93b3cca1cc
Commit5963e317b1("ftrace/x86: Do not change stacks in DEBUG when calling lockdep") prevented lockdep calls from the int3 breakpoint handler from reseting the stack if a function that was called was in the process of being converted for tracing and had a breakpoint on it. The idea is, before calling the lockdep code, do a load_idt() to the special IDT that kept the breakpoint stack from reseting. This worked well as a quick fix for this kernel release, until a certain config caused a lockup in the function tracer start up tests. Investigating it, I found that the load_idt that was used to prevent the int3 from changing stacks was itself being traced! Even though the config had CONFIG_OPTIMIZE_INLINING disabled, and all 'inline' tags were set to always inline, there were still cases that it did not inline! This was caused by CONFIG_PARAVIRT_GUEST, where it would add a pointer to the native_load_idt() which made that function to be traced. Commit45959ee7aa("ftrace: Do not function trace inlined functions") only touched the 'inline' tags when CONFIG_OPMITIZE_INLINING was enabled. PARAVIRT_GUEST shows that this was not enough and we need to also mark always_inline with notrace as well. Reported-by: Fengguang Wu <wfg@linux.intel.com> Tested-by: Fengguang Wu <wfg@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
112 lines
3.9 KiB
C
112 lines
3.9 KiB
C
#ifndef __LINUX_COMPILER_H
|
|
#error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
|
|
#endif
|
|
|
|
/*
|
|
* Common definitions for all gcc versions go here.
|
|
*/
|
|
|
|
|
|
/* Optimization barrier */
|
|
/* The "volatile" is due to gcc bugs */
|
|
#define barrier() __asm__ __volatile__("": : :"memory")
|
|
|
|
/*
|
|
* This macro obfuscates arithmetic on a variable address so that gcc
|
|
* shouldn't recognize the original var, and make assumptions about it.
|
|
*
|
|
* This is needed because the C standard makes it undefined to do
|
|
* pointer arithmetic on "objects" outside their boundaries and the
|
|
* gcc optimizers assume this is the case. In particular they
|
|
* assume such arithmetic does not wrap.
|
|
*
|
|
* A miscompilation has been observed because of this on PPC.
|
|
* To work around it we hide the relationship of the pointer and the object
|
|
* using this macro.
|
|
*
|
|
* Versions of the ppc64 compiler before 4.1 had a bug where use of
|
|
* RELOC_HIDE could trash r30. The bug can be worked around by changing
|
|
* the inline assembly constraint from =g to =r, in this particular
|
|
* case either is valid.
|
|
*/
|
|
#define RELOC_HIDE(ptr, off) \
|
|
({ unsigned long __ptr; \
|
|
__asm__ ("" : "=r"(__ptr) : "0"(ptr)); \
|
|
(typeof(ptr)) (__ptr + (off)); })
|
|
|
|
#ifdef __CHECKER__
|
|
#define __must_be_array(arr) 0
|
|
#else
|
|
/* &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]))
|
|
#endif
|
|
|
|
/*
|
|
* Force always-inline if the user requests it so via the .config,
|
|
* or if gcc is too old:
|
|
*/
|
|
#if !defined(CONFIG_ARCH_SUPPORTS_OPTIMIZED_INLINING) || \
|
|
!defined(CONFIG_OPTIMIZE_INLINING) || (__GNUC__ < 4)
|
|
# define inline inline __attribute__((always_inline)) notrace
|
|
# define __inline__ __inline__ __attribute__((always_inline)) notrace
|
|
# define __inline __inline __attribute__((always_inline)) notrace
|
|
#else
|
|
/* A lot of inline functions can cause havoc with function tracing */
|
|
# define inline inline notrace
|
|
# define __inline__ __inline__ notrace
|
|
# define __inline __inline notrace
|
|
#endif
|
|
|
|
#define __deprecated __attribute__((deprecated))
|
|
#define __packed __attribute__((packed))
|
|
#define __weak __attribute__((weak))
|
|
|
|
/*
|
|
* it doesn't make sense on ARM (currently the only user of __naked) to trace
|
|
* naked functions because then mcount is called without stack and frame pointer
|
|
* being set up and there is no chance to restore the lr register to the value
|
|
* before mcount was called.
|
|
*
|
|
* The asm() bodies of naked functions often depend on standard calling conventions,
|
|
* therefore they must be noinline and noclone. GCC 4.[56] currently fail to enforce
|
|
* this, so we must do so ourselves. See GCC PR44290.
|
|
*/
|
|
#define __naked __attribute__((naked)) noinline __noclone notrace
|
|
|
|
#define __noreturn __attribute__((noreturn))
|
|
|
|
/*
|
|
* From the GCC manual:
|
|
*
|
|
* Many functions have no effects except the return value and their
|
|
* return value depends only on the parameters and/or global
|
|
* variables. Such a function can be subject to common subexpression
|
|
* elimination and loop optimization just as an arithmetic operator
|
|
* would be.
|
|
* [...]
|
|
*/
|
|
#define __pure __attribute__((pure))
|
|
#define __aligned(x) __attribute__((aligned(x)))
|
|
#define __printf(a, b) __attribute__((format(printf, a, b)))
|
|
#define __scanf(a, b) __attribute__((format(scanf, a, b)))
|
|
#define noinline __attribute__((noinline))
|
|
#define __attribute_const__ __attribute__((__const__))
|
|
#define __maybe_unused __attribute__((unused))
|
|
#define __always_unused __attribute__((unused))
|
|
|
|
#define __gcc_header(x) #x
|
|
#define _gcc_header(x) __gcc_header(linux/compiler-gcc##x.h)
|
|
#define gcc_header(x) _gcc_header(x)
|
|
#include gcc_header(__GNUC__)
|
|
|
|
#if !defined(__noclone)
|
|
#define __noclone /* not needed */
|
|
#endif
|
|
|
|
/*
|
|
* A trick to suppress uninitialized variable warning without generating any
|
|
* code
|
|
*/
|
|
#define uninitialized_var(x) x = x
|
|
|
|
#define __always_inline inline __attribute__((always_inline))
|