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* sched/rt, s390: Use CONFIG_PREEMPTIONThomas Gleixner2019-12-081-0/+2
| | | | | | | | | | | | | | | | | | | | | | | CONFIG_PREEMPTION is selected by CONFIG_PREEMPT and by CONFIG_PREEMPT_RT. Both PREEMPT and PREEMPT_RT require the same functionality which today depends on CONFIG_PREEMPT. Switch the preemption and entry code over to use CONFIG_PREEMPTION. Add PREEMPT_RT output to die(). [bigeasy: +Kconfig, dumpstack.c] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: linux-s390@vger.kernel.org Link: https://lore.kernel.org/r/20191015191821.11479-18-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* s390/unwind: add stack pointer alignment sanity checksMiroslav Benes2019-11-301-0/+4
| | | | | | | | | | ABI requires SP to be aligned 8 bytes, report unwinding error otherwise. Link: https://lkml.kernel.org/r/20191106095601.29986-5-mbenes@suse.cz Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Tested-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/test_unwind: print verbose unwinding resultsVasily Gorbik2019-11-301-0/+1
| | | | | | | | | Add stack name, sp and reliable information into test unwinding results. Also consider ip outside of kernel text as failure if the state is reported reliable. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/unwind: unify task is current checksVasily Gorbik2019-11-301-4/+0
| | | | | | | | Avoid mixture of task == NULL and task == current meaning the same thing and simply always initialize task with current in unwind_start. Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390/unwind: remove stack recursion warningVasily Gorbik2019-08-061-5/+1
| | | | | | | | | | | | | | | | | | Remove pointless stack recursion on stack type ... warning, which only confuses people. There is no way to make backchain unwinder 100% reliable. When a task is interrupted in-between stack frame allocation and backchain write instructions new stack frame backchain pointer is left uninitialized (there are also sometimes additional instruction in-between stack frame allocation and backchain write instructions due to gcc shrink-wrapping). In attempt to unwind such stack the unwinder would still try to use that invalid backchain value and perform all kind of sanity checks on it to make sure we are not pointed out of stack. In some cases that invalid backchain value would be 0 and we would falsely treat next stackframe as pt_regs and again gprs[15] in those pt_regs might happen to point at some address within the task's stack. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
* s390: enforce CONFIG_SMPHeiko Carstens2019-06-071-2/+0
| | | | | | | | | | | | | There never have been distributions that shiped with CONFIG_SMP=n for s390. In addition the kernel currently doesn't even compile with CONFIG_SMP=n for s390. Most likely it wouldn't even work, even if we fix the compile error, since nobody tests it, since there is no use case that I can think of. Therefore simply enforce CONFIG_SMP and get rid of some more or less unused code. Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* s390/unwind: introduce stack unwind APIMartin Schwidefsky2019-05-021-69/+98
| | | | | | | | | | | | | | | | | | Rework the dump_trace() stack unwinder interface to support different unwinding algorithms. The new interface looks like this: struct unwind_state state; unwind_for_each_frame(&state, task, regs, start_stack) do_something(state.sp, state.ip, state.reliable); The unwind_bc.c file contains the implementation for the classic back-chain unwinder. One positive side effect of the new code is it now handles ftraced functions gracefully. It prints the real name of the return function instead of 'return_to_handler'. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dumpstack: print psw mask and address againHeiko Carstens2018-10-101-1/+1
| | | | | | | | | | | | | | | With pointer obfuscation the output of show_registers() became quite useless: Krnl PSW : (____ptrval____) (____ptrval____) (__list_add_valid+0x98/0xa8) In order to print the psw mask and address use %px instead of %p. And the output looks again like this: Krnl PSW : 0404d00180000000 00000000007c0dd0 (__list_add_valid+0x98/0xa8) Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dumpstack: disable __dump_trace kasan instrumentationVasily Gorbik2018-10-091-1/+1
| | | | | | | | Walking async_stack produces false positives. Disable __dump_trace function instrumentation for now. Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: unify stack size definitionsVasily Gorbik2018-10-091-2/+2
| | | | | | | | | | | | Remove STACK_ORDER and STACK_SIZE in favour of identical THREAD_SIZE_ORDER and THREAD_SIZE definitions. THREAD_SIZE and THREAD_SIZE_ORDER naming is misleading since it is used as general kernel stack size information. But both those definitions are used in the common code and throughout architectures specific code, so changing the naming is problematic. Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: add support for virtually mapped kernel stacksMartin Schwidefsky2018-10-091-3/+3
