1. 24 Aug, 2018 1 commit
    • Josh Poimboeuf's avatar
      objtool: Support GCC 8 '-fnoreorder-functions' · 0bcba956
      Josh Poimboeuf authored
      [ Upstream commit 08b393d0 ]
      
      Since the following commit:
      
        cd77849a ("objtool: Fix GCC 8 cold subfunction detection for aliased functions")
      
      ... if the kernel is built with EXTRA_CFLAGS='-fno-reorder-functions',
      objtool can get stuck in an infinite loop.
      
      That flag causes the new GCC 8 cold subfunctions to be placed in .text
      instead of .text.unlikely.  But it also has an unfortunate quirk: in the
      symbol table, the subfunction (e.g., nmi_panic.cold.7) is nested inside
      the parent (nmi_panic).
      
      That function overlap confuses objtool, and causes it to get into an
      infinite loop in next_insn_same_func().  Here's Allan's description of
      the loop:
      
        "Objtool iterates through the instructions in nmi_panic using
        next_insn_same_func. Once it reaches the end of nmi_panic at 0x534 it
        jumps to 0x528 as that's the start of nmi_panic.cold.7. However, since
        the instructions starting at 0x528 are still associated with nmi_panic
        objtool will get stuck in a loop, continually jumping back to 0x528
        after reaching 0x534."
      
      Fix it by shortening the length of the parent function so that the
      functions no longer overlap.
      Reported-and-analyzed-by: default avatarAllan Xavier <allan.x.xavier@oracle.com>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Allan Xavier <allan.x.xavier@oracle.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Borislav Petkov <bp@alien8.de>
      Cc: Brian Gerst <brgerst@gmail.com>
      Cc: Denys Vlasenko <dvlasenk@redhat.com>
      Cc: H. Peter Anvin <hpa@zytor.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/9e704c52bee651129b036be14feda317ae5606ae.1530136978.git.jpoimboe@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      0bcba956
  2. 11 Jul, 2018 1 commit
    • Rasmus Villemoes's avatar
      Kbuild: fix # escaping in .cmd files for future Make · e8288549
      Rasmus Villemoes authored
      commit 9564a8cf upstream.
      
      I tried building using a freshly built Make (4.2.1-69-g8a731d1), but
      already the objtool build broke with
      
      orc_dump.c: In function ‘orc_dump’:
      orc_dump.c:106:2: error: ‘elf_getshnum’ is deprecated [-Werror=deprecated-declarations]
        if (elf_getshdrnum(elf, &nr_sections)) {
      
      Turns out that with that new Make, the backslash was not removed, so cpp
      didn't see a #include directive, grep found nothing, and
      -DLIBELF_USE_DEPRECATED was wrongly put in CFLAGS.
      
      Now, that new Make behaviour is documented in their NEWS file:
      
        * WARNING: Backward-incompatibility!
          Number signs (#) appearing inside a macro reference or function invocation
          no longer introduce comments and should not be escaped with backslashes:
          thus a call such as:
            foo := $(shell echo '#')
          is legal.  Previously the number sign needed to be escaped, for example:
            foo := $(shell echo '\#')
          Now this latter will resolve to "\#".  If you want to write makefiles
          portable to both versions, assign the number sign to a variable:
            C := \#
            foo := $(shell echo '$C')
          This was claimed to be fixed in 3.81, but wasn't, for some reason.
          To detect this change search for 'nocomment' in the .FEATURES variable.
      
      This also fixes up the two make-cmd instances to replace # with $(pound)
      rather than with \#. There might very well be other places that need
      similar fixup in preparation for whatever future Make release contains
      the above change, but at least this builds an x86_64 defconfig with the
      new make.
      
      Link: https://bugzilla.kernel.org/show_bug.cgi?id=197847
      Cc: Randy Dunlap <rdunlap@infradead.org>
      Signed-off-by: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
      Signed-off-by: Masahiro Yamada's avatarMasahiro Yamada <yamada.masahiro@socionext.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      
      e8288549
  3. 20 Jun, 2018 1 commit
    • Ingo Molnar's avatar
      objtool, kprobes/x86: Sync the latest <asm/insn.h> header with... · 847f0cac
      Ingo Molnar authored
      objtool, kprobes/x86: Sync the latest <asm/insn.h> header with tools/objtool/arch/x86/include/asm/insn.h
      
      [ Upstream commit 4fe875e4 ]
      
      The following commit:
      
        ee6a7354: kprobes/x86: Prohibit probing on exception masking instructions
      
      Modified <asm/insn.h>, adding the insn_masking_exception() function.
      
