From patchwork Wed Sep 25 15:01:25 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ard Biesheuvel X-Patchwork-Id: 13812172 Received: from mail-wm1-f73.google.com (mail-wm1-f73.google.com [209.85.128.73]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9728819C559 for ; Wed, 25 Sep 2024 15:02:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.73 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727276578; cv=none; b=sHz57kJxPni3aAVFsjA7S9go5EW7/m4+PqTlo+GlEkAFNxOpH3sqQ+85EhRpUKQApqCJZDbAhogVjm+45oBDAAceIdqXPdSV903mQsBamo6ZwufgDH7g/xKL6n5s3rFPz/aWOXCcH+0kH6yS1PK9SNTy9PXtUi/FJ7juSYRjtyM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727276578; c=relaxed/simple; bh=Ojp+f8Ba/j3ywSUpNkHMxJUaSZwEN3iyyriDyS6ns1Q=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=iDIUf8tpNRfnHgevH7j7YrlZsFS9TOdY5+oXzyUzdPe13G9Ubvbb4kU7OCRMRrg4vhRJZSUfApYW+V8dWUrdbzs7LW33+YZXpHzvApYJzN2efT7FZfszKS66DiJplKXgnfB18pdkcmkcpIMJBt1jdbCHUPmIg0hFRBfhDXzEuAI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=y3T3x26s; arc=none smtp.client-ip=209.85.128.73 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--ardb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="y3T3x26s" Received: by mail-wm1-f73.google.com with SMTP id 5b1f17b1804b1-42cb635b108so47822155e9.2 for ; Wed, 25 Sep 2024 08:02:55 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1727276574; x=1727881374; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=O/+lA7axzWVX738v6MDlUUydsjXBcrFQn3zDJoV9Zlw=; b=y3T3x26sz6jhlZueXjpSSXL3amdsXx8Mbpd1yomI+UJdyfjbVZ3wxXIZu2eFjNJyEa mz+UPaOC2MS77QuK67CtQ5Ghwzedq/bAumcKNVhhTn5ZpFdC5dp8EDQ03RLeUZ0grXOy KY3BxHG2sAY3nwi4+XO4ywe7lyqJIYoly693zeMzurddsEafa5E2cPy88tCerp9YJVdi 6Y3CyMU3Q0DBNUkQVq63MZ5CVm7Wp/FdNAHI7XmYd7QbqrQcJPUcoAmiXiEa/WaJIyYp /AdSxodOvEYDXTWJ/4FTOoB8osxnYELNuHCDU3NUTwyEyIpVyXxbTS5RqNlxXpr3CMMW CbmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727276574; x=1727881374; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=O/+lA7axzWVX738v6MDlUUydsjXBcrFQn3zDJoV9Zlw=; b=NLOJqHyBy+T77zTlNPc/WT4Ywx0PA5v1xx6KuOPSCD+pJpQ7NUEn01EUhRbEDGXgSZ HAVNTd/Rh/xvIgqWCgbxPnO27fq7CHFl6TGke+bxcWDjSr6VhFaf/pHaxsncdAk366NH pvJ+BENWn+6sx4STjnSwywZM82psdoBV5h1Jp0FBkF4gE5jP2SOqlMkUX/CA3DCPQCgY s9MFWbceWijIc+XJL8uVzQK/yW7uAHQYyoI28Me+k+0lGzSb8E23O9pGWOkJ3vVhJHRz eDLOPQ7Gy5fXU6BfsYel16hgLEKrIjrXnqgiV0tkAo+qmMoIzqhbtrm1LupoxPStZbo+ Ej3w== X-Forwarded-Encrypted: i=1; AJvYcCWa1hrs6+rl98VA8HObuFnHgK5AOy4ttknMQ8pL0zbBS6qdW30KamEKxYVDRW9eK6hbGjCvmWsbdwlRNHw=@vger.kernel.org X-Gm-Message-State: AOJu0Yz+ga9JBgaWZFcDDRjdAqiYMyUAK/JDJT86dF0ZLeTSJdlwycDc 0JyqgascKSPAX1VvCmai2OjN4k6QGK+hkk/C+W2MI+hZ4iVAHxJqeR4EUwhBS0RwtZfSSg== X-Google-Smtp-Source: AGHT+IFNuvMvba4376xFzsyJ1BUDwRQ77lLDg4NDppuY0o3Frk8EdeKG+tmu68nrB2OUMQBq6qGzN/uY X-Received: from palermo.c.googlers.com ([fda3:e722:ac3:cc00:7b:198d:ac11:8138]) (user=ardb job=sendgmr) by 