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linux/arch/x86/kernel/ftrace_32.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 07:07:57 -07:00
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2017 Steven Rostedt, VMware Inc.
*/
#include <linux/export.h>
#include <linux/linkage.h>
#include <asm/page_types.h>
#include <asm/segment.h>
#include <asm/ftrace.h>
#include <asm/nospec-branch.h>
#include <asm/frame.h>
#include <asm/asm-offsets.h>
#ifdef CONFIG_FRAME_POINTER
# define MCOUNT_FRAME 1 /* using frame = true */
#else
# define MCOUNT_FRAME 0 /* using frame = false */
#endif
SYM_FUNC_START(__fentry__)
RET
SYM_FUNC_END(__fentry__)
EXPORT_SYMBOL(__fentry__)
SYM_CODE_START(ftrace_caller)
x86/ftrace: Add stack frame pointer to ftrace_caller The function hook ftrace_caller does not create its own stack frame, and this causes the ftrace stack trace to miss the first function when doing stack traces. # echo schedule:stacktrace > /sys/kernel/tracing/set_ftrace_filter Before: <idle>-0 [002] .N.. 29.865807: <stack trace> => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [001] .... 29.866509: <stack trace> => kthread => ret_from_fork <...>-1 [000] .... 29.865377: <stack trace> => poll_schedule_timeout => do_select => core_sys_select => SyS_select => do_fast_syscall_32 => entry_SYSENTER_32 After: <idle>-0 [002] .N.. 31.234853: <stack trace> => do_idle => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [003] .... 31.235140: <stack trace> => rcu_gp_kthread => kthread => ret_from_fork <...>-1819 [000] .... 31.264172: <stack trace> => schedule_hrtimeout_range => poll_schedule_timeout => do_sys_poll => SyS_ppoll => do_fast_syscall_32 => entry_SYSENTER_32 Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20170323143445.771707773@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23 07:33:50 -07:00
#ifdef CONFIG_FRAME_POINTER
/*
* Frame pointers are of ip followed by bp.
* Since fentry is an immediate jump, we are left with
* parent-ip, function-ip. We need to add a frame with
* parent-ip followed by ebp.
*/
pushl 4(%esp) /* parent ip */
x86/ftrace: Add stack frame pointer to ftrace_caller The function hook ftrace_caller does not create its own stack frame, and this causes the ftrace stack trace to miss the first function when doing stack traces. # echo schedule:stacktrace > /sys/kernel/tracing/set_ftrace_filter Before: <idle>-0 [002] .N.. 29.865807: <stack trace> => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [001] .... 29.866509: <stack trace> => kthread => ret_from_fork <...>-1 [000] .... 29.865377: <stack trace> => poll_schedule_timeout => do_select => core_sys_select => SyS_select => do_fast_syscall_32 => entry_SYSENTER_32 After: <idle>-0 [002] .N.. 31.234853: <stack trace> => do_idle => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [003] .... 31.235140: <stack trace> => rcu_gp_kthread => kthread => ret_from_fork <...>-1819 [000] .... 31.264172: <stack trace> => schedule_hrtimeout_range => poll_schedule_timeout => do_sys_poll => SyS_ppoll => do_fast_syscall_32 => entry_SYSENTER_32 Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20170323143445.771707773@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23 07:33:50 -07:00
pushl %ebp
movl %esp, %ebp
pushl 2*4(%esp) /* function ip */
/* For mcount, the function ip is directly above */
pushl %ebp
movl %esp, %ebp
#endif
pushl %eax
pushl %ecx
pushl %edx
pushl $0 /* Pass NULL as regs pointer */
#ifdef CONFIG_FRAME_POINTER
/* Load parent ebp into edx */
