* [tip:x86/pti 19/20] arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup
@ 2018-02-12 11:33 kbuild test robot
2018-02-12 13:13 ` Josh Poimboeuf
2018-02-12 17:45 ` [PATCH] x86/entry/64: Fix paranoid_entry() frame pointer warning Josh Poimboeuf
0 siblings, 2 replies; 4+ messages in thread
From: kbuild test robot @ 2018-02-12 11:33 UTC (permalink / raw)
To: Dominik Brodowski; +Cc: kbuild-all, linux-kernel, tipbuild, Ingo Molnar
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tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/pti
head: 5a10e729bc0aa9420a23a70b169eadd229c27bc1
commit: f09d160992d129b6d8fada7543761d40f5b33596 [19/20] x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros
config: x86_64-randconfig-s0-02121550 (attached as .config)
compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026
reproduce:
git checkout f09d160992d129b6d8fada7543761d40f5b33596
# save the attached .config to linux build tree
make ARCH=x86_64
All warnings (new ones prefixed by >>):
>> arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [tip:x86/pti 19/20] arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup 2018-02-12 11:33 [tip:x86/pti 19/20] arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup kbuild test robot @ 2018-02-12 13:13 ` Josh Poimboeuf 2018-02-12 17:45 ` [PATCH] x86/entry/64: Fix paranoid_entry() frame pointer warning Josh Poimboeuf 1 sibling, 0 replies; 4+ messages in thread From: Josh Poimboeuf @ 2018-02-12 13:13 UTC (permalink / raw) To: kbuild test robot Cc: Dominik Brodowski, kbuild-all, linux-kernel, tipbuild, Ingo Molnar On Mon, Feb 12, 2018 at 07:33:27PM +0800, kbuild test robot wrote: > tree: https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86/pti > head: 5a10e729bc0aa9420a23a70b169eadd229c27bc1 > commit: f09d160992d129b6d8fada7543761d40f5b33596 [19/20] x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros > config: x86_64-randconfig-s0-02121550 (attached as .config) > compiler: gcc-6 (Debian 6.4.0-9) 6.4.0 20171026 > reproduce: > git checkout f09d160992d129b6d8fada7543761d40f5b33596 > # save the attached .config to linux build tree > make ARCH=x86_64 > > All warnings (new ones prefixed by >>): > > >> arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup > > --- > 0-DAY kernel test infrastructure Open Source Technology Center > https://lists.01.org/pipermail/kbuild-all Intel Corporation Oops, looks like one of my suggested unwind hint changes wasn't so good for the frame pointer case. The below should fix it. I'll submit a proper patch in a little bit after running it through 0-day. diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index cfbf43366731..1c54204207d8 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1128,6 +1128,7 @@ idtentry machine_check do_mce has_error_code=0 paranoid=1 * Return: ebx=0: need swapgs on exit, ebx=1: otherwise */ ENTRY(paranoid_entry) + UNWIND_HINT_FUNC cld movl $1, %ebx movl $MSR_GS_BASE, %ecx @@ -1141,7 +1142,7 @@ ENTRY(paranoid_entry) SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg=%rax save_reg=%r14 ret -ENDPROC(paranoid_entry) +END(paranoid_entry) /* * "Paranoid" exit path from exception stack. This is invoked ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] x86/entry/64: Fix paranoid_entry() frame pointer warning 2018-02-12 11:33 [tip:x86/pti 19/20] arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup kbuild test robot 2018-02-12 13:13 ` Josh Poimboeuf @ 2018-02-12 17:45 ` Josh Poimboeuf 2018-02-13 9:03 ` [tip:x86/pti] " tip-bot for Josh Poimboeuf 1 sibling, 1 reply; 4+ messages in thread From: Josh Poimboeuf @ 2018-02-12 17:45 UTC (permalink / raw) To: kbuild test robot Cc: Dominik Brodowski, kbuild-all, linux-kernel, tipbuild, Ingo Molnar With the following commit: f09d160992d1 ("x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros") ... one of my suggested improvements triggered a frame pointer warning: arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup The warning is correct for the build-time code, but it's