2002:a5d:54cc:0:b0:374:c4ab:a87 with SMTP id ffacd0b85a97d-37cc24daa31mr1689f8f.10.1727276573709; Wed, 25 Sep 2024 08:02:53 -0700 (PDT) Date: Wed, 25 Sep 2024 17:01:25 +0200 In-Reply-To: <20240925150059.3955569-30-ardb+git@google.com> Precedence: bulk X-Mailing-List: linux-kbuild@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240925150059.3955569-30-ardb+git@google.com> X-Developer-Key: i=ardb@kernel.org; a=openpgp; fpr=F43D03328115A198C90016883D200E9CA6329909 X-Developer-Signature: v=1; a=openpgp-sha256; l=4435; i=ardb@kernel.org; h=from:subject; bh=kANZ4hMlm4/UDKey8x5hppB+h4SVBsDN4bipEdg9xMY=; b=owGbwMvMwCFmkMcZplerG8N4Wi2JIe2L6vknrr8ZmOQrG7s3Nc2KdXJ4vibh1dcKsQf8Readb AEJHvkdpSwMYhwMsmKKLAKz/77beXqiVK3zLFmYOaxMIEMYuDgFYCKL/Rj+Z1Y035g4dcnETV4f AzeGy0dnuYj7Gs68XGu9U01C7fDJWEaGptn9D/zPzyrzzArfXiITGJrvprug4muz0/qrb5bc6L/ LCQA= X-Mailer: git-send-email 2.46.0.792.g87dc391469-goog Message-ID: <20240925150059.3955569-55-ardb+git@google.com> Subject: [RFC PATCH 25/28] x86: Use PIE codegen for the core kernel From: Ard Biesheuvel To: linux-kernel@vger.kernel.org Cc: Ard Biesheuvel , x86@kernel.org, "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , Uros Bizjak , Dennis Zhou , Tejun Heo , Christoph Lameter , Mathieu Desnoyers , Paolo Bonzini , Vitaly Kuznetsov , Juergen Gross , Boris Ostrovsky , Greg Kroah-Hartman , Arnd Bergmann , Masahiro Yamada , Kees Cook , Nathan Chancellor , Keith Packard , Justin Stitt , Josh Poimboeuf , Arnaldo Carvalho de Melo , Namhyung Kim , Jiri Olsa , Ian Rogers , Adrian Hunter , Kan Liang , linux-doc@vger.kernel.org, linux-pm@vger.kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-efi@vger.kernel.org, linux-arch@vger.kernel.org, linux-sparse@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-perf-users@vger.kernel.org, rust-for-linux@vger.kernel.org, llvm@lists.linux.dev From: Ard Biesheuvel As an intermediate step towards enabling PIE linking for the 64-bit x86 kernel, enable PIE codegen for all objects that are linked into the kernel proper. This substantially reduces the number of relocations that need to be processed when booting a relocatable KASLR kernel. Before (size in bytes of the reloc table): 797372 arch/x86/boot/compressed/vmlinux.relocs After: 400252 arch/x86/boot/compressed/vmlinux.relocs Signed-off-by: Ard Biesheuvel --- arch/x86/Makefile | 11 ++++++++++- arch/x86/boot/Makefile | 1 + arch/x86/boot/compressed/Makefile | 2 +- arch/x86/entry/vdso/Makefile | 1 + arch/x86/realmode/rm/Makefile | 1 + include/asm-generic/vmlinux.lds.h | 1 + 6 files changed, 15 insertions(+), 2 deletions(-) diff --git a/arch/x86/Makefile b/arch/x86/Makefile index b78b7623a4a9..83d20f402535 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -193,13 +193,22 @@ else KBUILD_RUSTFLAGS += -Cno-redzone=y KBUILD_RUSTFLAGS += -Ccode-model=kernel + PIE_CFLAGS-y := -fpie -mcmodel=small \ + -include $(srctree)/include/linux/hidden.h + + PIE_CFLAGS-$(CONFIG_CC_IS_GCC) += $(call cc-option.