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2021-02-10objtool: Support Clang non-section symbols in ORC generationJosh Poimboeuf1-7/+26
commit e81e0724432542af8d8c702c31e9d82f57b1ff31 upstream. When compiling the kernel with AS=clang, objtool produces a lot of warnings: warning: objtool: missing symbol for section .text warning: objtool: missing symbol for section .init.text warning: objtool: missing symbol for section .ref.text It then fails to generate the ORC table. The problem is that objtool assumes text section symbols always exist. But the Clang assembler is aggressive about removing them. When generating relocations for the ORC table, objtool always tries to reference instructions by their section symbol offset. If the section symbol doesn't exist, it bails. Do a fallback: when a section symbol isn't available, reference a function symbol instead. Reported-by: Dmitry Golovin <dima@golovin.in> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://github.com/ClangBuiltLinux/linux/issues/669 Link: https://lkml.kernel.org/r/9a9cae7fcf628843aabe5a086b1a3c5bf50f42e8.1585761021.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-07objtool: Don't fail on missing symbol tableJosh Poimboeuf1-2/+5
[ Upstream commit 1d489151e9f9d1647110277ff77282fe4d96d09b ] Thanks to a recent binutils change which doesn't generate unused symbols, it's now possible for thunk_64.o be completely empty without CONFIG_PREEMPTION: no text, no data, no symbols. We could edit the Makefile to only build that file when CONFIG_PREEMPTION is enabled, but that will likely create confusion if/when the thunks end up getting used by some other code again. Just ignore it and move on. Reported-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Link: https://github.com/ClangBuiltLinux/linux/issues/1254 Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-12-11x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytesMasami Hiramatsu1-0/+15
commit 4e9a5ae8df5b3365183150f6df49e49dece80d8c upstream Since insn.prefixes.nbytes can be bigger than the size of insn.prefixes.bytes[] when a prefix is repeated, the proper check must be insn.prefixes.bytes[i] != 0 and i < 4 instead of using insn.prefixes.nbytes. Introduce a for_each_insn_prefix() macro for this purpose. Debugged by Kees Cook <keescook@chromium.org>. [ bp: Massage commit message, sync with the respective header in tools/ and drop "we". ] Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints") Reported-by: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/160697103739.3146288.7437620795200799020.stgit@devnote2 [sudip: adjust context, use old insn.h] Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-01objtool: Fix noreturn detection for ignored functionsJosh Poimboeuf1-1/+1
[ Upstream commit db6c6a0df840e3f52c84cc302cc1a08ba11a4416 ] When a function is annotated with STACK_FRAME_NON_STANDARD, objtool doesn't validate its code paths. It also skips sibling call detection within the function. But sibling call detection is actually needed for the case where the ignored function doesn't have any return instructions. Otherwise objtool naively marks the function as implicit static noreturn, which affects the reachability of its callers, resulting in "unreachable instruction" warnings. Fix it by just enabling sibling call detection for ignored functions. The 'insn->ignore' check in add_jump_destinations() is no longer needed after e6da9567959e ("objtool: Don't use ignore flag for fake jumps"). Fixes the following warning: arch/x86/kvm/vmx/vmx.o: warning: objtool: vmx_handle_exit_irqoff()+0x142: unreachable instruction which triggers on an allmodconfig with CONFIG_GCOV_KERNEL unset. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Link: https://lkml.kernel.org/r/5b1e2536cdbaa5246b60d7791b76130a74082c62.1599751464.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-20objtool: Ignore empty alternativesJulien Thierry1-0/+6
