From patchwork Wed Sep 24 14:20:55 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Berg X-Patchwork-Id: 2141420 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; secure) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=gtMWIYDb; dkim=fail reason="signature verification failed" (2048-bit key; secure) header.d=sipsolutions.net header.i=@sipsolutions.net header.a=rsa-sha256 header.s=mail header.b=KDgV9bM4; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lists.infradead.org (client-ip=2607:7c80:54:3::133; helo=bombadil.infradead.org; envelope-from=linux-um-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org; receiver=patchwork.ozlabs.org) Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4cWzZ53wZ5z1yZc for ; Thu, 25 Sep 2025 00:22:05 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=t7nIw84Rl79y66+K3kgQqOWSKjjzBQe7De/659OAugM=; b=gtMWIYDbdEt8gtOpTQW9wCXVEd nredQcySsrZ0wlmLS860kcoDclAYLFx19UPM8bgWTlsuFHkv2ZHuBgRCXbrs5y8FKujKOc3ZLrU7b ltExj0liOhSPeIhUCP47VVjPsMm1oGlvT7/4iqFS7gdqRsOxr2uwbITs88UTeqP1B0YnTXdOSylhg IN6Y20/yfWuKhnppl6/H7oCf/J84lMe0XP+gH1aCfKfb4jdY/cJeXYiLS9kEl5eDAItt8U8BeDvh3 rWZUjHVSqQmugz4Killuz7e30kkkWh/cS2l6OEr2xBvHY5SFnh36uNA734oqG0tfjlKJwx/5Xv5II dttCFDjw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1QNf-00000000b15-3fey; Wed, 24 Sep 2025 14:22:03 +0000 Received: from s3.sipsolutions.net ([2a01:4f8:242:246e::2] helo=sipsolutions.net) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v1QNc-00000000ast-34Ru for linux-um@lists.infradead.org; Wed, 24 Sep 2025 14:22:02 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Content-Type:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=t7nIw84Rl79y66+K3kgQqOWSKjjzBQe7De/659OAugM=; t=1758723720; x=1759933320; b=KDgV9bM432Q/60IpnEeD+KMrFEldXzIDvoeq+VRPiTxTwn9 JfbQWITmrocU1442/BY14eqi5DR8A3d1jUDEU8mnGjawh7QufJ45kyopI3ISF06LFfkPCIexcwBBY YfVG8HmJfp8rwTw85/9FzoNaX/nSyUFC8S8a+/GPilIg2wqy5Y0C4gOrb3rb07MO6g0MnFo4BYMKR pLe+9+WFMZzrsAdcvxMMZgq4lpySO8zjn2Wk63HvCwlMVKA012+ZTDDzDXJ7x4b1IKEUklM5OjpTa TGgJuNoAzoTxP6LQ1SzQ3FgLlYVgcjpedkiHcer5cNtYDb9dRPPkbxxa4L4+9/9Q==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.98.2) (envelope-from ) id 1v1QNZ-000000090Bz-1P4q; Wed, 24 Sep 2025 16:21:58 +0200 From: Benjamin Berg To: linux-um@lists.infradead.org, Willy Tarreau , =?utf-8?q?Thomas?= =?utf-8?q?_Wei=C3=9Fschuh?= , linux-kselftest@vger.kernel.org, Arnaldo Carvalho de Melo Cc: linux-kernel@vger.kernel.org, Benjamin Berg Subject: [PATCH v3 08/12] um: add infrastructure to build files using nolibc Date: Wed, 24 Sep 2025 16:20:55 +0200 Message-ID: <20250924142059.527768-9-benjamin@sipsolutions.net> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250924142059.527768-1-benjamin@sipsolutions.net> References: <20250924142059.527768-1-benjamin@sipsolutions.net> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250924_072200_788335_022CDFD1 X-CRM114-Status: GOOD ( 14.38 ) X-Spam-Score: -2.1 (--) X-Spam-Report: Spam detection software, running on the system "bombadil.infradead.org", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: From: Benjamin Berg Add NOLIBC_CFLAGS and NOLIBC_OBJS to build files against nolibc rather than libc. With this it is possible to move to nolibc in smaller steps. Set NOLIBC_IGNORE_ERRNO, as the nolibc errno implementation is overly simple and cannot handle threading. nolibc provides sys_* functions that do not emulate the libc errno behaviour and can be used i [...] Content analysis details: (-2.1 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 SPF_HELO_PASS SPF: HELO matches SPF record -0.0 SPF_PASS SPF: sender matches SPF record -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+incoming=patchwork.ozlabs.org@lists.infradead.org From: Benjamin Berg Add NOLIBC_CFLAGS and NOLIBC_OBJS to build files against nolibc rather than libc. With this it is possible to move to nolibc in smaller steps. Set NOLIBC_IGNORE_ERRNO, as the nolibc errno implementation is overly simple and