This is a note to let you know that I've just added the patch titled
x86/entry/64: Fix paranoid_entry() frame pointer warning
to the 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: x86-entry-64-fix-paranoid_entry-frame-pointer-warning.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From b3ccefaed922529e6a67de7b30af5aa38c76ace9 Mon Sep 17 00:00:00 2001
From: Josh Poimboeuf jpoimboe@redhat.com Date: Mon, 12 Feb 2018 11:45:03 -0600 Subject: x86/entry/64: Fix paranoid_entry() frame pointer warning
From: Josh Poimboeuf jpoimboe@redhat.com
commit b3ccefaed922529e6a67de7b30af5aa38c76ace9 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/entry/entry_64.S | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -1128,6 +1128,7 @@ idtentry machine_check do_mce has_err * 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
Patches currently in stable-queue which might be from jpoimboe@redhat.com are
queue-4.15/x86-entry-64-interleave-xor-register-clearing-with-push-instructions.patch queue-4.15/x86-entry-64-merge-the-pop_c_regs-and-pop_extra_regs-macros-into-a-single-pop_regs-macro.patch queue-4.15/x86-entry-64-remove-the-unused-icebp-macro.patch queue-4.15/kvm-nvmx-set-the-cpu_based_use_msr_bitmaps-if-we-have-a-valid-l02-msr-bitmap.patch queue-4.15/x86-nvmx-properly-set-spec_ctrl-and-pred_cmd-before-merging-msrs.patch queue-4.15/x86-speculation-add-asm-msr-index.h-dependency.patch queue-4.15/x86-entry-64-use-push_and_clean_regs-in-more-cases.patch queue-4.15/x86-debug-use-ud2-for-warn.patch queue-4.15/x86-entry-64-fix-paranoid_entry-frame-pointer-warning.patch queue-4.15/x86-speculation-update-speculation-control-microcode-blacklist.patch queue-4.15/x86-entry-64-clear-registers-for-exceptions-interrupts-to-reduce-speculation-attack-surface.patch queue-4.15/x86-speculation-correct-speculation-control-microcode-blacklist-again.patch queue-4.15/x86-entry-64-merge-save_c_regs-and-save_extra_regs-remove-unused-extensions.patch queue-4.15/x86-debug-objtool-annotate-warn-related-ud2-as-reachable.patch queue-4.15/objtool-fix-segfault-in-ignore_unreachable_insn.patch queue-4.15/x86-entry-64-indent-push_and_clear_regs-and-pop_regs-properly.patch queue-4.15/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch queue-4.15/kvm-x86-reduce-retpoline-performance-impact-in-slot_handle_level_range-by-always-inlining-iterator-helper-methods.patch queue-4.15/x86-mm-pti-fix-pti-comment-in-entry_syscall_64.patch queue-4.15/x86-entry-64-get-rid-of-the-alloc_pt_gpregs_on_stack-and-save_and_clear_regs-macros.patch queue-4.15/x86-speculation-clean-up-various-spectre-related-details.patch queue-4.15/x86-entry-64-introduce-the-push_and_clean_regs-macro.patch queue-4.15/revert-x86-speculation-simplify-indirect_branch_prediction_barrier.patch queue-4.15/x86-entry-64-compat-clear-registers-for-compat-syscalls-to-reduce-speculation-attack-surface.patch queue-4.15/x86-mm-rename-flush_tlb_single-and-flush_tlb_one-to-__flush_tlb_one_.patch queue-4.15/x86-entry-64-fix-cr3-restore-in-paranoid_exit.patch