[PATCH v4 0/5] add support for relative references in special sections

[PATCH v4 0/5] add support for relative references in special sections

[Ard Biesheuvel]

This adds support for emitting special sections such as initcall arrays,
PCI fixups and tracepoints as relative references rather than absolute
references. This reduces the size by 50% on 64-bit architectures, but
more importantly, it removes the need for carrying relocation metadata
for these sections in relocatables kernels (e.g., for KASLR) that need
to fix up these absolute references at boot time. On arm64, this reduces
the vmlinux footprint of such a reference by 8x (8 byte absolute reference
+ 24 byte RELA entry vs 4 byte relative reference)

Patch #2 was sent out before as a single patch. This series supersedes
the previous submission. This version makes relative ksymtab entries
dependent on the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS rather
than trying to infer from kbuild test robot replies for which architectures
it should be blacklisted.

Patch #1 introduces the new Kconfig symbol HAVE_ARCH_PREL32_RELOCATIONS,
and sets it for the main architectures that are expected to benefit the
most from this feature, i.e., 64-bit architectures, and ones that use
runtime relocation.

Patches #3 - #5 implement relative references for initcallls, PCI fixups
and tracepoints, respectively, all of which produce sections with order
~1000 entries on an arm64 defconfig kernel with tracing enabled. This
means we save about 28 KB of vmlinux space for each of these patches.

For the arm64 kernel, all patches combined reduce the size of vmlinux
by about 300 KB (with KASLR enabled).

Branch:
git://git.kernel.org/pub/scm/linux/kernel/git/ardb/linux.git relative-special-sections-v4

Changes since v3:
- fix module unload issue in patch #5 reported by Jessica, by reusing the
  updated routine for_each_tracepoint_range() for the quiescent check at
  module unload time; this requires this routine to be moved before
  tracepoint_module_going() in kernel/tracepoint.c
- add Jessica's ack to #2
- rebase onto v4.14-rc1

Changes since v2:
- Revert my slightly misguided attempt to appease checkpatch, which resulted
  in needless churn and worse code. This v3 is based on v1 with a few tweaks
  that were actually reasonable checkpatch warnings: unnecessary braces (as
  pointed out by Ingo) and other minor whitespace misdemeanors.

Changes since v1:
- Remove checkpatch errors to the extent feasible: in some cases, this
  involves moving extern declarations into C files, and switching to
  struct definitions rather than typedefs. Some errors are impossible
  to fix: please find the remaining ones after the diffstat.
- Used 'int' instead if 'signed int' for the various offset fields: there
  is no ambiguity between architectures regarding its signedness (unlike
  'char')
- Refactor the different patches to be more uniform in the way they define
  the section entry type and accessors in the .h file, and avoid the need to
  add #ifdefs to the C code.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jessica Yu <jeyu@kernel.org>

Ard Biesheuvel (5):
  arch: enable relative relocations for arm64, power, x86, s390 and x86
  module: use relative references for __ksymtab entries
  init: allow initcall tables to be emitted using relative references
  drivers: pci: add support for relative addressing in quirk tables
  kernel: tracepoints: add support for relative references

 arch/Kconfig                    | 10 ++++
 arch/arm64/Kconfig              |  1 +
 arch/arm64/kernel/vmlinux.lds.S |  2 +-
 arch/powerpc/Kconfig            |  1 +
 arch/s390/Kconfig               |  1 +
 arch/x86/Kconfig                |  1 +
 arch/x86/include/asm/Kbuild     |  1 +
 arch/x86/include/asm/export.h   |  4 --
 drivers/pci/quirks.c            | 13 +++--
 include/asm-generic/export.h    | 12 ++++-
 include/linux/compiler.h        | 11 +++++
 include/linux/export.h          | 45 +++++++++++++-----
 include/linux/init.h            | 44 ++++++++++++-----
 include/linux/pci.h             | 20 ++++++++
 include/linux/tracepoint.h      | 19 ++++++--
 init/main.c                     | 32 ++++++-------
 kernel/module.c                 | 33 ++++++++++---
 kernel/printk/printk.c          |  4 +-
 kernel/tracepoint.c             | 50 +++++++++++---------
 security/security.c             |  4 +-
 20 files changed, 223 insertions(+), 85 deletions(-)
 delete mode 100644 arch/x86/include/asm/export.h

-- 
2.11.0

[PATCH v4 1/5] arch: enable relative relocations for arm64, power, x86, s390 and x86