| | | | | | | | | | | | | | | | | | | | | With virtually mapped kernel stacks the kernel stack overflow detection is now fault based, every stack has a guard page in the vmalloc space. The panic_stack is renamed to nodat_stack and is used for all function that need to run without DAT, e.g. memcpy_real or do_start_kdump. The main effect is a reduction in the kernel image size as with vmap stacks the old style overflow checking that adds two instructions per function is not needed anymore. Result from bloat-o-meter: add/remove: 20/1 grow/shrink: 13/26854 up/down: 2198/-216240 (-214042) In regard to performance the micro-benchmark for fork has a hit of a few microseconds, allocating 4 pages in vmalloc space is more expensive compare to an order-2 page allocation. But with real workload I could not find a noticeable difference. Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: kernel: add SPDX identifiers to the remaining filesGreg Kroah-Hartman2017-11-241-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the arch/s390/kernel/ files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/mm: use new mm defines instead of magic valuesHeiko Carstens2017-07-261-1/+1
| | | | | | Reviewed-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: rename struct psw_bits membersHeiko Carstens2017-06-121-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | Rename a couple of the struct psw_bits members so it is more obvious for what they are good. Initially I thought using the single character names from the PoP would be sufficient and obvious, but admittedly that is not true. The current implementation is not easy to use, if one has to look into the source file to figure out which member represents the 'per' bit (which is the 'r' member). Therefore rename the members to sane names that are identical to the uapi psw mask defines: r -> per i -> io e -> ext t -> dat m -> mcheck w -> wait p -> pstate Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dumpstack: remove raw stack dumpHeiko Carstens2017-06-121-25/+4
| | | | | | | | | | | | | | | | | | | | | | | | Remove raw stack dumps that are printed before call traces in case of a warning, or the 'l' sysrq trigger (show a stack backtrace for all active CPUs). Besides that a raw stack dump should not be shown for the 'l' sysrq trigger the value of the dump is close to zero. That's also why we don't print it in case of a panic since ages anymore. That this is still printed on warnings is just a leftover. So get rid of this completely. The following won't be printed anymore with this change: Stack: 00000000bbc4fbc8 00000000bbc4fc58 0000000000000003 0000000000000000 00000000bbc4fcf8 00000000bbc4fc70 00000000bbc4fc70 0000000000000020 000000007fe00098 00000000bfe8be00 00000000bbc4fe94 000000000000000a 000000000000000c 00000000bbc4fcc0 0000000000000000 0000000000000000 000000000095b930 0000000000113366 00000000bbc4fc58 00000000bbc4fca0 Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/debug.h> We are going to split <linux/sched/debug.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/debug.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* s390/dumpstack: use pr_cont within show_stack and dieHeiko Carstens2016-10-241-8/+8
| | | | | | | | Use pr_cont instead of printk calls also within show_stack and die in order to avoid extra line breaks. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dumpstack: get rid of return_address againHeiko Carstens2016-10-171-24/+0
| | | | | | | | | | | | | | | | | With commit ef6000b4c670 ("Disable the __builtin_return_address() warning globally after all)" the kernel does not warn at all again if __builtin_return_address(n) is called with n > 0. Besides the fact that this was a false warning on s390 anyway, due to the always present backchain, we can now revert commit 5606330627ab ("s390/dumpstack: implement and use return_address()") again, to simplify the code again. After all I shouldn't have had return_address() implememted at all to workaround this issue. So get rid of this again. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dumpstack: use pr_cont where appropriateHeiko Carstens2016-10-171-4/+4
| | | | | | | | | | | | | | | | | | | | Use pr_cont instead of simple printk calls when lines will be continued. This fixes the kernel output of various lines printed on e.g. a warning: Before: [ 0.840604] Krnl PSW : 0404c00180000000 000000000017d1d2 [ 0.840606] (try_to_wake_up+0x382/0x5e0) [ 0.840610] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 [ 0.840611] RI:0 EA:3 After: [ 0.831772] Krnl PSW : 0404c00180000000 000000000017d14a (try_to_wake_up+0x382/0x5e0) [ 0.831776] R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3 Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dumpstack: restore reliable indicator for call tracesHeiko Carstens2016-10-171-6/+11
| | | | | | | | | | | | | | | | | | | | | | | | | Before merging all different stack tracers the call traces printed had an indicator if an entry can be considered reliable or not. Unreliable entries were put in braces, reliable not. Currently all lines contain these extra braces. This patch restores the old behaviour by adding an extra "reliable" parameter to the callback functions. Only show_trace makes currently use of it. Before: [ 0.804751] Call Trace: [ 0.804753] ([<000000000017d0e0>] try_to_wake_up+0x318/0x5e0) [ 0.804756] ([<0000000000161d64>] create_worker+0x174/0x1c0) After: [ 0.804751] Call Trace: [ 0.804753] ([<000000000017d0e0>] try_to_wake_up+0x318/0x5e0) [ 0.804756] [<0000000000161d64>] create_worker+0x174/0x1c0 Fixes: 758d39ebd3d5 ("s390/dumpstack: merge all four stack tracers") Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: stack address vs thread_infoHeiko Carstens2016-06-281-8/+4
