG(); \
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} else { \
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__asm__ __volatile__( \
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"1: "PPC_TLNEI" %4,0\n" \
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_EMIT_BUG_ENTRY \
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: : "i" (__FILE__), "i" (__LINE__), "i" (0), \
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"i" (sizeof(struct bug_entry)), \
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"r" ((__force long)(x))); \
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} \
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} while (0)
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#define __WARN() do { \
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__asm__ __volatile__( \
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"1: twi 31,0,0\n" \
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_EMIT_BUG_ENTRY \
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: : "i" (__FILE__), "i" (__LINE__), \
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"i" (BUGFLAG_WARNING), \
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"i" (sizeof(struct bug_entry))); \
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} while (0)
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#define WARN_ON(x) ({ \
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int __ret_warn_on = !!(x); \
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if (__builtin_constant_p(__ret_warn_on)) { \
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if (__ret_warn_on) \
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__WARN(); \
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} else { \
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__asm__ __volatile__( \
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"1: "PPC_TLNEI" %4,0\n" \
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_EMIT_BUG_ENTRY \
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: : "i" (__FILE__), "i" (__LINE__), \
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"i" (BUGFLAG_WARNING), \
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"i" (sizeof(struct bug_entry)), \
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"r" (__ret_warn_on)); \
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} \
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unlikely(__ret_warn_on); \
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})
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#define HAVE_ARCH_BUG
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#define HAVE_ARCH_BUG_ON
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#define HAVE_ARCH_WARN_ON
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#endif /* __ASSEMBLY __ */
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#endif /* CONFIG_BUG */
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#include <asm-generic/bug.h>
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#endif /* __KERNEL__ */
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#endif /* _ASM_POWERPC_BUG_H */
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