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2026-01-27s390/bug: Prevent tail-call optimizationHeiko Carstens
For the exception based __WARN_trap() implementation it is technically not necessary to prevent tail-call optimization, however it may be confusing to see warning messages like: WARNING: arch/s390/kernel/setup.c:1017 at foobar+0x2c/0x50, CPU#0: swapper/0/0 together with a disassembly of a different function caused by tail-call optimization for the __WARN_trap() call. Prevent that by adding an empty asm statement. This generates slightly worse code, but should hopefully avoid confusion. With this the output looks like: WARNING: arch/s390/kernel/setup.c:1017 at foobar+0x2c/0x50, CPU#0: swapper/0/0 ... Krnl PSW : 0704c00180000000 000003ffe0119788 (foobar+0x38/0x50) ... Krnl Code: 000003ffe0119776: e3e0f0980024 stg %r14,152(%r15) 000003ffe011977c: c02000b8992a larl %r2,000003ffe182c9d0 *000003ffe0119782: c0e5007270b7 brasl %r14,000003ffe0f678f0 >000003ffe0119788: ebeff0a00004 lmg %r14,%r15,160(%r15) 000003ffe011978e: 07fe bcr 15,%r14 000003ffe0119790: 47000700 bc 0,1792 000003ffe0119794: 0707 bcr 0,%r7 000003ffe0119796: 0707 bcr 0,%r7 Call Trace: [<000003ffe0119788>] foobar+0x38/0x50 [<000003ffe185bc2e>] arch_cpu_finalize_init+0x26/0x60 [<000003ffe185654c>] start_kernel+0x53c/0x5d8 [<000003ffe010002e>] startup_continue+0x2e/0x40 A better solution would be to replace or patch the branch instruction to __WARN_trap() with the monitor call instruction, similar to what is done for x86 [1]. However s390 does not support static_cond_calls(). Therefore use the simple approach for the time being. [1] commit 860238af7a33 ("x86_64/bug: Inline the UD1") Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2026-01-27s390/bug: Implement WARN_ONCE()Heiko Carstens
This is the s390 variant of commit 11bb4944f014 ("x86/bug: Implement WARN_ONCE()"). Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2026-01-27s390/bug: Implement __WARN_printf()Heiko Carstens
This is the s390 variant of commit 5b472b6e5bd9 ("x86_64/bug: Implement __WARN_printf()"). See the x86 commit for the general idea; there are only implementation details which are different. With the new exception based __WARN_printf() implementation the generated code for a simple WARN() is simplified. For example: void foo(int a) { WARN(a, "bar"); } Before this change the generated code looks like this: 0000000000000210 <foo>: 210: c0 04 00 00 00 00 jgnop 210 <foo> 216: ec 26 00 06 00 7c cgijne %r2,0,222 <foo+0x12> 21c: c0 f4 00 00 00 00 jg 21c <foo+0xc> 21e: R_390_PC32DBL __s390_indirect_jump_r14+0x2 222: eb ef f0 88 00 24 stmg %r14,%r15,136(%r15) 228: b9 04 00 ef lgr %r14,%r15 22c: e3 f0 ff e8 ff 71 lay %r15,-24(%r15) 232: e3 e0 f0 98 00 24 stg %r14,152(%r15) 238: c0 20 00 00 00 00 larl %r2,238 <foo+0x28> 23a: R_390_PC32DBL .LC48+0x2 23e: c0 e5 00 00 00 00 brasl %r14,23e <foo+0x2e> 240: R_390_PLT32DBL __warn_printk+0x2 244: af 00 00 00 mc 0,0 248: eb ef f0 a0 00 04 lmg %r14,%r15,160(%r15) 24e: c0 f4 00 00 00 00 jg 24e <foo+0x3e> 250: R_390_PC32DBL __s390_indirect_jump_r14+0x2 With this change the generated code looks like this: 0000000000000210 <foo>: 210: c0 04 00 00 00 00 jgnop 210 <foo> 216: ec 26 00 06 00 7c cgijne %r2,0,222 <foo+0x12> 21c: c0 f4 00 00 00 00 jg 21c <foo+0xc> 21e: R_390_PC32DBL __s390_indirect_jump_r14+0x2 222: c0 20 00 00 00 00 larl %r2,222 <foobar+0x12> 224: R_390_PC32DBL __bug_table+0x2 228: c0 f4 00 00 00 00 jg 228 <foobar+0x18> 22a: R_390_PLT32DBL __WARN_trap+0x2 Downside is that the call trace now starts at __WARN_trap(): ------------[ cut here ]------------ bar WARNING: arch/s390/kernel/setup.c:1017 at 0x0, CPU#0: swapper/0/0 ... Krnl PSW : 0704c00180000000 000003ffe0f6a3b4 (__WARN_trap+0x4/0x10) ... Krnl Code: 000003ffe0f6a3ac: 0707 bcr 0,%r7 000003ffe0f6a3ae: 0707 bcr 0,%r7 *000003ffe0f6a3b0: af000001 mc 1,0 >000003ffe0f6a3b4: 07fe bcr 15,%r14 000003ffe0f6a3b6: 47000700 bc 0,1792 000003ffe0f6a3ba: 0707 bcr 0,%r7 000003ffe0f6a3bc: 0707 bcr 0,%r7 000003ffe0f6a3be: 0707 bcr 0,%r7 Call Trace: [<000003ffe0f6a3b4>] __WARN_trap+0x4/0x10 ([<000003ffe185a54c>] start_kernel+0x53c/0x5d8) [<000003ffe010002e>] startup_continue+0x2e/0x40 Which isn't too helpful. This can be addressed by just skipping __WARN_trap(), which will be addressed in a later patch. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2026-01-27s390/bug: Introduce and use monitor code macroHeiko Carstens
