[PATCH v2 09/10] efi/zboot: Disentangle efi_remap_image() from efi_cache_sync_image()

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

From: Ard Biesheuvel <ardb@kernel.org>

Refactor efi_cache_sync_image() so that it is not in charge of calling
efi_remap_image(), which is really the wrong way around.

Instead, call efi_remap_image() from the primary zboot procedure, where
it is more straight-forward to obtain the code size from the loaded
image.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/arm64.c                 |  2 --
 drivers/firmware/efi/libstub/zboot-decompress-gzip.c |  2 --
 drivers/firmware/efi/libstub/zboot-decompress-zstd.c |  2 --
 drivers/firmware/efi/libstub/zboot.c                 | 14 +++++++++++++-
 4 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/drivers/firmware/efi/libstub/arm64.c b/drivers/firmware/efi/libstub/arm64.c
index 62fc8e53c8a0..fdd48ba0f9f1 100644
--- a/drivers/firmware/efi/libstub/arm64.c
+++ b/drivers/firmware/efi/libstub/arm64.c
@@ -114,8 +114,6 @@ void efi_cache_sync_image(unsigned long image_base,
 	asm("ic ialluis");
 	dsb(ish);
 	isb();
-
-	efi_remap_image(image_base, alloc_size, code_size);
 }
 
 unsigned long __weak primary_entry_offset(void)
diff --git a/drivers/firmware/efi/libstub/zboot-decompress-gzip.c b/drivers/firmware/efi/libstub/zboot-decompress-gzip.c
index e97a7e9d3c98..79cf8c48b033 100644
--- a/drivers/firmware/efi/libstub/zboot-decompress-gzip.c
+++ b/drivers/firmware/efi/libstub/zboot-decompress-gzip.c
@@ -62,7 +62,5 @@ efi_status_t efi_zboot_decompress(u8 *out, unsigned long outlen)
 		return EFI_LOAD_ERROR;
 	}
 
-	efi_cache_sync_image((unsigned long)out, outlen);
-
 	return EFI_SUCCESS;
 }
diff --git a/drivers/firmware/efi/libstub/zboot-decompress-zstd.c b/drivers/firmware/efi/libstub/zboot-decompress-zstd.c
index bde9d94dd2e3..dd7f11238154 100644
--- a/drivers/firmware/efi/libstub/zboot-decompress-zstd.c
+++ b/drivers/firmware/efi/libstub/zboot-decompress-zstd.c
@@ -43,7 +43,5 @@ efi_status_t efi_zboot_decompress(u8 *out, unsigned long outlen)
 		return EFI_LOAD_ERROR;
 	}
 
-	efi_cache_sync_image((unsigned long)out, outlen);
-
 	return EFI_SUCCESS;
 }
diff --git a/drivers/firmware/efi/libstub/zboot.c b/drivers/firmware/efi/libstub/zboot.c
index c6071b0e8f1a..25ff5960771c 100644
--- a/drivers/firmware/efi/libstub/zboot.c
+++ b/drivers/firmware/efi/libstub/zboot.c
@@ -38,6 +38,17 @@ const struct efi_image_info *zboot_get_image_info(unsigned long image_base)
 	return (void *)image_base + efistub_image_info_offset;
 }
 
+static efi_status_t efi_zboot_remap_image(const struct efi_image_info *image_info,
+					  unsigned long image_base,
+					  unsigned long image_size)
+{
+	unsigned long code_size = efistub_kernel_codesize(image_info);
+
+	efi_cache_sync_image(image_base, code_size);
+
+	return efi_remap_image(image_base, image_size, code_size);
+}
+
 asmlinkage efi_status_t __efiapi
 efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
 {
@@ -105,7 +116,8 @@ efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
 		goto error;
 
 	auto image_info = zboot_get_image_info(image_base);
-	status = efi_stub_common(handle, image, image_base, cmdline_ptr,
+	status = efi_zboot_remap_image(image_info, image_base, alloc_size) ?:
+	         efi_stub_common(handle, image, image_base, cmdline_ptr,
 				 image_info);
 
 error:
-- 
2.56.0.542.g3ef89b7020-goog