[v6,8/8] LoongArch: Add kernel livepatching support
Commit Message
The arch-specified function ftrace_regs_set_instruction_pointer() has been
implemented in arch/loongarch/include/asm/ftrace.h, so here only implement
arch_stack_walk_reliable() function.
Here are the test logs:
[root@linux fedora]# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-6.8.0-rc2 root=/dev/sda3
[root@linux fedora]# modprobe livepatch-sample
[root@linux fedora]# cat /proc/cmdline
this has been live patched
[root@linux fedora]# echo 0 > /sys/kernel/livepatch/livepatch_sample/enabled
[root@linux fedora]# rmmod livepatch_sample
[root@linux fedora]# cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-6.8.0-rc2 root=/dev/sda3
[root@linux fedora]# dmesg -t | tail -5
livepatch: enabling patch 'livepatch_sample'
livepatch: 'livepatch_sample': starting patching transition
livepatch: 'livepatch_sample': patching complete
livepatch: 'livepatch_sample': starting unpatching transition
livepatch: 'livepatch_sample': unpatching complete
Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
---
arch/loongarch/Kconfig | 4 +++
arch/loongarch/include/asm/thread_info.h | 2 ++
arch/loongarch/kernel/stacktrace.c | 41 ++++++++++++++++++++++++
3 files changed, 47 insertions(+)
@@ -132,6 +132,7 @@ config LOONGARCH
select HAVE_KPROBES_ON_FTRACE
select HAVE_KRETPROBES
select HAVE_KVM
+ select HAVE_LIVEPATCH
select HAVE_MOD_ARCH_SPECIFIC
select HAVE_NMI
select HAVE_OBJTOOL if AS_HAS_EXPLICIT_RELOCS
@@ -141,6 +142,7 @@ config LOONGARCH
select HAVE_PERF_USER_STACK_DUMP
select HAVE_PREEMPT_DYNAMIC_KEY
select HAVE_REGS_AND_STACK_ACCESS_API
+ select HAVE_RELIABLE_STACKTRACE if UNWINDER_ORC
select HAVE_RETHOOK
select HAVE_RSEQ
select HAVE_RUST
@@ -695,6 +697,8 @@ config KASAN_SHADOW_OFFSET
default 0x0
depends on KASAN
+source "kernel/livepatch/Kconfig"
+
menu "Power management options"
config ARCH_SUSPEND_POSSIBLE
@@ -86,6 +86,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
#define TIF_LASX_CTX_LIVE 18 /* LASX context must be preserved */
#define TIF_USEDLBT 19 /* LBT was used by this task this quantum (SMP) */
#define TIF_LBT_CTX_LIVE 20 /* LBT context must be preserved */
+#define TIF_PATCH_PENDING 21 /* pending live patching update */
#define _TIF_SIGPENDING (1<<TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1<<TIF_NEED_RESCHED)
@@ -105,6 +106,7 @@ register unsigned long current_stack_pointer __asm__("$sp");
#define _TIF_LASX_CTX_LIVE (1<<TIF_LASX_CTX_LIVE)
#define _TIF_USEDLBT (1<<TIF_USEDLBT)
#define _TIF_LBT_CTX_LIVE (1<<TIF_LBT_CTX_LIVE)
+#define _TIF_PATCH_PENDING (1<<TIF_PATCH_PENDING)
#endif /* __KERNEL__ */
#endif /* _ASM_THREAD_INFO_H */
@@ -40,6 +40,47 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
}
}
+int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
+ void *cookie, struct task_struct *task)
+{
+ unsigned long addr;
+ struct pt_regs dummyregs;
+ struct pt_regs *regs = &dummyregs;
+ struct unwind_state state;
+
+ if (task == current) {
+ regs->regs[3] = (unsigned long)__builtin_frame_address(0);
+ regs->csr_era = (unsigned long)__builtin_return_address(0);
+ } else {
+ regs->regs[3] = thread_saved_fp(task);
+ regs->csr_era = thread_saved_ra(task);
+ }
+ regs->regs[1] = 0;
+ regs->regs[22] = 0;
+
+ for (unwind_start(&state, task, regs);
+ !unwind_done(&state) && !unwind_error(&state);
+ unwind_next_frame(&state)) {
+ addr = unwind_get_return_address(&state);
+
+ /*
+ * A NULL or invalid return address probably means there's some
+ * generated code which __kernel_text_address() doesn't know about.
+ */
+ if (!addr)
+ return -EINVAL;
+
+ if (!consume_entry(cookie, addr))
+ return -EINVAL;
+ }
+
+ /* Check for stack corruption */
+ if (unwind_error(&state))
+ return -EINVAL;
+
+ return 0;
+}
+
static int
copy_stack_frame(unsigned long fp, struct stack_frame *frame)
{