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From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org, will@kernel.org,
	catalin.marinas@arm.com, mark.rutland@arm.com,
	broonie@Kernel.org, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH 6/6] efi/zboot: arm64: Grab code size from image header
Date: Tue,  4 Apr 2023 17:19:59 +0200	[thread overview]
Message-ID: <20230404151959.2774612-7-ardb@kernel.org> (raw)
In-Reply-To: <20230404151959.2774612-1-ardb@kernel.org>

Instead of relying on a dodgy dd hack to copy the image code size from
the uncompressed image's PE header to the end of the compressed image,
let's grab the code size from the arm64 image header after
decompression, which we can do now that we have added this information
to this header.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/Makefile.zboot | 14 +++-----------
 drivers/firmware/efi/libstub/arm64.c        | 18 ++++++++++++------
 drivers/firmware/efi/libstub/efistub.h      |  3 +--
 drivers/firmware/efi/libstub/zboot.c        | 15 ++++-----------
 4 files changed, 20 insertions(+), 30 deletions(-)

diff --git a/drivers/firmware/efi/libstub/Makefile.zboot b/drivers/firmware/efi/libstub/Makefile.zboot
index 0a9dcc2b13736519..d34d4f0ed33349d5 100644
--- a/drivers/firmware/efi/libstub/Makefile.zboot
+++ b/drivers/firmware/efi/libstub/Makefile.zboot
@@ -24,21 +24,13 @@ comp-type-$(CONFIG_KERNEL_ZSTD)		:= zstd22
 # causing the original tools to complain when checking image integrity.
 # So disregard it when calculating the payload size in the zimage header.
 zboot-method-y                         := $(comp-type-y)_with_size
-zboot-size-len-y                       := 12
+zboot-size-len-y                       := 4
 
 zboot-method-$(CONFIG_KERNEL_GZIP)     := gzip
-zboot-size-len-$(CONFIG_KERNEL_GZIP)   := 8
-
-# Copy the SizeOfHeaders and SizeOfCode fields from the payload to the end of
-# the compressed image. Note that this presupposes a PE header offset of 64
-# bytes, which is what arm64, RISC-V and LoongArch use.
-quiet_cmd_compwithsize = $(quiet_cmd_$(zboot-method-y))
-      cmd_compwithsize = $(cmd_$(zboot-method-y)) && ( \
-			   dd status=none if=$< bs=4 count=1 skip=37 ; \
-			   dd status=none if=$< bs=4 count=1 skip=23 ) >> $@
+zboot-size-len-$(CONFIG_KERNEL_GZIP)   := 0
 
 $(obj)/vmlinuz: $(obj)/vmlinux.bin FORCE
-	$(call if_changed,compwithsize)
+	$(call if_changed,$(zboot-method-y))
 
 OBJCOPYFLAGS_vmlinuz.o := -I binary -O $(EFI_ZBOOT_BFD_TARGET) \
 			  --rename-section .data=.gzdata,load,alloc,readonly,contents
diff --git a/drivers/firmware/efi/libstub/arm64.c b/drivers/firmware/efi/libstub/arm64.c
index 8aad8c49d43f18e0..b65bf5371d3d4700 100644
--- a/drivers/firmware/efi/libstub/arm64.c
+++ b/drivers/firmware/efi/libstub/arm64.c
@@ -9,6 +9,7 @@
 
 #include <linux/efi.h>
 #include <asm/efi.h>
+#include <asm/image.h>
 #include <asm/memory.h>
 #include <asm/sysreg.h>
 
@@ -89,25 +90,30 @@ efi_status_t check_platform_features(void)
 #endif
 
 void efi_cache_sync_image(unsigned long image_base,
-			  unsigned long alloc_size,
-			  unsigned long code_size)
+			  unsigned long alloc_size)
 {
+	const struct arm64_image_header *header = (void *)image_base;
 	u32 ctr = read_cpuid_effective_cachetype();
 	u64 lsize = 4 << cpuid_feature_extract_unsigned_field(ctr,
 						CTR_EL0_DminLine_SHIFT);
 
