302 lines
10 KiB
C
302 lines
10 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef __LINUX_COMPILER_H
|
|
#define __LINUX_COMPILER_H
|
|
|
|
#include <linux/compiler_types.h>
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
#ifdef __KERNEL__
|
|
|
|
/*
|
|
* Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
|
|
* to disable branch tracing on a per file basis.
|
|
*/
|
|
void ftrace_likely_update(struct ftrace_likely_data *f, int val,
|
|
int expect, int is_constant);
|
|
#if defined(CONFIG_TRACE_BRANCH_PROFILING) \
|
|
&& !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
|
|
#define likely_notrace(x) __builtin_expect(!!(x), 1)
|
|
#define unlikely_notrace(x) __builtin_expect(!!(x), 0)
|
|
|
|
#define __branch_check__(x, expect, is_constant) ({ \
|
|
long ______r; \
|
|
static struct ftrace_likely_data \
|
|
__aligned(4) \
|
|
__section("_ftrace_annotated_branch") \
|
|
______f = { \
|
|
.data.func = __func__, \
|
|
.data.file = __FILE__, \
|
|
.data.line = __LINE__, \
|
|
}; \
|
|
______r = __builtin_expect(!!(x), expect); \
|
|
ftrace_likely_update(&______f, ______r, \
|
|
expect, is_constant); \
|
|
______r; \
|
|
})
|
|
|
|
/*
|
|
* Using __builtin_constant_p(x) to ignore cases where the return
|
|
* value is always the same. This idea is taken from a similar patch
|
|
* written by Daniel Walker.
|
|
*/
|
|
# ifndef likely
|
|
# define likely(x) (__branch_check__(x, 1, __builtin_constant_p(x)))
|
|
# endif
|
|
# ifndef unlikely
|
|
# define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
|
|
# endif
|
|
|
|
#ifdef CONFIG_PROFILE_ALL_BRANCHES
|
|
/*
|
|
* "Define 'is'", Bill Clinton
|
|
* "Define 'if'", Steven Rostedt
|
|
*/
|
|
#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
|
|
|
|
#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
|
|
|
|
#define __trace_if_value(cond) ({ \
|
|
static struct ftrace_branch_data \
|
|
__aligned(4) \
|
|
__section("_ftrace_branch") \
|
|
__if_trace = { \
|
|
.func = __func__, \
|
|
.file = __FILE__, \
|
|
.line = __LINE__, \
|
|
}; \
|
|
(cond) ? \
|
|
(__if_trace.miss_hit[1]++,1) : \
|
|
(__if_trace.miss_hit[0]++,0); \
|
|
})
|
|
|
|
#endif /* CONFIG_PROFILE_ALL_BRANCHES */
|
|
|
|
#else
|
|
# define likely(x) __builtin_expect(!!(x), 1)
|
|
# define unlikely(x) __builtin_expect(!!(x), 0)
|
|
# define likely_notrace(x) likely(x)
|
|
# define unlikely_notrace(x) unlikely(x)
|
|
#endif
|
|
|
|
/* Optimization barrier */
|
|
#ifndef barrier
|
|
/* The "volatile" is due to gcc bugs */
|
|
# define barrier() __asm__ __volatile__("": : :"memory")
|
|
#endif
|
|
|
|
#ifndef barrier_data
|
|
/*
|
|
* 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 proved 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")
|
|
#endif
|
|
|
|
/* workaround for GCC PR82365 if needed */
|
|
#ifndef barrier_before_unreachable
|
|
# define barrier_before_unreachable() do { } while (0)
|
|
#endif
|
|
|
|
/* Unreachable code */
|
|
#ifdef CONFIG_OBJTOOL
|
|
/*
|
|
* These macros help objtool understand GCC code flow for unreachable code.
|
|
* The __COUNTER__ based labels are a hack to make each instance of the macros
|
|
* unique, to convince GCC not to merge duplicate inline asm statements.
