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uboot-imx6: fix build with GCC 7

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Backport the compiler support patches from upstream u-boot to this older
version to make it compile with GCC 7.
This was found by build bot.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
master
Hauke Mehrtens 7 years ago
parent d482356322
commit 43f35ce971
4 changed files with 1344 additions and 5 deletions
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  1. 480
      package/boot/uboot-imx6/patches/101-gcc-compiler-linux-3-16.patch
  2. 69
      package/boot/uboot-imx6/patches/102-compiler_gcc-prevent-redefining-attributes.patch
  3. 10
      package/boot/uboot-imx6/patches/103-Add-linux-compiler-gcc5.h-to-fix-builds-with-gcc5.patch
  4. 790
      package/boot/uboot-imx6/patches/104-gcc-compiler-linux-4-5.patch

480
package/boot/uboot-imx6/patches/101-gcc-compiler-linux-3-16.patch
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@ -0,0 +1,480 @@
From fb8ffd7cfc68b3dc44e182356a207d784cb30b34 Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <yamada.m@jp.panasonic.com>
Date: Thu, 4 Sep 2014 02:40:58 +0900
Subject: compiler*.h: sync include/linux/compiler*.h with Linux 3.16
Copy them from Linux v3.16 tag.
My main motivation of this commit is to add compiler-clang.h.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Jeroen Hofstee <jeroen@myspectrum.nl>
---
include/linux/compiler-clang.h | 12 ++++++
include/linux/compiler-gcc.h | 57 ++++++++++++++++++--------
include/linux/compiler-gcc3.h | 20 ++++-----
include/linux/compiler-gcc4.h | 59 +++++++++++++++++++--------
include/linux/compiler-intel.h | 40 ++++++++++++++++++
include/linux/compiler.h | 92 +++++++++++++++++++++++++++++++++++++++++-
6 files changed, 236 insertions(+), 44 deletions(-)
create mode 100644 include/linux/compiler-clang.h
create mode 100644 include/linux/compiler-intel.h
--- /dev/null
+++ b/include/linux/compiler-clang.h
@@ -0,0 +1,12 @@
+#ifndef __LINUX_COMPILER_H
+#error "Please don't include <linux/compiler-clang.h> directly, include <linux/compiler.h> instead."
+#endif
+
+/* Some compiler specific definitions are overwritten here
+ * for Clang compiler
+ */
+
+#ifdef uninitialized_var
+#undef uninitialized_var
+#define uninitialized_var(x) x = *(&(x))
+#endif
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -5,6 +5,9 @@
/*
* Common definitions for all gcc versions go here.
*/
+#define GCC_VERSION (__GNUC__ * 10000 \
+ + __GNUC_MINOR__ * 100 \
+ + __GNUC_PATCHLEVEL__)
/* Optimization barrier */
@@ -34,9 +37,15 @@
__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))
+
+#ifdef __CHECKER__
+#define __must_be_array(arr) 0
+#else
/* &a[0] degrades to a pointer: a different type from an array */
-#define __must_be_array(a) \
- BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(typeof(a), typeof(&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,
@@ -44,15 +53,18 @@
*/
#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
!defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
-# define inline inline __attribute__((always_inline))
-# define __inline__ __inline__ __attribute__((always_inline))
-# define __inline __inline __attribute__((always_inline))
+# 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
#endif
#define __deprecated __attribute__((deprecated))
-#ifndef __packed
-# define __packed __attribute__((packed))
-#endif
+#define __packed __attribute__((packed))
#define __weak __attribute__((weak))
/*
@@ -60,8 +72,12 @@
* 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. GCC 4.[56] currently fail to enforce
+ * this, so we must do so ourselves. See GCC PR44290.
*/
-#define __naked __attribute__((naked)) notrace
+#define __naked __attribute__((naked)) noinline __noclone notrace
#define __noreturn __attribute__((noreturn))
@@ -75,13 +91,10 @@
* would be.
* [...]
*/
-#ifndef __pure
-# define __pure __attribute__((pure))
-#endif
-#ifndef __aligned
-# define __aligned(x) __attribute__((aligned(x)))
-#endif
-#define __printf(a,b) __attribute__((format(printf,a,b)))
+#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 noinline __attribute__((noinline))
#define __attribute_const__ __attribute__((__const__))
#define __maybe_unused __attribute__((unused))
@@ -91,3 +104,15 @@
#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
#define gcc_header(x) _gcc_header(x)
#include gcc_header(__GNUC__)
+
+#if !defined(__noclone)
+#define __noclone /* not needed */
+#endif
+
+/*
+ * A trick to suppress uninitialized variable warning without generating any
+ * code
+ */
+#define uninitialized_var(x) x = x
+
+#define __always_inline inline __attribute__((always_inline))
--- a/include/linux/compiler-gcc3.h
+++ b/include/linux/compiler-gcc3.h
@@ -2,20 +2,22 @@
#error "Please don't include <linux/compiler-gcc3.h> directly, include <linux/compiler.h> instead."
