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From: Sami Tolvanen <samitolvanen@google.com>
To: Masahiro Yamada <masahiroy@kernel.org>, Will Deacon <will@kernel.org>
Cc: linux-arch@vger.kernel.org, x86@kernel.org,
	Kees Cook <keescook@chromium.org>,
	"Paul E. McKenney" <paulmck@kernel.org>,
	kernel-hardening@lists.openwall.com,
	Peter Zijlstra <peterz@infradead.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-kbuild@vger.kernel.org,
	Nick Desaulniers <ndesaulniers@google.com>,
	linux-kernel@vger.kernel.org,
	Steven Rostedt <rostedt@goodmis.org>,
	clang-built-linux@googlegroups.com,
	Sami Tolvanen <samitolvanen@google.com>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 19/30] PCI: Fix PREL32 relocations for LTO
Date: Fri, 18 Sep 2020 13:14:25 -0700	[thread overview]
Message-ID: <20200918201436.2932360-20-samitolvanen@google.com> (raw)
In-Reply-To: <20200918201436.2932360-1-samitolvanen@google.com>

With Clang's Link Time Optimization (LTO), the compiler can rename
static functions to avoid global naming collisions. As PCI fixup
functions are typically static, renaming can break references
to them in inline assembly. This change adds a global stub to
DECLARE_PCI_FIXUP_SECTION to fix the issue when PREL32 relocations
are used.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
 include/linux/pci.h | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 835530605c0d..4e64421981c7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1909,19 +1909,28 @@ enum pci_fixup_pass {
 };
 
 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
-#define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
-				    class_shift, hook)			\
-	__ADDRESSABLE(hook)						\
+#define ___DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
+				    class_shift, hook, stub)		\
+	void stub(struct pci_dev *dev);					\
+	void stub(struct pci_dev *dev)					\
+	{ 								\
+		hook(dev); 						\
+	}								\
 	asm(".section "	#sec ", \"a\"				\n"	\
 	    ".balign	16					\n"	\
 	    ".short "	#vendor ", " #device "			\n"	\
 	    ".long "	#class ", " #class_shift "		\n"	\
-	    ".long "	#hook " - .				\n"	\
+	    ".long "	#stub " - .				\n"	\
 	    ".previous						\n");
+
+#define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
+				  class_shift, hook, stub)		\
+	___DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
+				  class_shift, hook, stub)
 #define DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
 				  class_shift, hook)			\
 	__DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class,	\
-				  class_shift, hook)
+				  class_shift, hook, __UNIQUE_ID(hook))
 #else
 /* Anonymous variables would be nice... */
 #define DECLARE_PCI_FIXUP_SECTION(section, name, vendor, device, class,	\
-- 
2.28.0.681.g6f77f65b4e-goog


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  parent reply	other threads:[~2020-09-18 20:34 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-18 20:14 [PATCH v3 00/30] Add support for Clang LTO Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 01/30] lib/string.c: implement stpcpy Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 02/30] RAS/CEC: Fix cec_init() prototype Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 03/30] x86/boot/compressed: Disable relocation relaxation Sami Tolvanen
2020-09-21 15:53   ` Nick Desaulniers
2020-09-18 20:14 ` [PATCH v3 04/30] x86/asm: Replace __force_order with memory clobber Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 05/30] kbuild: preprocess module linker script Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 06/30] objtool: Add a pass for generating __mcount_loc Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 07/30] objtool: Don't autodetect vmlinux.o Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 08/30] kbuild: add support for objtool mcount Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 09/30] x86, build: use " Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 10/30] treewide: remove DISABLE_LTO Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 11/30] kbuild: add support for Clang LTO Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 12/30] kbuild: lto: fix module versioning Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 13/30] kbuild: lto: postpone objtool Sami Tolvanen
2020-09-18 21:27   ` Kees Cook
2020-09-21 18:58     ` Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 14/30] kbuild: lto: limit inlining Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 15/30] kbuild: lto: merge module sections Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 16/30] kbuild: lto: remove duplicate dependencies from .mod files Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 17/30] init: lto: ensure initcall ordering Sami Tolvanen
2020-09-18 21:29   ` Kees Cook
2020-09-18 20:14 ` [PATCH v3 18/30] init: lto: fix PREL32 relocations Sami Tolvanen
2020-09-18 20:14 ` Sami Tolvanen [this message]
2020-09-18 20:14 ` [PATCH v3 20/30] modpost: lto: strip .lto from module names Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 21/30] scripts/mod: disable LTO for empty.c Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 22/30] efi/libstub: disable LTO Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 23/30] drivers/misc/lkdtm: disable LTO for rodata.o Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 24/30] arm64: export CC_USING_PATCHABLE_FUNCTION_ENTRY Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 25/30] arm64: vdso: disable LTO Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 26/30] KVM: arm64: disable LTO for the nVHE directory Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 27/30] arm64: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 28/30] x86, vdso: disable LTO only for vDSO Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 29/30] x86, cpu: disable LTO for cpu.c Sami Tolvanen
2020-09-18 20:14 ` [PATCH v3 30/30] x86, build: allow LTO_CLANG and THINLTO to be selected Sami Tolvanen
2020-09-18 20:22 ` [PATCH v3 00/30] Add support for Clang LTO Sedat Dilek
2020-09-18 20:50   ` Sami Tolvanen
2020-09-18 20:53     ` Nick Desaulniers

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