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WSL2-Linux-Kernel/arch/s390/kernel/mcount.S

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license 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>
2017-11-01 17:07:57 +03:00
/* SPDX-License-Identifier: GPL-2.0 */
[S390] ftrace: function tracer backend for s390 This implements just the basic function tracer (_mcount) backend for s390. The dynamic variant will come later. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 15:38:56 +03:00
/*
s390/comments: unify copyright messages and remove file names Remove the file name from the comment at top of many files. In most cases the file name was wrong anyway, so it's rather pointless. Also unify the IBM copyright statement. We did have a lot of sightly different statements and wanted to change them one after another whenever a file gets touched. However that never happened. Instead people start to take the old/"wrong" statements to use as a template for new files. So unify all of them in one go. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2012-07-20 13:15:04 +04:00
* Copyright IBM Corp. 2008, 2009
[S390] ftrace: function tracer backend for s390 This implements just the basic function tracer (_mcount) backend for s390. The dynamic variant will come later. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 15:38:56 +03:00
*
* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
*
*/
[S390] fix s390 assembler code alignments The alignment is missing for various global symbols in s390 assembly code. With a recent gcc and an instruction like stgrl this can lead to a specification exception if the instruction uses such a mis-aligned address. Specify the alignment explicitely and while add it define __ALIGN for s390 and use the ENTRY define to save some lines of code. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 12:48:19 +04:00
#include <linux/linkage.h>
[S390] ftrace/mcount: fix kernel stack backchain With packed stack the backchain is at a different location. Just use __SF_BACKCHAIN as an offset to store the backchain. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 15:27:34 +03:00
#include <asm/asm-offsets.h>
s390/ftrace: fix mcount adjustment Tony Jones reported that the ftrace self tests on s390 do not work: <6>Testing dynamic ftrace ops #1: (0 0 0 0 0) FAILED! <6>Testing tracer irqsoff: <3>failed to start irqsoff tracer <4>.. no entries found ..FAILED! <6>Testing tracer wakeup: <3>failed to start wakeup tracer <4>.. no entries found ..FAILED! <6>Testing tracer function_graph: <4>Failed to init function_graph tracer, init returned -19 <4>FAILED! This happens because we forgot to adjust the instruction pointer that gets passed to the ftrace trace function by MCOUNT_INSN_SIZE. In addition change MCOUNT_INSN_SIZE to the correct value on 31 bit. It only worked so far because the to be patched instruction was identical. Reported-by: Tony Jones <tonyj@suse.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2013-05-13 16:48:52 +04:00
#include <asm/ftrace.h>
s390/ftrace: use expoline for indirect branches The return from the ftrace_stub, _mcount, ftrace_caller and return_to_handler functions is done with "br %r14" and "br %r1". These are indirect branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y. The ftrace_caller function is a special case as it returns to the start of a function and may only use %r0 and %r1. For a pre z10 machine the standard execute trampoline uses a LARL + EX to do this, but this requires *two* registers in the range %r1..%r15. To get around this the 'br %r1' located in the lowcore is used, then the EX instruction does not need an address register. But the lowcore trick may only be used for pre z14 machines, with noexec=on the mapping for the first page may not contain instructions. The solution for that is an ALTERNATIVE in the expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to EXRL, this relies on the fact that a machine that supports noexec=on has EXRL as well. Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-04-25 19:35:26 +03:00
