Re: [PATCH 14/16] include/linux: prefer __section from compiler_attributes.h

From: Sedat Dilek <sedat.dilek@gmail.com>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: akpm@linux-foundation.org, jpoimboe@redhat.com, yhs@fb.com,
	Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
	Clang-Built-Linux ML <clang-built-linux@googlegroups.com>,
	Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
	Lai Jiangshan <jiangshanlai@gmail.com>,
	"Paul E. McKenney" <paulmck@linux.ibm.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	Jiri Kosina <jkosina@suse.cz>, Will Deacon <will@kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Hans Liljestrand <ishkamiel@gmail.com>,
	Elena Reshetova <elena.reshetova@intel.com>,
	David Windsor <dwindsor@gmail.com>, Marc Zyngier <maz@kernel.org>,
	Ming Lei <ming.lei@redhat.com>, Dou Liyang <douliyangs@gmail.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Jens Axboe <axboe@kernel.dk>,
	linux-kernel@vger.kernel.org, linux-sparse@vger.kernel.org,
	rcu@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org
Subject: Re: [PATCH 14/16] include/linux: prefer __section from compiler_attributes.h
Date: Mon, 19 Aug 2019 20:05:28 +0200	[thread overview]
Message-ID: <CA+icZUVQ9ZBcrVskN3xOdgZ2Y7UJL_jyGY5LhoHHR7uxESmdmQ@mail.gmail.com> (raw)
In-Reply-To: <20190812215052.71840-14-ndesaulniers@google.com>

On Mon, Aug 12, 2019 at 11:53 PM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/619
> Reported-by: Sedat Dilek <sedat.dilek@gmail.com>
> Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>

Tested-by: Sedat Dilek <sedat.dilek@gmail.com> [ Linux v5.3-rc5 ]

Patchset "for-5.3/x86-section-name-escaping" (5 patches):

compiler_attributes.h: add note about __section
include/linux/compiler.h: remove unused KENTRY macro
include/linux: prefer __section from compiler_attributes.h
include/asm-generic: prefer __section from compiler_attributes.h
x86: prefer __section from compiler_attributes.h

Thanks.

