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b24413180f
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>
252 lines
7.0 KiB
C
252 lines
7.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Dynamic function tracer architecture backend.
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*
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* Copyright IBM Corp. 2009,2014
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*
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* Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
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* Martin Schwidefsky <schwidefsky@de.ibm.com>
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*/
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#include <linux/moduleloader.h>
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#include <linux/hardirq.h>
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#include <linux/uaccess.h>
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#include <linux/ftrace.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/kprobes.h>
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#include <trace/syscall.h>
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#include <asm/asm-offsets.h>
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#include <asm/cacheflush.h>
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#include <asm/set_memory.h>
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#include "entry.h"
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/*
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* The mcount code looks like this:
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* stg %r14,8(%r15) # offset 0
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* larl %r1,<&counter> # offset 6
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* brasl %r14,_mcount # offset 12
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* lg %r14,8(%r15) # offset 18
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* Total length is 24 bytes. Only the first instruction will be patched
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* by ftrace_make_call / ftrace_make_nop.
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* The enabled ftrace code block looks like this:
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* > brasl %r0,ftrace_caller # offset 0
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* larl %r1,<&counter> # offset 6
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* brasl %r14,_mcount # offset 12
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* lg %r14,8(%r15) # offset 18
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* The ftrace function gets called with a non-standard C function call ABI
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* where r0 contains the return address. It is also expected that the called
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* function only clobbers r0 and r1, but restores r2-r15.
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* For module code we can't directly jump to ftrace caller, but need a
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* trampoline (ftrace_plt), which clobbers also r1.
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* The return point of the ftrace function has offset 24, so execution
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* continues behind the mcount block.
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* The disabled ftrace code block looks like this:
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* > jg .+24 # offset 0
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* larl %r1,<&counter> # offset 6
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* brasl %r14,_mcount # offset 12
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* lg %r14,8(%r15) # offset 18
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* The jg instruction branches to offset 24 to skip as many instructions
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* as possible.
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* In case we use gcc's hotpatch feature the original and also the disabled
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* function prologue contains only a single six byte instruction and looks
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* like this:
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* > brcl 0,0 # offset 0
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* To enable ftrace the code gets patched like above and afterwards looks
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* like this:
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* > brasl %r0,ftrace_caller # offset 0
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*/
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unsigned long ftrace_plt;
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static inline void ftrace_generate_orig_insn(struct ftrace_insn *insn)
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{
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#ifdef CC_USING_HOTPATCH
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/* brcl 0,0 */
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insn->opc = 0xc004;
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insn->disp = 0;
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#else
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/* stg r14,8(r15) */
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insn->opc = 0xe3e0;
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insn->disp = 0xf0080024;
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#endif
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}
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static inline int is_kprobe_on_ftrace(struct ftrace_insn *insn)
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{
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#ifdef CONFIG_KPROBES
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if (insn->opc == BREAKPOINT_INSTRUCTION)
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return 1;
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#endif
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return 0;
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}
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static inline void ftrace_generate_kprobe_nop_insn(struct ftrace_insn *insn)
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{
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#ifdef CONFIG_KPROBES
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insn->opc = BREAKPOINT_INSTRUCTION;
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insn->disp = KPROBE_ON_FTRACE_NOP;
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#endif
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}
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static inline void ftrace_generate_kprobe_call_insn(struct ftrace_insn *insn)
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{
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#ifdef CONFIG_KPROBES
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insn->opc = BREAKPOINT_INSTRUCTION;
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insn->disp = KPROBE_ON_FTRACE_CALL;
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#endif
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}
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int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
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unsigned long addr)
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{
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return 0;
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}
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int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
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unsigned long addr)
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{
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struct ftrace_insn orig, new, old;
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if (probe_kernel_read(&old, (void *) rec->ip, sizeof(old)))
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return -EFAULT;
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if (addr == MCOUNT_ADDR) {
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/* Initial code replacement */
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ftrace_generate_orig_insn(&orig);
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ftrace_generate_nop_insn(&new);
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} else if (is_kprobe_on_ftrace(&old)) {
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/*
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* If we find a breakpoint instruction, a kprobe has been
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* placed at the beginning of the function. We write the
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* constant KPROBE_ON_FTRACE_NOP into the remaining four
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* bytes of the original instruction so that the kprobes
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* handler can execute a nop, if it reaches this breakpoint.
