6 Commits

Author SHA1 Message Date
Tiezhu Yang
00c2ca84c6 LoongArch: Use SYM_CODE_* to annotate exception handlers
As described in include/linux/linkage.h,

  FUNC -- C-like functions (proper stack frame etc.)
  CODE -- non-C code (e.g. irq handlers with different, special stack etc.)

  SYM_FUNC_{START, END} -- use for global functions
  SYM_CODE_{START, END} -- use for non-C (special) functions

So use SYM_CODE_* to annotate exception handlers.

Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-18 08:42:52 +08:00
Qing Zhang
e14dd07696 LoongArch: Add basic KGDB & KDB support
KGDB is intended to be used as a source level debugger for the Linux
kernel. It is used along with gdb to debug a Linux kernel. GDB can be
used to "break in" to the kernel to inspect memory, variables and regs
similar to the way an application developer would use GDB to debug an
application. KDB is a frontend of KGDB which is similar to GDB.

By now, in addition to the generic KGDB features, the LoongArch KGDB
implements the following features:
- Hardware breakpoints/watchpoints;
- Software single-step support for KDB.

Signed-off-by: Qing Zhang <zhangqing@loongson.cn>   # Framework & CoreFeature
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn> # BreakPoint & SingleStep
Signed-off-by: Hui Li <lihui@loongson.cn>           # Some Minor Improvements
Signed-off-by: Randy Dunlap <rdunlap@infradead.org> # Some Build Error Fixes
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-09-06 22:53:55 +08:00
Tiezhu Yang
fcf77d0162 LoongArch: Mark some assembler symbols as non-kprobe-able
Some assembler symbols are not kprobe safe, such as handle_syscall (used
as syscall exception handler), *memset*/*memcpy*/*memmove* (may cause
recursive exceptions), they can not be instrumented, just blacklist them
for kprobing.

Here is a related problem and discussion:
Link: https://lore.kernel.org/lkml/20230114143859.7ccc45c1c5d9ce302113ab0a@kernel.org/

Tested-by: Jeff Xie <xiehuan09@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-02-25 22:12:17 +08:00
Xi Ruoyao
f733f119e9 LoongArch: Use la.pcrel instead of la.abs when it's trivially possible
Let's start to kill la.abs in preparation for the subsequent support of
the PIE kernel.

BTW, Re-tab the indention in arch/loongarch/kernel/entry.S for alignment.

Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-02-25 22:12:16 +08:00
WANG Xuerui
f5c3c22f21 LoongArch: Re-tab the assembly files
Reflow the *.S files for better stylistic consistency, namely hard tabs
after mnemonic position, and vertical alignment of the first operand
with hard tabs. Tab width is obviously 8. Some pre-existing intra-block
vertical alignments are preserved.

Signed-off-by: WANG Xuerui <git@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-07-29 18:22:32 +08:00
Huacai Chen
be769645a2 LoongArch: Add system call support
Add system call support and related uaccess.h for LoongArch.

Q: Why keep _ARCH_WANT_SYS_CLONE definition while there is clone3:
A: The latest glibc release has some basic support for clone3 but it is
   not complete. E.g., pthread_create() and spawni() have converted to
   use clone3 but fork() will still use clone. Moreover, some seccomp
   related applications can still not work perfectly with clone3. E.g.,
   Chromium sandbox cannot work at all and there is no solution for it,
   which is more terrible than the fork() story [1].

[1] https://chromium-review.googlesource.com/c/chromium/src/+/2936184

Reviewed-by: WANG Xuerui <git@xen0n.name>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2022-06-03 20:09:28 +08:00