| | | | | | | | | | Avoid using the address of a process' thread_info structure as the kernel stack address. This will break as soon as the thread_info structure will be removed from the stack, and in addition it makes the code a bit more understandable. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dumpstack: implement and use return_address()Heiko Carstens2016-05-041-0/+24
| | | | | | | | | | | | | | Implement return_address() and use it instead of __builtin_return_address(n). __builtin_return_address(n) is not guaranteed to work for n > 0, therefore implement a private return_address() function which walks the stack frames and returns the proper return address. This way we get also rid of a compile warning which gcc 6.1 emits and look like all other architectures. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* Merge branch 'akpm' (patches from Andrew)Linus Torvalds2016-03-161-3/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge first patch-bomb from Andrew Morton: - some misc things - ofs2 updates - about half of MM - checkpatch updates - autofs4 update * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (120 commits) autofs4: fix string.h include in auto_dev-ioctl.h autofs4: use pr_xxx() macros directly for logging autofs4: change log print macros to not insert newline autofs4: make autofs log prints consistent autofs4: fix some white space errors autofs4: fix invalid ioctl return in autofs4_root_ioctl_unlocked() autofs4: fix coding style line length in autofs4_wait() autofs4: fix coding style problem in autofs4_get_set_timeout() autofs4: coding style fixes autofs: show pipe inode in mount options kallsyms: add support for relative offsets in kallsyms address table kallsyms: don't overload absolute symbol type for percpu symbols x86: kallsyms: disable absolute percpu symbols on !SMP checkpatch: fix another left brace warning checkpatch: improve UNSPECIFIED_INT test for bare signed/unsigned uses checkpatch: warn on bare unsigned or signed declarations without int checkpatch: exclude asm volatile from complex macro check mm: memcontrol: drop unnecessary lru locking from mem_cgroup_migrate() mm: migrate: consolidate mem_cgroup_migrate() calls mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous ...
| * s390: query dynamic DEBUG_PAGEALLOC settingChristian Borntraeger2016-03-161-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We can use debug_pagealloc_enabled() to check if we can map the identity mapping with 1MB/2GB pages as well as to print the current setting in dump_stack. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Acked-by: David Rientjes <rientjes@google.com> Cc: Laura Abbott <labbott@fedoraproject.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | s390/dumpstack: merge all four stack tracersHeiko Carstens2016-02-231-25/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have four different stack tracers of which three had bugs. So it's time to merge them to a single stack tracer which allows to specify a call back function which will be called for each step. This patch changes behavior a bit: - the "nosched" and "in_sched_functions" check within save_stack_trace_tsk did work only for the last stack frame within a context. Now it considers the check for each stack frame like it should. - both the oprofile variant and the perf_events variant did save a return address twice if a zero back chain was detected, which indicates an interrupt frame. The new dump_trace function will call the oprofile and perf_events backends with the psw address that is contained within the corresponding pt_regs structure instead. - the original show_trace and save_context_stack functions did already use the psw address of the pt_regs structure if a zero back chain was detected. However now we ignore the psw address if it is a user space address. After all we trace the kernel stack and not the user space stack. This way we also get rid of the garbage user space address in case of warnings and / or panic call traces. So this should make life easier since now there is only one stack tracer left which we can break. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390/dumpstack: use bit fields to decode psw mask in show_registers()Heiko Carstens2016-02-231-13/+4
| | | | | | | | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390/dumpstack: add missing ri bit to show_registers() outputHeiko Carstens2016-02-231-1/+2
| | | | | | | | | | Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* | s390: add current_stack_pointer() helper functionHeiko Carstens2016-02-231-8/+8
|/ | | | | | | | | | Implement current_stack_pointer() helper function and use it everywhere, instead of having several different inline assembly variants. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Tested-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: remove all usages of PSW_ADDR_INSNHeiko Carstens2016-01-191-5/+4
