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Kernel+LibC: Allow sys$mmap() callers to specify address alignment

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This is exposed via the non-standard serenity_mmap() call in userspace.
This commit is contained in:
Andreas Kling 2020-02-16 12:55:56 +01:00
parent 02e199a9cb
commit 31e1af732f
7 changed files with 66 additions and 30 deletions
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49
Kernel/Process.cpp
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@ -151,12 +151,12 @@ bool Process::in_group(gid_t gid) const
return m_gid == gid || m_extra_gids.contains(gid);
}
Range Process::allocate_range(VirtualAddress vaddr, size_t size)
Range Process::allocate_range(VirtualAddress vaddr, size_t size, size_t alignment)
{
vaddr.mask(PAGE_MASK);
size = PAGE_ROUND_UP(size);
if (vaddr.is_null())
return page_directory().range_allocator().allocate_anywhere(size);
return page_directory().range_allocator().allocate_anywhere(size, alignment);
return page_directory().range_allocator().allocate_specific(vaddr, size);
}
@ -185,11 +185,9 @@ Region& Process::allocate_split_region(const Region& source_region, const Range&
return region;
}
Region* Process::allocate_region(VirtualAddress vaddr, size_t size, const String& name, int prot, bool commit)
Region* Process::allocate_region(const Range& range, const String& name, int prot, bool commit)
{
auto range = allocate_range(vaddr, size);
if (!range.is_valid())
return nullptr;
ASSERT(range.is_valid());
auto& region = add_region(Region::create_user_accessible(range, name, prot_to_region_access_flags(prot)));
region.map(page_directory());
if (commit)
@ -197,6 +195,14 @@ Region* Process::allocate_region(VirtualAddress vaddr, size_t size, const String
return &region;
}
Region* Process::allocate_region(VirtualAddress vaddr, size_t size, const String& name, int prot, bool commit)
{
auto range = allocate_range(vaddr, size);
if (!range.is_valid())
return nullptr;
return allocate_region(range, name, prot, commit);
}
Region* Process::allocate_file_backed_region(VirtualAddress vaddr, size_t size, NonnullRefPtr<Inode> inode, const String& name, int prot)
{
auto range = allocate_range(vaddr, size);
@ -207,9 +213,10 @@ Region* Process::allocate_file_backed_region(VirtualAddress vaddr, size_t size,
return &region;
}
Region* Process::allocate_region_with_vmobject(VirtualAddress vaddr, size_t size, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const String& name, int prot, bool user_accessible)
Region* Process::allocate_region_with_vmobject(const Range& range, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const String& name, int prot, bool user_accessible)
{
size_t end_in_vmobject = offset_in_vmobject + size;
ASSERT(range.is_valid());
size_t end_in_vmobject = offset_in_vmobject + range.size();
if (end_in_vmobject < offset_in_vmobject) {
dbgprintf("allocate_region_with_vmobject: Overflow (offset + size)\n");
return nullptr;
@ -222,9 +229,6 @@ Region* Process::allocate_region_with_vmobject(VirtualAddress vaddr, size_t size
dbgprintf("allocate_region_with_vmobject: Attempt to allocate a region with an end past the end of its VMObject.\n");
return nullptr;
}
auto range = allocate_range(vaddr, size);
if (!range.is_valid())
return nullptr;
offset_in_vmobject &= PAGE_MASK;
Region* region;
if (user_accessible)
@ -235,6 +239,15 @@ Region* Process::allocate_region_with_vmobject(VirtualAddress vaddr, size_t size
return region;
}
Region* Process::allocate_region_with_vmobject(VirtualAddress vaddr, size_t size, NonnullRefPtr<VMObject> vmobject, size_t offset_in_vmobject, const String& name, int prot, bool user_accessible)
{
auto range = allocate_range(vaddr, size);
if (!range.is_valid())
return nullptr;
return allocate_region_with_vmobject(range, move(vmobject), offset_in_vmobject, name, prot, user_accessible);
}
bool Process::deallocate_region(Region& region)
{
InterruptDisabler disabler;
@ -364,11 +377,15 @@ void* Process::sys$mmap(const Syscall::SC_mmap_params* user_params)
void* addr = (void*)params.addr;
size_t size = params.size;
size_t alignment = params.alignment;
int prot = params.prot;
int flags = params.flags;
int fd = params.fd;
int offset = params.offset;
if (alignment & ~PAGE_MASK)
return (void*)-EINVAL;
if (!is_user_range(VirtualAddress(addr), size))
return (void*)-EFAULT;
@ -407,15 +424,19 @@ void* Process::sys$mmap(const Syscall::SC_mmap_params* user_params)
Region* region = nullptr;
auto range = allocate_range(VirtualAddress(addr), size, alignment);
if (!range.is_valid())
return (void*)-ENOMEM;
if (map_purgeable) {
auto vmobject = PurgeableVMObject::create_with_size(size);
region = allocate_region_with_vmobject(VirtualAddress(addr), size, vmobject, 0, !name.is_null() ? name : "mmap (purgeable)", prot);
region = allocate_region_with_vmobject(range, vmobject, 0, !name.is_null() ? name : "mmap (purgeable)", prot);
if (!region && (!map_fixed && addr != 0))
region = allocate_region_with_vmobject({}, size, vmobject, 0, !name.is_null() ? name : "mmap (purgeable)", prot);
} else if (map_anonymous) {
region = allocate_region(VirtualAddress(addr), size, !name.is_null() ? name : "mmap", prot, false);
region = allocate_region(range, !name.is_null() ? name : "mmap", prot, false);
if (!region && (!map_fixed && addr != 0))
region = allocate_region({}, size, !name.is_null() ? name : "mmap", prot, false);
region = allocate_region(allocate_range({}, size), !name.is_null() ? name : "mmap", prot, false);
} else {
if (offset < 0)
return (void*)-EINVAL;