|
|
*/
|
|
#define __stringify_label(n) #n
|
|
|
|
#define __annotate_reachable(c) ({ \
|
|
asm volatile(__stringify_label(c) ":\n\t" \
|
|
".pushsection .discard.reachable\n\t" \
|
|
".long " __stringify_label(c) "b - .\n\t" \
|
|
".popsection\n\t"); \
|
|
})
|
|
#define annotate_reachable() __annotate_reachable(__COUNTER__)
|
|
|
|
#define __annotate_unreachable(c) ({ \
|
|
asm volatile(__stringify_label(c) ":\n\t" \
|
|
".pushsection .discard.unreachable\n\t" \
|
|
".long " __stringify_label(c) "b - .\n\t" \
|
|
".popsection\n\t" : : "i" (c)); \
|
|
})
|
|
#define annotate_unreachable() __annotate_unreachable(__COUNTER__)
|
|
|
|
/* Annotate a C jump table to allow objtool to follow the code flow */
|
|
#define __annotate_jump_table __section(".rodata..c_jump_table")
|
|
|
|
#else /* !CONFIG_OBJTOOL */
|
|
#define annotate_reachable()
|
|
#define annotate_unreachable()
|
|
#define __annotate_jump_table
|
|
#endif /* CONFIG_OBJTOOL */
|
|
|
|
#ifndef unreachable
|
|
# define unreachable() do { \
|
|
annotate_unreachable(); \
|
|
__builtin_unreachable(); \
|
|
} while (0)
|
|
#endif
|
|
|
|
/*
|
|
* KENTRY - kernel entry point
|
|
* This can be used to annotate symbols (functions or data) that are used
|
|
* without their linker symbol being referenced explicitly. For example,
|
|
* interrupt vector handlers, or functions in the kernel image that are found
|
|
* programatically.
|
|
*
|
|
* Not required for symbols exported with EXPORT_SYMBOL, or initcalls. Those
|
|
* are handled in their own way (with KEEP() in linker scripts).
|
|
*
|
|
* KENTRY can be avoided if the symbols in question are marked as KEEP() in the
|
|
* linker script. For example an architecture could KEEP() its entire
|
|
* boot/exception vector code rather than annotate each function and data.
|
|
*/
|
|
#ifndef KENTRY
|
|
# define KENTRY(sym) \
|
|
extern typeof(sym) sym; \
|
|
static const unsigned long __kentry_##sym \
|
|
__used \
|
|
__attribute__((__section__("___kentry+" #sym))) \
|
|
= (unsigned long)&sym;
|
|
#endif
|
|
|
|
#ifndef RELOC_HIDE
|
|
# define RELOC_HIDE(ptr, off) \
|
|
({ unsigned long __ptr; \
|
|
__ptr = (unsigned long) (ptr); \
|
|
(typeof(ptr)) (__ptr + (off)); })
|
|
#endif
|
|
|
|
#define absolute_pointer(val) RELOC_HIDE((void *)(val), 0)
|
|
|
|
#ifndef OPTIMIZER_HIDE_VAR
|
|
/* Make the optimizer believe the variable can be manipulated arbitrarily. */
|
|
#define OPTIMIZER_HIDE_VAR(var) \
|
|
__asm__ ("" : "=r" (var) : "0" (var))
|
|
#endif
|
|
|
|
#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
|
|
|
|
/**
|
|
* data_race - mark an expression as containing intentional data races
|
|
*
|
|
* This data_race() macro is useful for situations in which data races
|
|
* should be forgiven. One example is diagnostic code that accesses
|
|
* shared variables but is not a part of the core synchronization design.
|
|
*
|
|
* This macro *does not* affect normal code generation, but is a hint
|
|
* to tooling that data races here are to be ignored.
|
|
*/
|
|
#define data_race(expr) \
|
|
({ \
|
|
__unqual_scalar_typeof(({ expr; })) __v = ({ \
|
|
__kcsan_disable_current(); \
|
|
expr; \
|
|
}); \
|
|
__kcsan_enable_current(); \
|
|
__v; \
|
|
})
|
|
|
|
#endif /* __KERNEL__ */
|
|
|
|
/*
|
|
* Force the compiler to emit 'sym' as a symbol, so that we can reference
|
|
* it from inline assembler. Necessary in case 'sym' could be inlined
|
|
* otherwise, or eliminated entirely due to lack of references that are
|
|
* visible to the compiler.