[Ard Biesheuvel]

Before updating certain subsystems to use place relative 32-bit
relocations in special sections, to save space  and reduce the
number of absolute relocations that need to be processed at runtime
by relocatable kernels, introduce the Kconfig symbol and define it
for some architectures that should be able to support and benefit
from it.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86 at kernel.org
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/Kconfig                    | 10 ++++++++++
 arch/arm64/Kconfig              |  1 +
 arch/arm64/kernel/vmlinux.lds.S |  2 +-
 arch/powerpc/Kconfig            |  1 +
 arch/s390/Kconfig               |  1 +
 arch/x86/Kconfig                |  1 +
 6 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/arch/Kconfig b/arch/Kconfig
index 1aafb4efbb51..0d78e377b208 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -961,4 +961,14 @@ config REFCOUNT_FULL
 	  against various use-after-free conditions that can be used in
 	  security flaw exploits.
 
+config HAVE_ARCH_PREL32_RELOCATIONS
+	bool
+	help
+	  May be selected by an architecture if it supports place-relative
+	  32-bit relocations, both in the toolchain and in the module loader,
+	  in which case relative references can be used in special sections
+	  for PCI fixup, initcalls etc which are only half the size on 64 bit
+	  architectures, and don't require runtime relocation on relocatable
+	  kernels.
+
 source "kernel/gcov/Kconfig"
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 0df64a6a56d4..30761f350d02 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -72,6 +72,7 @@ config ARM64
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_MMAP_RND_BITS
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT
+	select HAVE_ARCH_PREL32_RELOCATIONS
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index fe56c268a7d9..30dc991bbd85 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -155,7 +155,7 @@ SECTIONS
 		CON_INITCALL
 		SECURITY_INITCALL
 		INIT_RAM_FS
-		*(.init.rodata.* .init.bss)	/* from the EFI stub */
+		*(.init.rodata.* .init.bss .init.discard.*)	/* EFI stub */
 	}
 	.exit.data : {
 		ARM_EXIT_KEEP(EXIT_DATA)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 809c468edab1..86e2987b3a4a 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -174,6 +174,7 @@ config PPC
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_MMAP_RND_BITS
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if COMPAT
+	select HAVE_ARCH_PREL32_RELOCATIONS
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
 	select ARCH_HAS_STRICT_KERNEL_RWX	if ((PPC_BOOK3S_64 || PPC32) && !RELOCATABLE && !HIBERNATION)
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 48af970320cb..6c3b16a73024 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -127,6 +127,7 @@ config S390
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_JUMP_LABEL
 	select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
+	select HAVE_ARCH_PREL32_RELOCATIONS
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_SOFT_DIRTY
 	select HAVE_ARCH_TRACEHOOK
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 971feac13506..a50f96b08053 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -113,6 +113,7 @@ config X86
 	select HAVE_ARCH_MMAP_RND_BITS		if MMU
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if MMU && COMPAT
 	select HAVE_ARCH_COMPAT_MMAP_BASES	if MMU && COMPAT
+	select HAVE_ARCH_PREL32_RELOCATIONS
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
-- 
2.11.0

[PATCH v4 2/5] module: use relative references for __ksymtab entries

[Ard Biesheuvel]

An ordinary arm64 defconfig build has ~64 KB worth of __ksymtab
entries, each consisting of two 64-bit fields containing absolute
references, to the symbol itself and to a char array containing
its name, respectively.

When we build the same configuration with KASLR enabled, we end
up with an additional ~192 KB of relocations in the .init section,
i.e., one 24 byte entry for each absolute reference, which all need
to be processed at boot time.

Given how the struct kernel_symbol that describes each entry is
completely local to module.c (except for the references emitted
by EXPORT_SYMBOL() itself), we can easily modify it to contain
two 32-bit relative references instead. This reduces the size of
the __ksymtab section by 50% for all 64-bit architectures, and
gets rid of the runtime relocations entirely for architectures
implementing KASLR, either via standard PIE linking (arm64) or
using custom host tools (x86).

Note that the binary search involving __ksymtab contents relies
on each section being sorted by symbol name. This is implemented
based on the input section names, not the names in the ksymtab
entries, so this patch does not interfere with that.

