diff mbox

roseapplepi: backport upstream patches to fix build with gcc 6

Message ID 20170620114952.16292-1-peter@korsgaard.com
State Accepted
Headers show

Commit Message

Peter Korsgaard June 20, 2017, 11:49 a.m. UTC 
The recent change to default to gcc 6 for the internal toolchain broke this
defconfig as the u-boot and linux kernel are too old to build with gcc 6.

Fit it by backporting the following commits:

- u-boot: 9b2c282b34 (compiler*.h: sync include/linux/compiler*.h with Linux 4.5-rc6)
- linux:  cb984d101b (compiler-gcc: integrate the various compiler-gcc[345].h files)

Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
---
Andreas Färber has recently contributed minimal mainline Linux support for
this SoC, so I'll have a look at migrating to that once it ends up in Linus'
tree:

https://lists.infradead.org/pipermail/linux-arm-kernel/2017-June/510886.html

 ...c-integrate-the-various-compiler-gcc-345-.patch | 363 +++++++++
 ...-sync-include-linux-compiler-.h-with-Linu.patch | 809 +++++++++++++++++++++
 2 files changed, 1172 insertions(+)
 create mode 100644 board/roseapplepi/patches/linux/0005-compiler-gcc-integrate-the-various-compiler-gcc-345-.patch
 create mode 100644 board/roseapplepi/patches/uboot/0001-compiler-.h-sync-include-linux-compiler-.h-with-Linu.patch

Comments

Thomas Petazzoni June 20, 2017, 7:30 p.m. UTC | #1 
Hello,

On Tue, 20 Jun 2017 13:49:52 +0200, Peter Korsgaard wrote:
> The recent change to default to gcc 6 for the internal toolchain broke this
> defconfig as the u-boot and linux kernel are too old to build with gcc 6.
> 
> Fit it by backporting the following commits:
> 
> - u-boot: 9b2c282b34 (compiler*.h: sync include/linux/compiler*.h with Linux 4.5-rc6)
> - linux:  cb984d101b (compiler-gcc: integrate the various compiler-gcc[345].h files)
> 
> Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
> ---
> Andreas Färber has recently contributed minimal mainline Linux support for
> this SoC, so I'll have a look at migrating to that once it ends up in Linus'
> tree:

I've applied to master. But to be honest, I'm not thrilled with the idea
of adding 1100+ lines of patches just to make one single defconfig build
again with gcc 6.x. If the kernel doesn't build with gcc 6.x, it means
the HW platform is poorly maintained, and it will become worse and
worse.

Perhaps for such platforms we should change the defconfig to use gcc
5.x (or whatever older version works). And once we remove the support
for those older gcc versions, drop the defconfig as well.

What do you think?

Thomas
Peter Korsgaard June 20, 2017, 8:04 p.m. UTC | #2 
>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:

Hi,

 >> ---
 >> Andreas Färber has recently contributed minimal mainline Linux support for
 >> this SoC, so I'll have a look at migrating to that once it ends up in Linus'
 >> tree:

 > I've applied to master. But to be honest, I'm not thrilled with the idea
 > of adding 1100+ lines of patches just to make one single defconfig build
 > again with gcc 6.x. If the kernel doesn't build with gcc 6.x, it means
 > the HW platform is poorly maintained, and it will become worse and
 > worse.

 > Perhaps for such platforms we should change the defconfig to use gcc
 > 5.x (or whatever older version works). And once we remove the support
 > for those older gcc versions, drop the defconfig as well.

 > What do you think?

Yeah, it isn't really nice. I was also hessitating between sticking to
gcc5 or add the patches, but as mainline support seems to be finally
moving forward for this SoC (and we already carried patches for building
with gcc 5.x), I went for the patches.
Thomas Petazzoni June 20, 2017, 8:19 p.m. UTC | #3 
Hello,

On Tue, 20 Jun 2017 22:04:49 +0200, Peter Korsgaard wrote:

>  > What do you think?  
> 
> Yeah, it isn't really nice. I was also hessitating between sticking to
> gcc5 or add the patches, but as mainline support seems to be finally
> moving forward for this SoC (and we already carried patches for building
> with gcc 5.x), I went for the patches.

Regarding mainline support, I have no idea how far it is today. But
from experience, it takes a very long time to move from the
serial+MMC+Ethernet supported to a state where display+audio+GPU is
supported. So mainline may not necessarily be a drop-in replacement
before a long time.

Thomas
Peter Korsgaard June 20, 2017, 8:31 p.m. UTC | #4 
>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:

 > Hello,
 > On Tue, 20 Jun 2017 22:04:49 +0200, Peter Korsgaard wrote:

 >> > What do you think?  
 >> 
 >> Yeah, it isn't really nice. I was also hessitating between sticking to
 >> gcc5 or add the patches, but as mainline support seems to be finally
 >> moving forward for this SoC (and we already carried patches for building
 >> with gcc 5.x), I went for the patches.

 > Regarding mainline support, I have no idea how far it is today. But
 > from experience, it takes a very long time to move from the
 > serial+MMC+Ethernet supported to a state where display+audio+GPU is
 > supported. So mainline may not necessarily be a drop-in replacement
 > before a long time.

Yes, I know - But for a buildroot defconfig, serial+MMC+ethernet is
fine. We also don't have support the GPU or VPU in Buildroot today.
diff mbox