#include <asm/nospec-insn.h>
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
#include <asm/ptrace.h>
s390: move exports to definitions Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2016-01-12 21:30:03 +03:00
#include <asm/export.h>
[S390] ftrace/mcount: fix kernel stack backchain With packed stack the backchain is at a different location. Just use __SF_BACKCHAIN as an offset to store the backchain. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-03-18 15:27:34 +03:00
s390/ftrace: use expoline for indirect branches The return from the ftrace_stub, _mcount, ftrace_caller and return_to_handler functions is done with "br %r14" and "br %r1". These are indirect branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y. The ftrace_caller function is a special case as it returns to the start of a function and may only use %r0 and %r1. For a pre z10 machine the standard execute trampoline uses a LARL + EX to do this, but this requires *two* registers in the range %r1..%r15. To get around this the 'br %r1' located in the lowcore is used, then the EX instruction does not need an address register. But the lowcore trick may only be used for pre z14 machines, with noexec=on the mapping for the first page may not contain instructions. The solution for that is an ALTERNATIVE in the expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to EXRL, this relies on the fact that a machine that supports noexec=on has EXRL as well. Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-04-25 19:35:26 +03:00
GEN_BR_THUNK %r1
GEN_BR_THUNK %r14
[S390] add kprobes annotations Add kprobes annotations to get the massive 'probe kernel.function("*") {}' stress test working. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-01-05 14:47:25 +03:00
.section .kprobes.text, "ax"
[S390] fix s390 assembler code alignments The alignment is missing for various global symbols in s390 assembly code. With a recent gcc and an instruction like stgrl this can lead to a specification exception if the instruction uses such a mis-aligned address. Specify the alignment explicitely and while add it define __ALIGN for s390 and use the ENTRY define to save some lines of code. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 12:48:19 +04:00
ENTRY(ftrace_stub)
s390/ftrace: use expoline for indirect branches The return from the ftrace_stub, _mcount, ftrace_caller and return_to_handler functions is done with "br %r14" and "br %r1". These are indirect branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y. The ftrace_caller function is a special case as it returns to the start of a function and may only use %r0 and %r1. For a pre z10 machine the standard execute trampoline uses a LARL + EX to do this, but this requires *two* registers in the range %r1..%r15. To get around this the 'br %r1' located in the lowcore is used, then the EX instruction does not need an address register. But the lowcore trick may only be used for pre z14 machines, with noexec=on the mapping for the first page may not contain instructions. The solution for that is an ALTERNATIVE in the expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to EXRL, this relies on the fact that a machine that supports noexec=on has EXRL as well. Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-04-25 19:35:26 +03:00
BR_EX %r14
s390: add missing ENDPROC statements to assembler functions The assembler code in arch/s390 misses proper ENDPROC statements to properly end functions in a few places. Add them. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-01-17 12:02:22 +03:00
ENDPROC(ftrace_stub)
[S390] ftrace: add dynamic ftrace support Dynamic ftrace support for s390. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 12:26:44 +04:00