Given that the use of place-relative relocations requires support
both in the toolchain and in the module loader, we cannot enable
this feature for all architectures. So make it dependend on whether
CONFIG_HAVE_ARCH_PREL32_RELOCATIONS is defined.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Nicolas Pitre <nico@linaro.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/x86/include/asm/Kbuild   |  1 +
 arch/x86/include/asm/export.h |  4 --
 include/asm-generic/export.h  | 12 +++++-
 include/linux/compiler.h      | 11 +++++
 include/linux/export.h        | 45 +++++++++++++++-----
 kernel/module.c               | 33 +++++++++++---
 6 files changed, 83 insertions(+), 23 deletions(-)

diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index 5d6a53fd7521..3e8a88dcaa1d 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -9,5 +9,6 @@ generated-y += xen-hypercalls.h
 generic-y += clkdev.h
 generic-y += dma-contiguous.h
 generic-y += early_ioremap.h
+generic-y += export.h
 generic-y += mcs_spinlock.h
 generic-y += mm-arch-hooks.h
diff --git a/arch/x86/include/asm/export.h b/arch/x86/include/asm/export.h
deleted file mode 100644
index 138de56b13eb..000000000000
--- a/arch/x86/include/asm/export.h
+++ /dev/null
@@ -1,4 +0,0 @@
-#ifdef CONFIG_64BIT
-#define KSYM_ALIGN 16
-#endif
-#include <asm-generic/export.h>
diff --git a/include/asm-generic/export.h b/include/asm-generic/export.h
index 719db1968d81..97ce606459ae 100644
--- a/include/asm-generic/export.h
+++ b/include/asm-generic/export.h
@@ -5,12 +5,10 @@
 #define KSYM_FUNC(x) x
 #endif
 #ifdef CONFIG_64BIT
-#define __put .quad
 #ifndef KSYM_ALIGN
 #define KSYM_ALIGN 8
 #endif
 #else
-#define __put .long
 #ifndef KSYM_ALIGN
 #define KSYM_ALIGN 4
 #endif
@@ -25,6 +23,16 @@
 #define KSYM(name) name
 #endif
 
+.macro __put, val, name
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+	.long	\val - ., \name - .
+#elif defined(CONFIG_64BIT)
+	.quad	\val, \name
+#else
+	.long	\val, \name
+#endif
+.endm
+
 /*
  * note on .section use: @progbits vs %progbits nastiness doesn't matter,
  * since we immediately emit into those sections anyway.
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index e95a2631e545..9c253ffd0d93 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -624,4 +624,15 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s
 	(_________p1); \
 })
 
+/*
+ * Force the compiler to emit 'sym' as a symbol, so that we can reference
+ * it from inline assembler. Necessary in case 'sym' could be inlined
+ * otherwise, or eliminated entirely due to lack of references that are
+ * visibile to the compiler.
+ */
+#define __ADDRESSABLE(sym) \
+	static void *__attribute__((section(".discard.text"), used))	\
+		__PASTE(__discard_##sym, __LINE__)(void)		\
+			{ return (void *)&sym; }			\
+
 #endif /* __LINUX_COMPILER_H */
diff --git a/include/linux/export.h b/include/linux/export.h
index 1a1dfdb2a5c6..156b974181a4 100644
--- a/include/linux/export.h
+++ b/include/linux/export.h
@@ -24,12 +24,6 @@
 #define VMLINUX_SYMBOL_STR(x) __VMLINUX_SYMBOL_STR(x)
 
 #ifndef __ASSEMBLY__
-struct kernel_symbol
-{
-	unsigned long value;
-	const char *name;
-};
-
 #ifdef MODULE
 extern struct module __this_module;
 #define THIS_MODULE (&__this_module)
@@ -60,17 +54,46 @@ extern struct module __this_module;
 #define __CRC_SYMBOL(sym, sec)
 #endif
 
