forked from mirrors/linux
cb8a2ef084
The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is similar in concept to a DWARF unwinder. The difference is that the format of the ORC data is much simpler than DWARF, which in turn allows the ORC unwinder to be much simpler and faster. The ORC data consists of unwind tables which are generated by objtool. After analyzing all the code paths of a .o file, it determines information about the stack state at each instruction address in the file and outputs that information to the .orc_unwind and .orc_unwind_ip sections. The per-object ORC sections are combined at link time and are sorted and post-processed at boot time. The unwinder uses the resulting data to correlate instruction addresses with their stack states at run time. Most of the logic are similar with x86, in order to get ra info before ra is saved into stack, add ra_reg and ra_offset into orc_entry. At the same time, modify some arch-specific code to silence the objtool warnings. Co-developed-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Co-developed-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
262 lines
8.2 KiB
C
262 lines
8.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef __LINUX_COMPILER_H
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#define __LINUX_COMPILER_H
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#include <linux/compiler_types.h>
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#ifndef __ASSEMBLY__
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#ifdef __KERNEL__
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/*
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* Note: DISABLE_BRANCH_PROFILING can be used by special lowlevel code
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* to disable branch tracing on a per file basis.
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*/
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void ftrace_likely_update(struct ftrace_likely_data *f, int val,
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int expect, int is_constant);
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#if defined(CONFIG_TRACE_BRANCH_PROFILING) \
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&& !defined(DISABLE_BRANCH_PROFILING) && !defined(__CHECKER__)
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#define likely_notrace(x) __builtin_expect(!!(x), 1)
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#define unlikely_notrace(x) __builtin_expect(!!(x), 0)
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#define __branch_check__(x, expect, is_constant) ({ \
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long ______r; \
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static struct ftrace_likely_data \
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__aligned(4) \
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__section("_ftrace_annotated_branch") \
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______f = { \
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.data.func = __func__, \
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.data.file = __FILE__, \
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.data.line = __LINE__, \
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}; \
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______r = __builtin_expect(!!(x), expect); \
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ftrace_likely_update(&______f, ______r, \
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expect, is_constant); \
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______r; \
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})
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/*
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* Using __builtin_constant_p(x) to ignore cases where the return
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* value is always the same. This idea is taken from a similar patch
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* written by Daniel Walker.
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*/
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# ifndef likely
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# define likely(x) (__branch_check__(x, 1, __builtin_constant_p(x)))
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# endif
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# ifndef unlikely
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# define unlikely(x) (__branch_check__(x, 0, __builtin_constant_p(x)))
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# endif
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#ifdef CONFIG_PROFILE_ALL_BRANCHES
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/*
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* "Define 'is'", Bill Clinton
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* "Define 'if'", Steven Rostedt
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*/
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#define if(cond, ...) if ( __trace_if_var( !!(cond , ## __VA_ARGS__) ) )
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#define __trace_if_var(cond) (__builtin_constant_p(cond) ? (cond) : __trace_if_value(cond))
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#define __trace_if_value(cond) ({ \
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static struct ftrace_branch_data \
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__aligned(4) \
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__section("_ftrace_branch") \
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__if_trace = { \
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.func = __func__, \
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.file = __FILE__, \
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.line = __LINE__, \
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}; \
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(cond) ? \
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(__if_trace.miss_hit[1]++,1) : \
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(__if_trace.miss_hit[0]++,0); \
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})
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#endif /* CONFIG_PROFILE_ALL_BRANCHES */
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#else
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# define likely(x) __builtin_expect(!!(x), 1)
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# define unlikely(x) __builtin_expect(!!(x), 0)
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# define likely_notrace(x) likely(x)
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# define unlikely_notrace(x) unlikely(x)
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#endif
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/* Optimization barrier */
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#ifndef barrier
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/* The "volatile" is due to gcc bugs */
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# define barrier() __asm__ __volatile__("": : :"memory")
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#endif
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#ifndef barrier_data
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/*
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* This version is i.e. to prevent dead stores elimination on @ptr
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* where gcc and llvm may behave differently when otherwise using
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* normal barrier(): while gcc behavior gets along with a normal
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* barrier(), llvm needs an explicit input variable to be assumed
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* clobbered. The issue is as follows: while the inline asm might
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* access any memory it wants, the compiler could have fit all of
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* @ptr into memory registers instead, and since @ptr never escaped
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* from that, it proved that the inline asm wasn't touching any of
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* it. This version works well with both compilers, i.e. we're telling
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* the compiler that the inline asm absolutely may see the contents
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* of @ptr. See also: https://llvm.org/bugs/show_bug.cgi?id=15495
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*/
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# define barrier_data(ptr) __asm__ __volatile__("": :"r"(ptr) :"memory")
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#endif
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/* workaround for GCC PR82365 if needed */
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#ifndef barrier_before_unreachable
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# define barrier_before_unreachable() do { } while (0)
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#endif
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/* Unreachable code */
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#ifdef CONFIG_OBJTOOL
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/*
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* These macros help objtool understand GCC code flow for unreachable code.
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* The __COUNTER__ based labels are a hack to make each instance of the macros
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* unique, to convince GCC not to merge duplicate inline asm statements.
