linux-toradex.git/include/linux/compiler.h, branch v5.10-rc2 Linux kernel for Apalis and Colibri modules treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25T21:51:49+00:00 Joe Perches joe@perches.com 2020-10-22T02:36:07+00:00 33def8498fdde180023444b08e12b72a9efed41d Use a more generic form for __section that requires quotes to avoid complications with clang and gcc differences. Remove the quote operator # from compiler_attributes.h __section macro. Convert all unquoted __section(foo) uses to quoted __section("foo"). Also convert __attribute__((section("foo"))) uses to __section("foo") even if the __attribute__ has multiple list entry forms. Conversion done using the script at: https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl Signed-off-by: Joe Perches <joe@perches.com> Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com> Reviewed-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
Use a more generic form for __section that requires quotes to avoid
complications with clang and gcc differences.

Remove the quote operator # from compiler_attributes.h __section macro.

Convert all unquoted __section(foo) uses to quoted __section("foo").
Also convert __attribute__((section("foo"))) uses to __section("foo")
even if the __attribute__ has multiple list entry forms.

Conversion done using the script at:

    https://lore.kernel.org/lkml/75393e5ddc272dc7403de74d645e6c6e0f4e70eb.camel@perches.com/2-convert_section.pl

Signed-off-by: Joe Perches <joe@perches.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@gooogle.com>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
compiler.h: avoid escaped section names 2020-10-14T01:38:26+00:00 Nick Desaulniers ndesaulniers@google.com 2020-10-13T23:47:58+00:00 a25c13b3aa1bdbf100e8770902c30908728f8410 The stringification operator, `#`, in the preprocessor escapes strings. For example, `# "foo"` becomes `"\"foo\""`. GCC and Clang differ in how they treat section names that contain \". The portable solution is to not use a string literal with the preprocessor stringification operator. In this case, since __section unconditionally uses the stringification operator, we actually want the more verbose __attribute__((__section__())). Fixes: commit e04462fb82f8 ("Compiler Attributes: remove uses of __attribute__ from compiler.h") Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com> Cc: Nathan Chancellor <natechancellor@gmail.com> Cc: Arvind Sankar <nivedita@alum.mit.edu> Link: https://bugs.llvm.org/show_bug.cgi?id=42950 Link: https://lkml.kernel.org/r/20200929194318.548707-1-ndesaulniers@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
The stringification operator, `#`, in the preprocessor escapes strings.
For example, `# "foo"` becomes `"\"foo\""`.  GCC and Clang differ in how
they treat section names that contain \".

The portable solution is to not use a string literal with the preprocessor
stringification operator.

In this case, since __section unconditionally uses the stringification
operator, we actually want the more verbose
__attribute__((__section__())).

Fixes: commit e04462fb82f8 ("Compiler Attributes: remove uses of __attribute__ from compiler.h")
Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Cc: Nathan Chancellor <natechancellor@gmail.com>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://bugs.llvm.org/show_bug.cgi?id=42950
Link: https://lkml.kernel.org/r/20200929194318.548707-1-ndesaulniers@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
compiler.h: Make __ADDRESSABLE() symbol truly unique 2020-09-01T07:58:04+00:00 Josh Poimboeuf jpoimboe@redhat.com 2020-08-18T13:57:40+00:00 563a02b0c9704f69c0364befedd451f57fe88092 The __ADDRESSABLE() macro uses the __LINE__ macro to create a temporary symbol which has a unique name. However, if the macro is used multiple times from within another macro, the line number will always be the same, resulting in duplicate symbols. Make the temporary symbols truly unique by using __UNIQUE_ID instead of __LINE__. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Link: https://lore.kernel.org/r/20200818135804.564436253@infradead.org 
The __ADDRESSABLE() macro uses the __LINE__ macro to create a temporary
symbol which has a unique name.  However, if the macro is used multiple
times from within another macro, the line number will always be the
same, resulting in duplicate symbols.

Make the temporary symbols truly unique by using __UNIQUE_ID instead of
__LINE__.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Link: https://lore.kernel.org/r/20200818135804.564436253@infradead.org
Merge tag 'core-headers-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2020-08-03T21:25:40+00:00 Linus Torvalds torvalds@linux-foundation.org 2020-08-03T21:25:40+00:00 5ece08178d6567db5ef0090b1ae7f795c3c36161 Pull header cleanup from Ingo Molnar: "Separate out the instrumentation_begin()/end() bits from compiler.h" * tag 'core-headers-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: compiler.h: Move instrumentation_begin()/end() to new <linux/instrumentation.h> header 
Pull header cleanup from Ingo Molnar:
 "Separate out the instrumentation_begin()/end() bits from compiler.h"

