From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B19ACC6FD1C for ; Mon, 20 Mar 2023 20:10:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230145AbjCTUKy convert rfc822-to-8bit (ORCPT ); Mon, 20 Mar 2023 16:10:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229496AbjCTUKv (ORCPT ); Mon, 20 Mar 2023 16:10:51 -0400 Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ADCA683F3; Mon, 20 Mar 2023 13:10:49 -0700 (PDT) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.95) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1peLqA-0008E3-Qi; Mon, 20 Mar 2023 21:10:46 +0100 Received: from p57bd9952.dip0.t-ipconnect.de ([87.189.153.82] helo=[192.168.178.81]) by inpost2.zedat.fu-berlin.de (Exim 4.95) with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1peLqA-0035Z5-JM; Mon, 20 Mar 2023 21:10:46 +0100 Message-ID: Subject: Re: [PATCH 7/7 v4] sh: mcount.S: fix build error when PRINTK is not enabled From: John Paul Adrian Glaubitz To: Geert Uytterhoeven Cc: Randy Dunlap , linux-kernel@vger.kernel.org, Yoshinori Sato , Rich Felker , stable@vger.kernel.org Date: Mon, 20 Mar 2023 21:10:45 +0100 In-Reply-To: References: <20230306040037.20350-1-rdunlap@infradead.org> <20230306040037.20350-8-rdunlap@infradead.org> <056df6d548ad0e4f7f4ccb2782744b165ce20578.camel@physik.fu-berlin.de> <01f84314b2499b6859a4826ecf7363635e66a4fc.camel@physik.fu-berlin.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.46.4 MIME-Version: 1.0 X-Original-Sender: glaubitz@physik.fu-berlin.de X-Originating-IP: 87.189.153.82 X-ZEDAT-Hint: PO Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Geert! On Mon, 2023-03-20 at 13:42 +0100, Geert Uytterhoeven wrote: > Hi Adrian, > > On Mon, Mar 20, 2023 at 10:13 AM John Paul Adrian Glaubitz > wrote: > > On Mon, 2023-03-20 at 09:16 +0100, Geert Uytterhoeven wrote: > > > On Sun, Mar 19, 2023 at 9:49 PM John Paul Adrian Glaubitz > > > wrote: > > > > On Sun, 2023-03-05 at 20:00 -0800, Randy Dunlap wrote: > > > > > Fix a build error in mcount.S when CONFIG_PRINTK is not enabled. > > > > > Fixes this build error: > > > > > > > > > > sh2-linux-ld: arch/sh/lib/mcount.o: in function `stack_panic': > > > > > (.text+0xec): undefined reference to `dump_stack' > > > > > > > > > > Fixes: e460ab27b6c3 ("sh: Fix up stack overflow check with ftrace disabled.") > > > > > Signed-off-by: Randy Dunlap > > > > > Cc: John Paul Adrian Glaubitz > > > > > Cc: Yoshinori Sato > > > > > Cc: Rich Felker > > > > > Suggested-by: Geert Uytterhoeven > > > > > Cc: stable@vger.kernel.org > > > > > --- > > > > > v2: add PRINTK to STACK_DEBUG dependency (thanks, Geert) > > > > > v3: skipped > > > > > v4: refresh & resend > > > > > > > > > > arch/sh/Kconfig.debug | 2 +- > > > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > > > > > diff -- a/arch/sh/Kconfig.debug b/arch/sh/Kconfig.debug > > > > > --- a/arch/sh/Kconfig.debug > > > > > +++ b/arch/sh/Kconfig.debug > > > > > @@ -15,7 +15,7 @@ config SH_STANDARD_BIOS > > > > > > > > > > config STACK_DEBUG > > > > > bool "Check for stack overflows" > > > > > - depends on DEBUG_KERNEL > > > > > + depends on DEBUG_KERNEL && PRINTK > > > > > help > > > > > This option will cause messages to be printed if free stack space > > > > > drops below a certain limit. Saying Y here will add overhead to > > > > > > > > I can't really test this change as the moment I am enabling CONFIG_STACK_DEBUG, > > > > the build fails with: > > > > > > > > CC scripts/mod/devicetable-offsets.s > > > > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible > > > > make[1]: *** [scripts/Makefile.build:252: scripts/mod/empty.o] Error 1 > > > > make[1]: *** Waiting for unfinished jobs.... > > > > sh4-linux-gcc: error: -pg and -fomit-frame-pointer are incompatible > > > > make[1]: *** [scripts/Makefile.build:114: scripts/mod/devicetable-offsets.s] Error 1 > > > > make: *** [Makefile:1286: prepare0] Error 2 > > > > > > > > So, I assume we need to strip -fomit-frame-pointer from KBUILD_CFLAGS, correct? > > > > > > > > I tried this change, but that doesn't fix it for me: > > > > > > > > diff --git a/arch/sh/Makefile b/arch/sh/Makefile > > > > index 5c8776482530..83f535b73835 100644 > > > > --- a/arch/sh/Makefile > > > > +++ b/arch/sh/Makefile > > > > @@ -173,6 +173,7 @@ KBUILD_AFLAGS += $(cflags-y) > > > > > > > > ifeq ($(CONFIG_MCOUNT),y) > > > > KBUILD_CFLAGS += -pg > > > > + KBUILD_CFLAGS := $(subst -fomit-frame-pointer,,$(KBUILD_CFLAGS)) > > > > endif > > > > > > > > ifeq ($(CONFIG_DWARF_UNWINDER),y) > > > > > > > > Any ideas? > > > > > > Please try with "+=" instead of ":=". > > > > That doesn't work either. I tried the following, but that didn't strip -fomit-frame-pointer: > > Oops, obviously all of that happened before my morning coffee ;-) > > Makefile has: > > ifdef CONFIG_FRAME_POINTER > KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls > KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y > else > # Some targets (ARM with Thumb2, for example), can't be built with frame > # pointers. For those, we don't have FUNCTION_TRACER automatically > # select FRAME_POINTER. However, FUNCTION_TRACER adds -pg, and this is > # incompatible with -fomit-frame-pointer with current GCC, so we don't use > # -fomit-frame-pointer with FUNCTION_TRACER. > # In the Rust target specification, "frame-pointer" is set explicitly > # to "may-omit". > ifndef CONFIG_FUNCTION_TRACER > KBUILD_CFLAGS += -fomit-frame-pointer > endif > endif > > Your config probably has CONFIG_FRAME_POINTER set? > > arch/sh/Kconfig.debug=config DWARF_UNWINDER > arch/sh/Kconfig.debug- bool "Enable the DWARF unwinder for stacktraces" > arch/sh/Kconfig.debug- depends on DEBUG_KERNEL > arch/sh/Kconfig.debug: select FRAME_POINTER > > You should make sure that cannot happen when CONFIG_FUNCTION_TRACER > is enabled. I.e. make DWARF_UNWINDER depend on !FUNCTION_TRACER? > > Other architectures do something similar: > > arch/sparc/Kconfig.debug:config FRAME_POINTER > arch/sparc/Kconfig.debug- bool > arch/sparc/Kconfig.debug- depends on MCOUNT > > arch/x86/Kconfig.debug:config FRAME_POINTER > arch/x86/Kconfig.debug- depends on !UNWINDER_ORC && !UNWINDER_GUESS > arch/x86/Kconfig.debug- bool > > Probably you need to adjust the following, too: > > lib/Kconfig.debug:config FRAME_POINTER > lib/Kconfig.debug- bool "Compile the kernel with frame pointers" > lib/Kconfig.debug- depends on DEBUG_KERNEL && (M68K || UML || > SUPERH) || ARCH_WANT_FRAME_POINTERS > lib/Kconfig.debug- default y if (DEBUG_INFO && UML) || > ARCH_WANT_FRAME_POINTERS > > i.e. drop SUPERH from the list above, and select ARCH_WANT_FRAME_POINTERS > if !FUNCTION_TRACER. This change fixed it for me: diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig index 98e43a537826..04d310ee7384 100644 --- a/arch/sh/Kconfig +++ b/arch/sh/Kconfig @@ -55,6 +55,7 @@ config SUPERH select HAVE_SOFTIRQ_ON_OWN_STACK if IRQSTACKS select HAVE_STACKPROTECTOR select HAVE_SYSCALL_TRACEPOINTS + select ARCH_WANT_FRAME_POINTERS select IRQ_FORCED_THREADING select MODULES_USE_ELF_RELA select NEED_SG_DMA_LENGTH diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index c8b379e2e9ad..3cf45d8edace 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -523,7 +523,7 @@ config ARCH_WANT_FRAME_POINTERS config FRAME_POINTER bool "Compile the kernel with frame pointers" - depends on DEBUG_KERNEL && (M68K || UML || SUPERH) || ARCH_WANT_FRAME_POINTERS + depends on DEBUG_KERNEL && (M68K || UML) || ARCH_WANT_FRAME_POINTERS default y if (DEBUG_INFO && UML) || ARCH_WANT_FRAME_POINTERS help If you say Y here the resulting kernel image will be slightly It seems this is also what the other architectures do it seems. Adrian -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913