linux/include/asm-generic
Jeremy Fitzhardinge 7664c5a1da [PATCH] Generic BUG implementation
This patch adds common handling for kernel BUGs, for use by architectures as
they wish.  The code is derived from arch/powerpc.

The advantages of having common BUG handling are:
 - consistent BUG reporting across architectures
 - shared implementation of out-of-line file/line data
 - implement CONFIG_DEBUG_BUGVERBOSE consistently

This means that in inline impact of BUG is just the illegal instruction
itself, which is an improvement for i386 and x86-64.

A BUG is represented in the instruction stream as an illegal instruction,
which has file/line information associated with it.  This extra information is
stored in the __bug_table section in the ELF file.

When the kernel gets an illegal instruction, it first confirms it might
possibly be from a BUG (ie, in kernel mode, the right illegal instruction).
It then calls report_bug().  This searches __bug_table for a matching
instruction pointer, and if found, prints the corresponding file/line
information.  If report_bug() determines that it wasn't a BUG which caused the
trap, it returns BUG_TRAP_TYPE_NONE.

Some architectures (powerpc) implement WARN using the same mechanism; if the
illegal instruction was the result of a WARN, then report_bug(Q) returns
CONFIG_DEBUG_BUGVERBOSE; otherwise it returns BUG_TRAP_TYPE_BUG.

lib/bug.c keeps a list of loaded modules which can be searched for __bug_table
entries.  The architecture must call
module_bug_finalize()/module_bug_cleanup() from its corresponding
module_finalize/cleanup functions.

Unsetting CONFIG_DEBUG_BUGVERBOSE will reduce the kernel size by some amount.
At the very least, filename and line information will not be recorded for each
but, but architectures may decide to store no extra information per BUG at
all.

Unfortunately, gcc doesn't have a general way to mark an asm() as noreturn, so
architectures will generally have to include an infinite loop (or similar) in
the BUG code, so that gcc knows execution won't continue beyond that point.
gcc does have a __builtin_trap() operator which may be useful to achieve the
same effect, unfortunately it cannot be used to actually implement the BUG
itself, because there's no way to get the instruction's address for use in
generating the __bug_table entry.

[randy.dunlap@oracle.com: Handle BUG=n, GENERIC_BUG=n to prevent build errors]
[bunk@stusta.de: include/linux/bug.h must always #include <linux/module.h]
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>
Cc: Hugh Dickens <hugh@veritas.com>
Cc: Michael Ellerman <michael@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:39 -08:00
..
bitops [PATCH] sched: likely profiling 2006-10-11 11:14:22 -07:00
4level-fixup.h [PATCH] Standardize pxx_page macros 2006-09-26 08:48:51 -07:00
atomic.h [PATCH] cleanup include/asm-generic/atomic.h 2006-12-07 08:39:45 -08:00
audit_change_attr.h [PATCH] fix missing ifdefs in syscall classes hookup for generic targets 2006-09-22 17:48:56 -07:00
audit_dir_write.h [PATCH] fix missing ifdefs in syscall classes hookup for generic targets 2006-09-22 17:48:56 -07:00
audit_read.h [PATCH] audit: more syscall classes added 2006-09-11 13:32:27 -04:00
audit_write.h [PATCH] audit: more syscall classes added 2006-09-11 13:32:27 -04:00
bitops.h [PATCH] bitops: update include/asm-generic/bitops.h 2006-03-26 08:57:15 -08:00
bug.h [PATCH] Generic BUG implementation 2006-12-08 08:28:39 -08:00
cputime.h [CPUFREQ] Remove slowdown from ondemand sampling path. 2006-06-30 01:29:47 -04:00
device.h Driver core: add dev_archdata to struct device 2006-12-01 14:52:01 -08:00
div64.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
dma-mapping-broken.h [PATCH] gfp_t: dma-mapping (simple cases) 2005-10-28 08:16:49 -07:00
dma-mapping.h [PATCH] Pass struct dev pointer to dma_cache_sync() 2006-12-07 08:39:41 -08:00
emergency-restart.h [PATCH] Add emergency_restart() 2005-07-26 14:35:41 -07:00
errno-base.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
errno.h [PATCH] add EOWNERDEAD and ENOTRECOVERABLE version 2 2005-05-01 08:59:06 -07:00
fcntl.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
futex.h [PATCH] mm: pagefault_{disable,enable}() 2006-12-07 08:39:21 -08:00
ide_iops.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
ioctl.h [PATCH] Generic ioctl.h 2006-01-10 08:01:34 -08:00
iomap.h [PATCH] add Big Endian variants of ioread/iowrite 2005-04-16 15:25:54 -07:00
ipc.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
irq_regs.h IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
Kbuild [PATCH] cleanup include/asm-generic/atomic.h 2006-12-07 08:39:45 -08:00
Kbuild.asm [PATCH] cleanup asm/setup.h userspace visibility 2006-12-07 08:39:46 -08:00
libata-portmap.h [PATCH] libata: rework legacy handling to remove much of the cruft 2006-08-10 16:59:10 +09:00
local.h Don't include linux/config.h from anywhere else in include/ 2006-04-26 12:56:16 +01:00
memory_model.h [PATCH] squash duplicate page_to_pfn and pfn_to_page 2006-06-23 07:42:47 -07:00
mman.h [PATCH] add asm-generic/mman.h 2006-02-15 15:32:22 -08:00
mutex-dec.h fix file specification in comments 2006-10-03 23:01:26 +02:00
mutex-null.h fix file specification in comments 2006-10-03 23:01:26 +02:00
mutex-xchg.h fix file specification in comments 2006-10-03 23:01:26 +02:00
page.h [PATCH] mm: consolidate get_order 2005-09-05 00:05:39 -07:00
pci-dma-compat.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
pci.h [PATCH] Make sparc64 use setup-res.c 2005-09-08 14:57:25 -07:00
percpu.h [PATCH] Fix typo in "syntax error if percpu macros are incorrectly used" patch 2006-10-06 08:53:41 -07:00
pgtable-nopmd.h [PATCH] Standardize pxx_page macros 2006-09-26 08:48:51 -07:00
pgtable-nopud.h [PATCH] Standardize pxx_page macros 2006-09-26 08:48:51 -07:00
pgtable.h [PATCH] paravirt: remove set pte atomic 2006-10-01 00:39:34 -07:00
resource.h [PATCH] nice and rt-prio rlimits 2005-05-01 08:59:00 -07:00
rtc.h fix file specification in comments 2006-10-03 23:01:26 +02:00
sections.h [PATCH] add __[start|end]_rodata sections to asm-generic/sections.h 2006-07-01 09:56:03 -07:00
siginfo.h [PATCH] consolidate SIGEV_PAD_SIZE 2005-05-01 08:59:08 -07:00
signal.h Add standard include guard to asm-generic/signal and use compiler.h 2006-04-27 06:57:23 +01:00
statfs.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
termios.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
tlb.h fix file specification in comments 2006-10-03 23:01:26 +02:00
topology.h [PATCH] x86/x86_64: pcibus_to_node 2005-06-23 09:45:08 -07:00
uaccess.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00
unaligned.h [PATCH] __get_unaligned() gcc-4 fix 2006-03-08 14:14:00 -08:00
vmlinux.lds.h [PATCH] Generic BUG implementation 2006-12-08 08:28:39 -08:00
xor.h Linux-2.6.12-rc2 2005-04-16 15:20:36 -07:00