liyepan/openloongarch-linux-6.12
1
0
Fork 0
mirror of https://gitee.com/open-loongarch/linux-6.12.git synced 2026-10-25 12:37:11 +08:00
Code Issues Packages Projects Releases Wiki Activity

LoongArch: Add cflag -fno-isolate-erroneous-paths-dereference

Browse Source 
Currently, when compiling with GCC, there is no "break 7" instruction
for zero division due to using the option -mno-check-zero-division, but
the compiler still generates "break 0" instruction for zero division.

Here is a simple example:

  $ cat test.c
  int div(int a)
  {
      return a / 0;
  }
  $ gcc -O2 -S test.c -o test.s

GCC generates "break 0" on LoongArch and "ud2" on x86, objtool decodes
"ud2" as INSN_BUG for x86, so decode "break 0" as INSN_BUG can fix the
objtool warnings for LoongArch, but this is not the intention.

When decoding "break 0" as INSN_TRAP in the previous commit, the aim is
to handle "break 0" as a trap. The generated "break 0" for zero division
by GCC is not proper, it should generate a break instruction with proper
bug type, so add the GCC option -fno-isolate-erroneous-paths-dereference
to avoid generating the unexpected "break 0" instruction for now.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/r/202509200413.7uihAxJ5-lkp@intel.com/
Fixes: baad7830ee9a ("objtool/LoongArch: Mark types based on break immediate code")
Suggested-by: WANG Rui <wangrui@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: maoxiaochuan <maoxiaochuan@loongson.cn>
This commit is contained in:
maoxiaochuan
2025-11-10 08:55:42 +08:00
parent 26b4d62cd9
commit e2347c1e4a
1 changed files with 1 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/loongarch/Makefile
+1 -1
View File
@@ -131,7 +131,7 @@ LDFLAGS_vmlinux += -static -pie --no-dynamic-linker -z notext $(call ld-option
endif
entry-y = $(shell LC_ALL=C readelf -e vmlinux | grep 'Entry point address:'|grep -o '0x[0-9a-f]\{16\}')
cflags-y += $(call cc-option, -mno-check-zero-division)
cflags-y += $(call cc-option, -mno-check-zero-division -fno-isolate-erroneous-paths-dereference)
ifndef CONFIG_KASAN
cflags-y += -fno-builtin-memcpy -fno-builtin-memmove -fno-builtin-memset