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
#define STACK_FRAME_SIZE (STACK_FRAME_OVERHEAD + __PT_SIZE)
#define STACK_PTREGS (STACK_FRAME_OVERHEAD)
#define STACK_PTREGS_GPRS (STACK_PTREGS + __PT_GPRS)
#define STACK_PTREGS_PSW (STACK_PTREGS + __PT_PSW)
s390/ftrace: generate traced function stack frame Currently backtrace from ftraced function does not contain ftraced function itself. e.g. for "path_openat": arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15e/0x3d8 ftrace_graph_caller+0x0/0x1c <-- ftrace code do_filp_open+0x7c/0xe8 <-- ftraced function caller do_open_execat+0x76/0x1b8 open_exec+0x52/0x78 load_elf_binary+0x180/0x1160 search_binary_handler+0x8e/0x288 load_script+0x2a8/0x2b8 search_binary_handler+0x8e/0x288 __do_execve_file.isra.39+0x6fa/0xb40 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Ftraced function is expected in the backtrace by ftrace kselftests, which are now failing. It would also be nice to have it for clarity reasons. "ftrace_caller" itself is called without stack frame allocated for it and does not store its caller (ftraced function). Instead it simply allocates a stack frame for "ftrace_trace_function" and sets backchain to point to ftraced function stack frame (which contains ftraced function caller in saved r14). To fix this issue make "ftrace_caller" allocate a stack frame for itself just to store ftraced function for the stack unwinder. As a result backtrace looks like the following: arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15e/0x3d8 ftrace_graph_caller+0x0/0x1c <-- ftrace code path_openat+0x6/0xd60 <-- ftraced function do_filp_open+0x7c/0xe8 <-- ftraced function caller do_open_execat+0x76/0x1b8 open_exec+0x52/0x78 load_elf_binary+0x180/0x1160 search_binary_handler+0x8e/0x288 load_script+0x2a8/0x2b8 search_binary_handler+0x8e/0x288 __do_execve_file.isra.39+0x6fa/0xb40 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Reported-by: Sven Schnelle <sven.schnelle@ibm.com> Tested-by: Sven Schnelle <sven.schnelle@ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-12-10 16:33:39 +03:00
#ifdef __PACK_STACK
/* allocate just enough for r14, r15 and backchain */
#define TRACED_FUNC_FRAME_SIZE 24
#else
#define TRACED_FUNC_FRAME_SIZE STACK_FRAME_OVERHEAD
#endif
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
[S390] fix s390 assembler code alignments The alignment is missing for various global symbols in s390 assembly code. With a recent gcc and an instruction like stgrl this can lead to a specification exception if the instruction uses such a mis-aligned address. Specify the alignment explicitely and while add it define __ALIGN for s390 and use the ENTRY define to save some lines of code. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 12:48:19 +04:00
ENTRY(ftrace_caller)
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
.globl ftrace_regs_caller
.set ftrace_regs_caller,ftrace_caller
s390/ftrace: save traced function caller A typical backtrace acquired from ftraced function currently looks like the following (e.g. for "path_openat"): arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15a/0x3b8 ftrace_graph_caller+0x0/0x1c 0x3e0007e3c98 <- ftraced function caller (should be do_filp_open+0x7c/0xe8) do_open_execat+0x70/0x1b8 __do_execve_file.isra.0+0x7d8/0x860 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Note random "0x3e0007e3c98" stack value as ftraced function caller. This value causes either imprecise unwinder result or unwinding failure. That "0x3e0007e3c98" comes from r14 of ftraced function stack frame, which it haven't had a chance to initialize since the very first instruction calls ftrace code ("ftrace_caller"). (ftraced function might never save r14 as well). Nevertheless according to s390 ABI any function is called with stack frame allocated for it and r14 contains return address. "ftrace_caller" itself is called with "brasl %r0,ftrace_caller". So, to fix this issue simply always save traced function caller onto ftraced function stack frame. Reported-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-12-10 15:50:23 +03:00
