Linux Kernel https://git.etezian.org/cgit.cgi/linux.git/atom?h=bh1745 2023-03-01T17:27:00+00:00 2023-03-01T17:27:00+00:00 Linus Torvalds torvalds@linux-foundation.org 2023-03-01T17:27:00+00:00 urn:sha1:a8356cdb5bd5abc74f814d76bd37900997fad35d Pull LoongArch updates from Huacai Chen: - Make -mstrict-align configurable - Add kernel relocation and KASLR support - Add single kernel image implementation for kdump - Add hardware breakpoints/watchpoints support - Add kprobes/kretprobes/kprobes_on_ftrace support - Add LoongArch support for some selftests. * tag 'loongarch-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson: (23 commits) selftests/ftrace: Add LoongArch kprobe args string tests support selftests/seccomp: Add LoongArch selftesting support tools: Add LoongArch build infrastructure samples/kprobes: Add LoongArch support LoongArch: Mark some assembler symbols as non-kprobe-able LoongArch: Add kprobes on ftrace support LoongArch: Add kretprobes support LoongArch: Add kprobes support LoongArch: Simulate branch and PC* instructions LoongArch: ptrace: Add hardware single step support LoongArch: ptrace: Add function argument access API LoongArch: ptrace: Expose hardware breakpoints to debuggers LoongArch: Add hardware breakpoints/watchpoints support LoongArch: kdump: Add crashkernel=YM handling LoongArch: kdump: Add single kernel image implementation LoongArch: Add support for kernel address space layout randomization (KASLR) LoongArch: Add support for kernel relocation LoongArch: Add la_abs macro implementation LoongArch: Add JUMP_VIRT_ADDR macro implementation to avoid using la.abs LoongArch: Use la.pcrel instead of la.abs when it's trivially possible ... 2023-02-25T14:12:17+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:fcf77d016216ae75a19078e1079c2511a6319a49 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> 2023-02-25T14:12:17+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:09e679c28a4def4ea8d4f618503c1d55c355ae5c Add kprobe_ftrace_handler() and arch_prepare_kprobe_ftrace() to support kprobes on ftrace, the code is similar with x86 and riscv. Here is a simple example: # echo 'p:myprobe kernel_clone' > /sys/kernel/debug/tracing/kprobe_events # echo 'r:myretprobe kernel_clone $retval' >> /sys/kernel/debug/tracing/kprobe_events # echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable # echo 1 > /sys/kernel/debug/tracing/events/kprobes/myretprobe/enable # echo 1 > /sys/kernel/debug/tracing/tracing_on # cat /sys/kernel/debug/tracing/trace # tracer: nop # # entries-in-buffer/entries-written: 2/2 #P:4 # # _-----=> irqs-off/BH-disabled # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / _-=> migrate-disable # |||| / delay # TASK-PID CPU# ||||| TIMESTAMP FUNCTION # | | | ||||| | | bash-488 [002] ..... 2041.190681: myprobe: (kernel_clone+0x0/0x40c) bash-488 [002] ..... 2041.190788: myretprobe: (__do_sys_clone+0x84/0xb8 <- kernel_clone) arg1=0x200 Tested-by: Jeff Xie <xiehuan09@gmail.com> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2023-02-25T14:12:17+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:3f5536860086d906b01ec5ed68cf50c7edcc40af Use the generic kretprobe trampoline handler to add kretprobes support for LoongArch. Tested-by: Jeff Xie <xiehuan09@gmail.com> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2023-02-25T14:12:17+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:6d4cc40fb5f58147defc6c0e9d86e6232fe31616 Kprobes allows you to trap at almost any kernel address and execute a callback function, this commit adds kprobes support for LoongArch. Tested-by: Jeff Xie <xiehuan09@gmail.com> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2023-02-25T14:12:17+00:00 Tiezhu Yang yangtiezhu@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:9b3441a6b0e1ed4796e7f5a8586c4d6023c4e3ab According to LoongArch Reference Manual, simulate branch and PC* instructions, this is preparation for later patch. Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#branch-instructions Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#_pcaddi_pcaddu121_pcaddu18l_pcalau12i Tested-by: Jeff Xie <xiehuan09@gmail.com> Co-developed-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Jinyang He <hejinyang@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2023-02-25T14:12:17+00:00 Qing Zhang zhangqing@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:424421a7f34c1222d20a6c279f13b9caa71ecc83 Use the generic ptrace_resume code for PTRACE_SYSCALL, PTRACE_CONT, PTRACE_KILL and PTRACE_SINGLESTEP handling. This implies defining arch_has_single_step() and implementing the user_enable_single_step() and user_disable_single_step() functions. LoongArch cannot do hardware single-stepping per se, the hardware single-stepping it is achieved by configuring the instruction fetch watchpoints (FWPS) and specifies that the next instruction must trigger the watch exception by setting the mask bit. In some scenarios CSR.FWPS.Skip is used to ignore the next hit result, avoid endless repeated triggering of the same watchpoint without canceling it. Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2023-02-25T14:12:17+00:00 Qing Zhang zhangqing@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:356bd6f23682f11f7afe923d86c7f5f852b97fb2 Add regs_get_argument() which returns N th argument of the function call, This enables ftrace kprobe events to access kernel function arguments via $argN syntax for later use. E.g.: echo 'p bio_add_page arg1=$arg1' > kprobe_events bash: echo: write error: Invalid argument Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2023-02-25T14:12:17+00:00 Qing Zhang zhangqing@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:1a69f7a161a78aead07cd4b811d796950e892fa4 Implement the regset-based ptrace interface that exposes hardware breakpoints to user-space debuggers to query and set instruction and data breakpoints. Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> 2023-02-25T14:12:17+00:00 Qing Zhang zhangqing@loongson.cn 2023-02-25T07:52:57+00:00 urn:sha1:edffa33c7bb5a73e90c754c7a497162b77d7c55f Use perf framework to manage hardware instruction and data breakpoints. LoongArch defines hardware watchpoint functions for instruction fetch and memory load/store operations. After the software configures hardware watchpoints, the processor hardware will monitor the access address of the instruction fetch and load/store operation, and trigger an exception of the watchpoint when it meets the conditions set by the watchpoint. The hardware monitoring points for instruction fetching and load/store operations each have a register for the overall configuration of all monitoring points, a register for recording the status of all monitoring points, and four registers required for configuration of each watchpoint individually. Signed-off-by: Qing Zhang <zhangqing@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>