arm/linux: Unify ARM/arm64 vs Xen PE/COFF header handling

Xen has its own version of the image header, to account for the
additional PE/COFF header fields. Since we are adding references to
those in the shared EFI loader code, update the common definitions
and drop the Xen specific one which no longer has a purpose.

Since in both cases, the call to grub_arch_efi_linux_check_image() is
preceded by a load of the image header, let's move the load into that
function, and rename it to grub_arch_efi_linux_load_image_header().

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>

grub-core/loader/arm64/linux.c

@@ -49,8 +49,13 @@ static grub_addr_t initrd_start;
 static grub_addr_t initrd_end;
 
 grub_err_t
-grub_arch_efi_linux_check_image (struct linux_arch_kernel_header * lh)
+grub_arch_efi_linux_load_image_header (grub_file_t file,
+                                      struct linux_arch_kernel_header * lh)
 {
+  grub_file_seek (file, 0);
+  if (grub_file_read (file, lh, sizeof (*lh)) < (grub_ssize_t) sizeof (*lh))
+    return grub_error(GRUB_ERR_FILE_READ_ERROR, "failed to read Linux image header");
+
   if ((lh->code0 & 0xffff) != GRUB_PE32_MAGIC)
     return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
 		       N_("plain image kernel not supported - rebuild with CONFIG_(U)EFI_STUB enabled"));
@@ -301,10 +306,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
 
   kernel_size = grub_file_size (file);
 
-  if (grub_file_read (file, &lh, sizeof (lh)) < (long) sizeof (lh))
+  if (grub_arch_efi_linux_load_image_header (file, &lh) != GRUB_ERR_NONE)
-    return grub_errno;
-
-  if (grub_arch_efi_linux_check_image (&lh) != GRUB_ERR_NONE)
     goto fail;
 
   grub_loader_unset();

grub-core/loader/arm64/xen_boot.c

@@ -31,7 +31,6 @@
 #include <grub/efi/efi.h>
 #include <grub/efi/fdtload.h>
 #include <grub/efi/memory.h>
-#include <grub/efi/pe32.h>	/* required by struct xen_hypervisor_header */
 #include <grub/i18n.h>
 #include <grub/lib/cmdline.h>
 
@@ -65,18 +64,6 @@ enum module_type
 };
 typedef enum module_type module_type_t;
 
-struct xen_hypervisor_header
-{
-  struct linux_arm64_kernel_header efi_head;
-
-  /* This is always PE\0\0.  */
-  grub_uint8_t signature[GRUB_PE32_SIGNATURE_SIZE];
-  /* The COFF file header.  */
-  struct grub_pe32_coff_header coff_header;
-  /* The Optional header.  */
-  struct grub_pe64_optional_header optional_header;
-};
-
 struct xen_boot_binary
 {
   struct xen_boot_binary *next;
@@ -452,7 +439,7 @@ static grub_err_t
 grub_cmd_xen_hypervisor (grub_command_t cmd __attribute__ ((unused)),
 			 int argc, char *argv[])
 {
-  struct xen_hypervisor_header sh;
+  struct linux_arm64_kernel_header lh;
   grub_file_t file = NULL;
 
   grub_dl_ref (my_mod);
@@ -467,10 +454,7 @@ grub_cmd_xen_hypervisor (grub_command_t cmd __attribute__ ((unused)),
   if (!file)
     goto fail;
 
-  if (grub_file_read (file, &sh, sizeof (sh)) != (long) sizeof (sh))
+  if (grub_arch_efi_linux_load_image_header (file, &lh) != GRUB_ERR_NONE)
-    goto fail;
-  if (grub_arch_efi_linux_check_image
-      ((struct linux_arch_kernel_header *) &sh) != GRUB_ERR_NONE)
     goto fail;
   grub_file_seek (file, 0);
 
@@ -484,7 +468,8 @@ grub_cmd_xen_hypervisor (grub_command_t cmd __attribute__ ((unused)),
     return grub_errno;
 
   xen_hypervisor->is_hypervisor = 1;
-  xen_hypervisor->align = (grub_size_t) sh.optional_header.section_alignment;
+  xen_hypervisor->align
+    = (grub_size_t) lh.pe_image_header.optional_header.section_alignment;
 
   xen_boot_binary_load (xen_hypervisor, file, argc, argv);
   if (grub_errno == GRUB_ERR_NONE)

include/grub/arm/linux.h

@@ -22,6 +22,8 @@
 
 #include "system.h"
 
+#include <grub/efi/pe32.h>
+
 #define GRUB_LINUX_ARM_MAGIC_SIGNATURE 0x016f2818
 
 struct linux_arm_kernel_header {
@@ -32,6 +34,9 @@ struct linux_arm_kernel_header {
   grub_uint32_t end;   /* _edata */
   grub_uint32_t reserved2[3];
   grub_uint32_t hdr_offset;
+#if defined GRUB_MACHINE_EFI
+  struct grub_pe_image_header pe_image_header;
+#endif
 };
 
 #if defined(__arm__)

include/grub/arm64/linux.h

@@ -20,6 +20,7 @@
 #define GRUB_ARM64_LINUX_HEADER 1
 
 #include <grub/types.h>
+#include <grub/efi/pe32.h>
 
 #define GRUB_LINUX_ARM64_MAGIC_SIGNATURE 0x644d5241 /* 'ARM\x64' */
 
@@ -36,6 +37,7 @@ struct linux_arm64_kernel_header
   grub_uint64_t res4;		/* reserved */
   grub_uint32_t magic;		/* Magic number, little endian, "ARM\x64" */
   grub_uint32_t hdr_offset;	/* Offset of PE/COFF header */
+  struct grub_pe_image_header pe_image_header;
 };
 
 #if defined(__aarch64__)

include/grub/efi/efi.h

@@ -102,7 +102,9 @@ extern void (*EXPORT_VAR(grub_efi_net_config)) (grub_efi_handle_t hnd,
 void *EXPORT_FUNC(grub_efi_get_firmware_fdt)(void);
 grub_err_t EXPORT_FUNC(grub_efi_get_ram_base)(grub_addr_t *);
 #include <grub/cpu/linux.h>
-grub_err_t grub_arch_efi_linux_check_image(struct linux_arch_kernel_header *lh);
+#include <grub/file.h>
+grub_err_t grub_arch_efi_linux_load_image_header(grub_file_t file,
+                                                struct linux_arch_kernel_header *lh);
 grub_err_t grub_arch_efi_linux_boot_image(grub_addr_t addr, grub_size_t size,
                                            char *args);
 #endif