Patch

diff --git a/board/roseapplepi/patches/linux/0005-compiler-gcc-integrate-the-various-compiler-gcc-345-.patch b/board/roseapplepi/patches/linux/0005-compiler-gcc-integrate-the-various-compiler-gcc-345-.patch
new file mode 100644
index 0000000000..791dd930c7
--- /dev/null
+++ b/board/roseapplepi/patches/linux/0005-compiler-gcc-integrate-the-various-compiler-gcc-345-.patch
@@ -0,0 +1,363 @@ 
+From 21be6b635320321216dde9201fa57a3aed60ee12 Mon Sep 17 00:00:00 2001
+From: Joe Perches <joe@perches.com>
+Date: Thu, 25 Jun 2015 15:01:02 -0700
+Subject: [PATCH] compiler-gcc: integrate the various compiler-gcc[345].h files
+
+As gcc major version numbers are going to advance rather rapidly in the
+future, there's no real value in separate files for each compiler
+version.
+
+Deduplicate some of the macros #defined in each file too.
+
+Neaten comments using normal kernel commenting style.
+
+Signed-off-by: Joe Perches <joe@perches.com>
+Cc: Andi Kleen <andi@firstfloor.org>
+Cc: Michal Marek <mmarek@suse.cz>
+Cc: Segher Boessenkool <segher@kernel.crashing.org>
+Cc: Sasha Levin <levinsasha928@gmail.com>
+Cc: Anton Blanchard <anton@samba.org>
+Cc: Alan Modra <amodra@gmail.com>
+Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
+Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
+(cherry picked from commit cb984d101b30eb7478d32df56a0023e4603cba7f)
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ include/linux/compiler-gcc.h  | 120 ++++++++++++++++++++++++++++++++++++++++--
+ include/linux/compiler-gcc3.h |  23 --------
+ include/linux/compiler-gcc4.h |  88 -------------------------------
+ include/linux/compiler-gcc5.h |  66 -----------------------
+ 4 files changed, 116 insertions(+), 181 deletions(-)
+ delete mode 100644 include/linux/compiler-gcc3.h
+ delete mode 100644 include/linux/compiler-gcc4.h
+ delete mode 100644 include/linux/compiler-gcc5.h
+
+diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
+index 24545cd90a25..0c5d746850c2 100644
+--- a/include/linux/compiler-gcc.h
++++ b/include/linux/compiler-gcc.h
+@@ -97,10 +97,122 @@
+ #define __maybe_unused			__attribute__((unused))
+ #define __always_unused			__attribute__((unused))
+ 
+-#define __gcc_header(x) #x
+-#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
+-#define gcc_header(x) _gcc_header(x)
+-#include gcc_header(__GNUC__)
++/* gcc version specific checks */
++
++#if GCC_VERSION < 30200
++# error Sorry, your compiler is too old - please upgrade it.
++#endif
++
++#if GCC_VERSION < 30300
++# define __used			__attribute__((__unused__))
++#else
++# define __used			__attribute__((__used__))
++#endif
++
++#ifdef CONFIG_GCOV_KERNEL
++# if GCC_VERSION < 30400
++#   error "GCOV profiling support for gcc versions below 3.4 not included"
++# endif /* __GNUC_MINOR__ */
++#endif /* CONFIG_GCOV_KERNEL */
++
++#if GCC_VERSION >= 30400
++#define __must_check		__attribute__((warn_unused_result))
++#endif
++
++#if GCC_VERSION >= 40000
++
++/* GCC 4.1.[01] miscompiles __weak */
++#ifdef __KERNEL__
++# if GCC_VERSION >= 40100 &&  GCC_VERSION <= 40101
++#  error Your version of gcc miscompiles the __weak directive
++# endif
++#endif
++
++#define __used			__attribute__((__used__))
++#define __compiler_offsetof(a, b)					\
++	__builtin_offsetof(a, b)
++
++#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
++# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
++#endif
++
++#if GCC_VERSION >= 40300
++/* Mark functions as cold. gcc will assume any path leading to a call
++ * to them will be unlikely.  This means a lot of manual unlikely()s
++ * are unnecessary now for any paths leading to the usual suspects
++ * like BUG(), printk(), panic() etc. [but let's keep them for now for
++ * older compilers]
++ *
++ * Early snapshots of gcc 4.3 don't support this and we can't detect this
++ * in the preprocessor, but we can live with this because they're unreleased.
++ * Maketime probing would be overkill here.
++ *
++ * gcc also has a __attribute__((__hot__)) to move hot functions into
++ * a special section, but I don't see any sense in this right now in
++ * the kernel context
++ */
++#define __cold			__attribute__((__cold__))
++
++#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
++
++#ifndef __CHECKER__
++# define __compiletime_warning(message) __attribute__((warning(message)))
++# define __compiletime_error(message) __attribute__((error(message)))
++#endif /* __CHECKER__ */
++#endif /* GCC_VERSION >= 40300 */
++
++#if GCC_VERSION >= 40500
++/*
++ * Mark a position in code as unreachable.  This can be used to
++ * suppress control flow warnings after asm blocks that transfer
++ * control elsewhere.
++ *
++ * Early snapshots of gcc 4.5 don't support this and we can't detect
++ * this in the preprocessor, but we can live with this because they're
++ * unreleased.  Really, we need to have autoconf for the kernel.
++ */
++#define unreachable() __builtin_unreachable()
++
++/* Mark a function definition as prohibited from being cloned. */
++#define __noclone	__attribute__((__noclone__))
++
++#endif /* GCC_VERSION >= 40500 */
++
++#if GCC_VERSION >= 40600
++/*
++ * Tell the optimizer that something else uses this function or variable.
++ */
++#define __visible	__attribute__((externally_visible))
++#endif
++
++/*
++ * GCC 'asm goto' miscompiles certain code sequences:
++ *
++ *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
++ *
++ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
++ *
++ * (asm goto is automatically volatile - the naming reflects this.)
++ */
++#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
++
++#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
++#if GCC_VERSION >= 40400
++#define __HAVE_BUILTIN_BSWAP32__
++#define __HAVE_BUILTIN_BSWAP64__
++#endif
++#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
++#define __HAVE_BUILTIN_BSWAP16__
++#endif
++#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
++
++#if GCC_VERSION >= 50000
++#define KASAN_ABI_VERSION 4
++#elif GCC_VERSION >= 40902
++#define KASAN_ABI_VERSION 3
++#endif
++
++#endif	/* gcc version >= 40000 specific checks */
+ 
+ #if !defined(__noclone)
+ #define __noclone	/* not needed */
+diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
+deleted file mode 100644
+index 7d89febe4d79..000000000000
+--- a/include/linux/compiler-gcc3.h
++++ /dev/null
+@@ -1,23 +0,0 @@
+-#ifndef __LINUX_COMPILER_H
+-#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
+-#endif
+-
+-#if GCC_VERSION < 30200
+-# error Sorry, your compiler is too old - please upgrade it.
+-#endif
+-
+-#if GCC_VERSION >= 30300
+-# define __used			__attribute__((__used__))
+-#else
+-# define __used			__attribute__((__unused__))
+-#endif
+-
+-#if GCC_VERSION >= 30400
+-#define __must_check		__attribute__((warn_unused_result))
+-#endif
+-
+-#ifdef CONFIG_GCOV_KERNEL
+-# if GCC_VERSION < 30400
+-#   error "GCOV profiling support for gcc versions below 3.4 not included"
+-# endif /* __GNUC_MINOR__ */
+-#endif /* CONFIG_GCOV_KERNEL */
+diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
+deleted file mode 100644
+index 2507fd2a1eb4..000000000000
+--- a/include/linux/compiler-gcc4.h
++++ /dev/null
+@@ -1,88 +0,0 @@
+-#ifndef __LINUX_COMPILER_H
+-#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
+-#endif
+-
+-/* GCC 4.1.[01] miscompiles __weak */
+-#ifdef __KERNEL__
+-# if GCC_VERSION >= 40100 &&  GCC_VERSION <= 40101
+-#  error Your version of gcc miscompiles the __weak directive
+-# endif
+-#endif
+-
+-#define __used			__attribute__((__used__))
+-#define __must_check 		__attribute__((warn_unused_result))
+-#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
+-
+-#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
+-# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
+-#endif
+-
+-#if GCC_VERSION >= 40300
+-/* Mark functions as cold. gcc will assume any path leading to a call
+-   to them will be unlikely.  This means a lot of manual unlikely()s
+-   are unnecessary now for any paths leading to the usual suspects
+-   like BUG(), printk(), panic() etc. [but let's keep them for now for
+-   older compilers]
+-
+-   Early snapshots of gcc 4.3 don't support this and we can't detect this
+-   in the preprocessor, but we can live with this because they're unreleased.
+-   Maketime probing would be overkill here.
+-
+-   gcc also has a __attribute__((__hot__)) to move hot functions into
+-   a special section, but I don't see any sense in this right now in
+-   the kernel context */
+-#define __cold			__attribute__((__cold__))
+-
+-#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+-
+-#ifndef __CHECKER__
+-# define __compiletime_warning(message) __attribute__((warning(message)))
+-# define __compiletime_error(message) __attribute__((error(message)))
+-#endif /* __CHECKER__ */
+-#endif /* GCC_VERSION >= 40300 */
+-
+-#if GCC_VERSION >= 40500
+-/*
+- * Mark a position in code as unreachable.  This can be used to
+- * suppress control flow warnings after asm blocks that transfer
+- * control elsewhere.
+- *
+- * Early snapshots of gcc 4.5 don't support this and we can't detect
+- * this in the preprocessor, but we can live with this because they're
+- * unreleased.  Really, we need to have autoconf for the kernel.
+- */
+-#define unreachable() __builtin_unreachable()
+-
+-/* Mark a function definition as prohibited from being cloned. */
+-#define __noclone	__attribute__((__noclone__))
+-
+-#endif /* GCC_VERSION >= 40500 */
+-
+-#if GCC_VERSION >= 40600
+-/*
+- * Tell the optimizer that something else uses this function or variable.
+- */
+-#define __visible __attribute__((externally_visible))
+-#endif
+-
+-/*
+- * GCC 'asm goto' miscompiles certain code sequences:
+- *
+- *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
+- *
+- * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
+- * Fixed in GCC 4.8.2 and later versions.
+- *
+- * (asm goto is automatically volatile - the naming reflects this.)
+- */
+-#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
+-
+-#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+-#if GCC_VERSION >= 40400
+-#define __HAVE_BUILTIN_BSWAP32__
+-#define __HAVE_BUILTIN_BSWAP64__
+-#endif
+-#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
+-#define __HAVE_BUILTIN_BSWAP16__
+-#endif
+-#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
+diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h
+deleted file mode 100644
+index cdd1cc202d51..000000000000
+--- a/include/linux/compiler-gcc5.h
++++ /dev/null
+@@ -1,66 +0,0 @@
+-#ifndef __LINUX_COMPILER_H
+-#error "Please don't include <linux/compiler-gcc5.h> directly, include <linux/compiler.h> instead."
+-#endif
+-
+-#define __used				__attribute__((__used__))
+-#define __must_check			__attribute__((warn_unused_result))
+-#define __compiler_offsetof(a, b)	__builtin_offsetof(a, b)
+-
+-/* Mark functions as cold. gcc will assume any path leading to a call
+-   to them will be unlikely.  This means a lot of manual unlikely()s
+-   are unnecessary now for any paths leading to the usual suspects
+-   like BUG(), printk(), panic() etc. [but let's keep them for now for
+-   older compilers]
+-
+-   Early snapshots of gcc 4.3 don't support this and we can't detect this
+-   in the preprocessor, but we can live with this because they're unreleased.
+-   Maketime probing would be overkill here.
+-
+-   gcc also has a __attribute__((__hot__)) to move hot functions into
+-   a special section, but I don't see any sense in this right now in
+-   the kernel context */
+-#define __cold			__attribute__((__cold__))
+-
+-#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+-
+-#ifndef __CHECKER__
+-# define __compiletime_warning(message) __attribute__((warning(message)))
+-# define __compiletime_error(message) __attribute__((error(message)))
+-#endif /* __CHECKER__ */
+-
+-/*
+- * Mark a position in code as unreachable.  This can be used to
+- * suppress control flow warnings after asm blocks that transfer
+- * control elsewhere.
+- *
+- * Early snapshots of gcc 4.5 don't support this and we can't detect
+- * this in the preprocessor, but we can live with this because they're
+- * unreleased.  Really, we need to have autoconf for the kernel.
+- */
+-#define unreachable() __builtin_unreachable()
+-
+-/* Mark a function definition as prohibited from being cloned. */