x86/ftrace: Add stack frame pointer to ftrace_caller The function hook ftrace_caller does not create its own stack frame, and this causes the ftrace stack trace to miss the first function when doing stack traces. # echo schedule:stacktrace > /sys/kernel/tracing/set_ftrace_filter Before: <idle>-0 [002] .N.. 29.865807: <stack trace> => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [001] .... 29.866509: <stack trace> => kthread => ret_from_fork <...>-1 [000] .... 29.865377: <stack trace> => poll_schedule_timeout => do_select => core_sys_select => SyS_select => do_fast_syscall_32 => entry_SYSENTER_32 After: <idle>-0 [002] .N.. 31.234853: <stack trace> => do_idle => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [003] .... 31.235140: <stack trace> => rcu_gp_kthread => kthread => ret_from_fork <...>-1819 [000] .... 31.264172: <stack trace> => schedule_hrtimeout_range => poll_schedule_timeout => do_sys_poll => SyS_ppoll => do_fast_syscall_32 => entry_SYSENTER_32 Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20170323143445.771707773@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23 07:33:50 -07:00
movl 4*4(%esp), %edx
#else
/* There's no frame pointer, load the appropriate stack addr instead */
lea 4*4(%esp), %edx
#endif
movl (MCOUNT_FRAME+4)*4(%esp), %eax /* load the rip */
x86/ftrace: Add stack frame pointer to ftrace_caller The function hook ftrace_caller does not create its own stack frame, and this causes the ftrace stack trace to miss the first function when doing stack traces. # echo schedule:stacktrace > /sys/kernel/tracing/set_ftrace_filter Before: <idle>-0 [002] .N.. 29.865807: <stack trace> => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [001] .... 29.866509: <stack trace> => kthread => ret_from_fork <...>-1 [000] .... 29.865377: <stack trace> => poll_schedule_timeout => do_select => core_sys_select => SyS_select => do_fast_syscall_32 => entry_SYSENTER_32 After: <idle>-0 [002] .N.. 31.234853: <stack trace> => do_idle => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [003] .... 31.235140: <stack trace> => rcu_gp_kthread => kthread => ret_from_fork <...>-1819 [000] .... 31.264172: <stack trace> => schedule_hrtimeout_range => poll_schedule_timeout => do_sys_poll => SyS_ppoll => do_fast_syscall_32 => entry_SYSENTER_32 Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20170323143445.771707773@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23 07:33:50 -07:00
/* Get the parent ip */
movl 4(%edx), %edx /* edx has ebp */
movl function_trace_op, %ecx
subl $MCOUNT_INSN_SIZE, %eax
.globl ftrace_call
ftrace_call:
call ftrace_stub
addl $4, %esp /* skip NULL pointer */
popl %edx
popl %ecx
popl %eax
#ifdef CONFIG_FRAME_POINTER
x86/ftrace: Add stack frame pointer to ftrace_caller The function hook ftrace_caller does not create its own stack frame, and this causes the ftrace stack trace to miss the first function when doing stack traces. # echo schedule:stacktrace > /sys/kernel/tracing/set_ftrace_filter Before: <idle>-0 [002] .N.. 29.865807: <stack trace> => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [001] .... 29.866509: <stack trace> => kthread => ret_from_fork <...>-1 [000] .... 29.865377: <stack trace> => poll_schedule_timeout => do_select => core_sys_select => SyS_select => do_fast_syscall_32 => entry_SYSENTER_32 After: <idle>-0 [002] .N.. 31.234853: <stack trace> => do_idle => cpu_startup_entry => start_secondary => startup_32_smp <...>-7 [003] .... 31.235140: <stack trace> => rcu_gp_kthread => kthread => ret_from_fork <...>-1819 [000] .... 31.264172: <stack trace> => schedule_hrtimeout_range => poll_schedule_timeout => do_sys_poll => SyS_ppoll => do_fast_syscall_32 => entry_SYSENTER_32 Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20170323143445.771707773@goodmis.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-03-23 07:33:50 -07:00
popl %ebp
addl $4,%esp /* skip function ip */
popl %ebp /* this is the orig bp */
addl $4, %esp /* skip parent ip */
#endif
.Lftrace_ret:
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
.globl ftrace_graph_call
ftrace_graph_call:
jmp ftrace_stub
#endif
/* This is weak to keep gas from relaxing the jumps */
SYM_INNER_LABEL_ALIGN(ftrace_stub, SYM_L_WEAK)
RET
SYM_CODE_END(ftrace_caller)
SYM_CODE_START(ftrace_regs_caller)
/*
* We're here from an mcount/fentry CALL, and the stack frame looks like:
*
* <previous context>
* RET-IP
*
* The purpose of this function is to call out in an emulated INT3
* environment with a stack frame like:
*
* <previous context>
* gap / RET-IP
* gap
* gap
* gap
* pt_regs
*