- Sedat -

> ---
>  include/linux/cache.h       | 6 +++---
>  include/linux/compiler.h    | 8 ++++----
>  include/linux/cpu.h         | 2 +-
>  include/linux/export.h      | 2 +-
>  include/linux/init_task.h   | 4 ++--
>  include/linux/interrupt.h   | 5 ++---
>  include/linux/sched/debug.h | 2 +-
>  include/linux/srcutree.h    | 2 +-
>  8 files changed, 15 insertions(+), 16 deletions(-)
>
> diff --git a/include/linux/cache.h b/include/linux/cache.h
> index 750621e41d1c..3f4df9eef1e1 100644
> --- a/include/linux/cache.h
> +++ b/include/linux/cache.h
> @@ -28,7 +28,7 @@
>   * but may get written to during init, so can't live in .rodata (via "const").
>   */
>  #ifndef __ro_after_init
> -#define __ro_after_init __attribute__((__section__(".data..ro_after_init")))
> +#define __ro_after_init __section(.data..ro_after_init)
>  #endif
>
>  #ifndef ____cacheline_aligned
> @@ -45,8 +45,8 @@
>
>  #ifndef __cacheline_aligned
>  #define __cacheline_aligned                                    \
> -  __attribute__((__aligned__(SMP_CACHE_BYTES),                 \
> -                __section__(".data..cacheline_aligned")))
> +       __aligned(SMP_CACHE_BYTES)                              \
> +       __section(.data..cacheline_aligned)
>  #endif /* __cacheline_aligned */
>
>  #ifndef __cacheline_aligned_in_smp
> diff --git a/include/linux/compiler.h b/include/linux/compiler.h
> index f0fd5636fddb..5e88e7e33abe 100644
> --- a/include/linux/compiler.h
> +++ b/include/linux/compiler.h
> @@ -24,7 +24,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
>                         long ______r;                                   \
>                         static struct ftrace_likely_data                \
>                                 __aligned(4)                            \
> -                               __section("_ftrace_annotated_branch")   \
> +                               __section(_ftrace_annotated_branch)     \
>                                 ______f = {                             \
>                                 .data.func = __func__,                  \
>                                 .data.file = __FILE__,                  \
> @@ -60,7 +60,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
>  #define __trace_if_value(cond) ({                      \
>         static struct ftrace_branch_data                \
>                 __aligned(4)                            \
> -               __section("_ftrace_branch")             \
> +               __section(_ftrace_branch)               \
>                 __if_trace = {                          \
>                         .func = __func__,               \
>                         .file = __FILE__,               \
> @@ -118,7 +118,7 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
>         ".popsection\n\t"
>
>  /* Annotate a C jump table to allow objtool to follow the code flow */
> -#define __annotate_jump_table __section(".rodata..c_jump_table")
> +#define __annotate_jump_table __section(.rodata..c_jump_table)
>
>  #else
>  #define annotate_reachable()
> @@ -298,7 +298,7 @@ unsigned long read_word_at_a_time(const void *addr)
>   * visible to the compiler.
>   */
>  #define __ADDRESSABLE(sym) \
> -       static void * __section(".discard.addressable") __used \
> +       static void * __section(.discard.addressable) __used \
>                 __PASTE(__addressable_##sym, __LINE__) = (void *)&sym;
>
>  /**
> diff --git a/include/linux/cpu.h b/include/linux/cpu.h
> index fcb1386bb0d4..186bbd79d6ce 100644
> --- a/include/linux/cpu.h
> +++ b/include/linux/cpu.h
> @@ -166,7 +166,7 @@ void cpu_startup_entry(enum cpuhp_state state);
>  void cpu_idle_poll_ctrl(bool enable);
>
>  /* Attach to any functions which should be considered cpuidle. */
> -#define __cpuidle      __attribute__((__section__(".cpuidle.text")))
> +#define __cpuidle      __section(.cpuidle.text)
>
>  bool cpu_in_idle(unsigned long pc);
>
> diff --git a/include/linux/export.h b/include/linux/export.h
> index fd8711ed9ac4..808c1a0c2ef9 100644
> --- a/include/linux/export.h
> +++ b/include/linux/export.h
> @@ -104,7 +104,7 @@ struct kernel_symbol {
>   * discarded in the final link stage.
>   */
>  #define __ksym_marker(sym)     \
> -       static int __ksym_marker_##sym[0] __section(".discard.ksym") __used
> +       static int __ksym_marker_##sym[0] __section(.discard.ksym) __used
>
>  #define __EXPORT_SYMBOL(sym, sec)                              \
>         __ksym_marker(sym);                                     \
> diff --git a/include/linux/init_task.h b/include/linux/init_task.h
> index 6049baa5b8bc..50139505da34 100644
> --- a/include/linux/init_task.h
> +++ b/include/linux/init_task.h
> @@ -51,12 +51,12 @@ extern struct cred init_cred;
>
>  /* Attach to the init_task data structure for proper alignment */
>  #ifdef CONFIG_ARCH_TASK_STRUCT_ON_STACK
> -#define __init_task_data __attribute__((__section__(".data..init_task")))
> +#define __init_task_data __section(.data..init_task)
>  #else
>  #define __init_task_data /**/
>  #endif
>
>  /* Attach to the thread_info data structure for proper alignment */
> -#define __init_thread_info __attribute__((__section__(".data..init_thread_info")))
> +#define __init_thread_info __section(.data..init_thread_info)
>
>  #endif
> diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
> index 5b8328a99b2a..29debfe4dd0f 100644
> --- a/include/linux/interrupt.h
> +++ b/include/linux/interrupt.h
> @@ -741,8 +741,7 @@ extern int arch_early_irq_init(void);
>  /*
>   * We want to know which function is an entrypoint of a hardirq or a softirq.
>   */
> -#define __irq_entry             __attribute__((__section__(".irqentry.text")))
> -#define __softirq_entry  \
> -       __attribute__((__section__(".softirqentry.text")))
> +#define __irq_entry    __section(.irqentry.text)
> +#define __softirq_entry        __section(.softirqentry.text)
>
>  #endif
> diff --git a/include/linux/sched/debug.h b/include/linux/sched/debug.h
> index 95fb9e025247..e17b66221fdd 100644
> --- a/include/linux/sched/debug.h
> +++ b/include/linux/sched/debug.h
> @@ -42,7 +42,7 @@ extern void proc_sched_set_task(struct task_struct *p);
>  #endif
>
>  /* Attach to any functions which should be ignored in wchan output. */
> -#define __sched                __attribute__((__section__(".sched.text")))
> +#define __sched                __section(.sched.text)
>
>  /* Linker adds these: start and end of __sched functions */
>  extern char __sched_text_start[], __sched_text_end[];
> diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
> index 9cfcc8a756ae..9de652f4e1bd 100644
> --- a/include/linux/srcutree.h
> +++ b/include/linux/srcutree.h
> @@ -124,7 +124,7 @@ struct srcu_struct {
>  # define __DEFINE_SRCU(name, is_static)                                        \
>         is_static struct srcu_struct name;                              \
>         struct srcu_struct * const __srcu_struct_##name                 \
> -               __section("___srcu_struct_ptrs") = &name
> +               __section(___srcu_struct_ptrs) = &name
>  #else
>  # define __DEFINE_SRCU(name, is_static)                                        \
>         static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data);      \
> --
> 2.23.0.rc1.153.gdeed80330f-goog
>