From 895a050e04f19f0bed2b227f67902187daf09409 Mon Sep 17 00:00:00 2001
From: Jakub Berkop <jakub.berkop@gmail.com>
Date: Fri, 18 Feb 2022 22:12:35 +0100
Subject: [PATCH] Kernel: Fixed argument passing for profiling_enable syscall

Arguments larger than 32bit need to be passed as a pointer on a 32bit
architectures. sys$profiling_enable has u64 event_mask argument,
which means that it needs to be passed as an pointer. Previously upper
32bits were filled by garbage.
---
 Kernel/Process.h                     | 2 +-
 Kernel/Syscalls/profiling.cpp        | 6 +++++-
 Kernel/init.cpp                      | 3 ++-
 Userland/Libraries/LibC/serenity.cpp | 2 +-
 4 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/Kernel/Process.h b/Kernel/Process.h
index 092df9f8af..1043901d34 100644
--- a/Kernel/Process.h
+++ b/Kernel/Process.h
@@ -390,7 +390,7 @@ public:
     ErrorOr<FlatPtr> sys$getrandom(Userspace<void*>, size_t, unsigned int);
     ErrorOr<FlatPtr> sys$getkeymap(Userspace<const Syscall::SC_getkeymap_params*>);
     ErrorOr<FlatPtr> sys$setkeymap(Userspace<const Syscall::SC_setkeymap_params*>);
-    ErrorOr<FlatPtr> sys$profiling_enable(pid_t, u64);
+    ErrorOr<FlatPtr> sys$profiling_enable(pid_t, Userspace<u64 const*>);
     ErrorOr<FlatPtr> sys$profiling_disable(pid_t);
     ErrorOr<FlatPtr> sys$profiling_free_buffer(pid_t);
     ErrorOr<FlatPtr> sys$futex(Userspace<const Syscall::SC_futex_params*>);
diff --git a/Kernel/Syscalls/profiling.cpp b/Kernel/Syscalls/profiling.cpp
index 251eee7a5c..3c154f148b 100644
--- a/Kernel/Syscalls/profiling.cpp
+++ b/Kernel/Syscalls/profiling.cpp
@@ -16,11 +16,15 @@ bool g_profiling_all_threads;
 PerformanceEventBuffer* g_global_perf_events;
 u64 g_profiling_event_mask;
 
-ErrorOr<FlatPtr> Process::sys$profiling_enable(pid_t pid, u64 event_mask)
+// NOTE: event_mask needs to be passed as a pointer as u64
+//       does not fit into a register on 32bit architectures.
+ErrorOr<FlatPtr> Process::sys$profiling_enable(pid_t pid, Userspace<u64 const*> userspace_event_mask)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     TRY(require_no_promises());
 
+    const auto event_mask = TRY(copy_typed_from_user(userspace_event_mask));
+
     if (pid == -1) {
         if (!is_superuser())
             return EPERM;
diff --git a/Kernel/init.cpp b/Kernel/init.cpp
index 9a7da70dfa..50828444fc 100644
--- a/Kernel/init.cpp
+++ b/Kernel/init.cpp
@@ -373,7 +373,8 @@ void init_stage2(void*)
     if (boot_profiling) {
         dbgln("Starting full system boot profiling");
         MutexLocker mutex_locker(Process::current().big_lock());
-        auto result = Process::current().sys$profiling_enable(-1, ~0ull);
+        const auto enable_all = ~(u64)0;
+        auto result = Process::current().sys$profiling_enable(-1, reinterpret_cast<FlatPtr>(&enable_all));
         VERIFY(!result.is_error());
     }
 
diff --git a/Userland/Libraries/LibC/serenity.cpp b/Userland/Libraries/LibC/serenity.cpp
index 739c8fc8fd..e67e98e284 100644
--- a/Userland/Libraries/LibC/serenity.cpp
+++ b/Userland/Libraries/LibC/serenity.cpp
@@ -22,7 +22,7 @@ int disown(pid_t pid)
 
 int profiling_enable(pid_t pid, uint64_t event_mask)
 {
-    int rc = syscall(SC_profiling_enable, pid, event_mask);
+    int rc = syscall(SC_profiling_enable, pid, &event_mask);
     __RETURN_WITH_ERRNO(rc, rc, -1);
 }