From 4ca39c71104084be36b672fbe10952ba88326fba Mon Sep 17 00:00:00 2001
From: Idan Horowitz <idan.horowitz@gmail.com>
Date: Mon, 29 Nov 2021 21:19:58 +0200
Subject: [PATCH] Kernel: Move the expand_range_to_page_boundaries helper to
 MemoryManager

This helper can (and will) be used in more parts of the kernel besides
the mmap-family of syscalls.
---
 Kernel/Memory/MemoryManager.h | 17 +++++++++++++++++
 Kernel/Syscalls/mmap.cpp      | 25 ++++---------------------
 2 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/Kernel/Memory/MemoryManager.h b/Kernel/Memory/MemoryManager.h
index 17cf63a65e..69ea905391 100644
--- a/Kernel/Memory/MemoryManager.h
+++ b/Kernel/Memory/MemoryManager.h
@@ -329,4 +329,21 @@ inline bool PhysicalPage::is_lazy_committed_page() const
     return this == &MM.lazy_committed_page();
 }
 
+inline ErrorOr<Memory::VirtualRange> expand_range_to_page_boundaries(FlatPtr address, size_t size)
+{
+    if (Memory::page_round_up_would_wrap(size))
+        return EINVAL;
+
+    if ((address + size) < address)
+        return EINVAL;
+
+    if (Memory::page_round_up_would_wrap(address + size))
+        return EINVAL;
+
+    auto base = VirtualAddress { address }.page_base();
+    auto end = Memory::page_round_up(address + size);
+
+    return Memory::VirtualRange { base, end - base.get() };
+}
+
 }
diff --git a/Kernel/Syscalls/mmap.cpp b/Kernel/Syscalls/mmap.cpp
index 9660c8b1c2..4d2856fab8 100644
--- a/Kernel/Syscalls/mmap.cpp
+++ b/Kernel/Syscalls/mmap.cpp
@@ -250,23 +250,6 @@ ErrorOr<FlatPtr> Process::sys$mmap(Userspace<const Syscall::SC_mmap_params*> use
     return region->vaddr().get();
 }
 
-static ErrorOr<Memory::VirtualRange> expand_range_to_page_boundaries(FlatPtr address, size_t size)
-{
-    if (Memory::page_round_up_would_wrap(size))
-        return EINVAL;
-
-    if ((address + size) < address)
-        return EINVAL;
-
-    if (Memory::page_round_up_would_wrap(address + size))
-        return EINVAL;
-
-    auto base = VirtualAddress { address }.page_base();
-    auto end = Memory::page_round_up(address + size);
-
-    return Memory::VirtualRange { base, end - base.get() };
-}
-
 ErrorOr<FlatPtr> Process::sys$mprotect(Userspace<void*> addr, size_t size, int prot)
 {
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
@@ -276,7 +259,7 @@ ErrorOr<FlatPtr> Process::sys$mprotect(Userspace<void*> addr, size_t size, int p
         REQUIRE_PROMISE(prot_exec);
     }
 
-    auto range_to_mprotect = TRY(expand_range_to_page_boundaries(addr.ptr(), size));
+    auto range_to_mprotect = TRY(Memory::expand_range_to_page_boundaries(addr.ptr(), size));
     if (!range_to_mprotect.size())
         return EINVAL;
 
@@ -411,7 +394,7 @@ ErrorOr<FlatPtr> Process::sys$madvise(Userspace<void*> address, size_t size, int
     VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this)
     REQUIRE_PROMISE(stdio);
 
-    auto range_to_madvise = TRY(expand_range_to_page_boundaries(address.ptr(), size));
+    auto range_to_madvise = TRY(Memory::expand_range_to_page_boundaries(address.ptr(), size));
 
     if (!range_to_madvise.size())
         return EINVAL;
@@ -447,7 +430,7 @@ ErrorOr<FlatPtr> Process::sys$set_mmap_name(Userspace<const Syscall::SC_set_mmap
         return ENAMETOOLONG;
 
     auto name = TRY(try_copy_kstring_from_user(params.name));
-    auto range = TRY(expand_range_to_page_boundaries((FlatPtr)params.addr, params.size));
+    auto range = TRY(Memory::expand_range_to_page_boundaries((FlatPtr)params.addr, params.size));
 
     auto* region = address_space().find_region_from_range(range);
     if (!region)
@@ -475,7 +458,7 @@ ErrorOr<FlatPtr> Process::sys$mremap(Userspace<const Syscall::SC_mremap_params*>
     REQUIRE_PROMISE(stdio);
     auto params = TRY(copy_typed_from_user(user_params));
 
-    auto old_range = TRY(expand_range_to_page_boundaries((FlatPtr)params.old_address, params.old_size));
+    auto old_range = TRY(Memory::expand_range_to_page_boundaries((FlatPtr)params.old_address, params.old_size));
 
     auto* old_region = address_space().find_region_from_range(old_range);
     if (!old_region)