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

From: Sedat Dilek
Date: Mon Aug 19 2019 - 14:05:46 EST


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

Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> [ 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
>