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+/*
+ * Emit the ksymtab entry as a pair of relative references: this reduces
+ * the size by half on 64-bit architectures, and eliminates the need for
+ * absolute relocations that require runtime processing on relocatable
+ * kernels.
+ */
+#define __KSYMTAB_ENTRY(sym, sec)					\
+	__ADDRESSABLE(sym)						\
+	asm("	.section \"___ksymtab" sec "+" #sym "\", \"a\"	\n"	\
+	    "	.balign	8					\n"	\
+	    VMLINUX_SYMBOL_STR(__ksymtab_##sym) ":		\n"	\
+	    "	.long "	VMLINUX_SYMBOL_STR(sym) "- .		\n"	\
+	    "	.long "	VMLINUX_SYMBOL_STR(__kstrtab_##sym) "- .\n"	\
+	    "	.previous					\n")
+
+struct kernel_symbol {
+	signed int value_offset;
+	signed int name_offset;
+};
+#else
+#define __KSYMTAB_ENTRY(sym, sec)					\
+	static const struct kernel_symbol __ksymtab_##sym		\
+	__attribute__((section("___ksymtab" sec "+" #sym), used))	\
+	= { (unsigned long)&sym, __kstrtab_##sym }
+
+struct kernel_symbol {
+	unsigned long value;
+	const char *name;
+};
+#endif
+
 /* For every exported symbol, place a struct in the __ksymtab section */
 #define ___EXPORT_SYMBOL(sym, sec)					\
 	extern typeof(sym) sym;						\
 	__CRC_SYMBOL(sym, sec)						\
 	static const char __kstrtab_##sym[]				\
-	__attribute__((section("__ksymtab_strings"), aligned(1)))	\
+	__attribute__((section("__ksymtab_strings"), used, aligned(1)))	\
 	= VMLINUX_SYMBOL_STR(sym);					\
-	static const struct kernel_symbol __ksymtab_##sym		\
-	__used								\
-	__attribute__((section("___ksymtab" sec "+" #sym), used))	\
-	= { (unsigned long)&sym, __kstrtab_##sym }
+	__KSYMTAB_ENTRY(sym, sec)
 
 #if defined(__KSYM_DEPS__)
 
diff --git a/kernel/module.c b/kernel/module.c
index de66ec825992..4b9878c21698 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -539,12 +539,31 @@ static bool check_symbol(const struct symsearch *syms,
 	return true;
 }
 
+static unsigned long kernel_symbol_value(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+	return (unsigned long)&sym->value_offset + sym->value_offset;
+#else
+	return sym->value;
+#endif
+}
+
+static const char *kernel_symbol_name(const struct kernel_symbol *sym)
+{
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+	return (const char *)((unsigned long)&sym->name_offset +
+			      sym->name_offset);
+#else
+	return sym->name;
+#endif
+}
+
 static int cmp_name(const void *va, const void *vb)
 {
 	const char *a;
 	const struct kernel_symbol *b;
 	a = va; b = vb;
-	return strcmp(a, b->name);
+	return strcmp(a, kernel_symbol_name(b));
 }
 
 static bool find_symbol_in_section(const struct symsearch *syms,
@@ -2190,7 +2209,7 @@ void *__symbol_get(const char *symbol)
 		sym = NULL;
 	preempt_enable();
 
-	return sym ? (void *)sym->value : NULL;
+	return sym ? (void *)kernel_symbol_value(sym) : NULL;
 }
 EXPORT_SYMBOL_GPL(__symbol_get);
 
@@ -2220,10 +2239,12 @@ static int verify_export_symbols(struct module *mod)
 
 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
 		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
-			if (find_symbol(s->name, &owner, NULL, true, false)) {
+			if (find_symbol(kernel_symbol_name(s), &owner, NULL,
+					true, false)) {
 				pr_err("%s: exports duplicate symbol %s"
 				       " (owned by %s)\n",
-				       mod->name, s->name, module_name(owner));
+				       mod->name, kernel_symbol_name(s),
+				       module_name(owner));
 				return -ENOEXEC;
 			}
 		}
@@ -2272,7 +2293,7 @@ static int simplify_symbols(struct module *mod, const struct load_info *info)
 			ksym = resolve_symbol_wait(mod, info, name);
 			/* Ok if resolved.  */
 			if (ksym && !IS_ERR(ksym)) {
-				sym[i].st_value = ksym->value;
+				sym[i].st_value = kernel_symbol_value(ksym);
 				break;
 			}
 
@@ -2532,7 +2553,7 @@ static int is_exported(const char *name, unsigned long value,
 		ks = lookup_symbol(name, __start___ksymtab, __stop___ksymtab);
 	else
 		ks = lookup_symbol(name, mod->syms, mod->syms + mod->num_syms);
-	return ks != NULL && ks->value == value;
+	return ks != NULL && kernel_symbol_value(ks) == value;
 }
 
 /* As per nm */
-- 
2.11.0

[PATCH v4 3/5] init: allow initcall tables to be emitted using relative references

[Ard Biesheuvel]

Allow the initcall tables to be emitted using relative references that
are only half the size on 64-bit architectures and don't require fixups
at runtime on relocatable kernels.

