MIPS: math-emu: Reuse name array in debugfs_fpuemu()

The FPU_STAT_CREATE_EX() macro used 114 times in debugfs_fpuemu()
declares a 32 byte char array to hold the name of a debugfs file. Since
each use of the macro declares a new char array out of the scope of all
the other uses, we end up with an unnecessarily large stack frame of
3648 bytes (ie. 114*32) plus the size of 2 pointers
(fpuemu_debugfs_base_dir & fpuemu_debugfs_inst_dir). This is enough to
trigger the frame size warnings from GCC in common configurations.

Avoid the unnecessary stack bloat by using a single name char array
which each usage of FPU_STAT_CREATE_EX() will reinitialize via the
strcpy() in adjust_instruction_counter_name().

Signed-off-by: Paul Burton <paulburton@kernel.org>
Reported-by: kbuild test robot <lkp@intel.com>
URL: https://lore.kernel.org/linux-mips/201911090929.xvXYuHUz%25lkp@intel.com/

diff --git a/arch/mips/math-emu/me-debugfs.c b/arch/mips/math-emu/me-debugfs.c
index 3877248..d5ad76b 100644 (file)
--- a/arch/mips/math-emu/me-debugfs.c
+++ b/arch/mips/math-emu/me-debugfs.c
@@ -189,6 +189,7 @@ static int __init debugfs_fpuemu(void)
 {
        struct dentry *fpuemu_debugfs_base_dir;
        struct dentry *fpuemu_debugfs_inst_dir;
+       char name[32];
 
        fpuemu_debugfs_base_dir = debugfs_create_dir("fpuemustats",
                                                     mips_debugfs_dir);
@@ -225,8 +226,6 @@ do {                                                                        \
 
 #define FPU_STAT_CREATE_EX(m)                                          \
 do {                                                                   \
-       char name[32];                                                  \
-                                                                       \
        adjust_instruction_counter_name(name, #m);                      \
                                                                        \
        debugfs_create_file(name, 0444, fpuemu_debugfs_inst_dir,        \