[ Upstream commit 7170cf47d16f1ba29eca07fd818870b7af0a93a5 ] The .alternatives section can contain entries with no original instructions. Objtool will currently crash when handling such an entry. Just skip that entry, but still give a warning to discourage useless entries. Signed-off-by: Julien Thierry <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-20objtool: Fix stack offset tracking for indirect CFAsJosh Poimboeuf1-1/+1
commit d8dd25a461e4eec7190cb9d66616aceacc5110ad upstream. When the current frame address (CFA) is stored on the stack (i.e., cfa->base == CFI_SP_INDIRECT), objtool neglects to adjust the stack offset when there are subsequent pushes or pops. This results in bad ORC data at the end of the ENTER_IRQ_STACK macro, when it puts the previous stack pointer on the stack and does a subsequent push. This fixes the following unwinder warning: WARNING: can't dereference registers at 00000000f0a6bdba for ip interrupt_entry+0x9f/0xa0 Fixes: 627fce14809b ("objtool: Add ORC unwind table generation") Reported-by: Vince Weaver <vincent.weaver@maine.edu> Reported-by: Dave Jones <dsj@fb.com> Reported-by: Steven Rostedt <rostedt@goodmis.org> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Reported-by: Joe Mario <jmario@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/853d5d691b29e250333332f09b8e27410b2d9924.1587808742.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-02objtool: Support Clang non-section symbols in ORC dumpJosh Poimboeuf1-17/+27
[ Upstream commit 8782e7cab51b6bf01a5a86471dd82228af1ac185 ] Historically, the relocation symbols for ORC entries have only been section symbols: .text+0: sp:sp+8 bp:(und) type:call end:0 However, the Clang assembler is aggressive about stripping section symbols. In that case we will need to use function symbols: freezing_slow_path+0: sp:sp+8 bp:(und) type:call end:0 In preparation for the generation of such entries in "objtool orc generate", add support for reading them in "objtool orc dump". Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/b811b5eb1a42602c3b523576dc5efab9ad1c174d.1585761021.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-05-02objtool: Fix CONFIG_UBSAN_TRAP unreachable warningsJosh Poimboeuf1-2/+15
[ Upstream commit bd841d6154f5f41f8a32d3c1b0bc229e326e640a ] CONFIG_UBSAN_TRAP causes GCC to emit a UD2 whenever it encounters an unreachable code path. This includes __builtin_unreachable(). Because the BUG() macro uses __builtin_unreachable() after it emits its own UD2, this results in a double UD2. In this case objtool rightfully detects that the second UD2 is unreachable: init/main.o: warning: objtool: repair_env_string()+0x1c8: unreachable instruction We weren't able to figure out a way to get rid of the double UD2s, so just silence the warning. Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/6653ad73c6b59c049211bd7c11ed3809c20ee9f5.1585761021.git.jpoimboe@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-04-24objtool: Fix switch table detection in .text.unlikelyJosh Poimboeuf1-4/+1
commit b401efc120a399dfda1f4d2858a4de365c9b08ef upstream. If a switch jump table's indirect branch is in a ".cold" subfunction in .text.unlikely, objtool doesn't detect it, and instead prints a false warning: drivers/media/v4l2-core/v4l2-ioctl.o: warning: objtool: v4l_print_format.cold()+0xd6: sibling call from callable instruction with modified stack frame drivers/hwmon/max6650.o: warning: objtool: max6650_probe.cold()+0xa5: sibling call from callable instruction with modified stack frame drivers/media/dvb-frontends/drxk_hard.o: warning: objtool: init_drxk.cold()+0x16f: sibling call from callable instruction with modified stack frame Fix it by comparing the function, instead of the section and offset. Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions") Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/157c35d42ca9b6354bbb1604fe9ad7d1153ccb21.1585761021.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-28x86/decoder: Add TEST opcode to Group3-2Masami Hiramatsu1-1/+1
