arch/csky/kernel/ftrace.c:152:6: warning: no previous prototype for 'prepare_ftrace_return'

From: kernel test robot
Date: Sun Aug 15 2021 - 16:41:15 EST

Hi Julian,

First bad commit (maybe != root cause):

tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: ecf93431963a95c0f475921101bedc0dd62ec96d
commit: 7d37cb2c912dc5c25ffac784a4f9b98c06c6bd08 lib: fix kconfig dependency on ARCH_WANT_FRAME_POINTERS
date: 4 months ago
config: csky-randconfig-r026-20210816 (attached as .config)
compiler: csky-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7d37cb2c912dc5c25ffac784a4f9b98c06c6bd08
git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
git fetch --no-tags linus master
git checkout 7d37cb2c912dc5c25ffac784a4f9b98c06c6bd08
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=csky

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

>> arch/csky/kernel/ftrace.c:152:6: warning: no previous prototype for 'prepare_ftrace_return' [-Wmissing-prototypes]
152 | void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
| ^~~~~~~~~~~~~~~~~~~~~

Kconfig warnings: (for reference only)
WARNING: unmet direct dependencies detected for LOCKDEP
Depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT && (FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86)
Selected by
- PROVE_LOCKING && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
- LOCK_STAT && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT
- DEBUG_LOCK_ALLOC && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT


vim +/prepare_ftrace_return +152 arch/csky/kernel/ftrace.c

89a3927a775c0a Guo Ren 2020-02-18 150
d7950be145c84c Guo Ren 2018-12-15 151 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
d7950be145c84c Guo Ren 2018-12-15 @152 void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr,
d7950be145c84c Guo Ren 2018-12-15 153 unsigned long frame_pointer)
d7950be145c84c Guo Ren 2018-12-15 154 {
d7950be145c84c Guo Ren 2018-12-15 155 unsigned long return_hooker = (unsigned long)&return_to_handler;
d7950be145c84c Guo Ren 2018-12-15 156 unsigned long old;
230c77a5e92a29 Guo Ren 2018-12-09 157
d7950be145c84c Guo Ren 2018-12-15 158 if (unlikely(atomic_read(&current->tracing_graph_pause)))
d7950be145c84c Guo Ren 2018-12-15 159 return;
230c77a5e92a29 Guo Ren 2018-12-09 160
d7950be145c84c Guo Ren 2018-12-15 161 old = *parent;
230c77a5e92a29 Guo Ren 2018-12-09 162
d7950be145c84c Guo Ren 2018-12-15 163 if (!function_graph_enter(old, self_addr,
d7950be145c84c Guo Ren 2018-12-15 164 *(unsigned long *)frame_pointer, parent)) {
d7950be145c84c Guo Ren 2018-12-15 165 /*
d7950be145c84c Guo Ren 2018-12-15 166 * For csky-gcc function has sub-call:
d7950be145c84c Guo Ren 2018-12-15 167 * subi sp, sp, 8
d7950be145c84c Guo Ren 2018-12-15 168 * stw r8, (sp, 0)
d7950be145c84c Guo Ren 2018-12-15 169 * mov r8, sp
d7950be145c84c Guo Ren 2018-12-15 170 * st.w r15, (sp, 0x4)
d7950be145c84c Guo Ren 2018-12-15 171 * push r15
d7950be145c84c Guo Ren 2018-12-15 172 * jl _mcount
d7950be145c84c Guo Ren 2018-12-15 173 * We only need set *parent for resume
d7950be145c84c Guo Ren 2018-12-15 174 *
d7950be145c84c Guo Ren 2018-12-15 175 * For csky-gcc function has no sub-call:
d7950be145c84c Guo Ren 2018-12-15 176 * subi sp, sp, 4
d7950be145c84c Guo Ren 2018-12-15 177 * stw r8, (sp, 0)
d7950be145c84c Guo Ren 2018-12-15 178 * mov r8, sp
d7950be145c84c Guo Ren 2018-12-15 179 * push r15
d7950be145c84c Guo Ren 2018-12-15 180 * jl _mcount
d7950be145c84c Guo Ren 2018-12-15 181 * We need set *parent and *(frame_pointer + 4) for resume,
d7950be145c84c Guo Ren 2018-12-15 182 * because lr is resumed twice.
d7950be145c84c Guo Ren 2018-12-15 183 */
d7950be145c84c Guo Ren 2018-12-15 184 *parent = return_hooker;
d7950be145c84c Guo Ren 2018-12-15 185 frame_pointer += 4;
d7950be145c84c Guo Ren 2018-12-15 186 if (*(unsigned long *)frame_pointer == old)
d7950be145c84c Guo Ren 2018-12-15 187 *(unsigned long *)frame_pointer = return_hooker;
d7950be145c84c Guo Ren 2018-12-15 188 }
230c77a5e92a29 Guo Ren 2018-12-09 189 }
28bb030f933344 Guo Ren 2019-03-01 190

:::::: The code at line 152 was first introduced by commit
:::::: d7950be145c84ca5094c52bc1ad1e7f1893d0f19 csky: ftrace call graph supported.

:::::: TO: Guo Ren <ren_guo@xxxxxxxxx>
:::::: CC: Guo Ren <ren_guo@xxxxxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx

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