#endif
-#if __GNUC_MINOR__ >= 3
+#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 __GNUC_MINOR__ >= 4
+#if GCC_VERSION >= 30400
#define __must_check __attribute__((warn_unused_result))
#endif
-/*
- * A trick to suppress uninitialized variable warning without generating any
- * code
- */
-#define uninitialized_var(x) x = x
-
-#define __always_inline inline __attribute__((always_inline))
+#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 */
--- a/include/linux/compiler-gcc4.h
+++ b/include/linux/compiler-gcc4.h
@@ -4,7 +4,7 @@
/* GCC 4.1.[01] miscompiles __weak */
#ifdef __KERNEL__
-# if __GNUC_MINOR__ == 1 && __GNUC_PATCHLEVEL__ <= 1
+# if GCC_VERSION >= 40100 && GCC_VERSION <= 40101
# error Your version of gcc miscompiles the __weak directive
# endif
#endif
@@ -12,17 +12,12 @@
#define __used __attribute__((__used__))
#define __must_check __attribute__((warn_unused_result))
#define __compiler_offsetof(a,b) __builtin_offsetof(a,b)
-#ifndef __always_inline
-# define __always_inline inline __attribute__((always_inline))
-#endif
-/*
- * A trick to suppress uninitialized variable warning without generating any
- * code
- */
-#define uninitialized_var(x) x = x
+#if GCC_VERSION >= 40100 && GCC_VERSION < 40600
+# define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
+#endif
-#if __GNUC_MINOR__ >= 3
+#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
@@ -38,8 +33,15 @@
the kernel context */
#define __cold __attribute__((__cold__))
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
-#if __GNUC_MINOR__ >= 5
+#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
@@ -50,14 +52,37 @@
* unreleased. Really, we need to have autoconf for the kernel.
*/
#define unreachable() __builtin_unreachable()
-#endif
+/* 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
-#if __GNUC_MINOR__ > 0
-#define __compiletime_object_size(obj) __builtin_object_size(obj, 0)
+/*
+ * 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 __GNUC_MINOR__ >= 4
-#define __compiletime_warning(message) __attribute__((warning(message)))
-#define __compiletime_error(message) __attribute__((error(message)))
+#if GCC_VERSION >= 40800 || (defined(__powerpc__) && GCC_VERSION >= 40600)
+#define __HAVE_BUILTIN_BSWAP16__
#endif
+#endif /* CONFIG_ARCH_USE_BUILTIN_BSWAP */
--- /dev/null
+++ b/include/linux/compiler-intel.h
@@ -0,0 +1,40 @@
+#ifndef __LINUX_COMPILER_H
+#error "Please don't include <linux/compiler-intel.h> directly, include <linux/compiler.h> instead."
+#endif
+
+#ifdef __ECC
+
+/* Some compiler specific definitions are overwritten here
+ * for Intel ECC compiler
+ */
+
+#include <asm/intrinsics.h>
+
+/* Intel ECC compiler doesn't support gcc specific asm stmts.
+ * It uses intrinsics to do the equivalent things.
+ */
+#undef RELOC_HIDE
+#undef OPTIMIZER_HIDE_VAR
+
+#define RELOC_HIDE(ptr, off) \
+ ({ unsigned long __ptr; \
+ __ptr = (unsigned long) (ptr); \
+ (typeof(ptr)) (__ptr + (off)); })
+
+/* This should act as an optimization barrier on var.
+ * Given that this compiler does not have inline assembly, a compiler barrier
+ * is the best we can do.