 	/* only perform the cache maintenance if needed for I/D coherency */
 	if (!(ctr & BIT(CTR_EL0_IDC_SHIFT))) {
+		unsigned long base = image_base;
+		unsigned long size = le32_to_cpu(header->code_size);
+
 		do {
-			asm("dc " DCTYPE ", %0" :: "r"(image_base));
-			image_base += lsize;
-			code_size -= lsize;
-		} while (code_size >= lsize);
+			asm("dc " DCTYPE ", %0" :: "r"(base));
+			base += lsize;
+			size -= lsize;
+		} while (size >= lsize);
 	}
 
 	asm("ic ialluis");
 	dsb(ish);
 	isb();
+
+	efi_remap_image(image_base, alloc_size, le32_to_cpu(header->code_size));
 }
 
 unsigned long __weak primary_entry_offset(void)
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 148013bcb5f89fdd..67d5a20802e0b7c6 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -1066,8 +1066,7 @@ struct screen_info *__alloc_screen_info(void);
 void free_screen_info(struct screen_info *si);
 
 void efi_cache_sync_image(unsigned long image_base,
-			  unsigned long alloc_size,
-			  unsigned long code_size);
+			  unsigned long alloc_size);
 
 struct efi_smbios_record {
 	u8	type;
diff --git a/drivers/firmware/efi/libstub/zboot.c b/drivers/firmware/efi/libstub/zboot.c
index 63ece480090032c1..e5d7fa1f1d8fd160 100644
--- a/drivers/firmware/efi/libstub/zboot.c
+++ b/drivers/firmware/efi/libstub/zboot.c
@@ -50,8 +50,7 @@ static unsigned long alloc_preferred_address(unsigned long alloc_size)
 }
 
 void __weak efi_cache_sync_image(unsigned long image_base,
-				 unsigned long alloc_size,
-				 unsigned long code_size)
+				 unsigned long alloc_size)
 {
 	// Provided by the arch to perform the cache maintenance necessary for
 	// executable code loaded into memory to be safe for execution.
@@ -66,7 +65,7 @@ asmlinkage efi_status_t __efiapi
 efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
 {
 	unsigned long compressed_size = _gzdata_end - _gzdata_start;
-	unsigned long image_base, alloc_size, code_size;
+	unsigned long image_base, alloc_size;
 	efi_loaded_image_t *image;
 	efi_status_t status;
 	char *cmdline_ptr;
@@ -91,13 +90,9 @@ efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
 	efi_info("Decompressing Linux Kernel...\n");
 
 	// SizeOfImage from the compressee's PE/COFF header
-	alloc_size = round_up(get_unaligned_le32(_gzdata_end - 12),
+	alloc_size = round_up(get_unaligned_le32(_gzdata_end - 4),
 			      EFI_ALLOC_ALIGN);
 
-	// SizeOfHeaders and SizeOfCode from the compressee's PE/COFF header
-	code_size = get_unaligned_le32(_gzdata_end - 4) +
-		    get_unaligned_le32(_gzdata_end - 8);
-
 	 // If the architecture has a preferred address for the image,
 	 // try that first.
 	image_base = alloc_preferred_address(alloc_size);
@@ -140,9 +135,7 @@ efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
 		goto free_image;
 	}
 
-	efi_cache_sync_image(image_base, alloc_size, code_size);
-
-	efi_remap_image(image_base, alloc_size, code_size);
+	efi_cache_sync_image(image_base, alloc_size);
 
 	status = efi_stub_common(handle, image, image_base, cmdline_ptr);
 
-- 
2.39.2


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      parent reply	other threads:[~2023-04-04 15:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-04 15:19 [PATCH 0/6] arm64/efi/zboot: Clean up and enable BTI annotation Ard Biesheuvel
2023-04-04 15:19 ` [PATCH 1/6] efi/pe: Import new BTI/IBT header flags from the spec Ard Biesheuvel
2023-04-04 15:19 ` [PATCH 2/6] arm64: efi: Enable BTI codegen and add PE/COFF annotation Ard Biesheuvel
2023-04-05 16:33   ` Mark Brown
2023-04-04 15:19 ` [PATCH 3/6] arm64: image: Add code size to the image header Ard Biesheuvel
2023-04-04 15:19 ` [PATCH 4/6] efi/zboot: Add BSS padding before compression Ard Biesheuvel
2023-04-04 15:19 ` [PATCH 5/6] efi/zboot: Set forward edge CFI compat header flag if supported Ard Biesheuvel
2023-04-04 15:19 ` Ard Biesheuvel [this message]

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