ptrace_get_syscall_info: factor out ptrace_get_syscall_info_op

Move the code that calculates the type of the system call stop out of
ptrace_get_syscall_info() into a separate function
ptrace_get_syscall_info_op() which is going to be used later to implement
PTRACE_SET_SYSCALL_INFO API.

Link: https://lkml.kernel.org/r/20250303112038.GE24170@strace.io
Signed-off-by: Dmitry V. Levin <ldv@strace.io>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexey Gladkov (Intel) <legion@kernel.org>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: anton ivanov <anton.ivanov@cambridgegreys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Charlie Jenkins <charlie@rivosinc.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Zankel <chris@zankel.net>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Davide Berardi <berardi.dav@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Eugene Syromiatnikov <esyr@redhat.com>
Cc: Eugene Syromyatnikov <evgsyr@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Maciej W. Rozycki <macro@orcam.me.uk>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Renzo Davoi <renzo@cs.unibo.it>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index d5f89f9ef29f65f137ef8a6978e6dbe75564056b..22e7d74cf4cd418e78def1f1ecca22a1023e8812 100644 (file)
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -921,7 +921,6 @@ ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
        unsigned long args[ARRAY_SIZE(info->entry.args)];
        int i;
 
-       info->op = PTRACE_SYSCALL_INFO_ENTRY;
        info->entry.nr = syscall_get_nr(child, regs);
        syscall_get_arguments(child, regs, args);
        for (i = 0; i < ARRAY_SIZE(args); i++)
@@ -943,7 +942,6 @@ ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
         * diverge significantly enough.
         */
        ptrace_get_syscall_info_entry(child, regs, info);
-       info->op = PTRACE_SYSCALL_INFO_SECCOMP;
        info->seccomp.ret_data = child->ptrace_message;
 
        /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
@@ -954,7 +952,6 @@ static unsigned long
 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
                             struct ptrace_syscall_info *info)
 {
-       info->op = PTRACE_SYSCALL_INFO_EXIT;
        info->exit.rval = syscall_get_error(child, regs);
        info->exit.is_error = !!info->exit.rval;
        if (!info->exit.is_error)
@@ -965,19 +962,8 @@ ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
 }
 
 static int
-ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
-                       void __user *datavp)
+ptrace_get_syscall_info_op(struct task_struct *child)
 {
-       struct pt_regs *regs = task_pt_regs(child);
-       struct ptrace_syscall_info info = {
-               .op = PTRACE_SYSCALL_INFO_NONE,
-               .arch = syscall_get_arch(child),
-               .instruction_pointer = instruction_pointer(regs),
-               .stack_pointer = user_stack_pointer(regs),
-       };
-       unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
-       unsigned long write_size;
-
        /*
         * This does not need lock_task_sighand() to access
         * child->last_siginfo because ptrace_freeze_traced()
@@ -988,18 +974,42 @@ ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
        case SIGTRAP | 0x80:
                switch (child->ptrace_message) {
                case PTRACE_EVENTMSG_SYSCALL_ENTRY:
-                       actual_size = ptrace_get_syscall_info_entry(child, regs,
-                                                                   &info);
-                       break;
+                       return PTRACE_SYSCALL_INFO_ENTRY;
                case PTRACE_EVENTMSG_SYSCALL_EXIT:
-                       actual_size = ptrace_get_syscall_info_exit(child, regs,
-                                                                  &info);
-                       break;
+                       return PTRACE_SYSCALL_INFO_EXIT;
+               default:
+                       return PTRACE_SYSCALL_INFO_NONE;
                }
-               break;
        case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
-               actual_size = ptrace_get_syscall_info_seccomp(child, regs,
-                                                             &info);
+               return PTRACE_SYSCALL_INFO_SECCOMP;
+       default:
+               return PTRACE_SYSCALL_INFO_NONE;
+       }
+}
+
+static int
+ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
+                       void __user *datavp)
+{
+       struct pt_regs *regs = task_pt_regs(child);
+       struct ptrace_syscall_info info = {
+               .op = ptrace_get_syscall_info_op(child),
+               .arch = syscall_get_arch(child),
+               .instruction_pointer = instruction_pointer(regs),
+               .stack_pointer = user_stack_pointer(regs),
+       };
+       unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
+       unsigned long write_size;
+
+       switch (info.op) {
+       case PTRACE_SYSCALL_INFO_ENTRY:
+               actual_size = ptrace_get_syscall_info_entry(child, regs, &info);
+               break;
+       case PTRACE_SYSCALL_INFO_EXIT:
+               actual_size = ptrace_get_syscall_info_exit(child, regs, &info);
+               break;
+       case PTRACE_SYSCALL_INFO_SECCOMP:
+               actual_size = ptrace_get_syscall_info_seccomp(child, regs, &info);
                break;
        }