cannot handle threading. nolibc provides sys_* functions that do not emulate the libc errno behaviour and can be used instead. Leave the syscall definition for kernel code for now, but guard it as it is a macro in nolibc. Signed-off-by: Benjamin Berg --- v3: - Change the syscall guard to use __KERNEL__ v2: - Do not include nolibc.h via CFLAGS - Make syscall guard more explicit - Remove __UM_NOLIBC__ define, it is not needed - Fix out-of-tree building --- arch/um/Makefile | 20 +++++++++++++++++++- arch/um/include/shared/os.h | 2 ++ arch/um/include/shared/user.h | 1 - arch/um/scripts/Makefile.rules | 8 +++++++- 4 files changed, 28 insertions(+), 3 deletions(-) diff --git a/arch/um/Makefile b/arch/um/Makefile index f7c509262568..c3a81df50911 100644 --- a/arch/um/Makefile +++ b/arch/um/Makefile @@ -78,6 +78,24 @@ USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \ -include $(srctree)/include/linux/kern_levels.h \ -include $(srctree)/$(ARCH_DIR)/include/shared/user.h +NOLIBC_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \ + $(ARCH_INCLUDE) $(MODE_INCLUDE) $(filter -I%,$(CFLAGS)) \ + -I $(srctree)/tools/include \ + -D__EXPORTED_HEADERS__ \ + -D__UM_HOST__ \ + -DNOLIBC_NO_RUNTIME \ + -DNOLIBC_IGNORE_ERRNO \ + -nostdlib -nostdinc -static \ + -I$(srctree)/include/uapi \ + -I$(srctree)/$(HOST_DIR)/include/uapi \ + -I$(objtree)/$(HOST_DIR)/include/generated/uapi \ + -I $(srctree)/tools/include/nolibc \ + -I $(srctree)/usr/include \ + -include $(objtree)/include/generated/autoconf.h \ + -include $(srctree)/tools/include/linux/kconfig.h \ + -include $(srctree)/include/linux/kern_levels.h \ + -include $(srctree)/$(ARCH_DIR)/include/shared/user.h + #This will adjust *FLAGS accordingly to the platform. include $(srctree)/$(ARCH_DIR)/Makefile-os-Linux @@ -160,4 +178,4 @@ archclean: -o -name '*.gcov' \) -type f -print | xargs rm -f $(Q)$(MAKE) -f $(srctree)/Makefile ARCH=$(HEADER_ARCH) clean -export HEADER_ARCH SUBARCH USER_CFLAGS CFLAGS_NO_HARDENING DEV_NULL_PATH +export HEADER_ARCH SUBARCH USER_CFLAGS NOLIBC_CFLAGS CFLAGS_NO_HARDENING DEV_NULL_PATH diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h index b35cc8ce333b..5dae5635b1f8 100644 --- a/arch/um/include/shared/os.h +++ b/arch/um/include/shared/os.h @@ -327,7 +327,9 @@ extern int __ignore_sigio_fd(int fd); /* tty.c */ extern int get_pty(void); +#ifdef __KERNEL__ long syscall(long number, ...); +#endif /* irqflags tracing */ extern void block_signals_trace(void); diff --git a/arch/um/include/shared/user.h b/arch/um/include/shared/user.h index c9b853e1282f..e32bdd032029 100644 --- a/arch/um/include/shared/user.h +++ b/arch/um/include/shared/user.h @@ -16,7 +16,6 @@ */ #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) -#include #include extern void panic(const char *fmt, ...) diff --git a/arch/um/scripts/Makefile.rules b/arch/um/scripts/Makefile.rules index b4a2e0058503..5f07551935c3 100644 --- a/arch/um/scripts/Makefile.rules +++ b/arch/um/scripts/Makefile.rules @@ -11,6 +11,12 @@ USER_OBJS := $(foreach file,$(USER_OBJS),$(obj)/$(file)) $(USER_OBJS:.o=.%): \ c_flags = -Wp,-MD,$(depfile) $(USER_CFLAGS) $(CFLAGS_$(basetarget).o) +# Similar USER_OBJS but compiled against nolibc (may include kernel headers?) +NOLIBC_OBJS := $(foreach file,$(NOLIBC_OBJS),$(obj)/$(file)) + +$(NOLIBC_OBJS:.o=.%): \ + c_flags = -Wp,-MD,$(depfile) $(NOLIBC_CFLAGS) $(CFLAGS_$(basetarget).o) + # These are like USER_OBJS but filter USER_CFLAGS through unprofile instead of # using it directly. UNPROFILE_OBJS := $(foreach file,$(UNPROFILE_OBJS),$(obj)/$(file)) @@ -18,7 +24,7 @@ UNPROFILE_OBJS := $(foreach file,$(UNPROFILE_OBJS),$(obj)/$(file)) $(UNPROFILE_OBJS:.o=.%): \ c_flags = -Wp,-MD,$(depfile) $(call unprofile,$(USER_CFLAGS)) $(CFLAGS_$(basetarget).o) -$(USER_OBJS) $(UNPROFILE_OBJS): \ +$(USER_OBJS) $(NOLIBC_OBJS) $(UNPROFILE_OBJS): \ CHECKFLAGS := $(patsubst $(NOSTDINC_FLAGS),,$(CHECKFLAGS)) # The stubs can't try to call mcount or update basic block data