stg %r14,(__SF_GPRS+8*8)(%r15) # save traced function caller
s390: support KPROBES_ON_FTRACE Instead of using our own kprobes-on-ftrace handling convert the code to support KPROBES_ON_FTRACE. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-01-21 14:31:47 +03:00
lghi %r14,0 # save condition code
ipm %r14 # don't put any instructions
sllg %r14,%r14,16 # clobbering CC before this point
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
lgr %r1,%r15
s390/ftrace: generate traced function stack frame Currently backtrace from ftraced function does not contain ftraced function itself. e.g. for "path_openat": arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15e/0x3d8 ftrace_graph_caller+0x0/0x1c <-- ftrace code do_filp_open+0x7c/0xe8 <-- ftraced function caller do_open_execat+0x76/0x1b8 open_exec+0x52/0x78 load_elf_binary+0x180/0x1160 search_binary_handler+0x8e/0x288 load_script+0x2a8/0x2b8 search_binary_handler+0x8e/0x288 __do_execve_file.isra.39+0x6fa/0xb40 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Ftraced function is expected in the backtrace by ftrace kselftests, which are now failing. It would also be nice to have it for clarity reasons. "ftrace_caller" itself is called without stack frame allocated for it and does not store its caller (ftraced function). Instead it simply allocates a stack frame for "ftrace_trace_function" and sets backchain to point to ftraced function stack frame (which contains ftraced function caller in saved r14). To fix this issue make "ftrace_caller" allocate a stack frame for itself just to store ftraced function for the stack unwinder. As a result backtrace looks like the following: arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15e/0x3d8 ftrace_graph_caller+0x0/0x1c <-- ftrace code path_openat+0x6/0xd60 <-- ftraced function do_filp_open+0x7c/0xe8 <-- ftraced function caller do_open_execat+0x76/0x1b8 open_exec+0x52/0x78 load_elf_binary+0x180/0x1160 search_binary_handler+0x8e/0x288 load_script+0x2a8/0x2b8 search_binary_handler+0x8e/0x288 __do_execve_file.isra.39+0x6fa/0xb40 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Reported-by: Sven Schnelle <sven.schnelle@ibm.com> Tested-by: Sven Schnelle <sven.schnelle@ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-12-10 16:33:39 +03:00
# allocate stack frame for ftrace_caller to contain traced function
aghi %r15,-TRACED_FUNC_FRAME_SIZE
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
stg %r1,__SF_BACKCHAIN(%r15)
s390/ftrace: generate traced function stack frame Currently backtrace from ftraced function does not contain ftraced function itself. e.g. for "path_openat": arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15e/0x3d8 ftrace_graph_caller+0x0/0x1c <-- ftrace code do_filp_open+0x7c/0xe8 <-- ftraced function caller do_open_execat+0x76/0x1b8 open_exec+0x52/0x78 load_elf_binary+0x180/0x1160 search_binary_handler+0x8e/0x288 load_script+0x2a8/0x2b8 search_binary_handler+0x8e/0x288 __do_execve_file.isra.39+0x6fa/0xb40 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Ftraced function is expected in the backtrace by ftrace kselftests, which are now failing. It would also be nice to have it for clarity reasons. "ftrace_caller" itself is called without stack frame allocated for it and does not store its caller (ftraced function). Instead it simply allocates a stack frame for "ftrace_trace_function" and sets backchain to point to ftraced function stack frame (which contains ftraced function caller in saved r14). To fix this issue make "ftrace_caller" allocate a stack frame for itself just to store ftraced function for the stack unwinder. As a result backtrace looks like the following: arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15e/0x3d8 ftrace_graph_caller+0x0/0x1c <-- ftrace code path_openat+0x6/0xd60 <-- ftraced function do_filp_open+0x7c/0xe8 <-- ftraced function caller do_open_execat+0x76/0x1b8 open_exec+0x52/0x78 load_elf_binary+0x180/0x1160 search_binary_handler+0x8e/0x288 load_script+0x2a8/0x2b8 search_binary_handler+0x8e/0x288 __do_execve_file.isra.39+0x6fa/0xb40 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Reported-by: Sven Schnelle <sven.schnelle@ibm.com> Tested-by: Sven Schnelle <sven.schnelle@ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-12-10 16:33:39 +03:00
stg %r0,(__SF_GPRS+8*8)(%r15)
stg %r15,(__SF_GPRS+9*8)(%r15)
# allocate pt_regs and stack frame for ftrace_trace_function
aghi %r15,-STACK_FRAME_SIZE
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
stg %r1,(STACK_PTREGS_GPRS+15*8)(%r15)
s390: support KPROBES_ON_FTRACE Instead of using our own kprobes-on-ftrace handling convert the code to support KPROBES_ON_FTRACE. Signed-off-by: Sven Schnelle <svens@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2020-01-21 14:31:47 +03:00
stg %r14,(STACK_PTREGS_PSW)(%r15)
lg %r14,(__SF_GPRS+8*8)(%r1) # restore original return address
stosm (STACK_PTREGS_PSW)(%r15),0
s390/ftrace: generate traced function stack frame Currently backtrace from ftraced function does not contain ftraced function itself. e.g. for "path_openat": arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15e/0x3d8 ftrace_graph_caller+0x0/0x1c <-- ftrace code do_filp_open+0x7c/0xe8 <-- ftraced function caller do_open_execat+0x76/0x1b8 open_exec+0x52/0x78 load_elf_binary+0x180/0x1160 search_binary_handler+0x8e/0x288 load_script+0x2a8/0x2b8 search_binary_handler+0x8e/0x288 __do_execve_file.isra.39+0x6fa/0xb40 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Ftraced function is expected in the backtrace by ftrace kselftests, which are now failing. It would also be nice to have it for clarity reasons. "ftrace_caller" itself is called without stack frame allocated for it and does not store its caller (ftraced function). Instead it simply allocates a stack frame for "ftrace_trace_function" and sets backchain to point to ftraced function stack frame (which contains ftraced function caller in saved r14). To fix this issue make "ftrace_caller" allocate a stack frame for itself just to store ftraced function for the stack unwinder. As a result backtrace looks like the following: arch_stack_walk+0x15c/0x2d8 stack_trace_save+0x50/0x68 stack_trace_call+0x15e/0x3d8 ftrace_graph_caller+0x0/0x1c <-- ftrace code path_openat+0x6/0xd60 <-- ftraced function do_filp_open+0x7c/0xe8 <-- ftraced function caller do_open_execat+0x76/0x1b8 open_exec+0x52/0x78 load_elf_binary+0x180/0x1160 search_binary_handler+0x8e/0x288 load_script+0x2a8/0x2b8 search_binary_handler+0x8e/0x288 __do_execve_file.isra.39+0x6fa/0xb40 __s390x_sys_execve+0x56/0x68 system_call+0xdc/0x2d8 Reported-by: Sven Schnelle <sven.schnelle@ibm.com> Tested-by: Sven Schnelle <sven.schnelle@ibm.com> Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-12-10 16:33:39 +03:00
aghi %r1,-TRACED_FUNC_FRAME_SIZE
stg %r1,__SF_BACKCHAIN(%r15)
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
stg %r0,(STACK_PTREGS_PSW+8)(%r15)
stmg %r2,%r14,(STACK_PTREGS_GPRS+2*8)(%r15)
#ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
aghik %r2,%r0,-MCOUNT_INSN_SIZE
lgrl %r4,function_trace_op
