efi_loader: Fix loaded image alignment

We are ignoring the alignment communicated via the PE/COFF header.
Starting 5.10 the Linux kernel will loudly complain about it. For more
details look at [1] (in linux kernel).

So add a function that can allocate aligned EFI memory and use it for our
relocated loaded image.

[1] c32ac11da3f83 ("efi/libstub: arm64: Double check image alignment at entry")

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Vincent Stehlé <vincent.stehle@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

diff --git a/include/efi_loader.h b/include/efi_loader.h
index c440962..5cdc723 100644 (file)
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -675,6 +675,8 @@ struct efi_device_path *efi_get_dp_from_boot(const efi_guid_t guid);
 #define efi_size_in_pages(size) (((size) + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT)
 /* Generic EFI memory allocator, call this to get memory */
 void *efi_alloc(uint64_t len, int memory_type);
+/* Allocate pages on the specified alignment */
+void *efi_alloc_aligned_pages(u64 len, int memory_type, size_t align);
 /* More specific EFI memory allocator, called by EFI payloads */
 efi_status_t efi_allocate_pages(enum efi_allocate_type type,
                                enum efi_memory_type memory_type,

diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
index e9572d4..eb95580 100644 (file)
--- a/lib/efi_loader/efi_image_loader.c
+++ b/lib/efi_loader/efi_image_loader.c
@@ -898,9 +898,9 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
                image_base = opt->ImageBase;
                efi_set_code_and_data_type(loaded_image_info, opt->Subsystem);
                handle->image_type = opt->Subsystem;
-               virt_size = ALIGN(virt_size, opt->SectionAlignment);
-               efi_reloc = efi_alloc(virt_size,
-                                     loaded_image_info->image_code_type);
+               efi_reloc = efi_alloc_aligned_pages(virt_size,
+                                                   loaded_image_info->image_code_type,
+                                                   opt->SectionAlignment);
                if (!efi_reloc) {
                        log_err("Out of memory\n");
                        ret = EFI_OUT_OF_RESOURCES;
@@ -914,9 +914,9 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle,
                image_base = opt->ImageBase;
                efi_set_code_and_data_type(loaded_image_info, opt->Subsystem);
                handle->image_type = opt->Subsystem;
-               virt_size = ALIGN(virt_size, opt->SectionAlignment);
-               efi_reloc = efi_alloc(virt_size,
-                                     loaded_image_info->image_code_type);
+               efi_reloc = efi_alloc_aligned_pages(virt_size,
+                                                   loaded_image_info->image_code_type,
+                                                   opt->SectionAlignment);
                if (!efi_reloc) {
                        log_err("Out of memory\n");
                        ret = EFI_OUT_OF_RESOURCES;

diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c
index f4acbee..7f0b507 100644 (file)
--- a/lib/efi_loader/efi_memory.c
+++ b/lib/efi_loader/efi_memory.c
@@ -550,6 +550,58 @@ efi_status_t efi_free_pages(uint64_t memory, efi_uintn_t pages)
 }
 
 /**
+ * efi_alloc_aligned_pages - allocate
+ *
+ * @len:               len in bytes
+ * @memory_type:       usage type of the allocated memory
+ * @align:             alignment in bytes
+ * Return:             aligned memory or NULL
+ */
+void *efi_alloc_aligned_pages(u64 len, int memory_type, size_t align)
+{
+       u64 req_pages = efi_size_in_pages(len);
+       u64 true_pages = req_pages + efi_size_in_pages(align) - 1;
+       u64 free_pages;
+       u64 aligned_mem;
+       efi_status_t r;
+       u64 mem;
+
+       /* align must be zero or a power of two */
+       if (align & (align - 1))
+               return NULL;
+
+       /* Check for overflow */
+       if (true_pages < req_pages)
+               return NULL;
+
+       if (align < EFI_PAGE_SIZE) {
+               r = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES, memory_type,
+                                      req_pages, &mem);
+               return (r == EFI_SUCCESS) ? (void *)(uintptr_t)mem : NULL;
+       }
+
+       r = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES, memory_type,
+                              true_pages, &mem);
+       if (r != EFI_SUCCESS)
+               return NULL;
+
+       aligned_mem = ALIGN(mem, align);
+       /* Free pages before alignment */
+       free_pages = efi_size_in_pages(aligned_mem - mem);
+       if (free_pages)
+               efi_free_pages(mem, free_pages);
+
+       /* Free trailing pages */
+       free_pages = true_pages - (req_pages + free_pages);
+       if (free_pages) {
+               mem = aligned_mem + req_pages * EFI_PAGE_SIZE;
+               efi_free_pages(mem, free_pages);
+       }
+
+       return (void *)(uintptr_t)aligned_mem;
+}
+
+/**
  * efi_allocate_pool - allocate memory from pool
  *
  * @pool_type: type of the pool from which memory is to be allocated