actually not relevant at runtime because of paravirt patching. The paravirt swapgs call gets replaced with either a SWAPGS instruction or NOPs at runtime. Go back to the previous behavior by removing the ELF function annotation for paranoid_entry() and adding an unwind hint, which effectively silences the warning. Reported-by: kbuild test robot <fengguang.wu@intel.com> Fixes: f09d160992d1 ("x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros") Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> --- arch/x86/entry/entry_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index cfbf43366731..1c54204207d8 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1128,6 +1128,7 @@ idtentry machine_check do_mce has_error_code=0 paranoid=1 * Return: ebx=0: need swapgs on exit, ebx=1: otherwise */ ENTRY(paranoid_entry) + UNWIND_HINT_FUNC cld movl $1, %ebx movl $MSR_GS_BASE, %ecx @@ -1141,7 +1142,7 @@ ENTRY(paranoid_entry) SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg=%rax save_reg=%r14 ret -ENDPROC(paranoid_entry) +END(paranoid_entry) /* * "Paranoid" exit path from exception stack. This is invoked -- 2.14.3 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* [tip:x86/pti] x86/entry/64: Fix paranoid_entry() frame pointer warning 2018-02-12 17:45 ` [PATCH] x86/entry/64: Fix paranoid_entry() frame pointer warning Josh Poimboeuf @ 2018-02-13 9:03 ` tip-bot for Josh Poimboeuf 0 siblings, 0 replies; 4+ messages in thread From: tip-bot for Josh Poimboeuf @ 2018-02-13 9:03 UTC (permalink / raw) To: linux-tip-commits Cc: tglx, linux, hpa, fengguang.wu, linux-kernel, mingo, peterz, jpoimboe, torvalds Commit-ID: b3ccefaed922529e6a67de7b30af5aa38c76ace9 Gitweb: https://git.kernel.org/tip/b3ccefaed922529e6a67de7b30af5aa38c76ace9 Author: Josh Poimboeuf <jpoimboe@redhat.com> AuthorDate: Mon, 12 Feb 2018 11:45:03 -0600 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Tue, 13 Feb 2018 09:04:55 +0100 x86/entry/64: Fix paranoid_entry() frame pointer warning With the following commit: f09d160992d1 ("x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros") ... one of my suggested improvements triggered a frame pointer warning: arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup The warning is correct for the build-time code, but it's actually not relevant at runtime because of paravirt patching. The paravirt swapgs call gets replaced with either a SWAPGS instruction or NOPs at runtime. Go back to the previous behavior by removing the ELF function annotation for paranoid_entry() and adding an unwind hint, which effectively silences the warning. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kbuild-all@01.org Cc: tipbuild@zytor.com Fixes: f09d160992d1 ("x86/entry/64: Get rid of the ALLOC_PT_GPREGS_ON_STACK and SAVE_AND_CLEAR_REGS macros") Link: http://lkml.kernel.org/r/20180212174503.5acbymg5z6p32snu@treble Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/entry/entry_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index cfbf433..1c5420420 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1128,6 +1128,7 @@ idtentry machine_check do_mce has_error_code=0 paranoid=1 * Return: ebx=0: need swapgs on exit, ebx=1: otherwise */ ENTRY(paranoid_entry) + UNWIND_HINT_FUNC cld movl $1, %ebx movl $MSR_GS_BASE, %ecx @@ -1141,7 +1142,7 @@ ENTRY(paranoid_entry) SAVE_AND_SWITCH_TO_KERNEL_CR3 scratch_reg=%rax save_reg=%r14 ret -ENDPROC(paranoid_entry) +END(paranoid_entry) /* * "Paranoid" exit path from exception stack. This is invoked ^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-02-13 9:04 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-02-12 11:33 [tip:x86/pti 19/20] arch/x86/entry/entry_64.o: warning: objtool: paranoid_entry()+0x11: call without frame pointer save/setup kbuild test robot 2018-02-12 13:13 ` Josh Poimboeuf 2018-02-12 17:45 ` [PATCH] x86/entry/64: Fix paranoid_entry() frame pointer warning Josh Poimboeuf 2018-02-13 9:03 ` [tip:x86/pti] " tip-bot for Josh Poimboeuf
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