[ Upstream commit 8b7e20a7ba54836076ff35a28349dabea4cec48f ] Add TEST opcode to Group3-2 reg=001b as same as Group3-1 does. Commit 12a78d43de76 ("x86/decoder: Add new TEST instruction pattern") added a TEST opcode assignment to f6 XX/001/XXX (Group 3-1), but did not add f7 XX/001/XXX (Group 3-2). Actually, this TEST opcode variant (ModRM.reg /1) is not described in the Intel SDM Vol2 but in AMD64 Architecture Programmer's Manual Vol.3, Appendix A.2 Table A-6. ModRM.reg Extensions for the Primary Opcode Map. Without this fix, Randy found a warning by insn_decoder_test related to this issue as below. HOSTCC arch/x86/tools/insn_decoder_test HOSTCC arch/x86/tools/insn_sanity TEST posttest arch/x86/tools/insn_decoder_test: warning: Found an x86 instruction decoder bug, please report this. arch/x86/tools/insn_decoder_test: warning: ffffffff81000bf1: f7 0b 00 01 08 00 testl $0x80100,(%rbx) arch/x86/tools/insn_decoder_test: warning: objdump says 6 bytes, but insn_get_length() says 2 arch/x86/tools/insn_decoder_test: warning: Decoded and checked 11913894 instructions with 1 failures TEST posttest arch/x86/tools/insn_sanity: Success: decoded and checked 1000000 random instructions with 0 errors (seed:0x871ce29c) To fix this error, add the TEST opcode according to AMD64 APM Vol.3. [ bp: Massage commit message. ] Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Link: https://lkml.kernel.org/r/157966631413.9580.10311036595431878351.stgit@devnote2 Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-31x86/insn: Add some Intel instructions to the opcode mapAdrian Hunter1-6/+12
[ Upstream commit b980be189c9badba50634671e2303e92bf28e35a ] Add to the opcode map the following instructions: cldemote tpause umonitor umwait movdiri movdir64b enqcmd enqcmds encls enclu enclv pconfig wbnoinvd For information about the instructions, refer Intel SDM May 2019 (325462-070US) and Intel Architecture Instruction Set Extensions May 2019 (319433-037). The instruction decoding can be tested using the perf tools' "x86 instruction decoder - new instructions" test as folllows: $ perf test -v "new " 2>&1 | grep -i cldemote Decoded ok: 0f 1c 00 cldemote (%eax) Decoded ok: 0f 1c 05 78 56 34 12 cldemote 0x12345678 Decoded ok: 0f 1c 84 c8 78 56 34 12 cldemote 0x12345678(%eax,%ecx,8) Decoded ok: 0f 1c 00 cldemote (%rax) Decoded ok: 41 0f 1c 00 cldemote (%r8) Decoded ok: 0f 1c 04 25 78 56 34 12 cldemote 0x12345678 Decoded ok: 0f 1c 84 c8 78 56 34 12 cldemote 0x12345678(%rax,%rcx,8) Decoded ok: 41 0f 1c 84 c8 78 56 34 12 cldemote 0x12345678(%r8,%rcx,8) $ perf test -v "new " 2>&1 | grep -i tpause Decoded ok: 66 0f ae f3 tpause %ebx Decoded ok: 66 0f ae f3 tpause %ebx Decoded ok: 66 41 0f ae f0 tpause %r8d $ perf test -v "new " 2>&1 | grep -i umonitor Decoded ok: 67 f3 0f ae f0 umonitor %ax Decoded ok: f3 0f ae f0 umonitor %eax Decoded ok: 67 f3 0f ae f0 umonitor %eax Decoded ok: f3 0f ae f0 umonitor %rax Decoded ok: 67 f3 41 0f ae f0 umonitor %r8d $ perf test -v "new " 2>&1 | grep -i umwait Decoded ok: f2 0f ae f0 umwait %eax Decoded ok: f2 0f ae f0 umwait %eax Decoded ok: f2 41 0f ae f0 umwait %r8d $ perf test -v "new " 2>&1 | grep -i movdiri Decoded ok: 0f 38 f9 03 movdiri %eax,(%ebx) Decoded ok: 0f 38 f9 88 78 56 34 12 movdiri %ecx,0x12345678(%eax) Decoded ok: 48 0f 38 f9 03 movdiri %rax,(%rbx) Decoded ok: 48 0f 38 f9 88 78 56 34 12 movdiri %rcx,0x12345678(%rax) $ perf test -v "new " 2>&1 | grep -i movdir64b Decoded ok: 66 0f 38 f8 18 movdir64b (%eax),%ebx Decoded ok: 66 0f 38 f8 88 78 56 34 12 movdir64b 0x12345678(%eax),%ecx Decoded ok: 67 66 0f 38 f8 1c movdir64b (%si),%bx Decoded ok: 67 66 0f 38 f8 8c 34 12 movdir64b 0x1234(%si),%cx Decoded ok: 66 0f 38 f8 18 movdir64b (%rax),%rbx Decoded ok: 66 0f 38 f8 88 78 56 34 12 movdir64b 0x12345678(%rax),%rcx Decoded ok: 67 66 0f 38 f8 18 movdir64b (%eax),%ebx Decoded ok: 67 66 0f 38 f8 88 78 56 34 12 movdir64b 0x12345678(%eax),%ecx $ perf test -v "new " 2>&1 | grep -i enqcmd Decoded ok: f2 0f 38 f8 18 enqcmd (%eax),%ebx Decoded ok: f2 0f 38 f8 88 78 56 34 12 enqcmd 0x12345678(%eax),%ecx Decoded ok: 67 f2 0f 38 f8 1c enqcmd (%si),%bx Decoded ok: 67 f2 0f 38 