      Sync the tooling version of the header to it, to fix this warning:
      
        Warning: synced file at 'tools/objtool/arch/x86/include/asm/insn.h' differs from latest kernel version at 'arch/x86/include/asm/insn.h'
      
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Josh Poimboeuf <jpoimboe@redhat.com>
      Cc: Masami Hiramatsu <mhiramat@kernel.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
      Cc: Francis Deslauriers <francis.deslauriers@efficios.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Alexei Starovoitov <ast@kernel.org>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: "H . Peter Anvin" <hpa@zytor.com>
      Cc: Yonghong Song <yhs@fb.com>
      Cc: Borislav Petkov <bp@suse.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: "David S . Miller" <davem@davemloft.net>
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      847f0cac
  4. 05 Jun, 2018 5 commits
    • Josh Poimboeuf's avatar
      objtool: Fix "noreturn" detection for recursive sibling calls · 6bcf3b06
      Josh Poimboeuf authored
      commit 0afd0d9e upstream.
      
      Objtool has some crude logic for detecting static "noreturn" functions
      (aka "dead ends").  This is necessary for being able to correctly follow
      GCC code flow when such functions are called.
      
      It's remotely possible for two functions to call each other via sibling
      calls.  If they don't have RET instructions, objtool's noreturn
      detection logic goes into a recursive loop:
      
        drivers/char/ipmi/ipmi_ssif.o: warning: objtool: return_hosed_msg()+0x0: infinite recursion (objtool bug!)
        drivers/char/ipmi/ipmi_ssif.o: warning: objtool: deliver_recv_msg()+0x0: infinite recursion (objtool bug!)
      
      Instead of reporting an error in this case, consider the functions to be
      non-dead-ends.
      Reported-and-tested-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: David Laight <David.Laight@ACULAB.COM>
      Cc: Greg KH <gregkh@linuxfoundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: damian <damian.tometzki@icloud.com>
      Link: http://lkml.kernel.org/r/7cc156408c5781a1f62085d352ced1fe39fe2f91.1525923412.git.jpoimboe@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6bcf3b06
    • Josh Poimboeuf's avatar
      objtool: Detect RIP-relative switch table references, part 2 · 806a730c
      Josh Poimboeuf authored
      commit 7dec80cc upstream.
      
      With the following commit:
      
        fd35c88b ("objtool: Support GCC 8 switch tables")
      
      I added a "can't find switch jump table" warning, to stop covering up
      silent failures if add_switch_table() can't find anything.
      
      That warning found yet another bug in the objtool switch table detection
      logic.  For cases 1 and 2 (as described in the comments of
      find_switch_table()), the find_symbol_containing() check doesn't adjust
      the offset for RIP-relative switch jumps.
      
      Incidentally, this bug was already fixed for case 3 with:
      
        6f5ec299 ("objtool: Detect RIP-relative switch table references")
      
      However, that commit missed the fix for cases 1 and 2.
      
      The different cases are now starting to look more and more alike.  So
      fix the bug by consolidating them into a single case, by checking the
      original dynamic jump instruction in the case 3 loop.
      
      This also simplifies the code and makes it more robust against future
      switch table detection issues -- of which I'm sure there will be many...
      
      Switch table detection has been the most fragile area of objtool, by
      far.  I long for the day when we'll have a GCC plugin for annotating
      switch tables.  Linus asked me to delay such a plugin due to the
      flakiness of the plugin infrastructure in older versions of GCC, so this
      rickety code is what we're stuck with for now.  At least the code is now
      a little simpler than it was.
      Reported-by: default avatarkbuild test robot <lkp@intel.com>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/f400541613d45689086329432f3095119ffbc328.1526674218.git.jpoimboe@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      806a730c
    • Josh Poimboeuf's avatar
      objtool: Detect RIP-relative switch table references · afb5e5c8
      Josh Poimboeuf authored
      commit 6f5ec299 upstream.
      
      Typically a switch table can be found by detecting a .rodata access
      followed an indirect jump:
      
          1969:	4a 8b 0c e5 00 00 00 	mov    0x0(,%r12,8),%rcx
          1970:	00
      			196d: R_X86_64_32S	.rodata+0x438
          1971:	e9 00 00 00 00       	jmpq   1976 <dispc_runtime_suspend+0xb6a>
      			1972: R_X86_64_PC32	__x86_indirect_thunk_rcx-0x4
      
      Randy Dunlap reported a case (seen with GCC 4.8) where the .rodata
      access uses RIP-relative addressing:
      
          19bd:	48 8b 3d 00 00 00 00 	mov    0x0(%rip),%rdi        # 19c4 <dispc_runtime_suspend+0xbb8>
      			19c0: R_X86_64_PC32	.rodata+0x45c
          19c4:	e9 00 00 00 00       	jmpq   19c9 <dispc_runtime_suspend+0xbbd>
      			19c5: R_X86_64_PC32	__x86_indirect_thunk_rdi-0x4
      
      In this case the relocation addend needs to be adjusted accordingly in
      order to find the location of the switch table.
      