The first operand address of the monitor call (mc) instruction is the monitor code. Currently the monitor code is ignored, but this will change. Therefore add and use MONCODE_BUG instead of a hardcoded zero. Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2026-01-27s390/bug: Use BUG_FORMAT for DEBUG_BUGVERBOSE_DETAILEDHeiko Carstens
This is just the s390 variant of commit 4f1b701f24be ("x86/bug: Use BUG_FORMAT for DEBUG_BUGVERBOSE_DETAILED"). Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2026-01-27s390/bug: Convert to inline assembly with input operandsHeiko Carstens
Rewrite the bug inline assembly so it uses input operands again instead of pure macro replacements. This more or less reverts the conversion done when 'cond_str' support was added [1]. Reason for this is that the upcoming __WARN_printf() implementation requires an inline assembly with an output operand. At the same time input strings (format specifier and condition string) may contain the special '%' character. As soon as an inline assembly is specified to have input/output operands the '%' has a special meaning: e.g. converting the existing #define __BUG_FLAGS(cond_str, flags) \ asm_inline volatile(__stringify(ASM_BUG_FLAGS(cond_str, flags))); to #define __BUG_FLAGS(cond_str, flags) \ asm_inline volatile(__stringify(ASM_BUG_FLAGS(cond_str, flags))::); will result in a compile error as soon as 'cond_str' contains a '%' character: net/core/neighbour.c: In function ‘neigh_table_init’: ././include/linux/compiler_types.h:546:20: error: invalid 'asm': invalid %-code ... net/core/neighbour.c:1838:17: note: in expansion of macro ‘WARN_ON’ 1838 | WARN_ON(tbl->entry_size % NEIGH_PRIV_ALIGN); | ^~~~~~~ Convert the code, use immediate operands, and also add comments similar to x86 which are emitted to the generated assembly file, which makes debugging much easier. Note: since gcc-8 does not support strings as immediate input operands, guard the new implementation with CC_HAS_ASM_IMMEDIATE_STRINGS and fallback to the generic non-exception based warning implementation for incompatible compilers. [1] 6584ff203aec ("bugs/s390: Use 'cond_str' in __EMIT_BUG()") Reviewed-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2025-12-08s390/bug: Add missing alignmentHeiko Carstens
All objects are supposed to have a minimal alignment of two, since a couple of instructions only work with even addresses. Add the missing align statement for the file string. Fixes: 6584ff203aec ("bugs/s390: Use 'cond_str' in __EMIT_BUG()") Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2025-12-08s390/bug: Add missing CONFIG_BUG ifdef againHeiko Carstens
Fallback to generic BUG implementation in case CONFIG_BUG is disabled. This restores the old behaviour before 'cond_str' support was added. It probably doesn't matter, since nobody should disable CONFIG_BUG, but at least this is consistent to before. Fixes: 6584ff203aec ("bugs/s390: Use 'cond_str' in __EMIT_BUG()") Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2025-07-28bugs/s390: Remove private WARN_ON() implementationHeiko Carstens
Besides an odd __builtin_constant_p() optimization the s390 specific WARN_ON() implementation is identical to the generic variant. Drop the s390 variant in favor of the generic variant. Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> # Rebased ancestor commits Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Link: https://lore.kernel.org/r/20250617135042.1878068-2-hca@linux.ibm.com
2025-07-28bugs/s390: Use 'cond_str' in __EMIT_BUG()Heiko Carstens
The simple thing would be to add the string as an assembly immediate input operand. Some older gcc variants cannot handle strings as immediate input operands for inline assemblies. Doing so may result in compile errors. Rewrite the s390 generic bug support very similar to arm64 and loongarch, and get rid of all input operands to fix this. [ peterz: backmerge fix and massage changelog ] [ bp: clang integrated assembler concatenates only .ascii strings: https://lore.kernel.org/r/202507020528.N0LtekXt-lkp@intel.com ] Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> # Fixed the tags section Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-arch@vger.kernel.org Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: linux-s390@vger.kernel.org Link: https://lore.kernel.org/r/20250520133927.7932C19-hca@linux.ibm.com Link: https://lore.kernel.org/r/20250617135042.1878068-3-hca@linux.ibm.com