s390/ftrace: fix ftrace_update_ftrace_func implementation s390 enforces DYNAMIC_FTRACE if FUNCTION_TRACER is selected. At the same time implementation of ftrace_caller is not compliant with HAVE_DYNAMIC_FTRACE since it doesn't provide implementation of ftrace_update_ftrace_func() and calls ftrace_trace_function() directly. The subtle difference is that during ftrace code patching ftrace replaces function tracer via ftrace_update_ftrace_func() and activates it back afterwards. Unexpected direct calls to ftrace_trace_function() during ftrace code patching leads to nullptr-dereferences when tracing is activated for one of functions which are used during code patching. Those function currently are: copy_from_kernel_nofault() copy_from_kernel_nofault_allowed() preempt_count_sub() [with debug_defconfig] preempt_count_add() [with debug_defconfig] Corresponding KASAN report: BUG: KASAN: nullptr-dereference in function_trace_call+0x316/0x3b0 Read of size 4 at addr 0000000000001e08 by task migration/0/15 CPU: 0 PID: 15 Comm: migration/0 Tainted: G B 5.13.0-41423-g08316af3644d Hardware name: IBM 3906 M04 704 (LPAR) Stopper: multi_cpu_stop+0x0/0x3e0 <- stop_machine_cpuslocked+0x1e4/0x218 Call Trace: [<0000000001f77caa>] show_stack+0x16a/0x1d0 [<0000000001f8de42>] dump_stack+0x15a/0x1b0 [<0000000001f81d56>] print_address_description.constprop.0+0x66/0x2e0 [<000000000082b0ca>] kasan_report+0x152/0x1c0 [<00000000004cfd8e>] function_trace_call+0x316/0x3b0 [<0000000001fb7082>] ftrace_caller+0x7a/0x7e [<00000000006bb3e6>] copy_from_kernel_nofault_allowed+0x6/0x10 [<00000000006bb42e>] copy_from_kernel_nofault+0x3e/0xd0 [<000000000014605c>] ftrace_make_call+0xb4/0x1f8 [<000000000047a1b4>] ftrace_replace_code+0x134/0x1d8 [<000000000047a6e0>] ftrace_modify_all_code+0x120/0x1d0 [<000000000047a7ec>] __ftrace_modify_code+0x5c/0x78 [<000000000042395c>] multi_cpu_stop+0x224/0x3e0 [<0000000000423212>] cpu_stopper_thread+0x33a/0x5a0 [<0000000000243ff2>] smpboot_thread_fn+0x302/0x708 [<00000000002329ea>] kthread+0x342/0x408 [<00000000001066b2>] __ret_from_fork+0x92/0xf0 [<0000000001fb57fa>] ret_from_fork+0xa/0x30 The buggy address belongs to the page: page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1 flags: 0x1ffff00000001000(reserved|node=0|zone=0|lastcpupid=0x1ffff) raw: 1ffff00000001000 0000040000000048 0000040000000048 0000000000000000 raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: 0000000000001d00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 0000000000001d80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 >0000000000001e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 ^ 0000000000001e80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 0000000000001f00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 ================================================================== To fix that introduce ftrace_func callback to be called from ftrace_caller and update it in ftrace_update_ftrace_func(). Fixes: 4cc9bed034d1 ("[S390] cleanup ftrace backend functions") Cc: stable@vger.kernel.org Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-06-26 00:50:07 +03:00
lgrl %r1,ftrace_func
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
#else
lgr %r2,%r0
aghi %r2,-MCOUNT_INSN_SIZE
larl %r4,function_trace_op
lg %r4,0(%r4)
s390/ftrace: fix ftrace_update_ftrace_func implementation s390 enforces DYNAMIC_FTRACE if FUNCTION_TRACER is selected. At the same time implementation of ftrace_caller is not compliant with HAVE_DYNAMIC_FTRACE since it doesn't provide implementation of ftrace_update_ftrace_func() and calls ftrace_trace_function() directly. The subtle difference is that during ftrace code patching ftrace replaces function tracer via ftrace_update_ftrace_func() and activates it back afterwards. Unexpected direct calls to ftrace_trace_function() during ftrace code patching leads to nullptr-dereferences when tracing is activated for one of functions which are used during code patching. Those function currently are: copy_from_kernel_nofault() copy_from_kernel_nofault_allowed() preempt_count_sub() [with debug_defconfig] preempt_count_add() [with debug_defconfig] Corresponding KASAN report: BUG: KASAN: nullptr-dereference in function_trace_call+0x316/0x3b0 Read of size 4 at addr 0000000000001e08 by task migration/0/15 CPU: 0 PID: 15 Comm: migration/0 Tainted: G B 5.13.0-41423-g08316af3644d Hardware name: IBM 3906 M04 704 (LPAR) Stopper: multi_cpu_stop+0x0/0x3e0 <- stop_machine_cpuslocked+0x1e4/0x218 Call Trace: [<0000000001f77caa>] show_stack+0x16a/0x1d0 [<0000000001f8de42>] dump_stack+0x15a/0x1b0 [<0000000001f81d56>] print_address_description.constprop.0+0x66/0x2e0 [<000000000082b0ca>] kasan_report+0x152/0x1c0 [<00000000004cfd8e>] function_trace_call+0x316/0x3b0 [<0000000001fb7082>] ftrace_caller+0x7a/0x7e [<00000000006bb3e6>] copy_from_kernel_nofault_allowed+0x6/0x10 [<00000000006bb42e>] copy_from_kernel_nofault+0x3e/0xd0 [<000000000014605c>] ftrace_make_call+0xb4/0x1f8 [<000000000047a1b4>] ftrace_replace_code+0x134/0x1d8 [<000000000047a6e0>] ftrace_modify_all_code+0x120/0x1d0 [<000000000047a7ec>] __ftrace_modify_code+0x5c/0x78 [<000000000042395c>] multi_cpu_stop+0x224/0x3e0 [<0000000000423212>] cpu_stopper_thread+0x33a/0x5a0 [<0000000000243ff2>] smpboot_thread_fn+0x302/0x708 [<00000000002329ea>] kthread+0x342/0x408 [<00000000001066b2>] __ret_from_fork+0x92/0xf0 [<0000000001fb57fa>] ret_from_fork+0xa/0x30 The buggy address belongs to the page: page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1 flags: 0x1ffff00000001000(reserved|node=0|zone=0|lastcpupid=0x1ffff) raw: 1ffff00000001000 0000040000000048 0000040000000048 0000000000000000 raw: 0000000000000000 0000000000000000 ffffffff00000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: 0000000000001d00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 0000000000001d80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 >0000000000001e00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 ^ 0000000000001e80: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 0000000000001f00: f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 f7 ================================================================== To fix that introduce ftrace_func callback to be called from ftrace_caller and update it in ftrace_update_ftrace_func(). Fixes: 4cc9bed034d1 ("[S390] cleanup ftrace backend functions") Cc: stable@vger.kernel.org Reviewed-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2021-06-26 00:50:07 +03:00
larl %r1,ftrace_func
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
lg %r1,0(%r1)
#endif
lgr %r3,%r14
la %r5,STACK_PTREGS(%r15)
s390/ftrace: use expoline for indirect branches The return from the ftrace_stub, _mcount, ftrace_caller and return_to_handler functions is done with "br %r14" and "br %r1". These are indirect branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y. The ftrace_caller function is a special case as it returns to the start of a function and may only use %r0 and %r1. For a pre z10 machine the standard execute trampoline uses a LARL + EX to do this, but this requires *two* registers in the range %r1..%r15. To get around this the 'br %r1' located in the lowcore is used, then the EX instruction does not need an address register. But the lowcore trick may only be used for pre z14 machines, with noexec=on the mapping for the first page may not contain instructions. The solution for that is an ALTERNATIVE in the expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to EXRL, this relies on the fact that a machine that supports noexec=on has EXRL as well. Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-04-25 19:35:26 +03:00
BASR_EX %r14,%r1
[S390] ftrace: add function graph tracer support Function graph tracer support for s390. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 12:26:46 +04:00
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
# The j instruction gets runtime patched to a nop instruction.
s390/ftrace: simplify enabling/disabling of ftrace_graph_caller We can simply patch the mask field within the branch relative on condition instruction at the beginning of the ftrace_graph_caller code block. This makes the logic even simpler and we get rid of the displacement calculation. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-08 12:03:08 +04:00