* tag 'core-headers-2020-08-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  compiler.h: Move instrumentation_begin()/end() to new <linux/instrumentation.h> header
compiler.h: Move instrumentation_begin()/end() to new <linux/instrumentation.h> header 2020-07-24T11:56:23+00:00 Ingo Molnar mingo@kernel.org 2020-07-24T11:50:25+00:00 d19e789f068b3d633cbac430764962f404198022 Linus pointed out that compiler.h - which is a key header that gets included in every single one of the 28,000+ kernel files during a kernel build - was bloated in: 655389666643: ("vmlinux.lds.h: Create section for protection against instrumentation") Linus noted: > I have pulled this, but do we really want to add this to a header file > that is _so_ core that it gets included for basically every single > file built? > > I don't even see those instrumentation_begin/end() things used > anywhere right now. > > It seems excessive. That 53 lines is maybe not a lot, but it pushed > that header file to over 12kB, and while it's mostly comments, it's > extra IO and parsing basically for _every_ single file compiled in the > kernel. > > For what appears to be absolutely zero upside right now, and I really > don't see why this should be in such a core header file! Move these primitives into a new header: <linux/instrumentation.h>, and include that header in the headers that make use of it. Unfortunately one of these headers is asm-generic/bug.h, which does get included in a lot of places, similarly to compiler.h. So the de-bloating effect isn't as good as we'd like it to be - but at least the interfaces are defined separately. No change to functionality intended. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20200604071921.GA1361070@gmail.com Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org> 
Linus pointed out that compiler.h - which is a key header that gets included in every
single one of the 28,000+ kernel files during a kernel build - was bloated in:

  655389666643: ("vmlinux.lds.h: Create section for protection against instrumentation")

Linus noted:

 > I have pulled this, but do we really want to add this to a header file
 > that is _so_ core that it gets included for basically every single
 > file built?
 >
 > I don't even see those instrumentation_begin/end() things used
 > anywhere right now.
 >
 > It seems excessive. That 53 lines is maybe not a lot, but it pushed
 > that header file to over 12kB, and while it's mostly comments, it's
 > extra IO and parsing basically for _every_ single file compiled in the
 > kernel.
 >
 > For what appears to be absolutely zero upside right now, and I really
 > don't see why this should be in such a core header file!

Move these primitives into a new header: <linux/instrumentation.h>, and include that
header in the headers that make use of it.

Unfortunately one of these headers is asm-generic/bug.h, which does get included
in a lot of places, similarly to compiler.h. So the de-bloating effect isn't as
good as we'd like it to be - but at least the interfaces are defined separately.

No change to functionality intended.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200604071921.GA1361070@gmail.com
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
compiler.h: Move compiletime_assert() macros into compiler_types.h 2020-07-21T09:50:37+00:00 Will Deacon will@kernel.org 2020-07-21T08:54:15+00:00 eb5c2d4b45e3d2d5d052ea6b8f1463976b1020d5 The kernel test robot reports that moving READ_ONCE() out into its own header breaks a W=1 build for parisc, which is relying on the definition of compiletime_assert() being available: | In file included from ./arch/parisc/include/generated/asm/rwonce.h:1, | from ./include/asm-generic/barrier.h:16, | from ./arch/parisc/include/asm/barrier.h:29, | from ./arch/parisc/include/asm/atomic.h:11, | from ./include/linux/atomic.h:7, | from kernel/locking/percpu-rwsem.c:2: | ./arch/parisc/include/asm/atomic.h: In function 'atomic_read': | ./include/asm-generic/rwonce.h:36:2: error: implicit declaration of function 'compiletime_assert' [-Werror=implicit-function-declaration] | 36 | compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \ | | ^~~~~~~~~~~~~~~~~~ | ./include/asm-generic/rwonce.h:49:2: note: in expansion of macro 'compiletime_assert_rwonce_type' | 49 | compiletime_assert_rwonce_type(x); \ | | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | ./arch/parisc/include/asm/atomic.h:73:9: note: in expansion of macro 'READ_ONCE' | 73 | return READ_ONCE((v)->counter); | | ^~~~~~~~~ Move these macros into compiler_types.h, so that they are available to READ_ONCE() and friends. Link: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-July/587094.html Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Will Deacon <will@kernel.org> 
The kernel test robot reports that moving READ_ONCE() out into its own
header breaks a W=1 build for parisc, which is relying on the definition
of compiletime_assert() being available:

  | In file included from ./arch/parisc/include/generated/asm/rwonce.h:1,
  |                  from ./include/asm-generic/barrier.h:16,
  |                  from ./arch/parisc/include/asm/barrier.h:29,
  |                  from ./arch/parisc/include/asm/atomic.h:11,
  |                  from ./include/linux/atomic.h:7,
  |                  from kernel/locking/percpu-rwsem.c:2:
  | ./arch/parisc/include/asm/atomic.h: In function 'atomic_read':
  | ./include/asm-generic/rwonce.h:36:2: error: implicit declaration of function 'compiletime_assert' [-Werror=implicit-function-declaration]
  |    36 |  compiletime_assert(__native_word(t) || sizeof(t) == sizeof(long long), \
  |       |  ^~~~~~~~~~~~~~~~~~
  | ./include/asm-generic/rwonce.h:49:2: note: in expansion of macro 'compiletime_assert_rwonce_type'
  |    49 |  compiletime_assert_rwonce_type(x);    \
  |       |  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  | ./arch/parisc/include/asm/atomic.h:73:9: note: in expansion of macro 'READ_ONCE'
  |    73 |  return READ_ONCE((v)->counter);
  |       |         ^~~~~~~~~

Move these macros into compiler_types.h, so that they are available to
READ_ONCE() and friends.