+ */
+#define OPTIMIZER_HIDE_VAR(var) barrier()
+
+/* Intel ECC compiler doesn't support __builtin_types_compatible_p() */
+#define __must_be_array(a) 0
+
+#endif
+
+#ifndef __HAVE_BUILTIN_BSWAP16__
+/* icc has this, but it's called _bswap16 */
+#define __HAVE_BUILTIN_BSWAP16__
+#define __builtin_bswap16 _bswap16
+#endif
+
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -5,16 +5,23 @@
#ifdef __CHECKER__
# define __user __attribute__((noderef, address_space(1)))
-# define __kernel /* default address space */
+# define __kernel __attribute__((address_space(0)))
# define __safe __attribute__((safe))
# define __force __attribute__((force))
# define __nocast __attribute__((nocast))
# define __iomem __attribute__((noderef, address_space(2)))
+# define __must_hold(x) __attribute__((context(x,1,1)))
# define __acquires(x) __attribute__((context(x,0,1)))
# define __releases(x) __attribute__((context(x,1,0)))
# define __acquire(x) __context__(x,1)
# define __release(x) __context__(x,-1)
# define __cond_lock(x,c) ((c) ? ({ __acquire(x); 1; }) : 0)
+# define __percpu __attribute__((noderef, address_space(3)))
+#ifdef CONFIG_SPARSE_RCU_POINTER
+# define __rcu __attribute__((noderef, address_space(4)))
+#else
+# define __rcu
+#endif
extern void __chk_user_ptr(const volatile void __user *);
extern void __chk_io_ptr(const volatile void __iomem *);
#else
@@ -27,13 +34,20 @@ extern void __chk_io_ptr(const volatile
# define __chk_user_ptr(x) (void)0
# define __chk_io_ptr(x) (void)0
# define __builtin_warning(x, y...) (1)
+# define __must_hold(x)
# define __acquires(x)
# define __releases(x)
# define __acquire(x) (void)0
# define __release(x) (void)0
# define __cond_lock(x,c) (c)
+# define __percpu
+# define __rcu
#endif
+/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
+#define ___PASTE(a,b) a##b
+#define __PASTE(a,b) ___PASTE(a,b)
+
#ifdef __KERNEL__
#ifdef __GNUC__
@@ -49,6 +63,13 @@ extern void __chk_io_ptr(const volatile
# include <linux/compiler-intel.h>
#endif
+/* Clang compiler defines __GNUC__. So we will overwrite implementations
+ * coming from above header files here
+ */
+#ifdef __clang__
+#include <linux/compiler-clang.h>
+#endif
+
/*
* Generic compiler-dependent macros required for kernel
* build go below this comment. Actual compiler/compiler version
@@ -156,6 +177,15 @@ void ftrace_likely_update(struct ftrace_
(typeof(ptr)) (__ptr + (off)); })
#endif
+#ifndef OPTIMIZER_HIDE_VAR
+#define OPTIMIZER_HIDE_VAR(var) barrier()
+#endif
+
+/* Not-quite-unique ID. */
+#ifndef __UNIQUE_ID
+# define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
+#endif
+
#endif /* __KERNEL__ */
#endif /* __ASSEMBLY__ */
@@ -228,7 +258,7 @@ void ftrace_likely_update(struct ftrace_
/*
* Rather then using noinline to prevent stack consumption, use
- * noinline_for_stack instead. For documentaiton reasons.
+ * noinline_for_stack instead. For documentation reasons.
*/
#define noinline_for_stack noinline
@@ -270,11 +300,20 @@ void ftrace_likely_update(struct ftrace_
# define __section(S) __attribute__ ((__section__(#S)))
#endif
+#ifndef __visible
+#define __visible
+#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))
#endif
+/* 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))
+#endif
+
/* Compile time object size, -1 for unknown */
#ifndef __compiletime_object_size
# define __compiletime_object_size(obj) -1
@@ -284,7 +323,48 @@ void ftrace_likely_update(struct ftrace_
#endif
#ifndef __compiletime_error
# define __compiletime_error(message)
+/*
+ * Sparse complains of variable sized arrays due to the temporary variable in
+ * __compiletime_assert. Unfortunately we can't just expand it out to make
+ * sparse see a constant array size without breaking compiletime_assert on old
+ * versions of GCC (e.g. 4.2.4), so hide the array from sparse altogether.
+ */
+# ifndef __CHECKER__
+# define __compiletime_error_fallback(condition) \
+ do { ((void)sizeof(char[1 - 2 * condition])); } while (0)
+# endif
#endif
+#ifndef __compiletime_error_fallback
+# define __compiletime_error_fallback(condition) do { } while (0)
+#endif
+
+#define __compiletime_assert(condition, msg, prefix, suffix) \
+ do { \
+ bool __cond = !(condition); \
+ extern void prefix ## suffix(void) __compiletime_error(msg); \
+ if (__cond) \
+ prefix ## suffix(); \
+ __compiletime_error_fallback(__cond); \
+ } while (0)
+
+#define _compiletime_assert(condition, msg, prefix, suffix) \
+ __compiletime_assert(condition, msg, prefix, suffix)
+
+/**
+ * compiletime_assert - break build and emit msg if condition is false
+ * @condition: a compile-time constant condition to check
+ * @msg: a message to emit if condition is false
+ *
+ * In tradition of POSIX assert, this macro will break the build if the
+ * supplied condition is *false*, emitting the supplied error message if the
+ * compiler has support to do so.
+ */
+#define compiletime_assert(condition, msg) \
+ _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
+
+#define compiletime_assert_atomic_type(t) \
+ compiletime_assert(__native_word(t), \
+ "Need native word sized stores/loads for atomicity.")