2025-07-28bugs/s390: Pass in 'cond_str' to __EMIT_BUG()Ingo Molnar
Pass in the condition string from __WARN_FLAGS(), but do not concatenate it with __FILE__, because it results in s390 assembler build errors that are beyond my s390-asm-fu. Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: linux-s390@vger.kernel.org Cc: <linux-arch@vger.kernel.org> Link: https://lore.kernel.org/r/20250515124644.2958810-11-mingo@kernel.org
2025-06-13bugs/core: Extend __WARN_FLAGS() with the 'cond_str' parameterIngo Molnar
Push the new parameter down into every architecture that defines __WARN_FLAGS(): arm64 loongarch parisc powerpc riscv s390 sh x86 Don't pass anything substantial down yet, just propagate the new parameter with empty strings, without generating it or using it. ( The string is never NULL, so it can be concatenated at the preprocessor level. ) Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/r/20250515124644.2958810-2-mingo@kernel.org
2024-02-14s390/bug: remove entry size from __bug_table sectionHeiko Carstens
Commit e21f8baf8d9a ("s390/bug: add entry size to the __bug_table section") changed the __EMIT_BUG() inline assembly to emit mergeable __bug_table entries. This is at least currently not needed, but causes problems with the upcoming s390 ld.lld support: ld.lld: error: drivers/nvme/host/fc.o:(__bug_table): writable SHF_MERGE section is not supported Therefore revert the change for now. Reported-by: Nathan Chancellor <nathan@kernel.org> Closes: https://lore.kernel.org/all/20240207-s390-lld-and-orphan-warn-v1-0-8a665b3346ab@kernel.org/ Suggested-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2022-05-19bug: Use normal relative pointers in 'struct bug_entry'Josh Poimboeuf
With CONFIG_GENERIC_BUG_RELATIVE_POINTERS, the addr/file relative pointers are calculated weirdly: based on the beginning of the bug_entry struct address, rather than their respective pointer addresses. Make the relative pointers less surprising to both humans and tools by calculating them the normal way. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Sven Schnelle <svens@linux.ibm.com> # s390 Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by: Catalin Marinas <catalin.marinas@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64] Link: https://lkml.kernel.org/r/f0e05be797a16f4fc2401eeb88c8450dcbe61df6.1652362951.git.jpoimboe@kernel.org
2020-07-27printk: Make linux/printk.h self-containedHerbert Xu
As it stands if you include printk.h by itself it will fail to compile because it requires definitions from ratelimit.h. However, simply including ratelimit.h from printk.h does not work due to inclusion loops involving sched.h and kernel.h. This patch solves this by moving bits from ratelimit.h into a new header file which can then be included by printk.h without any worries about header loops. The build bot then revealed some intriguing failures arising out of this patch. On s390 there is an inclusion loop with asm/bug.h and linux/kernel.h that triggers a compile failure, because kernel.h will cause asm-generic/bug.h to be included before s390's own asm/bug.h has finished processing. This has been fixed by not including kernel.h in arch/s390/include/asm/bug.h. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Acked-by: Petr Mladek <pmladek@suse.com> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Link: https://lore.kernel.org/r/20200721062248.GA18383@gondor.apana.org.au
2020-01-22s390: fix __EMIT_BUG() macroSven Schnelle
Setting a kprobe on getname_flags() failed: $ echo 'p:tmr1 getname_flags +0(%r2):ustring' > kprobe_events -bash: echo: write error: Invalid argument Debugging the kprobes code showed that the address of getname_flags() is contained in the __bug_table. Kprobes doesn't allow to set probes at BUG() locations. $ objdump -j __bug_table -x build/fs/namei.o [..] 0000000000000108 R_390_PC32 .text+0x00000000000075a8 000000000000010c R_390_PC32 .L223+0x0000000000000004 I was expecting getname_flags() to start with a BUG(), but: 7598: e3 20 10 00 00 04 lg %r2,0(%r1) 759e: c0 f4 00 00 00 00 jg 759e <putname+0x7e> 75a0: R_390_PLT32DBL kmem_cache_free+0x2 75a4: a7 f4 00 01 j 75a6 <putname+0x86> 00000000000075a8 <getname_flags>: 75a8: c0 04 00 00 00 00 brcl 0,75a8 <getname_flags> 75ae: eb 6f f0 48 00 24 stmg %r6,%r15,72(%r15) 75b4: b9 04 00 ef lgr %r14,%r15 75b8: e3 f0 ff a8 ff 71 lay %r15,-88(%r15) So the BUG() is actually the last opcode of the previous function. Fix this by switching to using the MONITOR CALL (MC) instruction, and set the entry in __bug_table to the beginning of that MC. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-10-31s390/bug: make use of asm_inlineHeiko Carstens
