mirror of
https://gitee.com/open-loongarch/linux-6.12.git
synced 2026-10-25 20:47:11 +08:00
maoxiaochuan
395483d68b
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.