      The fix is for case 3 (as described in the comments), but also make the
      existing case 1 & 2 checks more precise by only adjusting the addend for
      R_X86_64_PC32 relocations.
      
      This fixes the following warnings:
      
        drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_suspend()+0xbb8: sibling call from callable instruction with modified stack frame
        drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_resume()+0xcc5: sibling call from callable instruction with modified stack frame
      Reported-by: default avatarRandy Dunlap <rdunlap@infradead.org>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/b6098294fd67afb69af8c47c9883d7a68bf0f8ea.1526305958.git.jpoimboe@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      afb5e5c8
    • Josh Poimboeuf's avatar
      objtool: Support GCC 8 switch tables · 2c26d578
      Josh Poimboeuf authored
      commit fd35c88b upstream.
      
      With GCC 8, some issues were found with the objtool switch table
      detection.
      
      1) In the .rodata section, immediately after the switch table, there can
         be another object which contains a pointer to the function which had
         the switch statement.  In this case objtool wrongly considers the
         function pointer to be part of the switch table.  Fix it by:
      
         a) making sure there are no pointers to the beginning of the
            function; and
      
         b) making sure there are no gaps in the switch table.
      
         Only the former was needed, the latter adds additional protection for
         future optimizations.
      
      2) In find_switch_table(), case 1 and case 2 are missing the check to
         ensure that the .rodata switch table data is anonymous, i.e. that it
         isn't already associated with an ELF symbol.  Fix it by adding the
         same find_symbol_containing() check which is used for case 3.
      
      This fixes the following warnings with GCC 8:
      
        drivers/block/virtio_blk.o: warning: objtool: virtio_queue_rq()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+72
        net/ipv6/icmp.o: warning: objtool: icmpv6_rcv()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64
        drivers/usb/core/quirks.o: warning: objtool: quirks_param_set()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+48
        drivers/mtd/nand/raw/nand_hynix.o: warning: objtool: hynix_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+24
        drivers/mtd/nand/raw/nand_samsung.o: warning: objtool: samsung_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+32
        drivers/gpu/drm/nouveau/nvkm/subdev/top/gk104.o: warning: objtool: gk104_top_oneinit()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64
      Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
      Reported-by: default avatarkbuild test robot <lkp@intel.com>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: David Laight <David.Laight@ACULAB.COM>
      Cc: Greg KH <gregkh@linuxfoundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Randy Dunlap <rdunlap@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: damian <damian.tometzki@icloud.com>
      Link: http://lkml.kernel.org/r/20180510224849.xwi34d6tzheb5wgw@trebleSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      2c26d578
    • Josh Poimboeuf's avatar
      objtool: Support GCC 8's cold subfunctions · 1bea53df
      Josh Poimboeuf authored
      commit 13810435 upstream.
      
      GCC 8 moves a lot of unlikely code out of line to "cold" subfunctions in
      .text.unlikely.  Properly detect the new subfunctions and treat them as
      extensions of the original functions.
      
      This fixes a bunch of warnings like:
      
        kernel/cgroup/cgroup.o: warning: objtool: parse_cgroup_root_flags()+0x33: sibling call from callable instruction with modified stack frame
        kernel/cgroup/cgroup.o: warning: objtool: cgroup_addrm_files()+0x290: sibling call from callable instruction with modified stack frame
        kernel/cgroup/cgroup.o: warning: objtool: cgroup_apply_control_enable()+0x25b: sibling call from callable instruction with modified stack frame
        kernel/cgroup/cgroup.o: warning: objtool: rebind_subsystems()+0x325: sibling call from callable instruction with modified stack frame
      Reported-and-tested-by: default avatardamian <damian.tometzki@icloud.com>
      Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Cc: David Laight <David.Laight@ACULAB.COM>
      Cc: Greg KH <gregkh@linuxfoundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Randy Dunlap <rdunlap@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/0965e7fcfc5f31a276f0c7f298ff770c19b68706.1525923412.git.jpoimboe@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      1bea53df
  5. 12 Apr, 2018 1 commit
  6. 15 Mar, 2018 5 commits
  7. 22 Feb, 2018 1 commit
  8. 16 Feb, 2018 1 commit
  9. 07 Feb, 2018 3 commits
  10. 23 Jan, 2018 5 commits
  11. 17 Jan, 2018 2 commits
    • Josh Poimboeuf's avatar
      objtool: Allow alternatives to be ignored · 6b95f61a
      Josh Poimboeuf authored
      commit 258c7605 upstream.
      