* We do _NOT_ restore: ss, flags, cs, gs, fs, es, ds
*/
subl $3*4, %esp # RET-IP + 3 gaps
pushl %ss # ss
pushl %esp # points at ss
addl $5*4, (%esp) # make it point at <previous context>
pushfl # flags
pushl $__KERNEL_CS # cs
pushl 7*4(%esp) # ip <- RET-IP
pushl $0 # orig_eax
pushl %gs
pushl %fs
pushl %es
pushl %ds
pushl %eax
pushl %ebp
pushl %edi
pushl %esi
pushl %edx
pushl %ecx
pushl %ebx
ENCODE_FRAME_POINTER
movl PT_EIP(%esp), %eax # 1st argument: IP
subl $MCOUNT_INSN_SIZE, %eax
movl 21*4(%esp), %edx # 2nd argument: parent ip
movl function_trace_op, %ecx # 3rd argument: ftrace_pos
pushl %esp # 4th argument: pt_regs
SYM_INNER_LABEL(ftrace_regs_call, SYM_L_GLOBAL)
call ftrace_stub
addl $4, %esp # skip 4th argument
/* place IP below the new SP */
movl PT_OLDESP(%esp), %eax
movl PT_EIP(%esp), %ecx
movl %ecx, -4(%eax)
/* place EAX below that */
movl PT_EAX(%esp), %ecx
movl %ecx, -8(%eax)
popl %ebx
popl %ecx
popl %edx
popl %esi
popl %edi
popl %ebp
lea -8(%eax), %esp
popl %eax
jmp .Lftrace_ret
SYM_CODE_END(ftrace_regs_caller)
ftrace: selftest: remove broken trace_direct_tramp The ftrace selftest code has a trace_direct_tramp() function which it uses as a direct call trampoline. This happens to work on x86, since the direct call's return address is in the usual place, and can be returned to via a RET, but in general the calling convention for direct calls is different from regular function calls, and requires a trampoline written in assembly. On s390, regular function calls place the return address in %r14, and an ftrace patch-site in an instrumented function places the trampoline's return address (which is within the instrumented function) in %r0, preserving the original %r14 value in-place. As a regular C function will return to the address in %r14, using a C function as the trampoline results in the trampoline returning to the caller of the instrumented function, skipping the body of the instrumented function. Note that the s390 issue is not detcted by the ftrace selftest code, as the instrumented function is trivial, and returning back into the caller happens to be equivalent. On arm64, regular function calls place the return address in x30, and an ftrace patch-site in an instrumented function saves this into r9 and places the trampoline's return address (within the instrumented function) in x30. A regular C function will return to the address in x30, but will not restore x9 into x30. Consequently, using a C function as the trampoline results in returning to the trampoline's return address having corrupted x30, such that when the instrumented function returns, it will return back into itself. To avoid future issues in this area, remove the trace_direct_tramp() function, and require that each architecture with direct calls provides a stub trampoline, named ftrace_stub_direct_tramp. This can be written to handle the architecture's trampoline calling convention, and in future could be used elsewhere (e.g. in the ftrace ops sample, to measure the overhead of direct calls), so we may as well always build it in. Link: https://lkml.kernel.org/r/20230321140424.345218-8-revest@chromium.org Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Li Huafei <lihuafei1@huawei.com> Cc: Xu Kuohai <xukuohai@huawei.com> Signed-off-by: Florent Revest <revest@chromium.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-03-21 07:04:24 -07:00
SYM_FUNC_START(ftrace_stub_direct_tramp)
CALL_DEPTH_ACCOUNT
RET
SYM_FUNC_END(ftrace_stub_direct_tramp)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
SYM_CODE_START(ftrace_graph_caller)
pushl %eax
pushl %ecx
pushl %edx
movl 3*4(%esp), %eax
/* Even with frame pointers, fentry doesn't have one here */
lea 4*4(%esp), %edx
movl $0, %ecx
subl $MCOUNT_INSN_SIZE, %eax
call prepare_ftrace_return
popl %edx
popl %ecx
popl %eax
RET
SYM_CODE_END(ftrace_graph_caller)
.globl return_to_handler
return_to_handler:
pushl $0
pushl %edx
pushl %eax
movl %esp, %eax
call ftrace_return_to_handler
movl %eax, %ecx
popl %eax
popl %edx
addl $4, %esp # skip ebp
JMP_NOSPEC ecx
#endif