This is the s390 version of commit 32ee8230b2b0 ("x86: bug.h: use asm_inline in _BUG_FLAGS definitions"). See commit eb111869301e ("compiler-types.h: add asm_inline definition") for more details. Just like on x86 the .text section size decreases a bit while the .data section size increases about the same amount (gcc 9.2 with defconfig). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-05-02s390/bug: add entry size to the __bug_table sectionMartin Schwidefsky
Change the __EMIT_BUG inline assembly to emit mergeable __bug_table entries with type @progbits and specify the size of each entry. The entry size is encoded sh_entsize field of the section definition, it allows to identify which struct bug_entry to use to decode the entries. This will be needed for the objtool support. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman
Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-07-20debug: Fix WARN_ON_ONCE() for modulesJosh Poimboeuf
Mike Galbraith reported a situation where a WARN_ON_ONCE() call in DRM code turned into an oops. As it turns out, WARN_ON_ONCE() seems to be completely broken when called from a module. The bug was introduced with the following commit: 19d436268dde ("debug: Add _ONCE() logic to report_bug()") That commit changed WARN_ON_ONCE() to move its 'once' logic into the bug trap handler. It requires a writable bug table so that the BUGFLAG_DONE bit can be written to the flags to indicate the first warning has occurred. The bug table was made writable for vmlinux, which relies on vmlinux.lds.S and vmlinux.lds.h for laying out the sections. However, it wasn't made writable for modules, which rely on the ELF section header flags. Reported-by: Mike Galbraith <efault@gmx.de> Tested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 19d436268dde ("debug: Add _ONCE() logic to report_bug()") Link: http://lkml.kernel.org/r/a53b04235a65478dd9afc51f5b329fdc65c84364.1500095401.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-03-30debug: Add _ONCE() logic to report_bug()Peter Zijlstra
Josh suggested moving the _ONCE logic inside the trap handler, using a bit in the bug_entry::flags field, avoiding the need for the extra variable. Sadly this only works for WARN_ON_ONCE(), since the others have printk() statements prior to triggering the trap. Still, this saves a fair amount of text and some data: text data filename 10682460 4530992 defconfig-build/vmlinux.orig 10665111 4530096 defconfig-build/vmlinux.patched Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2010-05-19panic: Allow warnings to set different taint flagsBen Hutchings
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> Acked-by: Helge Deller <deller@gmx.de> Tested-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2010-02-26[S390] bug: use relative pointers in bug table entriesHeiko Carstens
Reduces the size of the bug table entries by 50% on 64bit kernels. Saves around 30kb on a defconfig kernel. s390 version of b93a531e "allow bug table entries to use relative pointers (and use it on x86-64)". Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2010-01-13[S390] bug: implement arch specific __WARN macroHeiko Carstens
This one will trap, generates shorter code and emits better debug data than the generic version. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-12-05s390: Convert BUG() to use unreachable()David Daney
Use the new unreachable() macro instead of for(;;); Signed-off-by: David Daney <ddaney@caviumnetworks.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> CC: Heiko Carstens <heiko.carstens@de.ibm.com> CC: linux390@de.ibm.com CC: linux-s390@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-25[S390] remove warnings with functions ending in BUGMartin Schwidefsky
Functions which end in a BUG() statement and skip the return statement cause compile warnings on s390, e.g.: mm/bootmem.c: In function 'mark_bootmem': mm/bootmem.c:321: warning: control reaches end of non-void function To avoid the warning add an endless loop to the BUG() macro. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-08-01[S390] move include/asm-s390 to arch/s390/include/asmMartin Schwidefsky
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>