# See ftrace_enable_ftrace_graph_caller.
s390: add missing ENDPROC statements to assembler functions The assembler code in arch/s390 misses proper ENDPROC statements to properly end functions in a few places. Add them. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-01-17 12:02:22 +03:00
.globl ftrace_graph_caller
ftrace_graph_caller:
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
j ftrace_graph_caller_end
s390/ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR Make the call chain more reliable by tagging the ftrace stack entries with the stack pointer that is associated with the return address. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-02-18 18:51:28 +03:00
lmg %r2,%r3,(STACK_PTREGS_GPRS+14*8)(%r15)
lg %r4,(STACK_PTREGS_PSW+8)(%r15)
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
brasl %r14,prepare_ftrace_return
stg %r2,(STACK_PTREGS_GPRS+14*8)(%r15)
ftrace_graph_caller_end:
.globl ftrace_graph_caller_end
[S390] ftrace: add function graph tracer support Function graph tracer support for s390. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 12:26:46 +04:00
#endif
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
lg %r1,(STACK_PTREGS_PSW+8)(%r15)
lmg %r2,%r15,(STACK_PTREGS_GPRS+2*8)(%r15)
s390/ftrace: use expoline for indirect branches The return from the ftrace_stub, _mcount, ftrace_caller and return_to_handler functions is done with "br %r14" and "br %r1". These are indirect branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y. The ftrace_caller function is a special case as it returns to the start of a function and may only use %r0 and %r1. For a pre z10 machine the standard execute trampoline uses a LARL + EX to do this, but this requires *two* registers in the range %r1..%r15. To get around this the 'br %r1' located in the lowcore is used, then the EX instruction does not need an address register. But the lowcore trick may only be used for pre z14 machines, with noexec=on the mapping for the first page may not contain instructions. The solution for that is an ALTERNATIVE in the expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to EXRL, this relies on the fact that a machine that supports noexec=on has EXRL as well. Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-04-25 19:35:26 +03:00
BR_EX %r1
s390: add missing ENDPROC statements to assembler functions The assembler code in arch/s390 misses proper ENDPROC statements to properly end functions in a few places. Add them. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-01-17 12:02:22 +03:00
ENDPROC(ftrace_caller)
[S390] ftrace: function tracer backend for s390 This implements just the basic function tracer (_mcount) backend for s390. The dynamic variant will come later. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2008-12-25 15:38:56 +03:00
[S390] ftrace: add function graph tracer support Function graph tracer support for s390. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 12:26:46 +04:00
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
[S390] fix s390 assembler code alignments The alignment is missing for various global symbols in s390 assembly code. With a recent gcc and an instruction like stgrl this can lead to a specification exception if the instruction uses such a mis-aligned address. Specify the alignment explicitely and while add it define __ALIGN for s390 and use the ENTRY define to save some lines of code. Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 12:48:19 +04:00
ENTRY(return_to_handler)
s390/ftrace: remove 31 bit ftrace support 31 bit and 64 bit diverge more and more and it is rather painful to keep both parts running. To make things simpler just remove the 31 bit support which nobody uses anyway. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-10-07 17:45:10 +04:00
stmg %r2,%r5,32(%r15)
lgr %r1,%r15
aghi %r15,-STACK_FRAME_OVERHEAD
stg %r1,__SF_BACKCHAIN(%r15)
brasl %r14,ftrace_return_to_handler
aghi %r15,STACK_FRAME_OVERHEAD
lgr %r14,%r2
lmg %r2,%r5,32(%r15)
s390/ftrace: use expoline for indirect branches The return from the ftrace_stub, _mcount, ftrace_caller and return_to_handler functions is done with "br %r14" and "br %r1". These are indirect branches as well and need to use execute trampolines for CONFIG_EXPOLINE=y. The ftrace_caller function is a special case as it returns to the start of a function and may only use %r0 and %r1. For a pre z10 machine the standard execute trampoline uses a LARL + EX to do this, but this requires *two* registers in the range %r1..%r15. To get around this the 'br %r1' located in the lowcore is used, then the EX instruction does not need an address register. But the lowcore trick may only be used for pre z14 machines, with noexec=on the mapping for the first page may not contain instructions. The solution for that is an ALTERNATIVE in the expoline THUNK generated by 'GEN_BR_THUNK %r1' to switch to EXRL, this relies on the fact that a machine that supports noexec=on has EXRL as well. Cc: stable@vger.kernel.org # 4.16 Fixes: f19fbd5ed6 ("s390: introduce execute-trampolines for branches") Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2018-04-25 19:35:26 +03:00
BR_EX %r14
s390: add missing ENDPROC statements to assembler functions The assembler code in arch/s390 misses proper ENDPROC statements to properly end functions in a few places. Add them. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2019-01-17 12:02:22 +03:00
ENDPROC(return_to_handler)
[S390] ftrace: add function graph tracer support Function graph tracer support for s390. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-06-12 12:26:46 +04:00
[S390] improve mcount code Move the 64 bit mount code from mcount.S into mcount64.S and avoid code duplication. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2009-09-11 12:28:33 +04:00
#endif