|
|
*/
|
|
#define ___ADDRESSABLE(sym, __attrs) \
|
|
static void * __used __attrs \
|
|
__UNIQUE_ID(__PASTE(__addressable_,sym)) = (void *)(uintptr_t)&sym;
|
|
#define __ADDRESSABLE(sym) \
|
|
___ADDRESSABLE(sym, __section(".discard.addressable"))
|
|
|
|
/**
|
|
* offset_to_ptr - convert a relative memory offset to an absolute pointer
|
|
* @off: the address of the 32-bit offset value
|
|
*/
|
|
static inline void *offset_to_ptr(const int *off)
|
|
{
|
|
return (void *)((unsigned long)off + *off);
|
|
}
|
|
|
|
#endif /* __ASSEMBLY__ */
|
|
|
|
/* &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]))
|
|
|
|
/*
|
|
* This returns a constant expression while determining if an argument is
|
|
* a constant expression, most importantly without evaluating the argument.
|
|
* Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
|
|
*
|
|
* Details:
|
|
* - sizeof() return an integer constant expression, and does not evaluate
|
|
* the value of its operand; it only examines the type of its operand.
|
|
* - The results of comparing two integer constant expressions is also
|
|
* an integer constant expression.
|
|
* - The first literal "8" isn't important. It could be any literal value.
|
|
* - The second literal "8" is to avoid warnings about unaligned pointers;
|
|
* this could otherwise just be "1".
|
|
* - (long)(x) is used to avoid warnings about 64-bit types on 32-bit
|
|
* architectures.
|
|
* - The C Standard defines "null pointer constant", "(void *)0", as
|
|
* distinct from other void pointers.
|
|
* - If (x) is an integer constant expression, then the "* 0l" resolves
|
|
* it into an integer constant expression of value 0. Since it is cast to
|
|
* "void *", this makes the second operand a null pointer constant.
|
|
* - If (x) is not an integer constant expression, then the second operand
|
|
* resolves to a void pointer (but not a null pointer constant: the value
|
|
* is not an integer constant 0).
|
|
* - The conditional operator's third operand, "(int *)8", is an object
|
|
* pointer (to type "int").
|
|
* - The behavior (including the return type) of the conditional operator
|
|
* ("operand1 ? operand2 : operand3") depends on the kind of expressions
|
|
* given for the second and third operands. This is the central mechanism
|
|
* of the macro:
|
|
* - When one operand is a null pointer constant (i.e. when x is an integer
|
|
* constant expression) and the other is an object pointer (i.e. our
|
|
* third operand), the conditional operator returns the type of the
|
|
* object pointer operand (i.e. "int *"). Here, within the sizeof(), we
|
|
* would then get:
|
|
* sizeof(*((int *)(...)) == sizeof(int) == 4
|
|
* - When one operand is a void pointer (i.e. when x is not an integer
|
|
* constant expression) and the other is an object pointer (i.e. our
|
|
* third operand), the conditional operator returns a "void *" type.
|
|
* Here, within the sizeof(), we would then get:
|
|
* sizeof(*((void *)(...)) == sizeof(void) == 1
|
|
* - The equality comparison to "sizeof(int)" therefore depends on (x):
|
|
* sizeof(int) == sizeof(int) (x) was a constant expression
|
|
* sizeof(int) != sizeof(void) (x) was not a constant expression
|
|
*/
|
|
#define __is_constexpr(x) \
|
|
(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
|
|
|
|
/*
|
|
* Whether 'type' is a signed type or an unsigned type. Supports scalar types,
|
|
* bool and also pointer types.
|
|
*/
|
|
#define is_signed_type(type) (((type)(-1)) < (__force type)1)
|
|
#define is_unsigned_type(type) (!is_signed_type(type))
|
|
|
|
/*
|
|
* This is needed in functions which generate the stack canary, see
|
|
* arch/x86/kernel/smpboot.c::start_secondary() for an example.
|
|
*/
|
|
#define prevent_tail_call_optimization() mb()
|
|
|
|
#include <asm/rwonce.h>
|
|
|
|
#endif /* __LINUX_COMPILER_H */
|