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2024-03-11LoongArch: Add ORC stack unwinder supportTiezhu Yang1-0/+5
The kernel CONFIG_UNWINDER_ORC option enables the ORC unwinder, which is similar in concept to a DWARF unwinder. The difference is that the format of the ORC data is much simpler than DWARF, which in turn allows the ORC unwinder to be much simpler and faster. The ORC data consists of unwind tables which are generated by objtool. After analyzing all the code paths of a .o file, it determines information about the stack state at each instruction address in the file and outputs that information to the .orc_unwind and .orc_unwind_ip sections. The per-object ORC sections are combined at link time and are sorted and post-processed at boot time. The unwinder uses the resulting data to correlate instruction addresses with their stack states at run time. Most of the logic are similar with x86, in order to get ra info before ra is saved into stack, add ra_reg and ra_offset into orc_entry. At the same time, modify some arch-specific code to silence the objtool warnings. Co-developed-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Co-developed-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Youling Tang <tangyouling@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-10-18LoongArch: Use SYM_CODE_* to annotate exception handlersTiezhu Yang1-2/+2
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>
2023-09-06LoongArch: Add basic KGDB & KDB supportQing Zhang1-0/+5
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>
2023-02-25LoongArch: Mark some assembler symbols as non-kprobe-ableTiezhu Yang1-0/+1
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>
2023-02-25LoongArch: Use la.pcrel instead of la.abs when it's trivially possibleXi Ruoyao1-45/+45
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>
2022-07-29LoongArch: Re-tab the assembly filesWANG Xuerui1-2/+2
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>
2022-06-03LoongArch: Add system call supportHuacai Chen1-0/+89
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>