      Getting objtool to understand retpolines is going to be a bit of a
      challenge.  For now, take advantage of the fact that retpolines are
      patched in with alternatives.  Just read the original (sane)
      non-alternative instruction, and ignore the patched-in retpoline.
      
      This allows objtool to understand the control flow *around* the
      retpoline, even if it can't yet follow what's inside.  This means the
      ORC unwinder will fail to unwind from inside a retpoline, but will work
      fine otherwise.
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: gnomes@lxorguk.ukuu.org.uk
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: thomas.lendacky@amd.com
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Jiri Kosina <jikos@kernel.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Kees Cook <keescook@google.com>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
      Cc: Paul Turner <pjt@google.com>
      Link: https://lkml.kernel.org/r/1515707194-20531-3-git-send-email-dwmw@amazon.co.ukSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6b95f61a
    • Josh Poimboeuf's avatar
      objtool: Detect jumps to retpoline thunks · 6a4d1182
      Josh Poimboeuf authored
      commit 39b73533 upstream.
      
      A direct jump to a retpoline thunk is really an indirect jump in
      disguise.  Change the objtool instruction type accordingly.
      
      Objtool needs to know where indirect branches are so it can detect
      switch statement jump tables.
      
      This fixes a bunch of warnings with CONFIG_RETPOLINE like:
      
        arch/x86/events/intel/uncore_nhmex.o: warning: objtool: nhmex_rbox_msr_enable_event()+0x44: sibling call from callable instruction with modified stack frame
        kernel/signal.o: warning: objtool: copy_siginfo_to_user()+0x91: sibling call from callable instruction with modified stack frame
        ...
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Signed-off-by: default avatarDavid Woodhouse <dwmw@amazon.co.uk>
      Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Cc: gnomes@lxorguk.ukuu.org.uk
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Andi Kleen <ak@linux.intel.com>
      Cc: thomas.lendacky@amd.com
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Jiri Kosina <jikos@kernel.org>
      Cc: Andy Lutomirski <luto@amacapital.net>
      Cc: Dave Hansen <dave.hansen@intel.com>
      Cc: Kees Cook <keescook@google.com>
      Cc: Tim Chen <tim.c.chen@linux.intel.com>
      Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
      Cc: Paul Turner <pjt@google.com>
      Link: https://lkml.kernel.org/r/1515707194-20531-2-git-send-email-dwmw@amazon.co.ukSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      6a4d1182
  12. 29 Dec, 2017 6 commits
  13. 25 Dec, 2017 2 commits
  14. 04 Nov, 2017 1 commit
  15. 02 Nov, 2017 1 commit
    • Greg Kroah-Hartman's avatar
      License cleanup: add SPDX GPL-2.0 license identifier to files with no license · b2441318
      Greg Kroah-Hartman authored
      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: default avatarKate Stewart <kstewart@linuxfoundation.org>
      Reviewed-by: default avatarPhilippe Ombredanne <pombredanne@nexb.com>
      Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b2441318
  16. 20 Oct, 2017 1 commit
  17. 28 Sep, 2017 1 commit
    • Josh Poimboeuf's avatar
      objtool: Support unoptimized frame pointer setup · 607a4029
      Josh Poimboeuf authored
      Arnd Bergmann reported a bunch of warnings like:
      
        crypto/jitterentropy.o: warning: objtool: jent_fold_time()+0x3b: call without frame pointer save/setup
        crypto/jitterentropy.o: warning: objtool: jent_stuck()+0x1d: call without frame pointer save/setup
        crypto/jitterentropy.o: warning: objtool: jent_unbiased_bit()+0x15: call without frame pointer save/setup
        crypto/jitterentropy.o: warning: objtool: jent_read_entropy()+0x32: call without frame pointer save/setup
        crypto/jitterentropy.o: warning: objtool: jent_entropy_collector_free()+0x19: call without frame pointer save/setup
      
      and
      
        arch/x86/events/core.o: warning: objtool: collect_events uses BP as a scratch register
        arch/x86/events/core.o: warning: objtool: events_ht_sysfs_show()+0x22: call without frame pointer save/setup
      