Cc: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: James Morris <james.l.morris@oracle.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 include/linux/init.h   | 44 +++++++++++++++-----
 init/main.c            | 32 +++++++-------
 kernel/printk/printk.c |  4 +-
 security/security.c    |  4 +-
 4 files changed, 53 insertions(+), 31 deletions(-)

diff --git a/include/linux/init.h b/include/linux/init.h
index 94769d687cf0..e816dfdbbd21 100644
--- a/include/linux/init.h
+++ b/include/linux/init.h
@@ -110,8 +110,24 @@
 typedef int (*initcall_t)(void);
 typedef void (*exitcall_t)(void);
 
-extern initcall_t __con_initcall_start[], __con_initcall_end[];
-extern initcall_t __security_initcall_start[], __security_initcall_end[];
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+typedef signed int initcall_entry_t;
+
+static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
+{
+	return (initcall_t)((unsigned long)entry + *entry);
+}
+#else
+typedef initcall_t initcall_entry_t;
+
+static inline initcall_t initcall_from_entry(initcall_entry_t *entry)
+{
+	return *entry;
+}
+#endif
+
+extern initcall_entry_t __con_initcall_start[], __con_initcall_end[];
+extern initcall_entry_t __security_initcall_start[], __security_initcall_end[];
 
 /* Used for contructor calls. */
 typedef void (*ctor_fn_t)(void);
@@ -161,9 +177,20 @@ extern bool initcall_debug;
  * as KEEP() in the linker script.
  */
 
-#define __define_initcall(fn, id) \
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define ___define_initcall(fn, id, __sec)			\
+	__ADDRESSABLE(fn)					\
+	asm(".section	\"" #__sec ".init\", \"a\"	\n"	\
+	"__initcall_" #fn #id ":			\n"	\
+	    ".long "	VMLINUX_SYMBOL_STR(fn) " - .	\n"	\
+	    ".previous					\n");
+#else
+#define ___define_initcall(fn, id, __sec) \
 	static initcall_t __initcall_##fn##id __used \
-	__attribute__((__section__(".initcall" #id ".init"))) = fn;
+		__attribute__((__section__(#__sec ".init"))) = fn;
+#endif
+
+#define __define_initcall(fn, id) ___define_initcall(fn, id, .initcall##id)
 
 /*
  * Early initcalls run before initializing SMP.
@@ -202,13 +229,8 @@ extern bool initcall_debug;
 #define __exitcall(fn)						\
 	static exitcall_t __exitcall_##fn __exit_call = fn
 
-#define console_initcall(fn)					\
-	static initcall_t __initcall_##fn			\
-	__used __section(.con_initcall.init) = fn
-
-#define security_initcall(fn)					\
-	static initcall_t __initcall_##fn			\
-	__used __section(.security_initcall.init) = fn
+#define console_initcall(fn)	___define_initcall(fn,, .con_initcall)
+#define security_initcall(fn)	___define_initcall(fn,, .security_initcall)
 
 struct obs_kernel_param {
 	const char *str;
diff --git a/init/main.c b/init/main.c
index 0ee9c6866ada..a3a083d2b217 100644
--- a/init/main.c
+++ b/init/main.c
@@ -842,18 +842,18 @@ int __init_or_module do_one_initcall(initcall_t fn)
 }
 
 
-extern initcall_t __initcall_start[];
-extern initcall_t __initcall0_start[];
-extern initcall_t __initcall1_start[];
-extern initcall_t __initcall2_start[];
-extern initcall_t __initcall3_start[];
-extern initcall_t __initcall4_start[];
-extern initcall_t __initcall5_start[];
-extern initcall_t __initcall6_start[];
-extern initcall_t __initcall7_start[];
-extern initcall_t __initcall_end[];
-
-static initcall_t *initcall_levels[] __initdata = {
+extern initcall_entry_t __initcall_start[];
+extern initcall_entry_t __initcall0_start[];
+extern initcall_entry_t __initcall1_start[];
+extern initcall_entry_t __initcall2_start[];
+extern initcall_entry_t __initcall3_start[];
+extern initcall_entry_t __initcall4_start[];
+extern initcall_entry_t __initcall5_start[];
+extern initcall_entry_t __initcall6_start[];
+extern initcall_entry_t __initcall7_start[];
+extern initcall_entry_t __initcall_end[];
+
+static initcall_entry_t *initcall_levels[] __initdata = {
 	__initcall0_start,
 	__initcall1_start,
 	__initcall2_start,
@@ -879,7 +879,7 @@ static char *initcall_level_names[] __initdata = {
 
