entry: Add arch_ptrace_report_syscall_entry/exit()

ARM64 requires a architecture specific ptrace wrapper as it needs to save
and restore scratch registers.

Provide arch_ptrace_report_syscall_entry/exit() wrappers which fall back to
ptrace_report_syscall_entry/exit() if the architecture does not provide
them.

No functional change intended.

[ tglx: Massaged changelog and comments ]

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com>
Link: https://patch.msgid.link/20260128031934.3906955-11-ruanjinjie@huawei.com

Author: ruanjinjie-eng

include/linux/entry-common.h

@@ -45,6 +45,24 @@
 				 SYSCALL_WORK_SYSCALL_EXIT_TRAP	|	\
 				 ARCH_SYSCALL_WORK_EXIT)
 
+/**
+ * arch_ptrace_report_syscall_entry - Architecture specific ptrace_report_syscall_entry() wrapper
+ *
+ * Invoked from syscall_trace_enter() to wrap ptrace_report_syscall_entry().
+ *
+ * This allows architecture specific ptrace_report_syscall_entry()
+ * implementations. If not defined by the architecture this falls back to
+ * to ptrace_report_syscall_entry().
+ */
+static __always_inline int arch_ptrace_report_syscall_entry(struct pt_regs *regs);
+
+#ifndef arch_ptrace_report_syscall_entry
+static __always_inline int arch_ptrace_report_syscall_entry(struct pt_regs *regs)
+{
+	return ptrace_report_syscall_entry(regs);
+}
+#endif
+
 long syscall_trace_enter(struct pt_regs *regs, unsigned long work);
 
 /**
@@ -112,6 +130,24 @@ static __always_inline long syscall_enter_from_user_mode(struct pt_regs *regs, l
 	return ret;
 }
 
+/**
+ * arch_ptrace_report_syscall_exit - Architecture specific ptrace_report_syscall_exit()
+ *
+ * This allows architecture specific ptrace_report_syscall_exit()
+ * implementations. If not defined by the architecture this falls back to
+ * to ptrace_report_syscall_exit().
+ */
+static __always_inline void arch_ptrace_report_syscall_exit(struct pt_regs *regs,
+							    int step);
+
+#ifndef arch_ptrace_report_syscall_exit
+static __always_inline void arch_ptrace_report_syscall_exit(struct pt_regs *regs,
+							    int step)
+{
+	ptrace_report_syscall_exit(regs, step);
+}
+#endif
+
 /**
  * syscall_exit_work - Handle work before returning to user mode
  * @regs:	Pointer to current pt_regs

kernel/entry/syscall-common.c

@@ -33,7 +33,7 @@ long syscall_trace_enter(struct pt_regs *regs, unsigned long work)
 
 	/* Handle ptrace */
 	if (work & (SYSCALL_WORK_SYSCALL_TRACE | SYSCALL_WORK_SYSCALL_EMU)) {
-		ret = ptrace_report_syscall_entry(regs);
+		ret = arch_ptrace_report_syscall_entry(regs);
 		if (ret || (work & SYSCALL_WORK_SYSCALL_EMU))
 			return -1L;
 	}
@@ -99,5 +99,5 @@ void syscall_exit_work(struct pt_regs *regs, unsigned long work)
 
 	step = report_single_step(work);
 	if (step || work & SYSCALL_WORK_SYSCALL_TRACE)
-		ptrace_report_syscall_exit(regs, step);
+		arch_ptrace_report_syscall_exit(regs, step);
 }