+-#define __noclone	__attribute__((__noclone__))
+-
+-/*
+- * Tell the optimizer that something else uses this function or variable.
+- */
+-#define __visible __attribute__((externally_visible))
+-
+-/*
+- * GCC 'asm goto' miscompiles certain code sequences:
+- *
+- *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
+- *
+- * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
+- * Fixed in GCC 4.8.2 and later versions.
+- *
+- * (asm goto is automatically volatile - the naming reflects this.)
+- */
+-#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
+-
+-#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+-#define __HAVE_BUILTIN_BSWAP32__
+-#define __HAVE_BUILTIN_BSWAP64__
+-#define __HAVE_BUILTIN_BSWAP16__
+-#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
+-- 
+2.11.0
+
diff --git a/board/roseapplepi/patches/uboot/0001-compiler-.h-sync-include-linux-compiler-.h-with-Linu.patch b/board/roseapplepi/patches/uboot/0001-compiler-.h-sync-include-linux-compiler-.h-with-Linu.patch
new file mode 100644
index 0000000000..ae19a49031
--- /dev/null
+++ b/board/roseapplepi/patches/uboot/0001-compiler-.h-sync-include-linux-compiler-.h-with-Linu.patch
@@ -0,0 +1,809 @@ 
+From 9b2c282b348dfe966bbba967dc7a45ce817cce50 Mon Sep 17 00:00:00 2001
+From: Tom Rini <trini@konsulko.com>
+Date: Mon, 29 Feb 2016 11:34:15 -0500
+Subject: [PATCH] compiler*.h: sync include/linux/compiler*.h with Linux
+ 4.5-rc6
+
+Copy these from Linux v4.5-rc6 tag.
+
+This is needed so that we can keep up with newer gcc versions.  Note
+that we don't have the uapi/ hierarchy from the kernel so continue to
+use <linux/types.h>
+
+Signed-off-by: Tom Rini <trini@konsulko.com>
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ include/linux/compiler-gcc.h   | 259 ++++++++++++++++++++++++++++++++---------
+ include/linux/compiler-gcc3.h  |  23 ----
+ include/linux/compiler-gcc4.h  |  88 --------------
+ include/linux/compiler-gcc5.h  |  65 -----------
+ include/linux/compiler-intel.h |   5 +
+ include/linux/compiler.h       | 178 ++++++++++++++++++++++++++--
+ 6 files changed, 383 insertions(+), 235 deletions(-)
+ delete mode 100644 include/linux/compiler-gcc3.h
+ delete mode 100644 include/linux/compiler-gcc4.h
+ delete mode 100644 include/linux/compiler-gcc5.h
+
+diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
+index e057bd2a84..22ab246fee 100644
+--- a/include/linux/compiler-gcc.h
++++ b/include/linux/compiler-gcc.h
+@@ -5,14 +5,28 @@
+ /*
+  * Common definitions for all gcc versions go here.
+  */
+-#define GCC_VERSION (__GNUC__ * 10000 \
+-		   + __GNUC_MINOR__ * 100 \
+-		   + __GNUC_PATCHLEVEL__)
+-
++#define GCC_VERSION (__GNUC__ * 10000		\
++		     + __GNUC_MINOR__ * 100	\
++		     + __GNUC_PATCHLEVEL__)
+ 
+ /* Optimization barrier */
++
+ /* The "volatile" is due to gcc bugs */
+ #define barrier() __asm__ __volatile__("": : :"memory")
++/*
++ * This version is i.e. to prevent dead stores elimination on @ptr
++ * where gcc and llvm may behave differently when otherwise using
++ * normal barrier(): while gcc behavior gets along with a normal
++ * barrier(), llvm needs an explicit input variable to be assumed
++ * clobbered. The issue is as follows: while the inline asm might
++ * access any memory it wants, the compiler could have fit all of
++ * @ptr into memory registers instead, and since @ptr never escaped
++ * from that, it proofed that the inline asm wasn't touching any of
++ * it. This version works well with both compilers, i.e. we're telling
++ * the compiler that the inline asm absolutely may see the contents
++ * of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
++ */
++#define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
+ 
+ /*
+  * This macro obfuscates arithmetic on a variable address so that gcc
+@@ -32,58 +46,63 @@
+  * the inline assembly constraint from =g to =r, in this particular
+  * case either is valid.
+  */
+-#define RELOC_HIDE(ptr, off)					\
+-  ({ unsigned long __ptr;					\
+-    __asm__ ("" : "=r"(__ptr) : "0"(ptr));		\
+-    (typeof(ptr)) (__ptr + (off)); })
++#define RELOC_HIDE(ptr, off)						\
++({									\
++	unsigned long __ptr;						\
++	__asm__ ("" : "=r"(__ptr) : "0"(ptr));				\
++	(typeof(ptr)) (__ptr + (off));					\
++})
+ 
+ /* Make the optimizer believe the variable can be manipulated arbitrarily. */
+-#define OPTIMIZER_HIDE_VAR(var) __asm__ ("" : "=r" (var) : "0" (var))
++#define OPTIMIZER_HIDE_VAR(var)						\
++	__asm__ ("" : "=r" (var) : "0" (var))
+ 
+ #ifdef __CHECKER__
+-#define __must_be_array(arr) 0
++#define __must_be_array(a)	0
+ #else
+ /* &a[0] degrades to a pointer: a different type from an array */
+-#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
++#define __must_be_array(a)	BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
+ #endif
+ 
+ /*
+  * Force always-inline if the user requests it so via the .config,
+  * or if gcc is too old:
+  */
+-#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
++#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) ||		\
+     !defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
+-# define inline		inline		__attribute__((always_inline)) notrace
+-# define __inline__	__inline__	__attribute__((always_inline)) notrace
+-# define __inline	__inline	__attribute__((always_inline)) notrace
++#define inline		inline		__attribute__((always_inline)) notrace
++#define __inline__	__inline__	__attribute__((always_inline)) notrace
++#define __inline	__inline	__attribute__((always_inline)) notrace
+ #else
+ /* A lot of inline functions can cause havoc with function tracing */
+-# define inline		inline		notrace
+-# define __inline__	__inline__	notrace
+-# define __inline	__inline	notrace
++#define inline		inline		notrace
++#define __inline__	__inline__	notrace
++#define __inline	__inline	notrace
+ #endif
+ 
+-#define __deprecated			__attribute__((deprecated))
+-#ifndef __packed
+-#define __packed			__attribute__((packed))
+-#endif
+-#ifndef __weak
+-#define __weak				__attribute__((weak))
+-#endif
++#define __always_inline	inline __attribute__((always_inline))
++#define  noinline	__attribute__((noinline))
++