f8 8c 34 12 enqcmd 0x1234(%si),%cx Decoded ok: f3 0f 38 f8 18 enqcmds (%eax),%ebx Decoded ok: f3 0f 38 f8 88 78 56 34 12 enqcmds 0x12345678(%eax),%ecx Decoded ok: 67 f3 0f 38 f8 1c enqcmds (%si),%bx Decoded ok: 67 f3 0f 38 f8 8c 34 12 enqcmds 0x1234(%si),%cx Decoded ok: f2 0f 38 f8 18 enqcmd (%rax),%rbx Decoded ok: f2 0f 38 f8 88 78 56 34 12 enqcmd 0x12345678(%rax),%rcx Decoded ok: 67 f2 0f 38 f8 18 enqcmd (%eax),%ebx Decoded ok: 67 f2 0f 38 f8 88 78 56 34 12 enqcmd 0x12345678(%eax),%ecx Decoded ok: f3 0f 38 f8 18 enqcmds (%rax),%rbx Decoded ok: f3 0f 38 f8 88 78 56 34 12 enqcmds 0x12345678(%rax),%rcx Decoded ok: 67 f3 0f 38 f8 18 enqcmds (%eax),%ebx Decoded ok: 67 f3 0f 38 f8 88 78 56 34 12 enqcmds 0x12345678(%eax),%ecx $ perf test -v "new " 2>&1 | grep -i enqcmds Decoded ok: f3 0f 38 f8 18 enqcmds (%eax),%ebx Decoded ok: f3 0f 38 f8 88 78 56 34 12 enqcmds 0x12345678(%eax),%ecx Decoded ok: 67 f3 0f 38 f8 1c enqcmds (%si),%bx Decoded ok: 67 f3 0f 38 f8 8c 34 12 enqcmds 0x1234(%si),%cx Decoded ok: f3 0f 38 f8 18 enqcmds (%rax),%rbx Decoded ok: f3 0f 38 f8 88 78 56 34 12 enqcmds 0x12345678(%rax),%rcx Decoded ok: 67 f3 0f 38 f8 18 enqcmds (%eax),%ebx Decoded ok: 67 f3 0f 38 f8 88 78 56 34 12 enqcmds 0x12345678(%eax),%ecx $ perf test -v "new " 2>&1 | grep -i encls Decoded ok: 0f 01 cf encls Decoded ok: 0f 01 cf encls $ perf test -v "new " 2>&1 | grep -i enclu Decoded ok: 0f 01 d7 enclu Decoded ok: 0f 01 d7 enclu $ perf test -v "new " 2>&1 | grep -i enclv Decoded ok: 0f 01 c0 enclv Decoded ok: 0f 01 c0 enclv $ perf test -v "new " 2>&1 | grep -i pconfig Decoded ok: 0f 01 c5 pconfig Decoded ok: 0f 01 c5 pconfig $ perf test -v "new " 2>&1 | grep -i wbnoinvd Decoded ok: f3 0f 09 wbnoinvd Decoded ok: f3 0f 09 wbnoinvd Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Link: http://lore.kernel.org/lkml/20191115135447.6519-3-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-01x86/insn: Fix awk regexp warningsAlexander Kapshuk1-2/+2
commit 700c1018b86d0d4b3f1f2d459708c0cdf42b521d upstream. gawk 5.0.1 generates the following regexp warnings: GEN /home/sasha/torvalds/tools/objtool/arch/x86/lib/inat-tables.c awk: ../arch/x86/tools/gen-insn-attr-x86.awk:260: warning: regexp escape sequence `\:' is not a known regexp operator awk: ../arch/x86/tools/gen-insn-attr-x86.awk:350: (FILENAME=../arch/x86/lib/x86-opcode-map.txt FNR=41) warning: regexp escape sequence `\&' is not a known regexp operator Ealier versions of gawk are not known to generate these warnings. The gawk manual referenced below does not list characters ':' and '&' as needing escaping, so 'unescape' them. See https://www.gnu.org/software/gawk/manual/html_node/Escape-Sequences.html for more info. Running diff on the output generated by the script before and after applying the patch reported no differences. [ bp: Massage commit message. ] [ Caught the respective tools header discrepancy. ] Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Alexander Kapshuk <alexander.kapshuk@gmail.com> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190924044659.3785-1-alexander.kapshuk@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-05objtool: Clobber user CFLAGS variableJosh Poimboeuf1-1/+1
commit f73b3cc39c84220e6dccd463b5c8279b03514646 upstream. If the build user has the CFLAGS variable set in their environment, objtool blindly appends to it, which can cause unexpected behavior. Clobber CFLAGS to ensure consistent objtool compilation behavior. Reported-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Tested-by: Valdis Kletnieks <valdis.kletnieks@vt.edu> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/83a276df209962e6058fcb6c615eef9d401c21bc.1567121311.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> CC: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-05objtool: Query pkg-config for libelf locationRolf Eike Beer1-2/+5