| | | | | | | | | | | Yet another leftover from the 31 bit era. The usual operation "y = x & PSW_ADDR_INSN" with the PSW_ADDR_INSN mask is a nop for CONFIG_64BIT. Therefore remove all usages and hope the code is a bit less confusing. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
* s390: remove 31 bit supportHeiko Carstens2015-03-251-20/+6
| | | | | | | | | | | | | | | | | | | Remove the 31 bit support in order to reduce maintenance cost and effectively remove dead code. Since a couple of years there is no distribution left that comes with a 31 bit kernel. The 31 bit kernel also has been broken since more than a year before anybody noticed. In addition I added a removal warning to the kernel shown at ipl for 5 minutes: a960062e5826 ("s390: add 31 bit warning message") which let everybody know about the plan to remove 31 bit code. We didn't get any response. Given that the last 31 bit only machine was introduced in 1999 let's remove the code. Anybody with 31 bit user space code can still use the compat mode. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/traps: print interrupt code and instruction length codeHeiko Carstens2014-11-211-1/+2
| | | | | | | | | | | | It always confuses me to see the mixed instruction length code and interruption code on user space faults, while the message clearly says it is the interruption code. So split the value and print both values separately. Also add the ILC output to the die() message, so thar user and kernel space faults contain the same information. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390: show_registers() should not map user space addresses to kernel symbolsHeiko Carstens2014-04-111-4/+4
| | | | | | | | | It doesn't make sense to map user space addresses to kernel symbols when show_registers() prints a user space psw. So just skip the translation part if a user space psw is handled. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dis: move disassembler function prototypes to proper header fileHeiko Carstens2013-10-241-0/+1
| | | | | | | | Now that the in-kernel disassembler has an own header file move the disassembler related function prototypes to that header file. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* s390/dumpstack: convert print_symbol to %pSRHeiko Carstens2013-09-041-10/+10
| | | | | | | | This is the same as what other architectures did. The change has also the advantage that there won't be any interleaving messages between printk() and print_symbol(). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
* s390/dumpstack: fix address ranges for asynchronous and panic stackMartin Schwidefsky2013-06-051-4/+8
| | | | | | | | | | git commit dc7ee00d4771b321 "s390: lowcore stack pointer offsets" introduced a regression in regard to show_stack(). The stack pointer for the asynchronous and the panic stack in the lowcore now have an additional offset applied to them. This offset needs to be taken into account in the calculation for the low and high address for the stacks. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
* dump_stack: unify debug information printed by show_regs()Tejun Heo2013-05-011-8/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | show_regs() is inherently arch-dependent but it does make sense to print generic debug information and some archs already do albeit in slightly different forms. This patch introduces a generic function to print debug information from show_regs() so that different archs print out the same information and it's much easier to modify what's printed. show_regs_print_info() prints out the same debug info as dump_stack() does plus task and thread_info pointers. * Archs which didn't print debug info now do. alpha, arc, blackfin, c6x, cris, frv, h8300, hexagon, ia64, m32r, metag, microblaze, mn10300, openrisc, parisc, score, sh64, sparc, um, xtensa * Already prints debug info. Replaced with show_regs_print_info(). The printed information is superset of what used to be there. arm, arm64, avr32, mips, powerpc, sh32, tile, unicore32, x86 * s390 is special in that it used to print arch-specific information along with generic debug info. Heiko and Martin think that the arch-specific extra isn't worth keeping s390 specfic implementation. Converted to use the generic version. Note that now all archs print the debug info before actual register dumps. An example BUG() dump follows. kernel BUG at /work/os/work/kernel/workqueue.c:4841! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #7 Hardware name: empty empty/S3992, BIOS 080011 10/26/2007 task: ffff88007c85e040 ti: ffff88007c860000 task.ti: ffff88007c860000 RIP: 0010:[<ffffffff8234a07e>] [<ffffffff8234a07e>] init_workqueues+0x4/0x6 RSP: 0000:ffff88007c861ec8 EFLAGS: 00010246 RAX: ffff88007c861fd8 RBX: ffffffff824466a8 RCX: 0000000000000001 RDX: 0000000000000046 RSI: 0000000000000001 RDI: ffffffff8234a07a RBP: ffff88007c861ec8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8234a07a R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: ffff88015f7ff000 CR3: 00000000021f1000 CR4: 00000000000007f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Stack: ffff88007c861ef8 ffffffff81000312 ffffffff824466a8 ffff88007c85e650 0000000000000003 0000000000000000 ffff88007c861f38 ffffffff82335e5d ffff88007c862080 ffffffff8223d8c0 ffff88007c862080 ffffffff81c47760 Call Trace: [<ffffffff81000312>] do_one_initcall+0x122/0x170 [<ffffffff82335e5d>] kernel_init_freeable+0x9b/0x1c8 [<ffffffff81c47760>] ? rest_init+0x140/0x140 [<ffffffff81c4776e>] kernel_init+0xe/0xf0 [<ffffffff81c6be9c>] ret_from_fork+0x7c/0xb0 [<ffffffff81c47760>] ? rest_init+0x140/0x140 ... v2: Typo fix in x86-32. v3: CPU number dropped from show_regs_print_info() as dump_stack_print_info() has been updated to print it. s390 specific implementation dropped as requested by s390 maintainers. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Sam Ravnborg <sam@ravnborg.org> Acked-by: Chris Metcalf <cmetcalf@tilera.com> [tile bits] Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon bits] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dump_stack: consolidate dump_stack() implementations and unify their behaviorsTejun Heo2013-05-011-17/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Both dump_stack() and show_stack() are currently implemented by each architecture. show_stack(NULL, NULL) dumps the backtrace for the current task as does dump_stack(). On some archs, dump_stack() prints extra information - pid, utsname and so on - in addition to the backtrace while the two are identical on other archs. The usages in arch-independent code of the two functions indicate show_stack(NULL, NULL) should print out bare backtrace while dump_stack() is used for debugging purposes when something went wrong, so it does make sense to print additional information on the task which triggered dump_stack(). There's no reason to require archs to implement two separate but mostly identical functions. It leads to unnecessary subtle information. This patch expands the dummy fallback dump_stack() implementation in lib/dump_stack.c such that it prints out debug information (taken from x86) and invokes show_stack(NULL, NULL) and drops arch-specific dump_stack() implementations in all archs except blackfin. Blackfin's dump_stack() does something wonky that I don't understand. Debug information can be printed separately by calling dump_stack_print_info() so that arch-specific dump_stack() implementation can still emit the same debug information. This is used in blackfin. This patch brings the following behavior changes. * On some archs, an extra level in backtrace for show_stack() could be printed. This is because the top frame was determined in dump_stack() on those archs while generic dump_stack() can't do that reliably. It can be compensated by inlining dump_stack() but not sure whether that'd be necessary. * Most archs didn't use to print debug info on dump_stack(). They do now. An example WARN dump follows. WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505() Hardware name: empty Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9 0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48 ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c 0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58 Call Trace: [<ffffffff81c614dc>] dump_stack+0x19/0x1b [<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0 [<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20 [<ffffffff8234a071>] init_workqueues+0x35/0x505 ... v2: CPU number added to the generic debug info as requested by s390 folks and dropped the s390 specific dump_stack(). This loses %ksp from the debug message which the maintainers think isn't important enough to keep the s390-specific dump_stack() implementation. dump_stack_print_info() is moved to kernel/printk.c from lib/dump_stack.c. Because linkage is per objecct file, dump_stack_print_info() living in the same lib file as generic dump_stack() means that archs which implement custom dump_stack() - at this point, only blackfin - can't use dump_stack_print_info() as that will bring in the generic version of dump_stack() too. v1 The v1 patch broke build on blackfin due to this issue. The build breakage was reported by Fengguang Wu. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Vineet Gupta <vgupta@synopsys.com> Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390 bits] Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Sam Ravnborg <sam@ravnborg.org> Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon bits] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* s390/dumpstack: fix call chain walkingHeiko Carstens2013-04-171-0/+236
dumpstack() did not always print a sane callchain when being called. The reason is that show_trace() accessed register 15 directly to get the current stack pointer and passed that pointer to __show_trace() which expects a valid stack frame pointer as argument. However due to tail call optimization the stack frame may not exist anymore when __show_trace() gets called and therefore an invalid stack frame pointer gets passed. To prevent that disable tail call optimization for call chain walking functions. So move all the show_* functions to a dumpstack.c file like other architectures have it already and add a -fno-optimize-sibling-calls compile flag to both dumpstack.c and stacktrace.c to prevent tail call optimization. Fixes callchains that looked e.g. like this: [ 12.868258] Call Trace: [ 12.868262] ([<0000000000008000>] 0x8000) Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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