EFI: add heap memory support

Signed-off-by: Stephan Mueller <smueller@chronox.de>

Author: smuellerDD

README.md

@@ -130,11 +130,6 @@ implement the exact algorithms required.
 When programming with `leancrypto` in the EFI environment, the following
 considerations must be applied:
 
-* Only stack support is currently provided. All memory allocations using heap
-  will fail with `ENOMEM` as an appropriate implementation of `free` and
-  `posix_memalign` is not available in `internal/api/ext_headers.h`. If you want
-  heap support, feel free to provide patches for these functions.
-  
 * The API specified by the header files installed as part of the
   `meson install -C build` command for the user space library is applicable to
   the EFI environment as well.

internal/src/memory_support.c

@@ -50,24 +50,6 @@ int posix_memalign(void **ptr, size_t align, size_t size)
 	return 0;
 }
 
-#elif defined(LC_EFI_ENVIRONMENT)
-
-int posix_memalign(void **ptr, size_t align, size_t size);
-int posix_memalign(void **memptr, size_t alignment, size_t size)
-{
-	(void)memptr;
-	(void)alignment;
-	(void)size;
-	return ENOMEM;
-}
-
-void free(void *ptr);
-void free(void *ptr)
-{
-	(void)ptr;
-}
-
-
 #endif
 
 LC_INTERFACE_FUNCTION(int, lc_alloc_aligned, void **memptr, size_t alignment,

internal/src/memory_support_efi.c

@@ -0,0 +1,99 @@
+/*
+ * Copyright (C) 2024, Stephan Mueller <smueller@chronox.de>
+ *
+ * License: see LICENSE file in root directory
+ *
+ * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ALL OF
+ * WHICH ARE HEREBY DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
+ * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+ * USE OF THIS SOFTWARE, EVEN IF NOT ADVISED OF THE POSSIBILITY OF SUCH
+ * DAMAGE.
+ */
+
+#include "ext_headers.h"
+#include "lc_memory_support.h"
+#include "visibility.h"
+
+#define LC_EFI_PAGESIZE 4096
+
+/*
+ * Implementation follows guidance outlined at
+ * https://tianocore-docs.github.io/edk2-UefiDriverWritersGuide/draft/5_uefi_services/51_services_that_uefi_drivers_commonly_use/511_memory_allocation_services.html
+ */
+
+LC_INTERFACE_FUNCTION(int, lc_alloc_aligned, void **memptr, size_t alignment,
+		      size_t size)
+{
+	if (alignment > 8)
+		return lc_alloc_high_aligned(memptr, alignment, size);
+
+	*memptr = AllocatePool(size);
+
+	if (!*memptr)
+		return -ENOMEM;
+
+	return 0;
+}
+
+LC_INTERFACE_FUNCTION(int, lc_alloc_aligned_secure, void **memptr,
+		      size_t alignment, size_t size)
+{
+	return lc_alloc_aligned(memptr, alignment, size);
+}
+
+LC_INTERFACE_FUNCTION(int, lc_alloc_high_aligned, void **memptr,
+		      size_t alignment, size_t size)
+{
+	EFI_PHYSICAL_ADDRESS PhysicalBuffer = 0;
+	EFI_STATUS efi_status;
+	size_t pages = (size + LC_EFI_PAGESIZE - 1) / LC_EFI_PAGESIZE;
+
+	if (alignment > LC_EFI_PAGESIZE)
+		return -ENOMEM;
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+	efi_status = uefi_call_wrapper(BS->AllocatePages, 4, AllocateAnyPages,
+				       EfiBootServicesData, pages,
+				       &PhysicalBuffer);
+#pragma GCC diagnostic pop
+	if (EFI_ERROR(efi_status))
+		return -ENOMEM;
+
+	*memptr = (VOID *)(UINTN)PhysicalBuffer;
+
+	return 0;
+}
+
+LC_INTERFACE_FUNCTION(void, lc_free, void *ptr)
+{
+	if (!ptr)
+		return;
+	FreePool(ptr);
+}
+
+LC_INTERFACE_FUNCTION(void, lc_free_high_aligned, void *ptr, size_t size)
+{
+	EFI_STATUS efi_status;
+	EFI_PHYSICAL_ADDRESS PhysicalBuffer;
+	size_t pages = (size + LC_EFI_PAGESIZE - 1) / LC_EFI_PAGESIZE;
+
+	if (!ptr)
+		return;
+
+	PhysicalBuffer = (UINTN)ptr;
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wpedantic"
+	efi_status = uefi_call_wrapper(BS->FreePages, 2, PhysicalBuffer, pages);
+#pragma GCC diagnostic pop
+
+	(void)efi_status;
+}

internal/src/meson.build

@@ -14,8 +14,9 @@ if get_option('efi').disabled()
 	])
 endif
 
-if (host_machine.system() == 'linux' and
-    get_option('efi').disabled())
+if get_option('efi').enabled()
+	internal_src += files([ 'memory_support_efi.c' ])
+elif host_machine.system() == 'linux'
 	internal_src += files([ 'memory_support_linux.c' ])
 else
 	internal_src += files([ 'memory_support.c' ])