commit 056d28d135bca0b1d0908990338e00e9dadaf057 upstream. If it is not in the default location, compilation fails at several points. Signed-off-by: Rolf Eike Beer <eb@emlix.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/91a25e992566a7968fedc89ec80e7f4c83ad0548.1553622500.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-09objtool: Add rewind_stack_do_exit() to the noreturn listJosh Poimboeuf1-0/+1
commit 4fa5ecda2bf96be7464eb406df8aba9d89260227 upstream. This fixes the following warning seen on GCC 7.3: arch/x86/kernel/dumpstack.o: warning: objtool: oops_end() falls through to next function show_regs() Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/3418ebf5a5a9f6ed7e80954c741c0b904b67b5dc.1554398240.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-09objtool: Add machine_real_restart() to the noreturn listJosh Poimboeuf1-0/+1
commit 684fb246578b9e81fc7b4ca5c71eae22edb650b2 upstream. machine_real_restart() is annotated as '__noreturn", so add it to the objtool noreturn list. This fixes the following warning with clang and CONFIG_CC_OPTIMIZE_FOR_SIZE=y: arch/x86/kernel/reboot.o: warning: objtool: native_machine_emergency_restart() falls through to next function machine_power_off() Reported-by: Matthias Kaehlcke <mka@chromium.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Matthias Kaehlcke <mka@chromium.org> Reviewed-by: Matthias Kaehlcke <mka@chromium.org> Link: https://lkml.kernel.org/r/791712792aa4431bdd55bf1beb33a169ddf3b4a2.1529423255.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-08-06objtool: Support GCC 9 cold subfunction naming schemeJosh Poimboeuf1-1/+1
commit bcb6fb5da77c2a228adf07cc9cb1a0c2aa2001c6 upstream. Starting with GCC 8, a lot of unlikely code was moved out of line to "cold" subfunctions in .text.unlikely. For example, the unlikely bits of: irq_do_set_affinity() are moved out to the following subfunction: irq_do_set_affinity.cold.49() Starting with GCC 9, the numbered suffix has been removed. So in the above example, the cold subfunction is instead: irq_do_set_affinity.cold() Tweak the objtool subfunction detection logic so that it detects both GCC 8 and GCC 9 naming schemes. Reported-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/015e9544b1f188d36a7f02fa31e9e95629aa5f50.1541040800.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-25objtool: Support per-function rodata sectionsAllan Xavier4-9/+37
commit 4a60aa05a0634241ce17f957bf9fb5ac1eed6576 upstream. Add support for processing switch jump tables in objects with multiple .rodata sections, such as those created by '-ffunction-sections' and '-fdata-sections'. Currently, objtool always looks in .rodata for jump table information, which results in many "sibling call from callable instruction with modified stack frame" warnings with objects compiled using those flags. The fix is comprised of three parts: 1. Flagging all .rodata sections when importing ELF information for easier checking later. 2. Keeping a reference to the section each relocation is from in order to get the list_head for the other relocations in that section. 3. Finding jump tables by following relocations to .rodata sections, rather than always referencing a single global .rodata section. The patch has been tested without data sections enabled and no differences in the resulting orc unwind information were seen. Note that as objtool adds terminators to end of each .text section the unwind information generated between a function+data sections build and a normal build aren't directly comparable. Manual inspection suggests that objtool is now generating the correct information, or at least making more of an effort to do so than it did previously. Signed-off-by: Allan Xavier <allan.x.xavier@oracle.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/099bdc375195c490dda04db777ee0b95d566ded1.1536325914.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-15objtool: Don't use ignore flag for fake jumpsJosh Poimboeuf1-3/+5