      With certain rare configurations, GCC sometimes sets up the frame
      pointer with:
      
        lea    (%rsp),%rbp
      
      instead of:
      
        mov    %rsp,%rbp
      
      The instructions are equivalent, so treat the former like the latter.
      Reported-by: default avatarArnd Bergmann <arnd@arndb.de>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/a468af8b28a69b83fffc6d7668be9b6fcc873699.1506526584.git.jpoimboe@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      607a4029
  18. 23 Sep, 2017 2 commits
    • Josh Poimboeuf's avatar
      x86/asm: Fix inline asm call constraints for Clang · f5caf621
      Josh Poimboeuf authored
      For inline asm statements which have a CALL instruction, we list the
      stack pointer as a constraint to convince GCC to ensure the frame
      pointer is set up first:
      
        static inline void foo()
        {
      	register void *__sp asm(_ASM_SP);
      	asm("call bar" : "+r" (__sp))
        }
      
      Unfortunately, that pattern causes Clang to corrupt the stack pointer.
      
      The fix is easy: convert the stack pointer register variable to a global
      variable.
      
      It should be noted that the end result is different based on the GCC
      version.  With GCC 6.4, this patch has exactly the same result as
      before:
      
      	defconfig	defconfig-nofp	distro		distro-nofp
       before	9820389		9491555		8816046		8516940
       after	9820389		9491555		8816046		8516940
      
      With GCC 7.2, however, GCC's behavior has changed.  It now changes its
      behavior based on the conversion of the register variable to a global.
      That somehow convinces it to *always* set up the frame pointer before
      inserting *any* inline asm.  (Therefore, listing the variable as an
      output constraint is a no-op and is no longer necessary.)  It's a bit
      overkill, but the performance impact should be negligible.  And in fact,
      there's a nice improvement with frame pointers disabled:
      
      	defconfig	defconfig-nofp	distro		distro-nofp
       before	9796316		9468236		9076191		8790305
       after	9796957		9464267		9076381		8785949
      
      So in summary, while listing the stack pointer as an output constraint
      is no longer necessary for newer versions of GCC, it's still needed for
      older versions.
      Suggested-by: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
      Reported-by: default avatarMatthias Kaehlcke <mka@chromium.org>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Dmitriy Vyukov <dvyukov@google.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Link: http://lkml.kernel.org/r/3db862e970c432ae823cf515c52b54fec8270e0e.1505942196.git.jpoimboe@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      f5caf621
    • Josh Poimboeuf's avatar
      objtool: Handle another GCC stack pointer adjustment bug · 0d0970ee
      Josh Poimboeuf authored
      The kbuild bot reported the following warning with GCC 4.4 and a
      randconfig:
      
        net/socket.o: warning: objtool: compat_sock_ioctl()+0x1083: stack state mismatch: cfa1=7+160 cfa2=-1+0
      
      This is caused by another GCC non-optimization, where it backs up and
      restores the stack pointer for no apparent reason:
      
          2f91:       48 89 e0                mov    %rsp,%rax
          2f94:       4c 89 e7                mov    %r12,%rdi
          2f97:       4c 89 f6                mov    %r14,%rsi
          2f9a:       ba 20 00 00 00          mov    $0x20,%edx
          2f9f:       48 89 c4                mov    %rax,%rsp
      
      This issue would have been happily ignored before the following commit:
      
        dd88a0a0 ("objtool: Handle GCC stack pointer adjustment bug")
      
      But now that objtool is paying attention to such stack pointer writes
      to/from a register, it needs to understand them properly.  In this case
      that means recognizing that the "mov %rsp, %rax" instruction is
      potentially a backup of the stack pointer.
      Reported-by: default avatarkbuild test robot <fengguang.wu@intel.com>
      Signed-off-by: default avatarJosh Poimboeuf <jpoimboe@redhat.com>
      Cc: Alexander Potapenko <glider@google.com>
      Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Cc: Arnd Bergmann <arnd@arndb.de>
      Cc: Dmitriy Vyukov <dvyukov@google.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Matthias Kaehlcke <mka@chromium.org>
      Cc: Miguel Bernal Marin <miguel.bernal.marin@linux.intel.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Fixes: dd88a0a0 ("objtool: Handle GCC stack pointer adjustment bug")
      Link: http://lkml.kernel.org/r/8c7aa8e9a36fbbb6655d9d8e7cea58958c912da8.1505942196.git.jpoimboe@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      0d0970ee