 static void __init do_initcall_level(int level)
 {
-	initcall_t *fn;
+	initcall_entry_t *fn;
 
 	strcpy(initcall_command_line, saved_command_line);
 	parse_args(initcall_level_names[level],
@@ -889,7 +889,7 @@ static void __init do_initcall_level(int level)
 		   NULL, &repair_env_string);
 
 	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)
-		do_one_initcall(*fn);
+		do_one_initcall(initcall_from_entry(fn));
 }
 
 static void __init do_initcalls(void)
@@ -920,10 +920,10 @@ static void __init do_basic_setup(void)
 
 static void __init do_pre_smp_initcalls(void)
 {
-	initcall_t *fn;
+	initcall_entry_t *fn;
 
 	for (fn = __initcall_start; fn < __initcall0_start; fn++)
-		do_one_initcall(*fn);
+		do_one_initcall(initcall_from_entry(fn));
 }
 
 /*
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 512f7c2baedd..71636172abc8 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2611,7 +2611,7 @@ EXPORT_SYMBOL(unregister_console);
  */
 void __init console_init(void)
 {
-	initcall_t *call;
+	initcall_entry_t *call;
 
 	/* Setup the default TTY line discipline. */
 	n_tty_init();
@@ -2622,7 +2622,7 @@ void __init console_init(void)
 	 */
 	call = __con_initcall_start;
 	while (call < __con_initcall_end) {
-		(*call)();
+		initcall_from_entry(call)();
 		call++;
 	}
 }
diff --git a/security/security.c b/security/security.c
index 4bf0f571b4ef..4ddca9a008a0 100644
--- a/security/security.c
+++ b/security/security.c
@@ -44,10 +44,10 @@ static __initdata char chosen_lsm[SECURITY_NAME_MAX + 1] =
 
 static void __init do_security_initcalls(void)
 {
-	initcall_t *call;
+	initcall_entry_t *call;
 	call = __security_initcall_start;
 	while (call < __security_initcall_end) {
-		(*call) ();
+		initcall_from_entry(call)();
 		call++;
 	}
 }
-- 
2.11.0

[PATCH v4 4/5] drivers: pci: add support for relative addressing in quirk tables

[Ard Biesheuvel]

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)

Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 drivers/pci/quirks.c | 13 ++++++++++---
 include/linux/pci.h  | 20 ++++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index a4d33619a7bb..82a66235d60c 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3548,9 +3548,16 @@ static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f,
 		     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 = (void *)((unsigned long)&f->hook_offset +
+					f->hook_offset);
+#else
+			hook = f->hook;
+#endif
+			calltime = fixup_debug_start(dev, hook);
+			hook(dev);
+			fixup_debug_report(dev, calltime, hook);
 		}
 }
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index f68c58a93dd0..d7a01d7fc3a7 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1791,7 +1791,11 @@ struct pci_fixup {
 	u16 device;		/* You can use PCI_ANY_ID here of course */
 	u32 class;		/* You can use PCI_ANY_ID here too */
 	unsigned int class_shift;	/* should be 0, 8, 16 */
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+	signed int hook_offset;
+#else
 	void (*hook)(struct pci_dev *dev);
+#endif
 };
 
 enum pci_fixup_pass {
@@ -1805,12 +1809,28 @@ 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 "	VMLINUX_SYMBOL_STR(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)		\
-- 
2.11.0

[PATCH v4 5/5] kernel: tracepoints: add support for relative references

[Ard Biesheuvel]

To avoid the need for relocating absolute references to tracepoint
structures at boot time when running relocatable kernels (which may
take a disproportionate amount of space), add the option to emit
these tables as relative references instead.

Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 include/linux/tracepoint.h | 19 ++++++--
 kernel/tracepoint.c        | 50 +++++++++++---------
 2 files changed, 42 insertions(+), 27 deletions(-)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index a26ffbe09e71..d02bf1a695e8 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -228,6 +228,19 @@ extern void syscall_unregfunc(void);
 		return static_key_false(&__tracepoint_##name.key);	\
 	}
 
+#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
+#define __TRACEPOINT_ENTRY(name)					 \
+	asm("	.section \"__tracepoints_ptrs\", \"a\"		     \n" \
+	    "	.balign 4					     \n" \
+	    "	.long " VMLINUX_SYMBOL_STR(__tracepoint_##name) " - .\n" \
+	    "	.previous					     \n")
+#else
+#define __TRACEPOINT_ENTRY(name)					 \
+	static struct tracepoint * const __tracepoint_ptr_##name __used	 \
+	__attribute__((section("__tracepoints_ptrs"))) =		 \
+		&__tracepoint_##name
+#endif
+
 /*
  * We have no guarantee that gcc and the linker won't up-align the tracepoint
  * structures, so we create an array of pointers that will be used for iteration
@@ -237,11 +250,9 @@ extern void syscall_unregfunc(void);
 	static const char __tpstrtab_##name[]				 \
 	__attribute__((section("__tracepoints_strings"))) = #name;	 \
 	struct tracepoint __tracepoint_##name				 \
-	__attribute__((section("__tracepoints"))) =			 \
+	__attribute__((section("__tracepoints"), used)) =		 \
 		{ __tpstrtab_##name, STATIC_KEY_INIT_FALSE, reg, unreg, NULL };\
-	static struct tracepoint * const __tracepoint_ptr_##name __used	 \
-	__attribute__((section("__tracepoints_ptrs"))) =		 \
-		&__tracepoint_##name;
+	__TRACEPOINT_ENTRY(name);
 
 #define DEFINE_TRACE(name)						\
 	DEFINE_TRACE_FN(name, NULL, NULL);
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 685c50ae6300..05649fef106c 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -327,6 +327,28 @@ int tracepoint_probe_unregister(struct tracepoint *tp, void *probe, void *data)
 }
 EXPORT_SYMBOL_GPL(tracepoint_probe_unregister);
 
+static void for_each_tracepoint_range(struct tracepoint * const *begin,
+		struct tracepoint * const *end,
+		void (*fct)(struct tracepoint *tp, void *priv),
+		void *priv)
+{
+	if (!begin)
+		return;
+
+	if (IS_ENABLED(CONFIG_HAVE_ARCH_PREL32_RELOCATIONS)) {
+		const int *iter;
+
+		for (iter = (const int *)begin; iter < (const int *)end; iter++)
+			fct((struct tracepoint *)((unsigned long)iter + *iter),
+			    priv);
+	} else {
+		struct tracepoint * const *iter;
+
+		for (iter = begin; iter < end; iter++)
+			fct(*iter, priv);
+	}
+}
+
 #ifdef CONFIG_MODULES
 bool trace_module_has_bad_taint(struct module *mod)
 {
@@ -391,15 +413,9 @@ EXPORT_SYMBOL_GPL(unregister_tracepoint_module_notifier);
  * Ensure the tracer unregistered the module's probes before the module
  * teardown is performed. Prevents leaks of probe and data pointers.
  */
-static void tp_module_going_check_quiescent(struct tracepoint * const *begin,
-		struct tracepoint * const *end)
+static void tp_module_going_check_quiescent(struct tracepoint *tp, void *priv)
 {
-	struct tracepoint * const *iter;
-
-	if (!begin)
-		return;
-	for (iter = begin; iter < end; iter++)
-		WARN_ON_ONCE((*iter)->funcs);
+	WARN_ON_ONCE(tp->funcs);
 }
 
 static int tracepoint_module_coming(struct module *mod)
@@ -450,8 +466,9 @@ static void tracepoint_module_going(struct module *mod)
 			 * Called the going notifier before checking for
 			 * quiescence.
 			 */
-			tp_module_going_check_quiescent(mod->tracepoints_ptrs,
-				mod->tracepoints_ptrs + mod->num_tracepoints);
+			for_each_tracepoint_range(mod->tracepoints_ptrs,
+				mod->tracepoints_ptrs + mod->num_tracepoints,
+				tp_module_going_check_quiescent, NULL);
 			break;
 		}
 	}
@@ -503,19 +520,6 @@ static __init int init_tracepoints(void)
 __initcall(init_tracepoints);
 #endif /* CONFIG_MODULES */
 
-static void for_each_tracepoint_range(struct tracepoint * const *begin,
-		struct tracepoint * const *end,
-		void (*fct)(struct tracepoint *tp, void *priv),
-		void *priv)
-{
-	struct tracepoint * const *iter;
-
-	if (!begin)
-		return;
-	for (iter = begin; iter < end; iter++)
-		fct(*iter, priv);
-}
-
 /**
  * for_each_kernel_tracepoint - iteration on all kernel tracepoints
  * @fct: callback
-- 
2.11.0

Re: [PATCH v4 4/5] drivers: pci: add support for relative addressing in quirk tables

[Bjorn Helgaas]

[+cc linux-pci]

You copied LKML on some previous versions, but not this one.  Seems
like that would be useful.