-mdirect-extern-access) + PIE_CFLAGS-$(CONFIG_CC_IS_CLANG) += -fdirect-access-external-data + ifeq ($(CONFIG_STACKPROTECTOR),y) KBUILD_CFLAGS += -mstack-protector-guard-symbol=fixed_percpu_data + + # the 'small' C model defaults to %fs + PIE_CFLAGS-$(CONFIG_SMP) += -mstack-protector-guard-reg=gs endif # Don't emit relaxable GOTPCREL relocations KBUILD_AFLAGS_KERNEL += -Wa,-mrelax-relocations=no - KBUILD_CFLAGS_KERNEL += -Wa,-mrelax-relocations=no + KBUILD_CFLAGS_KERNEL += -Wa,-mrelax-relocations=no $(PIE_CFLAGS-y) endif # diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index 9cc0ff6e9067..4d3ba35cb619 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -57,6 +57,7 @@ KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ KBUILD_CFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=) KBUILD_CFLAGS += -fno-asynchronous-unwind-tables KBUILD_CFLAGS += $(CONFIG_CC_IMPLICIT_FALLTHROUGH) +KBUILD_CFLAGS_KERNEL := $(obj)/bzImage: asflags-y := $(SVGA_MODE) diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index f2051644de94..c362d36b5b69 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -73,7 +73,7 @@ LDFLAGS_vmlinux += -T hostprogs := mkpiggy HOST_EXTRACFLAGS += -I$(srctree)/tools/include -sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABCDGRSTVW] \(_text\|__start_rodata\|__bss_start\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p' +sed-voffset := -e 's/^\([0-9a-fA-F]*\) [ABbCDdGRSTtVW] \(_text\|__start_rodata\|__bss_start\|_end\)$$/\#define VO_\2 _AC(0x\1,UL)/p' quiet_cmd_voffset = VOFFSET $@ cmd_voffset = $(NM) $< | sed -n $(sed-voffset) > $@ diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile index c9216ac4fb1e..7af9fecf9abb 100644 --- a/arch/x86/entry/vdso/Makefile +++ b/arch/x86/entry/vdso/Makefile @@ -141,6 +141,7 @@ endif endif $(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32) +$(obj)/vdso32.so.dbg: KBUILD_CFLAGS_KERNEL := $(obj)/vdso32.so.dbg: $(obj)/vdso32/vdso32.lds $(vobjs32) FORCE $(call if_changed,vdso_and_check) diff --git a/arch/x86/realmode/rm/Makefile b/arch/x86/realmode/rm/Makefile index a0fb39abc5c8..70bf0a26da91 100644 --- a/arch/x86/realmode/rm/Makefile +++ b/arch/x86/realmode/rm/Makefile @@ -67,3 +67,4 @@ KBUILD_CFLAGS := $(REALMODE_CFLAGS) -D_SETUP -D_WAKEUP \ -I$(srctree)/arch/x86/boot KBUILD_AFLAGS := $(KBUILD_CFLAGS) -D__ASSEMBLY__ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables +KBUILD_CFLAGS_KERNEL := diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index 2b079f73820f..3a084ac77109 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -349,6 +349,7 @@ *(DATA_MAIN) \ *(.data..decrypted) \ *(.ref.data) \ + *(.data.rel*) \ *(.data..shared_aligned) /* percpu related */ \ *(.data.unlikely) \ __start_once = .; \