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FROMLIST: PCI: Fix PREL32 relocations for LTO

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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.

Bug: 145210207
Change-Id: Iaf4a28d14c5ab86d49d6fec07704c3cb48301d64
Link: https://lore.kernel.org/lkml/20201211184633.3213045-10-samitolvanen@google.com/
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Sami Tolvanen
2020-03-19 17:09:17 -07:00
parent 13968440c3
commit 7ffcc1cf4c
1 changed files with 14 additions and 5 deletions
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19
include/linux/pci.h
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@@ -1912,19 +1912,28 @@ 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, \