[ Upstream commit e6da9567959e164f82bc81967e0d5b10dee870b4 ] The ignore flag is set on fake jumps in order to keep add_jump_destinations() from setting their jump_dest, since it already got set when the fake jump was created. But using the ignore flag is a bit of a hack. It's normally used to skip validation of an instruction, which doesn't really make sense for fake jumps. Also, after the next patch, using the ignore flag for fake jumps can trigger a false "why am I validating an ignored function?" warning. Instead just add an explicit check in add_jump_destinations() to skip fake jumps. Signed-off-by: Josh 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/71abc072ff48b2feccc197723a9c52859476c068.1557766718.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-05-25objtool: Allow AR to be overridden with HOSTARNathan Chancellor1-1/+2
commit 8ea58f1e8b11cca3087b294779bf5959bf89cc10 upstream. Currently, this Makefile hardcodes GNU ar, meaning that if it is not available, there is no way to supply a different one and the build will fail. $ make AR=llvm-ar CC=clang LD=ld.lld HOSTAR=llvm-ar HOSTCC=clang \ HOSTLD=ld.lld HOSTLDFLAGS=-fuse-ld=lld defconfig modules_prepare ... AR /out/tools/objtool/libsubcmd.a /bin/sh: 1: ar: not found ... Follow the logic of HOST{CC,LD} and allow the user to specify a different ar tool via HOSTAR (which is used elsewhere in other tools/ Makefiles). Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Mukesh Ojha <mojha@codeaurora.org> Cc: <stable@vger.kernel.org> 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/80822a9353926c38fd7a152991c6292491a9d0e8.1558028966.git.jpoimboe@redhat.com Link: https://github.com/ClangBuiltLinux/linux/issues/481 Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-21objtool: Fix function fallthrough detectionJosh Poimboeuf1-1/+2
commit e6f393bc939d566ce3def71232d8013de9aaadde upstream. When a function falls through to the next function due to a compiler bug, objtool prints some obscure warnings. For example: drivers/regulator/core.o: warning: objtool: regulator_count_voltages()+0x95: return with modified stack frame drivers/regulator/core.o: warning: objtool: regulator_count_voltages()+0x0: stack state mismatch: cfa1=7+32 cfa2=7+8 Instead it should be printing: drivers/regulator/core.o: warning: objtool: regulator_supply_is_couple() falls through to next function regulator_count_voltages() This used to work, but was broken by the following commit: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions") The padding nops at the end of a function aren't actually part of the function, as defined by the symbol table. So the 'func' variable in validate_branch() is getting cleared to NULL when a padding nop is encountered, breaking the fallthrough detection. If the current instruction doesn't have a function associated with it, just consider it to be part of the previously detected function by not overwriting the previous value of 'func'. Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions") Link: http://lkml.kernel.org/r/546d143820cd08a46624ae8440d093dd6c902cae.1557766718.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-27objtool: Move objtool_file struct off the stackJosh Poimboeuf1-1/+2
commit 0c671812f152b628bd87c0af49da032cc2a2c319 upstream. Objtool uses over 512k of stack, thanks to the hash table embedded in the objtool_file struct. This causes an unnecessarily large stack allocation and breaks users with low stack limits. Move the struct off the stack. Fixes: 042ba73fe7eb ("objtool: Add several performance improvements") Reported-by: Vassili Karpov <moosotc@gmail.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/df92dcbc4b84b02ffa252f46876df125fb56e2d7.1552954176.git.jpoimboe@redhat.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-12-17objtool: Fix segfault in .cold detection with -ffunction-sectionsArtem Savkov1-3/+14
