Messages in this thread Patch in this message | | | Date | Tue, 27 Aug 2019 13:40:05 -0700 | Subject | [PATCH v2 12/14] include/linux: prefer __section from compiler_attributes.h | From | Nick Desaulniers <> |
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GCC unescapes escaped string section names while Clang does not. Because __section uses the `#` stringification operator for the section name, it doesn't need to be escaped.
Instead, we should: 1. Prefer __section(.section_name_no_quotes). 2. Only use __attribute__((__section(".section"))) when creating the section name via C preprocessor (see the definition of __define_initcall in arch/um/include/shared/init.h).
This antipattern was found with: $ grep -e __section\(\" -e __section__\(\" -r
See the discussions in: Link: https://bugs.llvm.org/show_bug.cgi?id=42950 Link: https://marc.info/?l=linux-netdev&m=156412960619946&w=2 Acked-by: Will Deacon <will@kernel.org> Reported-by: Sedat Dilek <sedat.dilek@gmail.com> Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> --- include/linux/cache.h | 6 +++--- 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 +- 7 files changed, 11 insertions(+), 12 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/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); \ -- 2.23.0.187.g17f5b7556c-goog
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