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From b8a624d8f629a31cc567f34f64053fab031e70f3 Mon Sep 17 00:00:00 2001
From: Sami Tolvanen <samitolvanen@google.com>
Date: Thu, 19 Mar 2020 17:09:17 -0700
Subject: [PATCH 13/24] PCI: Fix PREL32 relocations for LTO
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>
---
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 34c1c4f45288..fd8ee60b812f 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
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