[PATCH v2 05/10] efi/libstub: arm64: Use struct efi_image_info to access image properties

[Ard Biesheuvel <ardb+git@google.com>]

From: Ard Biesheuvel <ardb@kernel.org>

Instead of exposing individual symbols to the EFI stub explicitly via
the linker script, use the generic struct efi_image_info, which accesses
the original symbols via PC-relative references from the stub itself.

This improves code reuse across architectures, and makes it easier to
add new references in a generic manner.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/kernel/image-vars.h            |  6 ------
 drivers/firmware/efi/libstub/arm64-stub.c | 20 ++++++++++----------
 2 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 19d602e45523..9ab71d103f64 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -20,8 +20,6 @@
 	PROVIDE(pisym = sym);		\
 	ASSERT((sym - KIMAGE_VADDR) < (__bss_start - KIMAGE_VADDR), #msg)
 
-PROVIDE(__efistub_primary_entry		= primary_entry);
-
 /*
  * The EFI stub has its own symbol namespace prefixed by __efistub_, to
  * isolate it from the kernel proper. The following symbols are legally
@@ -33,10 +31,6 @@ PROVIDE(__efistub_primary_entry		= primary_entry);
  */
 PROVIDE(__efistub_caches_clean_inval_pou = __pi_caches_clean_inval_pou);
 
-PROVIDE(__efistub__text			= _text);
-PROVIDE(__efistub__end			= _end);
-PROVIDE(__efistub___inittext_end       	= __inittext_end);
-PROVIDE(__efistub__edata		= _edata);
 #if defined(CONFIG_EFI_EARLYCON) || defined(CONFIG_SYSFB)
 PROVIDE(__efistub_sysfb_primary_display	= sysfb_primary_display);
 #endif
diff --git a/drivers/firmware/efi/libstub/arm64-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
index 2c3869356147..8184b345af69 100644
--- a/drivers/firmware/efi/libstub/arm64-stub.c
+++ b/drivers/firmware/efi/libstub/arm64-stub.c
@@ -10,7 +10,6 @@
 #include <linux/efi.h>
 #include <asm/efi.h>
 #include <asm/memory.h>
-#include <asm/sections.h>
 
 #include "efistub.h"
 
@@ -21,22 +20,23 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
 				 efi_loaded_image_t *image,
 				 efi_handle_t image_handle)
 {
-	unsigned long kernel_size, kernel_codesize, kernel_memsize;
+	auto image_info			= efistub_get_image_info();
+	unsigned long kernel_base	= efistub_kernel_base(image_info);
+	unsigned long kernel_size	= efistub_kernel_size(image_info);
+	unsigned long kernel_codesize	= efistub_kernel_codesize(image_info);
+	unsigned long kernel_memsize	= efistub_kernel_memsize(image_info);
 
-	if (image->image_base != _text) {
+	if (image->image_base != (void *)kernel_base) {
 		efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n");
-		image->image_base = _text;
+		image->image_base = (void *)kernel_base;
 	}
 
-	if (!IS_ALIGNED((u64)_text, SEGMENT_ALIGN))
+	if (!IS_ALIGNED(kernel_base, SEGMENT_ALIGN))
 		efi_err("FIRMWARE BUG: kernel image not aligned on %dk boundary\n",
 			SEGMENT_ALIGN >> 10);
 
-	kernel_size = _edata - _text;
-	kernel_codesize = __inittext_end - _text;
-	kernel_memsize = kernel_size + (_end - _edata);
 	*reserve_size = kernel_memsize;
-	*image_addr = (unsigned long)_text;
+	*image_addr = kernel_base;
 
 	return efi_kaslr_relocate_kernel(image_addr, reserve_addr, reserve_size,
 					 kernel_size, kernel_codesize, kernel_memsize,
@@ -54,7 +54,7 @@ unsigned long primary_entry_offset(void)
 	 * of the file representation. So instead, we need to jump to the
 	 * actual entrypoint in the .text region of the image.
 	 */
-	return (char *)primary_entry - _text;
+	return efistub_kernel_entry_offset(efistub_get_image_info());
 }
 
 void efi_icache_sync(unsigned long start, unsigned long end)
-- 
2.56.0.542.g3ef89b7020-goog