[ Upstream commit 22566c1603030f0a036ad564634b064ad1a55db2 ] Because find_symbol_by_name() traverses the same lists as read_symbols(), changing sym->name in place without copying it affects the result of find_symbol_by_name(). In the case where a ".cold" function precedes its parent in sec->symbol_list, it can result in a function being considered a parent of itself. This leads to function length being set to 0 and other consequent side-effects including a segfault in add_switch_table(). The effects of this bug are only visible when building with -ffunction-sections in KCFLAGS. Fix by copying the search string instead of modifying it in place. Signed-off-by: Artem Savkov <asavkov@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions") Link: http://lkml.kernel.org/r/910abd6b5a4945130fd44f787c24e07b9e07c8da.1542736240.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-12-17objtool: Fix double-free in .cold detection error pathArtem Savkov1-1/+1
[ Upstream commit 0b9301fb632f7111a3293a30cc5b20f1b82ed08d ] If read_symbols() fails during second list traversal (the one dealing with ".cold" subfunctions) it frees the symbol, but never deletes it from the list/hash_table resulting in symbol being freed again in elf_close(). Fix it by just returning an error, leaving cleanup to elf_close(). Signed-off-by: Artem Savkov <asavkov@redhat.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions") Link: http://lkml.kernel.org/r/beac5a9b7da9e8be90223459dcbe07766ae437dd.1542736240.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2018-08-24objtool: Support GCC 8 '-fnoreorder-functions'Josh Poimboeuf1-13/+28
[ Upstream commit 08b393d01c88aff27347ed2b1b354eb4db2f1532 ] Since the following commit: cd77849a69cf ("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: Allan Xavier <allan.x.xavier@oracle.com> Signed-off-by: Josh 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.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-07-11Kbuild: fix # escaping in .cmd files for future MakeRasmus Villemoes1-1/+1
commit 9564a8cf422d7b58f6e857e3546d346fa970191e 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: Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-21objtool, kprobes/x86: Sync the latest <asm/insn.h> header with ↵Ingo Molnar1-0/+18
tools/objtool/arch/x86/include/asm/insn.h [ Upstream commit 4fe875e4bd3cae85ae6f6eaf77f63fabe613b66e ] The following commit: ee6a7354a362: 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: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-05objtool: Fix "noreturn" detection for recursive sibling callsJosh Poimboeuf1-3/+7
commit 0afd0d9e0e7879d666c1df2fa1bea4d8716909fe 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: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter 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.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-05objtool: Detect RIP-relative switch table references, part 2Josh Poimboeuf1-25/+12
commit 7dec80ccbe310fb7e225bf21c48c672bb780ce7b upstream. With the following commit: fd35c88b7417 ("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: 6f5ec2993b1f ("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: kbuild test robot <lkp@intel.com> Signed-off-by: Josh 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.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-05objtool: Detect RIP-relative switch table referencesJosh Poimboeuf1-15/+18
commit 6f5ec2993b1f39aed12fa6fd56e8dc2272ee8a33 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: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Josh 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.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-05objtool: Support GCC 8 switch tablesJosh Poimboeuf1-2/+22
commit fd35c88b74170d9335530d9abf271d5d73eb5401 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: Arnd Bergmann <arnd@arndb.de> Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter 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@treble Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-06-05objtool: Support GCC 8's cold subfunctionsJosh Poimboeuf3-44/+93
commit 13810435b9a7014fb92eb715f77da488f3b65b99 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: damian <damian.tometzki@icloud.com> Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: David Laight <David.Laight@ACULAB.COM> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Linus Torvalds