Link: http://lists.infradead.org/pipermail/linux-arm-kernel/2020-July/587094.html
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Will Deacon <will@kernel.org>
compiler.h: Split {READ,WRITE}_ONCE definitions out into rwonce.h 2020-07-21T09:50:35+00:00 Will Deacon will@kernel.org 2019-10-15T23:29:32+00:00 e506ea451254ab17e0bf918ca36232fec2a9b10c In preparation for allowing architectures to define their own implementation of the READ_ONCE() macro, move the generic {READ,WRITE}_ONCE() definitions out of the unwieldy 'linux/compiler.h' file and into a new 'rwonce.h' header under 'asm-generic'. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Will Deacon <will@kernel.org> 
In preparation for allowing architectures to define their own
implementation of the READ_ONCE() macro, move the generic
{READ,WRITE}_ONCE() definitions out of the unwieldy 'linux/compiler.h'
file and into a new 'rwonce.h' header under 'asm-generic'.

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
rcu: Fixup noinstr warnings 2020-06-25T15:24:32+00:00 Peter Zijlstra peterz@infradead.org 2020-06-15T16:24:27+00:00 b58e733fd774f3f4b49d9e7640d172a57e35200e A KCSAN build revealed we have explicit annoations through atomic_*() usage, switch to arch_atomic_*() for the respective functions. vmlinux.o: warning: objtool: rcu_nmi_exit()+0x4d: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: rcu_dynticks_eqs_enter()+0x25: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: rcu_nmi_enter()+0x4f: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: rcu_dynticks_eqs_exit()+0x2a: call to __kcsan_check_access() leaves .noinstr.text section vmlinux.o: warning: objtool: __rcu_is_watching()+0x25: call to __kcsan_check_access() leaves .noinstr.text section Additionally, without the NOP in instrumentation_begin(), objtool would not detect the lack of the 'else instrumentation_begin();' branch in rcu_nmi_enter(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> 
A KCSAN build revealed we have explicit annoations through atomic_*()
usage, switch to arch_atomic_*() for the respective functions.

vmlinux.o: warning: objtool: rcu_nmi_exit()+0x4d: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: rcu_dynticks_eqs_enter()+0x25: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: rcu_nmi_enter()+0x4f: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: rcu_dynticks_eqs_exit()+0x2a: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: __rcu_is_watching()+0x25: call to __kcsan_check_access() leaves .noinstr.text section

Additionally, without the NOP in instrumentation_begin(), objtool would
not detect the lack of the 'else instrumentation_begin();' branch in
rcu_nmi_enter().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
compiler.h: Move function attributes to compiler_types.h 2020-06-11T18:04:04+00:00 Marco Elver elver@google.com 2020-05-21T14:20:46+00:00 eb73876c74313231c35cee6310f8ad62c56fa2b3 Cleanup and move the KASAN and KCSAN related function attributes to compiler_types.h, where the rest of the same kind live. No functional change intended. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20200521142047.169334-11-elver@google.com 
Cleanup and move the KASAN and KCSAN related function attributes to
compiler_types.h, where the rest of the same kind live.

No functional change intended.

Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/20200521142047.169334-11-elver@google.com
compiler.h: Avoid nested statement expression in data_race() 2020-06-11T18:04:03+00:00 Marco Elver elver@google.com 2020-05-21T14:20:45+00:00 95c094fccb85422eff3c12930ebebbda9278f76b It appears that compilers have trouble with nested statement expressions. Therefore, remove one level of statement expression nesting from the data_race() macro. This will help avoiding potential problems in the future as its usage increases. Reported-by: Borislav Petkov <bp@suse.de> Reported-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Borislav Petkov <bp@suse.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will@kernel.org> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Link: https://lkml.kernel.org/r/20200520221712.GA21166@zn.tnic Link: https://lkml.kernel.org/r/20200521142047.169334-10-elver@google.com 
It appears that compilers have trouble with nested statement
expressions. Therefore, remove one level of statement expression nesting
from the data_race() macro. This will help avoiding potential problems
in the future as its usage increases.

Reported-by: Borislav Petkov <bp@suse.de>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lkml.kernel.org/r/20200520221712.GA21166@zn.tnic
Link: https://lkml.kernel.org/r/20200521142047.169334-10-elver@google.com