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*/
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ftrace_generate_kprobe_call_insn(&orig);
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ftrace_generate_kprobe_nop_insn(&new);
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} else {
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/* Replace ftrace call with a nop. */
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ftrace_generate_call_insn(&orig, rec->ip);
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ftrace_generate_nop_insn(&new);
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}
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/* Verify that the to be replaced code matches what we expect. */
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if (memcmp(&orig, &old, sizeof(old)))
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return -EINVAL;
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s390_kernel_write((void *) rec->ip, &new, sizeof(new));
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return 0;
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}
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int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
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{
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struct ftrace_insn orig, new, old;
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if (probe_kernel_read(&old, (void *) rec->ip, sizeof(old)))
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return -EFAULT;
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if (is_kprobe_on_ftrace(&old)) {
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/*
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* If we find a breakpoint instruction, a kprobe has been
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* placed at the beginning of the function. We write the
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* constant KPROBE_ON_FTRACE_CALL into the remaining four
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* bytes of the original instruction so that the kprobes
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* handler can execute a brasl if it reaches this breakpoint.
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*/
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ftrace_generate_kprobe_nop_insn(&orig);
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ftrace_generate_kprobe_call_insn(&new);
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} else {
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/* Replace nop with an ftrace call. */
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ftrace_generate_nop_insn(&orig);
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ftrace_generate_call_insn(&new, rec->ip);
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}
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/* Verify that the to be replaced code matches what we expect. */
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if (memcmp(&orig, &old, sizeof(old)))
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return -EINVAL;
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s390_kernel_write((void *) rec->ip, &new, sizeof(new));
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return 0;
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}
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int ftrace_update_ftrace_func(ftrace_func_t func)
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{
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return 0;
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}
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int __init ftrace_dyn_arch_init(void)
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{
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return 0;
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}
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#ifdef CONFIG_MODULES
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static int __init ftrace_plt_init(void)
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{
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unsigned int *ip;
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ftrace_plt = (unsigned long) module_alloc(PAGE_SIZE);
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if (!ftrace_plt)
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panic("cannot allocate ftrace plt\n");
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ip = (unsigned int *) ftrace_plt;
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ip[0] = 0x0d10e310; /* basr 1,0; lg 1,10(1); br 1 */
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ip[1] = 0x100a0004;
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ip[2] = 0x07f10000;
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ip[3] = FTRACE_ADDR >> 32;
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ip[4] = FTRACE_ADDR & 0xffffffff;
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set_memory_ro(ftrace_plt, 1);
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return 0;
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}
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device_initcall(ftrace_plt_init);
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#endif /* CONFIG_MODULES */
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#ifdef CONFIG_FUNCTION_GRAPH_TRACER
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/*
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* Hook the return address and push it in the stack of return addresses
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* in current thread info.
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*/
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unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip)
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{
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struct ftrace_graph_ent trace;
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if (unlikely(ftrace_graph_is_dead()))
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goto out;
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if (unlikely(atomic_read(¤t->tracing_graph_pause)))
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goto out;
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ip -= MCOUNT_INSN_SIZE;
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trace.func = ip;
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trace.depth = current->curr_ret_stack + 1;
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/* Only trace if the calling function expects to. */
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if (!ftrace_graph_entry(&trace))
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goto out;
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if (ftrace_push_return_trace(parent, ip, &trace.depth, 0,
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NULL) == -EBUSY)
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goto out;
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parent = (unsigned long) return_to_handler;
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out:
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return parent;
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}
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NOKPROBE_SYMBOL(prepare_ftrace_return);
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/*
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* Patch the kernel code at ftrace_graph_caller location. The instruction
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* there is branch relative on condition. To enable the ftrace graph code
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* block, we simply patch the mask field of the instruction to zero and
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* turn the instruction into a nop.
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* To disable the ftrace graph code the mask field will be patched to
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* all ones, which turns the instruction into an unconditional branch.
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*/
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int ftrace_enable_ftrace_graph_caller(void)
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{
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u8 op = 0x04; /* set mask field to zero */
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s390_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op));
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return 0;
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}
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int ftrace_disable_ftrace_graph_caller(void)
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{
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u8 op = 0xf4; /* set mask field to all ones */
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s390_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op));
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return 0;
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}
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#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
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