++#define __deprecated	__attribute__((deprecated))
++#define __packed	__attribute__((packed))
++#define __weak		__attribute__((weak))
++#define __alias(symbol)	__attribute__((alias(#symbol)))
+ 
+ /*
+- * it doesn't make sense on ARM (currently the only user of __naked) to trace
+- * naked functions because then mcount is called without stack and frame pointer
+- * being set up and there is no chance to restore the lr register to the value
+- * before mcount was called.
++ * it doesn't make sense on ARM (currently the only user of __naked)
++ * to trace naked functions because then mcount is called without
++ * stack and frame pointer being set up and there is no chance to
++ * restore the lr register to the value before mcount was called.
++ *
++ * The asm() bodies of naked functions often depend on standard calling
++ * conventions, therefore they must be noinline and noclone.
+  *
+- * The asm() bodies of naked functions often depend on standard calling conventions,
+- * therefore they must be noinline and noclone.  GCC 4.[56] currently fail to enforce
+- * this, so we must do so ourselves.  See GCC PR44290.
++ * GCC 4.[56] currently fail to enforce this, so we must do so ourselves.
++ * See GCC PR44290.
+  */
+-#define __naked				__attribute__((naked)) noinline __noclone notrace
++#define __naked		__attribute__((naked)) noinline __noclone notrace
+ 
+-#define __noreturn			__attribute__((noreturn))
++#define __noreturn	__attribute__((noreturn))
+ 
+ /*
+  * From the GCC manual:
+@@ -95,34 +114,170 @@
+  * would be.
+  * [...]
+  */
+-#ifndef __pure
+-#define __pure				__attribute__((pure))
++#define __pure			__attribute__((pure))
++#define __aligned(x)		__attribute__((aligned(x)))
++#define __printf(a, b)		__attribute__((format(printf, a, b)))
++#define __scanf(a, b)		__attribute__((format(scanf, a, b)))
++#define __attribute_const__	__attribute__((__const__))
++#define __maybe_unused		__attribute__((unused))
++#define __always_unused		__attribute__((unused))
++
++/* gcc version specific checks */
++
++#if GCC_VERSION < 30200
++# error Sorry, your compiler is too old - please upgrade it.
++#endif
++
++#if GCC_VERSION < 30300
++# define __used			__attribute__((__unused__))
++#else
++# define __used			__attribute__((__used__))
++#endif
++
++#ifdef CONFIG_GCOV_KERNEL
++# if GCC_VERSION < 30400
++#   error "GCOV profiling support for gcc versions below 3.4 not included"
++# endif /* __GNUC_MINOR__ */
++#endif /* CONFIG_GCOV_KERNEL */
++
++#if GCC_VERSION >= 30400
++#define __must_check		__attribute__((warn_unused_result))
++#endif
++
++#if GCC_VERSION >= 40000
++
++/* GCC 4.1.[01] miscompiles __weak */
++#ifdef __KERNEL__
++# if GCC_VERSION >= 40100 &&  GCC_VERSION <= 40101
++#  error Your version of gcc miscompiles the __weak directive
++# endif
++#endif
++
++#define __used			__attribute__((__used__))
++#define __compiler_offsetof(a, b)					\
++	__builtin_offsetof(a, b)
++
++#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
++# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
++#endif
++
++#if GCC_VERSION >= 40300
++/* Mark functions as cold. gcc will assume any path leading to a call
++ * to them will be unlikely.  This means a lot of manual unlikely()s
++ * are unnecessary now for any paths leading to the usual suspects
++ * like BUG(), printk(), panic() etc. [but let's keep them for now for
++ * older compilers]
++ *
++ * Early snapshots of gcc 4.3 don't support this and we can't detect this
++ * in the preprocessor, but we can live with this because they're unreleased.
++ * Maketime probing would be overkill here.
++ *
++ * gcc also has a __attribute__((__hot__)) to move hot functions into
++ * a special section, but I don't see any sense in this right now in
++ * the kernel context
++ */
++#define __cold			__attribute__((__cold__))
++
++#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
++
++#ifndef __CHECKER__
++# define __compiletime_warning(message) __attribute__((warning(message)))
++# define __compiletime_error(message) __attribute__((error(message)))
++#endif /* __CHECKER__ */
++#endif /* GCC_VERSION >= 40300 */
++
++#if GCC_VERSION >= 40500
++/*
++ * Mark a position in code as unreachable.  This can be used to
++ * suppress control flow warnings after asm blocks that transfer
++ * control elsewhere.
++ *
++ * Early snapshots of gcc 4.5 don't support this and we can't detect
++ * this in the preprocessor, but we can live with this because they're
++ * unreleased.  Really, we need to have autoconf for the kernel.
++ */
++#define unreachable() __builtin_unreachable()
++
++/* Mark a function definition as prohibited from being cloned. */
++#define __noclone	__attribute__((__noclone__))
++
++#endif /* GCC_VERSION >= 40500 */
++
++#if GCC_VERSION >= 40600
++/*
++ * When used with Link Time Optimization, gcc can optimize away C functions or
++ * variables which are referenced only from assembly code.  __visible tells the
++ * optimizer that something else uses this function or variable, thus preventing
++ * this.
++ */
++#define __visible	__attribute__((externally_visible))
+ #endif
+-#ifndef __aligned
+-#define __aligned(x)			__attribute__((aligned(x)))
++
++
++#if GCC_VERSION >= 40900 && !defined(__CHECKER__)
++/*
++ * __assume_aligned(n, k): Tell the optimizer that the returned
++ * pointer can be assumed to be k modulo n. The second argument is
++ * optional (default 0), so we use a variadic macro to make the
++ * shorthand.
++ *
++ * Beware: Do not apply this to functions which may return
++ * ERR_PTRs. Also, it is probably unwise to apply it to functions
++ * returning extra information in the low bits (but in that case the
++ * compiler should see some alignment anyway, when the return value is
++ * massaged by 'flags = ptr & 3; ptr &= ~3;').
++ */
++#define __assume_aligned(a, ...) __attribute__((__assume_aligned__(a, ## __VA_ARGS__)))
+ #endif
+-#define __printf(a, b)			__attribute__((format(printf, a, b)))
+-#define __scanf(a, b)			__attribute__((format(scanf, a, b)))
+-#define  noinline			__attribute__((noinline))
+-#define __attribute_const__		__attribute__((__const__))
+-#define __maybe_unused			__attribute__((unused))
