From mboxrd@z Thu Jan 1 00:00:00 1970 From: Subject: Patch "x86/paravirt: Make native_save_fl() extern inline" has been added to the 4.14-stable tree Date: Wed, 18 Jul 2018 11:17:50 +0200 Message-ID: <1531905470227223@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: 20180621162324.36656-4-ndesaulniers@google.com, acme@redhat.com, akataria@vmware.com, akpm@linux-foundation.org, andrea.parri@amarulasolutions.com, ard.biesheuvel@linaro.org, arnd@arndb.de, aryabinin@virtuozzo.com, astrachan@google.com, boris.ostrovsky@oracle.com, brijesh.singh@amd.com, caoj.fnst@cn.fujitsu.com, geert@linux-m68k.org, ghackmann@google.com, gregkh@linuxfoundation.org, hpa@zytor.com, jan.kiszka@siemens.com, jarkko.sakkinen@linux.intel.com, jgross@suse.com, joe@perches.com, jpoimboe@redhat.com, keescook@google.com, kirill.shutemov@linux.intel.com, kstewart@linuxfoundation.org, manojgupta@google.com, mawilcox@microsoft.com, michal.lkml@markovi.net, mingo@kernel.org, mjg59@google.com, mka@chromium.orgndesaulniers@google.com, peterz@infradead.org, pombredanne@nexb.com, rientjes@google.com, rostedt@goodmis.org, sedat.dilek@gmail.com, tglx@linutronix.de, tho Cc: stable-commits@vger.kernel.org List-Id: virtualization@lists.linuxfoundation.org This is a note to let you know that I've just added the patch titled x86/paravirt: Make native_save_fl() extern inline to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-paravirt-make-native_save_fl-extern-inline.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From d0a8d9378d16eb3c69bd8e6d23779fbdbee3a8c7 Mon Sep 17 00:00:00 2001 From: Nick Desaulniers Date: Thu, 21 Jun 2018 09:23:24 -0700 Subject: x86/paravirt: Make native_save_fl() extern inline From: Nick Desaulniers commit d0a8d9378d16eb3c69bd8e6d23779fbdbee3a8c7 upstream. native_save_fl() is marked static inline, but by using it as a function pointer in arch/x86/kernel/paravirt.c, it MUST be outlined. paravirt's use of native_save_fl() also requires that no GPRs other than %rax are clobbered. Compilers have different heuristics which they use to emit stack guard code, the emittance of which can break paravirt's callee saved assumption by clobbering %rcx. Marking a function definition extern inline means that if this version cannot be inlined, then the out-of-line version will be preferred. By having the out-of-line version be implemented in assembly, it cannot be instrumented with a stack protector, which might violate custom calling conventions that code like paravirt rely on. The semantics of extern inline has changed since gnu89. This means that folks using GCC versions >= 5.1 may see symbol redefinition errors at link time for subdirs that override KBUILD_CFLAGS (making the C standard used implicit) regardless of this patch. This has been cleaned up earlier in the patch set, but is left as a note in the commit message for future travelers. Reports: https://lkml.org/lkml/2018/5/7/534 https://github.com/ClangBuiltLinux/linux/issues/16 Discussion: https://bugs.llvm.org/show_bug.cgi?id=37512 https://lkml.org/lkml/2018/5/24/1371 Thanks to the many folks that participated in the discussion. Debugged-by: Alistair Strachan Debugged-by: Matthias Kaehlcke Suggested-by: Arnd Bergmann Suggested-by: H. Peter Anvin Suggested-by: Tom Stellar Reported-by: Sedat Dilek Tested-by: Sedat Dilek Signed-off-by: Nick Desaulniers Acked-by: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: acme@redhat.com Cc: akataria@vmware.com Cc: akpm@linux-foundation.org Cc: andrea.parri@amarulasolutions.com Cc: ard.biesheuvel@linaro.org Cc: aryabinin@virtuozzo.com Cc: astrachan@google.com Cc: boris.ostrovsky@oracle.com Cc: brijesh.singh@amd.com Cc: caoj.fnst@cn.fujitsu.com Cc: geert@linux-m68k.org Cc: ghackmann@google.com Cc: gregkh@linuxfoundation.org Cc: jan.kiszka@siemens.com Cc: jarkko.sakkinen@linux.intel.com Cc: joe@perches.com Cc: jpoimboe@redhat.com Cc: keescook@google.com Cc: kirill.shutemov@linux.intel.com Cc: kstewart@linuxfoundation.org Cc: linux-efi@vger.kernel.org Cc: linux-kbuild@vger.kernel.org Cc: manojgupta@google.com Cc: mawilcox@microsoft.com Cc: michal.lkml@markovi.net Cc: mjg59@google.com Cc: mka@chromium.org Cc: pombredanne@nexb.com Cc: rientjes@google.com Cc: rostedt@goodmis.org Cc: thomas.lendacky@amd.com Cc: tweek@google.com Cc: virtualization@lists.linux-foundation.org Cc: will.deacon@arm.com Cc: yamada.masahiro@socionext.com Link: http://lkml.kernel.org/r/20180621162324.36656-4-ndesaulniers@google.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/irqflags.h | 2 +- arch/x86/kernel/Makefile | 1 + arch/x86/kernel/irqflags.S | 26 ++++++++++++++++++++++++++ 3 files changed, 28 insertions(+), 1 deletion(-) --- a/arch/x86/include/asm/irqflags.h +++ b/arch/x86/include/asm/irqflags.h @@ -13,7 +13,7 @@ * Interrupt control: */ -static inline unsigned long native_save_fl(void) +extern inline unsigned long native_save_fl(void) { unsigned long flags; --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -58,6 +58,7 @@ obj-y += alternative.o i8253.o pci-nom obj-y += tsc.o tsc_msr.o io_delay.o rtc.o obj-y += pci-iommu_table.o obj-y += resource.o +obj-y += irqflags.o obj-y += process.o obj-y += fpu/ --- /dev/null +++ b/arch/x86/kernel/irqflags.S @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#include +#include +#include + +/* + * unsigned long native_save_fl(void) + */ +ENTRY(native_save_fl) + pushf + pop %_ASM_AX + ret +ENDPROC(native_save_fl) +EXPORT_SYMBOL(native_save_fl) + +/* + * void native_restore_fl(unsigned long flags) + * %eax/%rdi: flags + */ +ENTRY(native_restore_fl) + push %_ASM_ARG1 + popf + ret +ENDPROC(native_restore_fl) +EXPORT_SYMBOL(native_restore_fl) Patches currently in stable-queue which might be from ndesaulniers@google.com are queue-4.14/x86-asm-add-_asm_arg-constants-for-argument-registers-to-asm-asm.h.patch queue-4.14/compiler-gcc.h-add-__attribute__-gnu_inline-to-all-inline-declarations.patch queue-4.14/x86-paravirt-make-native_save_fl-extern-inline.patch