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*/
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#define __stringify_label(n) #n
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#define __annotate_reachable(c) ({ \
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asm volatile(__stringify_label(c) ":\n\t" \
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".pushsection .discard.reachable\n\t" \
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".long " __stringify_label(c) "b - .\n\t" \
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".popsection\n\t"); \
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})
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#define annotate_reachable() __annotate_reachable(__COUNTER__)
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#define __annotate_unreachable(c) ({ \
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asm volatile(__stringify_label(c) ":\n\t" \
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".pushsection .discard.unreachable\n\t" \
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".long " __stringify_label(c) "b - .\n\t" \
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".popsection\n\t" : : "i" (c)); \
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})
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#define annotate_unreachable() __annotate_unreachable(__COUNTER__)
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/* Annotate a C jump table to allow objtool to follow the code flow */
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#define __annotate_jump_table __section(".rodata..c_jump_table")
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#else /* !CONFIG_OBJTOOL */
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#define annotate_reachable()
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#define annotate_unreachable()
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#define __annotate_jump_table
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#endif /* CONFIG_OBJTOOL */
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#ifndef unreachable
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# define unreachable() do { \
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annotate_unreachable(); \
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__builtin_unreachable(); \
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} while (0)
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#endif
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/*
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* KENTRY - kernel entry point
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* This can be used to annotate symbols (functions or data) that are used
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* without their linker symbol being referenced explicitly. For example,
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* interrupt vector handlers, or functions in the kernel image that are found
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* programatically.
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*
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* Not required for symbols exported with EXPORT_SYMBOL, or initcalls. Those
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* are handled in their own way (with KEEP() in linker scripts).
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*
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* KENTRY can be avoided if the symbols in question are marked as KEEP() in the
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* linker script. For example an architecture could KEEP() its entire
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* boot/exception vector code rather than annotate each function and data.
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*/
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#ifndef KENTRY
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# define KENTRY(sym) \
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extern typeof(sym) sym; \
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static const unsigned long __kentry_##sym \
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__used \
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__attribute__((__section__("___kentry+" #sym))) \
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= (unsigned long)&sym;
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#endif
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#ifndef RELOC_HIDE
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# define RELOC_HIDE(ptr, off) \
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({ unsigned long __ptr; \
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__ptr = (unsigned long) (ptr); \
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(typeof(ptr)) (__ptr + (off)); })
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#endif
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#define absolute_pointer(val) RELOC_HIDE((void *)(val), 0)
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#ifndef OPTIMIZER_HIDE_VAR
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/* Make the optimizer believe the variable can be manipulated arbitrarily. */
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#define OPTIMIZER_HIDE_VAR(var) \
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__asm__ ("" : "=r" (var) : "0" (var))
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#endif
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#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
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/**
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* data_race - mark an expression as containing intentional data races
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*
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* This data_race() macro is useful for situations in which data races
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* should be forgiven. One example is diagnostic code that accesses
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* shared variables but is not a part of the core synchronization design.
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*
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* This macro *does not* affect normal code generation, but is a hint
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* to tooling that data races here are to be ignored.
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*/
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#define data_race(expr) \
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({ \
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__unqual_scalar_typeof(({ expr; })) __v = ({ \
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__kcsan_disable_current(); \
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expr; \
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}); \
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__kcsan_enable_current(); \
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__v; \
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})
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#endif /* __KERNEL__ */
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/*
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* Force the compiler to emit 'sym' as a symbol, so that we can reference
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* it from inline assembler. Necessary in case 'sym' could be inlined
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* otherwise, or eliminated entirely due to lack of references that are
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* visible to the compiler.
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*/
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#define ___ADDRESSABLE(sym, __attrs) \
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static void * __used __attrs \
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__UNIQUE_ID(__PASTE(__addressable_,sym)) = (void *)&sym;
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#define __ADDRESSABLE(sym) \
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___ADDRESSABLE(sym, __section(".discard.addressable"))
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/**
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* offset_to_ptr - convert a relative memory offset to an absolute pointer
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* @off: the address of the 32-bit offset value
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*/
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static inline void *offset_to_ptr(const int *off)
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{
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return (void *)((unsigned long)off + *off);
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}
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#endif /* __ASSEMBLY__ */
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/* &a[0] degrades to a pointer: a different type from an array */
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#define __must_be_array(a) BUILD_BUG_ON_ZERO(__same_type((a), &(a)[0]))
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/*
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* This returns a constant expression while determining if an argument is
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* a constant expression, most importantly without evaluating the argument.
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* Glory to Martin Uecker <Martin.Uecker@med.uni-goettingen.de>
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*/
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#define __is_constexpr(x) \
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(sizeof(int) == sizeof(*(8 ? ((void *)((long)(x) * 0l)) : (int *)8)))
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/*
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* Whether 'type' is a signed type or an unsigned type. Supports scalar types,
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* bool and also pointer types.
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*/
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#define is_signed_type(type) (((type)(-1)) < (__force type)1)
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#define is_unsigned_type(type) (!is_signed_type(type))
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/*
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* This is needed in functions which generate the stack canary, see
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* arch/x86/kernel/smpboot.c::start_secondary() for an example.
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*/
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#define prevent_tail_call_optimization() mb()
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#include <asm/rwonce.h>
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#endif /* __LINUX_COMPILER_H */
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