+-#define __always_unused			__attribute__((unused))
+ 
+-#define __gcc_header(x) #x
+-#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
+-#define gcc_header(x) _gcc_header(x)
+-#include gcc_header(__GNUC__)
++/*
++ * GCC 'asm goto' miscompiles certain code sequences:
++ *
++ *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
++ *
++ * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
++ *
++ * (asm goto is automatically volatile - the naming reflects this.)
++ */
++#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
++
++#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
++#if GCC_VERSION >= 40400
++#define __HAVE_BUILTIN_BSWAP32__
++#define __HAVE_BUILTIN_BSWAP64__
++#endif
++#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
++#define __HAVE_BUILTIN_BSWAP16__
++#endif
++#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
++
++#if GCC_VERSION >= 50000
++#define KASAN_ABI_VERSION 4
++#elif GCC_VERSION >= 40902
++#define KASAN_ABI_VERSION 3
++#endif
++
++#if GCC_VERSION >= 40902
++/*
++ * Tell the compiler that address safety instrumentation (KASAN)
++ * should not be applied to that function.
++ * Conflicts with inlining: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
++ */
++#define __no_sanitize_address __attribute__((no_sanitize_address))
++#endif
++
++#endif	/* gcc version >= 40000 specific checks */
+ 
+ #if !defined(__noclone)
+ #define __noclone	/* not needed */
+ #endif
+ 
++#if !defined(__no_sanitize_address)
++#define __no_sanitize_address
++#endif
++
+ /*
+  * A trick to suppress uninitialized variable warning without generating any
+  * code
+  */
+ #define uninitialized_var(x) x = x
+-
+-#ifndef __always_inline
+-#define __always_inline		inline __attribute__((always_inline))
+-#endif
+diff --git a/include/linux/compiler-gcc3.h b/include/linux/compiler-gcc3.h
+deleted file mode 100644
+index 7d89febe4d..0000000000
+--- a/include/linux/compiler-gcc3.h
++++ /dev/null
+@@ -1,23 +0,0 @@
+-#ifndef __LINUX_COMPILER_H
+-#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
+-#endif
+-
+-#if GCC_VERSION < 30200
+-# error Sorry, your compiler is too old - please upgrade it.
+-#endif
+-
+-#if GCC_VERSION >= 30300
+-# define __used			__attribute__((__used__))
+-#else
+-# define __used			__attribute__((__unused__))
+-#endif
+-
+-#if GCC_VERSION >= 30400
+-#define __must_check		__attribute__((warn_unused_result))
+-#endif
+-
+-#ifdef CONFIG_GCOV_KERNEL
+-# if GCC_VERSION < 30400
+-#   error "GCOV profiling support for gcc versions below 3.4 not included"
+-# endif /* __GNUC_MINOR__ */
+-#endif /* CONFIG_GCOV_KERNEL */
+diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
+deleted file mode 100644
+index 2507fd2a1e..0000000000
+--- a/include/linux/compiler-gcc4.h
++++ /dev/null
+@@ -1,88 +0,0 @@
+-#ifndef __LINUX_COMPILER_H
+-#error "Please don't include <linux/compiler-gcc4.h> directly, include <linux/compiler.h> instead."
+-#endif
+-
+-/* GCC 4.1.[01] miscompiles __weak */
+-#ifdef __KERNEL__
+-# if GCC_VERSION >= 40100 &&  GCC_VERSION <= 40101
+-#  error Your version of gcc miscompiles the __weak directive
+-# endif
+-#endif
+-
+-#define __used			__attribute__((__used__))
+-#define __must_check 		__attribute__((warn_unused_result))
+-#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
+-
+-#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
+-# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
+-#endif
+-
+-#if GCC_VERSION >= 40300
+-/* Mark functions as cold. gcc will assume any path leading to a call
+-   to them will be unlikely.  This means a lot of manual unlikely()s
+-   are unnecessary now for any paths leading to the usual suspects
+-   like BUG(), printk(), panic() etc. [but let's keep them for now for
+-   older compilers]
+-
+-   Early snapshots of gcc 4.3 don't support this and we can't detect this
+-   in the preprocessor, but we can live with this because they're unreleased.
+-   Maketime probing would be overkill here.
+-
+-   gcc also has a __attribute__((__hot__)) to move hot functions into
+-   a special section, but I don't see any sense in this right now in
+-   the kernel context */
+-#define __cold			__attribute__((__cold__))
+-
+-#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+-
+-#ifndef __CHECKER__
+-# define __compiletime_warning(message) __attribute__((warning(message)))
+-# define __compiletime_error(message) __attribute__((error(message)))
+-#endif /* __CHECKER__ */
+-#endif /* GCC_VERSION >= 40300 */
+-
+-#if GCC_VERSION >= 40500
+-/*
+- * Mark a position in code as unreachable.  This can be used to
+- * suppress control flow warnings after asm blocks that transfer
+- * control elsewhere.
+- *
+- * Early snapshots of gcc 4.5 don't support this and we can't detect
+- * this in the preprocessor, but we can live with this because they're
+- * unreleased.  Really, we need to have autoconf for the kernel.
+- */
+-#define unreachable() __builtin_unreachable()
+-
+-/* Mark a function definition as prohibited from being cloned. */
+-#define __noclone	__attribute__((__noclone__))
+-
+-#endif /* GCC_VERSION >= 40500 */
+-
+-#if GCC_VERSION >= 40600
+-/*
+- * Tell the optimizer that something else uses this function or variable.
+- */
+-#define __visible __attribute__((externally_visible))
+-#endif
+-
+-/*
+- * GCC 'asm goto' miscompiles certain code sequences:
+- *
+- *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
+- *
+- * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
+- * Fixed in GCC 4.8.2 and later versions.
+- *
+- * (asm goto is automatically volatile - the naming reflects this.)
+- */
+-#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
+-
+-#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+-#if GCC_VERSION >= 40400
+-#define __HAVE_BUILTIN_BSWAP32__
+-#define __HAVE_BUILTIN_BSWAP64__
+-#endif
+-#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
+-#define __HAVE_BUILTIN_BSWAP16__
+-#endif
+-#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
+diff --git a/include/linux/compiler-gcc5.h b/include/linux/compiler-gcc5.h
+deleted file mode 100644
+index c8c5659525..0000000000
+--- a/include/linux/compiler-gcc5.h
++++ /dev/null
+@@ -1,65 +0,0 @@
+-#ifndef __LINUX_COMPILER_H
+-#error "Please don't include <linux/compiler-gcc5.h> directly, include <linux/compiler.h> instead."
+-#endif
+-
+-#define __used				__attribute__((__used__))
+-#define __must_check			__attribute__((warn_unused_result))
+-#define __compiler_offsetof(a, b)	__builtin_offsetof(a, b)
+-
+-/* Mark functions as cold. gcc will assume any path leading to a call
+-   to them will be unlikely.  This means a lot of manual unlikely()s
+-   are unnecessary now for any paths leading to the usual suspects
+-   like BUG(), printk(), panic() etc. [but let's keep them for now for
+-   older compilers]
+-
+-   Early snapshots of gcc 4.3 don't support this and we can't detect this
+-   in the preprocessor, but we can live with this because they're unreleased.
+-   Maketime probing would be overkill here.
+-
+-   gcc also has a __attribute__((__hot__)) to move hot functions into
+-   a special section, but I don't see any sense in this right now in
+-   the kernel context */
+-#define __cold			__attribute__((__cold__))
+-
+-#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+-
+-#ifndef __CHECKER__
+-# define __compiletime_warning(message) __attribute__((warning(message)))
+-# define __compiletime_error(message) __attribute__((error(message)))
+-#endif /* __CHECKER__ */
+-
+-/*
+- * Mark a position in code as unreachable.  This can be used to
+- * suppress control flow warnings after asm blocks that transfer
+- * control elsewhere.
+- *
+- * Early snapshots of gcc 4.5 don't support this and we can't detect
+- * this in the preprocessor, but we can live with this because they're
+- * unreleased.  Really, we need to have autoconf for the kernel.
+- */
+-#define unreachable() __builtin_unreachable()
+-
+-/* Mark a function definition as prohibited from being cloned. */
+-#define __noclone	__attribute__((__noclone__))
+-
+-/*
+- * Tell the optimizer that something else uses this function or variable.
+- */
+-#define __visible __attribute__((externally_visible))
+-
+-/*
+- * GCC 'asm goto' miscompiles certain code sequences:
+- *
+- *   http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58670
+- *
+- * Work it around via a compiler barrier quirk suggested by Jakub Jelinek.
+- *
+- * (asm goto is automatically volatile - the naming reflects this.)
+- */
+-#define asm_volatile_goto(x...)	do { asm goto(x); asm (""); } while (0)
+-
+-#ifdef CONFIG_ARCH_USE_BUILTIN_BSWAP
+-#define __HAVE_BUILTIN_BSWAP32__
+-#define __HAVE_BUILTIN_BSWAP64__
+-#define __HAVE_BUILTIN_BSWAP16__
+-#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
+diff --git a/include/linux/compiler-intel.h b/include/linux/compiler-intel.h
+index ba147a1727..d4c71132d0 100644
+--- a/include/linux/compiler-intel.h
++++ b/include/linux/compiler-intel.h
+@@ -13,9 +13,14 @@
+ /* Intel ECC compiler doesn't support gcc specific asm stmts.
+  * It uses intrinsics to do the equivalent things.
+  */
++#undef barrier
++#undef barrier_data
+ #undef RELOC_HIDE
+ #undef OPTIMIZER_HIDE_VAR
+ 
++#define barrier() __memory_barrier()
++#define barrier_data(ptr) barrier()
++
+ #define RELOC_HIDE(ptr, off)					\
+   ({ unsigned long __ptr;					\
+      __ptr = (unsigned long) (ptr);				\
+diff --git a/include/linux/compiler.h b/include/linux/compiler.h
+index d5ad7b1118..020ad16a04 100644
+--- a/include/linux/compiler.h
++++ b/include/linux/compiler.h
+@@ -17,6 +17,7 @@
+ # define __release(x)	__context__(x,-1)
+ # define __cond_lock(x,c)	((c) ? ({ __acquire(x); 1; }) : 0)
+ # define __percpu	__attribute__((noderef, address_space(3)))
++# define __pmem		__attribute__((noderef, address_space(5)))
+ #ifdef CONFIG_SPARSE_RCU_POINTER
+ # define __rcu		__attribute__((noderef, address_space(4)))
+ #else
+@@ -42,6 +43,7 @@ extern void __chk_io_ptr(const volatile void __iomem *);
+ # define __cond_lock(x,c) (c)
+ # define __percpu
+ # define __rcu
++# define __pmem
+ #endif
+ 
+ /* Indirect macros required for expanded argument pasting, eg. __LINE__. */
+@@ -54,7 +56,11 @@ extern void __chk_io_ptr(const volatile void __iomem *);
+ #include <linux/compiler-gcc.h>
+ #endif
+ 
++#if defined(CC_USING_HOTPATCH) && !defined(__CHECKER__)
++#define notrace __attribute__((hotpatch(0,0)))
++#else
+ #define notrace __attribute__((no_instrument_function))
++#endif
+ 
+ /* Intel compiler defines __GNUC__. So we will overwrite implementations
+  * coming from above header files here
+@@ -138,7 +144,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+  */
+ #define if(cond, ...) __trace_if( (cond , ## __VA_ARGS__) )
+ #define __trace_if(cond) \
+-	if (__builtin_constant_p((cond)) ? !!(cond) :			\
++	if (__builtin_constant_p(!!(cond)) ? !!(cond) :			\
+ 	({								\
+ 		int ______r;						\
+ 		static struct ftrace_branch_data			\
+@@ -165,6 +171,10 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ # define barrier() __memory_barrier()
+ #endif
+ 
++#ifndef barrier_data
++# define barrier_data(ptr) barrier()
++#endif
++
+ /* Unreachable code */
+ #ifndef unreachable
+ # define unreachable() do { } while (1)
+@@ -186,6 +196,126 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ # define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
+ #endif
+ 
++#include <linux/types.h>
++
++#define __READ_ONCE_SIZE						\
++({									\
++	switch (size) {							\
++	case 1: *(__u8 *)res = *(volatile __u8 *)p; break;		\
++	case 2: *(__u16 *)res = *(volatile __u16 *)p; break;		\
++	case 4: *(__u32 *)res = *(volatile __u32 *)p; break;		\
++	case 8: *(__u64 *)res = *(volatile __u64 *)p; break;		\
++	default:							\
++		barrier();						\
++		__builtin_memcpy((void *)res, (const void *)p, size);	\
++		barrier();						\
++	}								\
++})
++
++static __always_inline
++void __read_once_size(const volatile void *p, void *res, int size)
++{
++	__READ_ONCE_SIZE;
++}
++
++#ifdef CONFIG_KASAN
++/*
++ * This function is not 'inline' because __no_sanitize_address confilcts
++ * with inlining. Attempt to inline it may cause a build failure.
++ * 	https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67368
++ * '__maybe_unused' allows us to avoid defined-but-not-used warnings.
++ */
++static __no_sanitize_address __maybe_unused
++void __read_once_size_nocheck(const volatile void *p, void *res, int size)
++{
++	__READ_ONCE_SIZE;
++}
++#else
++static __always_inline
++void __read_once_size_nocheck(const volatile void *p, void *res, int size)
++{
++	__READ_ONCE_SIZE;
++}
++#endif
++
++static __always_inline void __write_once_size(volatile void *p, void *res, int size)
++{
++	switch (size) {
++	case 1: *(volatile __u8 *)p = *(__u8 *)res; break;
++	case 2: *(volatile __u16 *)p = *(__u16 *)res; break;
++	case 4: *(volatile __u32 *)p = *(__u32 *)res; break;
++	case 8: *(volatile __u64 *)p = *(__u64 *)res; break;
++	default:
++		barrier();
++		__builtin_memcpy((void *)p, (const void *)res, size);
++		barrier();
++	}
++}
++
++/*
++ * Prevent the compiler from merging or refetching reads or writes. The
++ * compiler is also forbidden from reordering successive instances of
++ * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the
++ * compiler is aware of some particular ordering.  One way to make the
++ * compiler aware of ordering is to put the two invocations of READ_ONCE,
++ * WRITE_ONCE or ACCESS_ONCE() in different C statements.
++ *
++ * In contrast to ACCESS_ONCE these two macros will also work on aggregate
++ * data types like structs or unions. If the size of the accessed data
++ * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)
++ * READ_ONCE() and WRITE_ONCE()  will fall back to memcpy and print a
++ * compile-time warning.
++ *
++ * Their two major use cases are: (1) Mediating communication between
++ * process-level code and irq/NMI handlers, all running on the same CPU,
++ * and (2) Ensuring that the compiler does not  fold, spindle, or otherwise
++ * mutilate accesses that either do not require ordering or that interact
++ * with an explicit memory barrier or atomic instruction that provides the
++ * required ordering.
++ */
++
++#define __READ_ONCE(x, check)						\
++({									\
++	union { typeof(x) __val; char __c[1]; } __u;			\
++	if (check)							\
++		__read_once_size(&(x), __u.__c, sizeof(x));		\
++	else								\
++		__read_once_size_nocheck(&(x), __u.__c, sizeof(x));	\
++	__u.__val;							\
++})
++#define READ_ONCE(x) __READ_ONCE(x, 1)
++
++/*
++ * Use READ_ONCE_NOCHECK() instead of READ_ONCE() if you need
++ * to hide memory access from KASAN.
++ */
++#define READ_ONCE_NOCHECK(x) __READ_ONCE(x, 0)
++
++#define WRITE_ONCE(x, val) \
++({							\
++	union { typeof(x) __val; char __c[1]; } __u =	\
++		{ .__val = (__force typeof(x)) (val) }; \
++	__write_once_size(&(x), __u.__c, sizeof(x));	\
++	__u.__val;					\
++})
++
++/**
++ * smp_cond_acquire() - Spin wait for cond with ACQUIRE ordering
++ * @cond: boolean expression to wait for
++ *
++ * Equivalent to using smp_load_acquire() on the condition variable but employs
++ * the control dependency of the wait to reduce the barrier on many platforms.
++ *
++ * The control dependency provides a LOAD->STORE order, the additional RMB
++ * provides LOAD->LOAD order, together they provide LOAD->{LOAD,STORE} order,
++ * aka. ACQUIRE.
++ */
++#define smp_cond_acquire(cond)	do {		\
++	while (!(cond))				\
++		cpu_relax();			\
++	smp_rmb(); /* ctrl + rmb := acquire */	\
++} while (0)
++
+ #endif /* __KERNEL__ */
+ 
+ #endif /* __ASSEMBLY__ */
+@@ -304,6 +434,14 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ #define __visible
+ #endif
+ 
++/*
++ * Assume alignment of return value.
++ */
++#ifndef __assume_aligned
++#define __assume_aligned(a, ...)
++#endif
++
++
+ /* Are two types/vars the same type (ignoring qualifiers)? */
+ #ifndef __same_type
+ # define __same_type(a, b) __builtin_types_compatible_p(typeof(a), typeof(b))
+@@ -311,7 +449,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+ 
+ /* Is this type a native word size -- useful for atomic operations */
+ #ifndef __native_word
+-# define __native_word(t) (sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
++# define __native_word(t) (sizeof(t) == sizeof(char) || sizeof(t) == sizeof(short) || sizeof(t) == sizeof(int) || sizeof(t) == sizeof(long))
+ #endif
+ 
+ /* Compile time object size, -1 for unknown */
+@@ -373,12 +511,38 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
+  * to make the compiler aware of ordering is to put the two invocations of
+  * ACCESS_ONCE() in different C statements.
+  *
+- * This macro does absolutely -nothing- to prevent the CPU from reordering,
+- * merging, or refetching absolutely anything at any time.  Its main intended
+- * use is to mediate communication between process-level code and irq/NMI
+- * handlers, all running on the same CPU.
++ * ACCESS_ONCE will only work on scalar types. For union types, ACCESS_ONCE
++ * on a union member will work as long as the size of the member matches the
++ * size of the union and the size is smaller than word size.
++ *
++ * The major use cases of ACCESS_ONCE used to be (1) Mediating communication
++ * between process-level code and irq/NMI handlers, all running on the same CPU,
++ * and (2) Ensuring that the compiler does not  fold, spindle, or otherwise
++ * mutilate accesses that either do not require ordering or that interact
++ * with an explicit memory barrier or atomic instruction that provides the
++ * required ordering.
++ *
++ * If possible use READ_ONCE()/WRITE_ONCE() instead.
++ */
++#define __ACCESS_ONCE(x) ({ \
++	 __maybe_unused typeof(x) __var = (__force typeof(x)) 0; \
++	(volatile typeof(x) *)&(x); })
++#define ACCESS_ONCE(x) (*__ACCESS_ONCE(x))
++
++/**
++ * lockless_dereference() - safely load a pointer for later dereference
++ * @p: The pointer to load
++ *
++ * Similar to rcu_dereference(), but for situations where the pointed-to
++ * object's lifetime is managed by something other than RCU.  That
++ * "something other" might be reference counting or simple immortality.
+  */
+-#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
++#define lockless_dereference(p) \
++({ \
++	typeof(p) _________p1 = READ_ONCE(p); \
++	smp_read_barrier_depends(); /* Dependency order vs. p above. */ \
++	(_________p1); \
++})
+ 
+ /* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
+ #ifdef CONFIG_KPROBES
+-- 
+2.11.0
+