From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Subject: PCI: Add support for relative addressing in quirk tables Allow the PCI quirk tables to be emitted in a way that avoids absolute references to the hook functions. This reduces the size of the entries, and, more importantly, makes them invariant under runtime relocation (e.g., for KASLR) Link: http://lkml.kernel.org/r/20180704083651.24360-6-ard.biesheuvel@xxxxxxxxxx Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Acked-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: James Morris <james.morris@xxxxxxxxxxxxx> Cc: James Morris <jmorris@xxxxxxxxx> Cc: Jessica Yu <jeyu@xxxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Nicolas Pitre <nico@xxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Petr Mladek <pmladek@xxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: "Serge E. Hallyn" <serge@xxxxxxxxxx> Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Thomas Garnier <thgarnie@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- drivers/pci/quirks.c | 12 +++++++++--- include/linux/pci.h | 20 ++++++++++++++++++++ 2 files changed, 29 insertions(+), 3 deletions(-) --- a/drivers/pci/quirks.c~pci-add-support-for-relative-addressing-in-quirk-tables +++ a/drivers/pci/quirks.c @@ -66,9 +66,15 @@ static void pci_do_fixups(struct pci_dev f->vendor == (u16) PCI_ANY_ID) && (f->device == dev->device || f->device == (u16) PCI_ANY_ID)) { - calltime = fixup_debug_start(dev, f->hook); - f->hook(dev); - fixup_debug_report(dev, calltime, f->hook); + void (*hook)(struct pci_dev *dev); +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS + hook = offset_to_ptr(&f->hook_offset); +#else + hook = f->hook; +#endif + calltime = fixup_debug_start(dev, hook); + hook(dev); + fixup_debug_report(dev, calltime, hook); } } --- a/include/linux/pci.h~pci-add-support-for-relative-addressing-in-quirk-tables +++ a/include/linux/pci.h @@ -1809,7 +1809,11 @@ struct pci_fixup { u16 device; /* Or PCI_ANY_ID */ u32 class; /* Or PCI_ANY_ID */ unsigned int class_shift; /* should be 0, 8, 16 */ +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS + int hook_offset; +#else void (*hook)(struct pci_dev *dev); +#endif }; enum pci_fixup_pass { @@ -1823,12 +1827,28 @@ enum pci_fixup_pass { pci_fixup_suspend_late, /* pci_device_suspend_late() */ }; +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS +#define __DECLARE_PCI_FIXUP_SECTION(sec, name, vendor, device, class, \ + class_shift, hook) \ + __ADDRESSABLE(hook) \ + asm(".section " #sec ", \"a\" \n" \ + ".balign 16 \n" \ + ".short " #vendor ", " #device " \n" \ + ".long " #class ", " #class_shift " \n" \ + ".long " #hook " - . \n" \ + ".previous \n"); +#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) +#else /* Anonymous variables would be nice... */ #define DECLARE_PCI_FIXUP_SECTION(section, name, vendor, device, class, \ class_shift, hook) \ static const struct pci_fixup __PASTE(__pci_fixup_##name,__LINE__) __used \ __attribute__((__section__(#section), aligned((sizeof(void *))))) \ = { vendor, device, class, class_shift, hook }; +#endif #define DECLARE_PCI_FIXUP_CLASS_EARLY(vendor, device, class, \ class_shift, hook) \ _