/*
* Prevent the compiler from merging or refetching accesses. The compiler
@@ -300,4 +380,12 @@ void ftrace_likely_update(struct ftrace_
*/
#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))
+/* Ignore/forbid kprobes attach on very low level functions marked by this attribute: */
+#ifdef CONFIG_KPROBES
+# define __kprobes __attribute__((__section__(".kprobes.text")))
+# define nokprobe_inline __always_inline
+#else
+# define __kprobes
+# define nokprobe_inline inline
+#endif
#endif /* __LINUX_COMPILER_H */

69
package/boot/uboot-imx6/patches/102-compiler_gcc-prevent-redefining-attributes.patch
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@ -0,0 +1,69 @@
From 0a5051ce6ebd5f6fad58fd50d6922493d8447f14 Mon Sep 17 00:00:00 2001
From: Jeroen Hofstee <jeroen@myspectrum.nl>
Date: Thu, 18 Sep 2014 20:10:27 +0200
Subject: compiler_gcc: prevent redefining attributes
The libc headers on FreeBSD and likely related projects as well contain an
header file, cdefs.h which provides similiar functionality as linux/compiler.h.
It provides compiler independent defines like __weak __packed, to allow
compiling with multiple compilers which might have a different syntax for such
extension.
Since that header file is included in multiple standard headers, like stddef.h
and stdarg.h, multiple definitions of those defines will be present if both are
included. When compiling u-boot the compiler will warn about it hundreds of
times since e.g. common.h will include both files indirectly.
commit 7ea50d52849fe8ffa5b5b74c979b60b1045d6fc9 "compiler_gcc: do not redefine
__gnu_attributes" prevented such redefinitions, but this was undone by commit
fb8ffd7cfc68b3dc44e182356a207d784cb30b34 "compiler*.h: sync
include/linux/compiler*.h with Linux 3.16".
Add the checks back where necessary to prevent such warnings.
As the original patch this checkpatch warning is ignored:
"WARNING: Adding new packed members is to be done with care"
Cc: Masahiro Yamada <yamada.m@jp.panasonic.com>
Cc: Tom Rini <trini@ti.com>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
Acked-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
---
include/linux/compiler-gcc.h | 10 ++++++++++
1 file changed, 10 insertions(+)
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -64,8 +64,12 @@
#endif
#define __deprecated __attribute__((deprecated))
+#ifndef __packed
#define __packed __attribute__((packed))
+#endif
+#ifndef __weak
#define __weak __attribute__((weak))
+#endif
/*
* it doesn't make sense on ARM (currently the only user of __naked) to trace
@@ -91,8 +95,12 @@
* would be.
* [...]
*/
+#ifndef __pure
#define __pure __attribute__((pure))
+#endif
+#ifndef __aligned
#define __aligned(x) __attribute__((aligned(x)))
+#endif
#define __printf(a, b) __attribute__((format(printf, a, b)))
#define __scanf(a, b) __attribute__((format(scanf, a, b)))
#define noinline __attribute__((noinline))
@@ -115,4 +123,6 @@
*/
#define uninitialized_var(x) x = x
+#ifndef __always_inline
#define __always_inline inline __attribute__((always_inline))
+#endif

10
package/boot/uboot-imx6/patches/001-gcc-5-compiler.patch → package/boot/uboot-imx6/patches/103-Add-linux-compiler-gcc5.h-to-fix-builds-with-gcc5.patch
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@ -1,10 +1,7 @@
From 478b02f1a7043b673565075ea5016376f3293b23 Mon Sep 17 00:00:00 2001
From: Hans de Goede <hdegoede@redhat.com>
Date: Sat, 7 Feb 2015 21:52:40 +0000 (+0100)
Date: Sat, 7 Feb 2015 22:52:40 +0100
Subject: Add linux/compiler-gcc5.h to fix builds with gcc5
X-Git-Tag: v2015.04-rc2~31
X-Git-Url: http://git.denx.de/?p=u-boot.git;a=commitdiff_plain;h=478b02f1a7043b673565075ea5016376f3293b23
Add linux/compiler-gcc5.h to fix builds with gcc5
Add linux/compiler-gcc5/h from the kernel sources at:
@ -16,6 +13,9 @@ Date: Sat Oct 25 15:09:42 2014 -0700
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
include/linux/compiler-gcc5.h | 65 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
create mode 100644 include/linux/compiler-gcc5.h
--- /dev/null
+++ b/include/linux/compiler-gcc5.h

790
package/boot/uboot-imx6/patches/104-gcc-compiler-linux-4-5.patch
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@ -0,0 +1,790 @@
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: 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>
---
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
--- 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
-#ifndef __aligned
-#define __aligned(x) __attribute__((aligned(x)))
+
+#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
-#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__)
+
+#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
+
+
+#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
+
+/*
+ * 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
--- 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 */
--- 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 */
--- 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 */
--- 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); \
--- 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
# 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
#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_
*/
#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_
# 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_
# 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_
#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_
/* 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_
* 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) (*(volatile typeof(x) *)&(x))
+#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 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
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