Please adjust the subject line of this one so it matches the typical
ones for this file, e.g.,

  PCI: Add support for relative addressing in quirk tables

On Wed, Sep 20, 2017 at 12:57:20PM -0700, Ard Biesheuvel wrote:
> 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)
> 
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

This really uglifies the code (and initcall_from_entry() in the other
patch makes my head hurt), but I don't have any cleaner implementation
ideas, and it does seem like a worthwhile space optimization.

> ---
>  drivers/pci/quirks.c | 13 ++++++++++---
>  include/linux/pci.h  | 20 ++++++++++++++++++++
>  2 files changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index a4d33619a7bb..82a66235d60c 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3548,9 +3548,16 @@ static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f,
>  		     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 = (void *)((unsigned long)&f->hook_offset +
> +					f->hook_offset);
> +#else
> +			hook = f->hook;
> +#endif
> +			calltime = fixup_debug_start(dev, hook);
> +			hook(dev);
> +			fixup_debug_report(dev, calltime, hook);
>  		}
>  }
>  
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index f68c58a93dd0..d7a01d7fc3a7 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1791,7 +1791,11 @@ struct pci_fixup {
>  	u16 device;		/* You can use PCI_ANY_ID here of course */
>  	u32 class;		/* You can use PCI_ANY_ID here too */
>  	unsigned int class_shift;	/* should be 0, 8, 16 */
> +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
> +	signed int hook_offset;
> +#else
>  	void (*hook)(struct pci_dev *dev);
> +#endif
>  };
>  
>  enum pci_fixup_pass {
> @@ -1805,12 +1809,28 @@ 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 "	VMLINUX_SYMBOL_STR(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)		\
> -- 
> 2.11.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[PATCH v4 4/5] drivers: pci: add support for relative addressing in quirk tables

[Bjorn Helgaas]

[+cc linux-pci]

You copied LKML on some previous versions, but not this one.  Seems
like that would be useful.

Please adjust the subject line of this one so it matches the typical
ones for this file, e.g.,

  PCI: Add support for relative addressing in quirk tables

On Wed, Sep 20, 2017 at 12:57:20PM -0700, Ard Biesheuvel wrote:
> 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)
> 
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

Acked-by: Bjorn Helgaas <bhelgaas@google.com>

This really uglifies the code (and initcall_from_entry() in the other
patch makes my head hurt), but I don't have any cleaner implementation
ideas, and it does seem like a worthwhile space optimization.

> ---
>  drivers/pci/quirks.c | 13 ++++++++++---
>  include/linux/pci.h  | 20 ++++++++++++++++++++
>  2 files changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index a4d33619a7bb..82a66235d60c 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3548,9 +3548,16 @@ static void pci_do_fixups(struct pci_dev *dev, struct pci_fixup *f,
>  		     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 = (void *)((unsigned long)&f->hook_offset +
> +					f->hook_offset);
> +#else
> +			hook = f->hook;
> +#endif
> +			calltime = fixup_debug_start(dev, hook);
> +			hook(dev);
> +			fixup_debug_report(dev, calltime, hook);
>  		}
>  }
>  
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index f68c58a93dd0..d7a01d7fc3a7 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -1791,7 +1791,11 @@ struct pci_fixup {
>  	u16 device;		/* You can use PCI_ANY_ID here of course */
>  	u32 class;		/* You can use PCI_ANY_ID here too */
>  	unsigned int class_shift;	/* should be 0, 8, 16 */
> +#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
> +	signed int hook_offset;
> +#else
>  	void (*hook)(struct pci_dev *dev);
> +#endif
>  };
>  
>  enum pci_fixup_pass {
> @@ -1805,12 +1809,28 @@ 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 "	VMLINUX_SYMBOL_STR(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)		\
> -- 
> 2.11.0
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel