[RFC PATCH 0/4] efi: implement generic compressed boot support

[RFC PATCH 0/4] efi: implement generic compressed boot support

[Ard Biesheuvel]

Relatively modern architectures such as arm64 or RISC-V don't implement
a self-decompressing kernel, and leave it up to the bootloader to
decompress the compressed image before executing it. Not doing so makes
sense for bare metal boot, as it essentially duplicates a lot of fiddly
preparation work to create a 1:1 mapping and set up the C runtime, and
to discover or infer where DRAM lives from device trees or other
firmware tables.

For EFI boot, the situation is a bit different: the EFI entrypoint is
called with a 1:1 mapping covering all of DRAM already active, and with
a stack, a heap, a memory map and boot services to load and start
images. This means it is rather trivial to implement a
self-decompressing wrapper for EFI boot in a generic manner, and reuse
it across architectures that implement EFI boot.

The downside is that two signatures are needed for UEFI secure boot: one
for the decompressed image and one for the compressed images, as they
are both PE/COFF EFI executables that are launched by the firmware. But
that is actually the whole point, so it is simply the other side of the
same coin.

Related discussion going on here:
https://lore.kernel.org/all/20220430090518.3127980-22-chenhuacai@loongson.cn/

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Huacai Chen <chenhuacai@loongson.cn>

Ard Biesheuvel (4):
  efi: stub: add prototypes for load_image and start_image
  efi: stub: split off printk() routines
  efi: stub: implement generic EFI zboot
  arm64: efi: enable generic EFI compressed boot

 arch/arm64/Makefile                            |   5 +
 arch/arm64/boot/Makefile                       |  17 ++-
 drivers/firmware/efi/Kconfig                   |   6 +
 drivers/firmware/efi/libstub/Makefile          |   4 +-
 drivers/firmware/efi/libstub/efi-stub-helper.c | 141 -----------------
 drivers/firmware/efi/libstub/efistub.h         |   8 +-
 drivers/firmware/efi/libstub/printk.c          | 158 ++++++++++++++++++++
 drivers/firmware/efi/libstub/zboot-header.S    |  88 +++++++++++
 drivers/firmware/efi/libstub/zboot.c           |  86 +++++++++++
 drivers/firmware/efi/libstub/zboot.lds         |  44 ++++++
 10 files changed, 412 insertions(+), 145 deletions(-)
 create mode 100644 drivers/firmware/efi/libstub/printk.c
 create mode 100644 drivers/firmware/efi/libstub/zboot-header.S
 create mode 100644 drivers/firmware/efi/libstub/zboot.c
 create mode 100644 drivers/firmware/efi/libstub/zboot.lds

-- 
2.30.2

[RFC PATCH 0/4] efi: implement generic compressed boot support

[Ard Biesheuvel]

Relatively modern architectures such as arm64 or RISC-V don't implement
a self-decompressing kernel, and leave it up to the bootloader to
decompress the compressed image before executing it. Not doing so makes
sense for bare metal boot, as it essentially duplicates a lot of fiddly
preparation work to create a 1:1 mapping and set up the C runtime, and
to discover or infer where DRAM lives from device trees or other
firmware tables.

For EFI boot, the situation is a bit different: the EFI entrypoint is
called with a 1:1 mapping covering all of DRAM already active, and with
a stack, a heap, a memory map and boot services to load and start
images. This means it is rather trivial to implement a
self-decompressing wrapper for EFI boot in a generic manner, and reuse
it across architectures that implement EFI boot.

The downside is that two signatures are needed for UEFI secure boot: one
for the decompressed image and one for the compressed images, as they
are both PE/COFF EFI executables that are launched by the firmware. But
that is actually the whole point, so it is simply the other side of the
same coin.

Related discussion going on here:
https://lore.kernel.org/all/20220430090518.3127980-22-chenhuacai@loongson.cn/

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Huacai Chen <chenhuacai@loongson.cn>

Ard Biesheuvel (4):
  efi: stub: add prototypes for load_image and start_image
  efi: stub: split off printk() routines
  efi: stub: implement generic EFI zboot
  arm64: efi: enable generic EFI compressed boot

 arch/arm64/Makefile                            |   5 +
 arch/arm64/boot/Makefile                       |  17 ++-
 drivers/firmware/efi/Kconfig                   |   6 +
 drivers/firmware/efi/libstub/Makefile          |   4 +-
 drivers/firmware/efi/libstub/efi-stub-helper.c | 141 -----------------
 drivers/firmware/efi/libstub/efistub.h         |   8 +-
 drivers/firmware/efi/libstub/printk.c          | 158 ++++++++++++++++++++
 drivers/firmware/efi/libstub/zboot-header.S    |  88 +++++++++++
 drivers/firmware/efi/libstub/zboot.c           |  86 +++++++++++
 drivers/firmware/efi/libstub/zboot.lds         |  44 ++++++
 10 files changed, 412 insertions(+), 145 deletions(-)
 create mode 100644 drivers/firmware/efi/libstub/printk.c
 create mode 100644 drivers/firmware/efi/libstub/zboot-header.S
 create mode 100644 drivers/firmware/efi/libstub/zboot.c
 create mode 100644 drivers/firmware/efi/libstub/zboot.lds

-- 
2.30.2


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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[RFC PATCH 1/4] efi: stub: add prototypes for load_image and start_image

[Ard Biesheuvel]

Define the correct prototypes for the load_image and start_image boot
service pointers so we can call them from the EFI zboot code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/efistub.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index a0477afaa55f..af51ccc01ce2 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -254,8 +254,12 @@ union efi_boot_services {
 							    efi_handle_t *);
 		efi_status_t (__efiapi *install_configuration_table)(efi_guid_t *,
 								     void *);
-		void *load_image;
-		void *start_image;
+		efi_status_t (__efiapi *load_image)(bool, efi_handle_t,
+						    efi_device_path_protocol_t *,
+						    void *, unsigned long,
+						    efi_handle_t *);
+		efi_status_t (__efiapi *start_image)(efi_handle_t, unsigned long *,
+						     efi_char16_t **);
 		efi_status_t __noreturn (__efiapi *exit)(efi_handle_t,
 							 efi_status_t,
 							 unsigned long,
-- 
2.30.2

[RFC PATCH 1/4] efi: stub: add prototypes for load_image and start_image

[Ard Biesheuvel]

Define the correct prototypes for the load_image and start_image boot
service pointers so we can call them from the EFI zboot code.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/efistub.h | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index a0477afaa55f..af51ccc01ce2 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -254,8 +254,12 @@ union efi_boot_services {
 							    efi_handle_t *);
 		efi_status_t (__efiapi *install_configuration_table)(efi_guid_t *,
 								     void *);
-		void *load_image;
-		void *start_image;
+		efi_status_t (__efiapi *load_image)(bool, efi_handle_t,
+						    efi_device_path_protocol_t *,
+						    void *, unsigned long,
+						    efi_handle_t *);
+		efi_status_t (__efiapi *start_image)(efi_handle_t, unsigned long *,
+						     efi_char16_t **);
 		efi_status_t __noreturn (__efiapi *exit)(efi_handle_t,
 							 efi_status_t,
 							 unsigned long,
-- 
2.30.2


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linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[RFC PATCH 2/4] efi: stub: split off printk() routines

[Ard Biesheuvel]

We will be using the libstub static library also to build the EFI zboot
decompressor, which is a separate binary and does not carry all the
dependencies of efi-stub-helper.c, which is where efi_printk() currently
lives.

So split it off into printk.c so we can incorporate it separately.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/Makefile          |   2 +-
 drivers/firmware/efi/libstub/efi-stub-helper.c | 141 -----------------
 drivers/firmware/efi/libstub/printk.c          | 158 ++++++++++++++++++++
 3 files changed, 159 insertions(+), 142 deletions(-)

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index d0537573501e..475224be08e1 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -55,7 +55,7 @@ KCOV_INSTRUMENT			:= n
 lib-y				:= efi-stub-helper.o gop.o secureboot.o tpm.o \
 				   file.o mem.o random.o randomalloc.o pci.o \
 				   skip_spaces.o lib-cmdline.o lib-ctype.o \
-				   alignedmem.o relocate.o vsprintf.o
+				   alignedmem.o relocate.o vsprintf.o printk.o
 
 # include the stub's generic dependencies from lib/ when building for ARM/arm64
 efi-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 3d972061c1b0..45910c834133 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -20,7 +20,6 @@
 
 bool efi_nochunk;
 bool efi_nokaslr = !IS_ENABLED(CONFIG_RANDOMIZE_BASE);
-int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
 bool efi_novamap;
 
 static bool efi_noinitrd;
@@ -32,146 +31,6 @@ bool __pure __efi_soft_reserve_enabled(void)
 	return !efi_nosoftreserve;
 }
 
-/**
- * efi_char16_puts() - Write a UCS-2 encoded string to the console
- * @str:	UCS-2 encoded string
- */
-void efi_char16_puts(efi_char16_t *str)
-{
-	efi_call_proto(efi_table_attr(efi_system_table, con_out),
-		       output_string, str);
-}
-
-static
-u32 utf8_to_utf32(const u8 **s8)
-{
-	u32 c32;
-	u8 c0, cx;
-	size_t clen, i;
-
-	c0 = cx = *(*s8)++;
-	/*
-	 * The position of the most-significant 0 bit gives us the length of
-	 * a multi-octet encoding.
-	 */
-	for (clen = 0; cx & 0x80; ++clen)
-		cx <<= 1;
-	/*
-	 * If the 0 bit is in position 8, this is a valid single-octet
-	 * encoding. If the 0 bit is in position 7 or positions 1-3, the
-	 * encoding is invalid.
-	 * In either case, we just return the first octet.
-	 */
-	if (clen < 2 || clen > 4)
-		return c0;
-	/* Get the bits from the first octet. */
-	c32 = cx >> clen--;
-	for (i = 0; i < clen; ++i) {
-		/* Trailing octets must have 10 in most significant bits. */
-		cx = (*s8)[i] ^ 0x80;
-		if (cx & 0xc0)
-			return c0;
-		c32 = (c32 << 6) | cx;
-	}
-	/*
-	 * Check for validity:
-	 * - The character must be in the Unicode range.
-	 * - It must not be a surrogate.
-	 * - It must be encoded using the correct number of octets.
-	 */
-	if (c32 > 0x10ffff ||
-	    (c32 & 0xf800) == 0xd800 ||
-	    clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000))
-		return c0;
-	*s8 += clen;
-	return c32;
-}
-
-/**
- * efi_puts() - Write a UTF-8 encoded string to the console
- * @str:	UTF-8 encoded string
- */
-void efi_puts(const char *str)
-{
-	efi_char16_t buf[128];
-	size_t pos = 0, lim = ARRAY_SIZE(buf);
-	const u8 *s8 = (const u8 *)str;
-	u32 c32;
-
-	while (*s8) {
-		if (*s8 == '\n')
-			buf[pos++] = L'\r';
-		c32 = utf8_to_utf32(&s8);
-		if (c32 < 0x10000) {
-			/* Characters in plane 0 use a single word. */
-			buf[pos++] = c32;
-		} else {
-			/*
-			 * Characters in other planes encode into a surrogate
-			 * pair.
-			 */
-			buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10);
-			buf[pos++] = 0xdc00 + (c32 & 0x3ff);
-		}
-		if (*s8 == '\0' || pos >= lim - 2) {
-			buf[pos] = L'\0';
-			efi_char16_puts(buf);
-			pos = 0;
-		}
-	}
-}
-
-/**
- * efi_printk() - Print a kernel message
- * @fmt:	format string
- *
- * The first letter of the format string is used to determine the logging level
- * of the message. If the level is less then the current EFI logging level, the
- * message is suppressed. The message will be truncated to 255 bytes.
- *
- * Return:	number of printed characters
- */
-int efi_printk(const char *fmt, ...)
-{
-	char printf_buf[256];
-	va_list args;
-	int printed;
-	int loglevel = printk_get_level(fmt);
-
-	switch (loglevel) {
-	case '0' ... '9':
-		loglevel -= '0';
-		break;
-	default:
-		/*
-		 * Use loglevel -1 for cases where we just want to print to
-		 * the screen.
-		 */
-		loglevel = -1;
-		break;
-	}
-
-	if (loglevel >= efi_loglevel)
-		return 0;
-
-	if (loglevel >= 0)
-		efi_puts("EFI stub: ");
-
-	fmt = printk_skip_level(fmt);
-
-	va_start(args, fmt);
-	printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args);
-	va_end(args);
-
-	efi_puts(printf_buf);
-	if (printed >= sizeof(printf_buf)) {
-		efi_puts("[Message truncated]\n");
-		return -1;
-	}
-
-	return printed;
-}
-
 /**
  * efi_parse_options() - Parse EFI command line options
  * @cmdline:	kernel command line
diff --git a/drivers/firmware/efi/libstub/printk.c b/drivers/firmware/efi/libstub/printk.c
new file mode 100644
index 000000000000..ec09bf895c1a
--- /dev/null
+++ b/drivers/firmware/efi/libstub/printk.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helper functions used by the EFI stub on multiple
+ * architectures. This should be #included by the EFI stub
+ * implementation files.
+ *
+ * Copyright 2011 Intel Corporation; author Matt Fleming
+ */
+
+#include <linux/ctype.h>
+#include <linux/efi.h>
+#include <linux/kernel.h>
+#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
+
+/**
+ * efi_char16_puts() - Write a UCS-2 encoded string to the console
+ * @str:	UCS-2 encoded string
+ */
+void efi_char16_puts(efi_char16_t *str)
+{
+	efi_call_proto(efi_table_attr(efi_system_table, con_out),
+		       output_string, str);
+}
+
+static
+u32 utf8_to_utf32(const u8 **s8)
+{
+	u32 c32;
+	u8 c0, cx;
+	size_t clen, i;
+
+	c0 = cx = *(*s8)++;
+	/*
+	 * The position of the most-significant 0 bit gives us the length of
+	 * a multi-octet encoding.
+	 */
+	for (clen = 0; cx & 0x80; ++clen)
+		cx <<= 1;
+	/*
+	 * If the 0 bit is in position 8, this is a valid single-octet
+	 * encoding. If the 0 bit is in position 7 or positions 1-3, the
+	 * encoding is invalid.
+	 * In either case, we just return the first octet.
+	 */
+	if (clen < 2 || clen > 4)
+		return c0;
+	/* Get the bits from the first octet. */
+	c32 = cx >> clen--;
+	for (i = 0; i < clen; ++i) {
+		/* Trailing octets must have 10 in most significant bits. */
+		cx = (*s8)[i] ^ 0x80;
+		if (cx & 0xc0)
+			return c0;
+		c32 = (c32 << 6) | cx;
+	}
+	/*
+	 * Check for validity:
+	 * - The character must be in the Unicode range.
+	 * - It must not be a surrogate.
+	 * - It must be encoded using the correct number of octets.
+	 */
+	if (c32 > 0x10ffff ||
+	    (c32 & 0xf800) == 0xd800 ||
+	    clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000))
+		return c0;
+	*s8 += clen;
+	return c32;
+}
+
+/**
+ * efi_puts() - Write a UTF-8 encoded string to the console
+ * @str:	UTF-8 encoded string
+ */
+void efi_puts(const char *str)
+{
+	efi_char16_t buf[128];
+	size_t pos = 0, lim = ARRAY_SIZE(buf);
+	const u8 *s8 = (const u8 *)str;
+	u32 c32;
+
+	while (*s8) {
+		if (*s8 == '\n')
+			buf[pos++] = L'\r';
+		c32 = utf8_to_utf32(&s8);
+		if (c32 < 0x10000) {
+			/* Characters in plane 0 use a single word. */
+			buf[pos++] = c32;
+		} else {
+			/*
+			 * Characters in other planes encode into a surrogate
+			 * pair.
+			 */
+			buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10);
+			buf[pos++] = 0xdc00 + (c32 & 0x3ff);
+		}
+		if (*s8 == '\0' || pos >= lim - 2) {
+			buf[pos] = L'\0';
+			efi_char16_puts(buf);
+			pos = 0;
+		}
+	}
+}
+
+/**
+ * efi_printk() - Print a kernel message
+ * @fmt:	format string
+ *
+ * The first letter of the format string is used to determine the logging level
+ * of the message. If the level is less then the current EFI logging level, the
+ * message is suppressed. The message will be truncated to 255 bytes.
+ *
+ * Return:	number of printed characters
+ */
+int efi_printk(const char *fmt, ...)
+{
+	char printf_buf[256];
+	va_list args;
+	int printed;
+	int loglevel = printk_get_level(fmt);
+
+	switch (loglevel) {
+	case '0' ... '9':
+		loglevel -= '0';
+		break;
+	default:
+		/*
+		 * Use loglevel -1 for cases where we just want to print to
+		 * the screen.
+		 */
+		loglevel = -1;
+		break;
+	}
+
+	if (loglevel >= efi_loglevel)
+		return 0;
+
+	if (loglevel >= 0)
+		efi_puts("EFI stub: ");
+
+	fmt = printk_skip_level(fmt);
+
+	va_start(args, fmt);
+	printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args);
+	va_end(args);
+
+	efi_puts(printf_buf);
+	if (printed >= sizeof(printf_buf)) {
+		efi_puts("[Message truncated]\n");
+		return -1;
+	}
+
+	return printed;
+}
-- 
2.30.2

[RFC PATCH 2/4] efi: stub: split off printk() routines

[Ard Biesheuvel]

We will be using the libstub static library also to build the EFI zboot
decompressor, which is a separate binary and does not carry all the
dependencies of efi-stub-helper.c, which is where efi_printk() currently
lives.

So split it off into printk.c so we can incorporate it separately.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/libstub/Makefile          |   2 +-
 drivers/firmware/efi/libstub/efi-stub-helper.c | 141 -----------------
 drivers/firmware/efi/libstub/printk.c          | 158 ++++++++++++++++++++
 3 files changed, 159 insertions(+), 142 deletions(-)

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index d0537573501e..475224be08e1 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -55,7 +55,7 @@ KCOV_INSTRUMENT			:= n
 lib-y				:= efi-stub-helper.o gop.o secureboot.o tpm.o \
 				   file.o mem.o random.o randomalloc.o pci.o \
 				   skip_spaces.o lib-cmdline.o lib-ctype.o \
-				   alignedmem.o relocate.o vsprintf.o
+				   alignedmem.o relocate.o vsprintf.o printk.o
 
 # include the stub's generic dependencies from lib/ when building for ARM/arm64
 efi-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c
diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 3d972061c1b0..45910c834133 100644
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -20,7 +20,6 @@
 
 bool efi_nochunk;
 bool efi_nokaslr = !IS_ENABLED(CONFIG_RANDOMIZE_BASE);
-int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
 bool efi_novamap;
 
 static bool efi_noinitrd;
@@ -32,146 +31,6 @@ bool __pure __efi_soft_reserve_enabled(void)
 	return !efi_nosoftreserve;
 }
 
-/**
- * efi_char16_puts() - Write a UCS-2 encoded string to the console
- * @str:	UCS-2 encoded string
- */
-void efi_char16_puts(efi_char16_t *str)
-{
-	efi_call_proto(efi_table_attr(efi_system_table, con_out),
-		       output_string, str);
-}
-
-static
-u32 utf8_to_utf32(const u8 **s8)
-{
-	u32 c32;
-	u8 c0, cx;
-	size_t clen, i;
-
-	c0 = cx = *(*s8)++;
-	/*
-	 * The position of the most-significant 0 bit gives us the length of
-	 * a multi-octet encoding.
-	 */
-	for (clen = 0; cx & 0x80; ++clen)
-		cx <<= 1;
-	/*
-	 * If the 0 bit is in position 8, this is a valid single-octet
-	 * encoding. If the 0 bit is in position 7 or positions 1-3, the
-	 * encoding is invalid.
-	 * In either case, we just return the first octet.
-	 */
-	if (clen < 2 || clen > 4)
-		return c0;
-	/* Get the bits from the first octet. */
-	c32 = cx >> clen--;
-	for (i = 0; i < clen; ++i) {
-		/* Trailing octets must have 10 in most significant bits. */
-		cx = (*s8)[i] ^ 0x80;
-		if (cx & 0xc0)
-			return c0;
-		c32 = (c32 << 6) | cx;
-	}
-	/*
-	 * Check for validity:
-	 * - The character must be in the Unicode range.
-	 * - It must not be a surrogate.
-	 * - It must be encoded using the correct number of octets.
-	 */
-	if (c32 > 0x10ffff ||
-	    (c32 & 0xf800) == 0xd800 ||
-	    clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000))
-		return c0;
-	*s8 += clen;
-	return c32;
-}
-
-/**
- * efi_puts() - Write a UTF-8 encoded string to the console
- * @str:	UTF-8 encoded string
- */
-void efi_puts(const char *str)
-{
-	efi_char16_t buf[128];
-	size_t pos = 0, lim = ARRAY_SIZE(buf);
-	const u8 *s8 = (const u8 *)str;
-	u32 c32;
-
-	while (*s8) {
-		if (*s8 == '\n')
-			buf[pos++] = L'\r';
-		c32 = utf8_to_utf32(&s8);
-		if (c32 < 0x10000) {
-			/* Characters in plane 0 use a single word. */
-			buf[pos++] = c32;
-		} else {
-			/*
-			 * Characters in other planes encode into a surrogate
-			 * pair.
-			 */
-			buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10);
-			buf[pos++] = 0xdc00 + (c32 & 0x3ff);
-		}
-		if (*s8 == '\0' || pos >= lim - 2) {
-			buf[pos] = L'\0';
-			efi_char16_puts(buf);
-			pos = 0;
-		}
-	}
-}
-
-/**
- * efi_printk() - Print a kernel message
- * @fmt:	format string
- *
- * The first letter of the format string is used to determine the logging level
- * of the message. If the level is less then the current EFI logging level, the
- * message is suppressed. The message will be truncated to 255 bytes.
- *
- * Return:	number of printed characters
- */
-int efi_printk(const char *fmt, ...)
-{
-	char printf_buf[256];
-	va_list args;
-	int printed;
-	int loglevel = printk_get_level(fmt);
-
-	switch (loglevel) {
-	case '0' ... '9':
-		loglevel -= '0';
-		break;
-	default:
-		/*
-		 * Use loglevel -1 for cases where we just want to print to
-		 * the screen.
-		 */
-		loglevel = -1;
-		break;
-	}
-
-	if (loglevel >= efi_loglevel)
-		return 0;
-
-	if (loglevel >= 0)
-		efi_puts("EFI stub: ");
-
-	fmt = printk_skip_level(fmt);
-
-	va_start(args, fmt);
-	printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args);
-	va_end(args);
-
-	efi_puts(printf_buf);
-	if (printed >= sizeof(printf_buf)) {
-		efi_puts("[Message truncated]\n");
-		return -1;
-	}
-
-	return printed;
-}
-
 /**
  * efi_parse_options() - Parse EFI command line options
  * @cmdline:	kernel command line
diff --git a/drivers/firmware/efi/libstub/printk.c b/drivers/firmware/efi/libstub/printk.c
new file mode 100644
index 000000000000..ec09bf895c1a
--- /dev/null
+++ b/drivers/firmware/efi/libstub/printk.c
@@ -0,0 +1,158 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Helper functions used by the EFI stub on multiple
+ * architectures. This should be #included by the EFI stub
+ * implementation files.
+ *
+ * Copyright 2011 Intel Corporation; author Matt Fleming
+ */
+
+#include <linux/ctype.h>
+#include <linux/efi.h>
+#include <linux/kernel.h>
+#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
+
+/**
+ * efi_char16_puts() - Write a UCS-2 encoded string to the console
+ * @str:	UCS-2 encoded string
+ */
+void efi_char16_puts(efi_char16_t *str)
+{
+	efi_call_proto(efi_table_attr(efi_system_table, con_out),
+		       output_string, str);
+}
+
+static
+u32 utf8_to_utf32(const u8 **s8)
+{
+	u32 c32;
+	u8 c0, cx;
+	size_t clen, i;
+
+	c0 = cx = *(*s8)++;
+	/*
+	 * The position of the most-significant 0 bit gives us the length of
+	 * a multi-octet encoding.
+	 */
+	for (clen = 0; cx & 0x80; ++clen)
+		cx <<= 1;
+	/*
+	 * If the 0 bit is in position 8, this is a valid single-octet
+	 * encoding. If the 0 bit is in position 7 or positions 1-3, the
+	 * encoding is invalid.
+	 * In either case, we just return the first octet.
+	 */
+	if (clen < 2 || clen > 4)
+		return c0;
+	/* Get the bits from the first octet. */
+	c32 = cx >> clen--;
+	for (i = 0; i < clen; ++i) {
+		/* Trailing octets must have 10 in most significant bits. */
+		cx = (*s8)[i] ^ 0x80;
+		if (cx & 0xc0)
+			return c0;
+		c32 = (c32 << 6) | cx;
+	}
+	/*
+	 * Check for validity:
+	 * - The character must be in the Unicode range.
+	 * - It must not be a surrogate.
+	 * - It must be encoded using the correct number of octets.
+	 */
+	if (c32 > 0x10ffff ||
+	    (c32 & 0xf800) == 0xd800 ||
+	    clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000))
+		return c0;
+	*s8 += clen;
+	return c32;
+}
+
+/**
+ * efi_puts() - Write a UTF-8 encoded string to the console
+ * @str:	UTF-8 encoded string
+ */
+void efi_puts(const char *str)
+{
+	efi_char16_t buf[128];
+	size_t pos = 0, lim = ARRAY_SIZE(buf);
+	const u8 *s8 = (const u8 *)str;
+	u32 c32;
+
+	while (*s8) {
+		if (*s8 == '\n')
+			buf[pos++] = L'\r';
+		c32 = utf8_to_utf32(&s8);
+		if (c32 < 0x10000) {
+			/* Characters in plane 0 use a single word. */
+			buf[pos++] = c32;
+		} else {
+			/*
+			 * Characters in other planes encode into a surrogate
+			 * pair.
+			 */
+			buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10);
+			buf[pos++] = 0xdc00 + (c32 & 0x3ff);
+		}
+		if (*s8 == '\0' || pos >= lim - 2) {
+			buf[pos] = L'\0';
+			efi_char16_puts(buf);
+			pos = 0;
+		}
+	}
+}
+
+/**
+ * efi_printk() - Print a kernel message
+ * @fmt:	format string
+ *
+ * The first letter of the format string is used to determine the logging level
+ * of the message. If the level is less then the current EFI logging level, the
+ * message is suppressed. The message will be truncated to 255 bytes.
+ *
+ * Return:	number of printed characters
+ */
+int efi_printk(const char *fmt, ...)
+{
+	char printf_buf[256];
+	va_list args;
+	int printed;
+	int loglevel = printk_get_level(fmt);
+
+	switch (loglevel) {
+	case '0' ... '9':
+		loglevel -= '0';
+		break;
+	default:
+		/*
+		 * Use loglevel -1 for cases where we just want to print to
+		 * the screen.
+		 */
+		loglevel = -1;
+		break;
+	}
+
+	if (loglevel >= efi_loglevel)
+		return 0;
+
+	if (loglevel >= 0)
+		efi_puts("EFI stub: ");
+
+	fmt = printk_skip_level(fmt);
+
+	va_start(args, fmt);
+	printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args);
+	va_end(args);
+
+	efi_puts(printf_buf);
+	if (printed >= sizeof(printf_buf)) {
+		efi_puts("[Message truncated]\n");
+		return -1;
+	}
+
+	return printed;
+}
-- 
2.30.2


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

[RFC PATCH 3/4] efi: stub: implement generic EFI zboot

[Ard Biesheuvel]

Implement a minimal EFI app that decompresses the real kernel image and
launches it using the firmware's LoadImage and StartImage boot services.
This removes the need for any arch-specific hacks.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/Kconfig                |  6 ++
 drivers/firmware/efi/libstub/Makefile       |  2 +
 drivers/firmware/efi/libstub/zboot-header.S | 88 ++++++++++++++++++++
 drivers/firmware/efi/libstub/zboot.c        | 86 +++++++++++++++++++
 drivers/firmware/efi/libstub/zboot.lds      | 44 ++++++++++
 5 files changed, 226 insertions(+)

diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 4720ba98cec3..5fc986f66505 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -116,6 +116,12 @@ config EFI_RUNTIME_WRAPPERS
 config EFI_GENERIC_STUB
 	bool
 
+config EFI_ZBOOT
+	bool "Enable the generic EFI decompressor"
+	depends on EFI_GENERIC_STUB
+	depends on !ARM && !X86
+	select HAVE_KERNEL_GZIP
+
 config EFI_ARMSTUB_DTB_LOADER
 	bool "Enable the DTB loader"
 	depends on EFI_GENERIC_STUB && !RISCV
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 475224be08e1..71bd877077b1 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -111,8 +111,10 @@ STUBCOPY_RELOC-$(CONFIG_ARM)	:= R_ARM_ABS
 # a verification pass to see if any absolute relocations exist in any of the
 # object files.
 #
+lib-$(CONFIG_EFI_ZBOOT)		+= zboot.o
 extra-y				:= $(lib-y)
 lib-y				:= $(patsubst %.o,%.stub.o,$(lib-y))
+lib-$(CONFIG_EFI_ZBOOT)		+= zboot-header.o
 
 STUBCOPY_FLAGS-$(CONFIG_ARM64)	+= --prefix-alloc-sections=.init \
 				   --prefix-symbols=__efistub_
diff --git a/drivers/firmware/efi/libstub/zboot-header.S b/drivers/firmware/efi/libstub/zboot-header.S
new file mode 100644
index 000000000000..8f471866081a
--- /dev/null
+++ b/drivers/firmware/efi/libstub/zboot-header.S
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/pe.h>
+
+	.section	".head", "a"
+	.globl		__efistub_efi_zboot_header
+__efistub_efi_zboot_header:
+.Ldoshdr:
+	.long		MZ_MAGIC
+	.org		.Ldoshdr + 0x3c
+	.long		.Lpehdr - .Ldoshdr
+
+.Lpehdr:
+	.long		PE_MAGIC
+	.short		pe_machine_type
+	.short		.Lsection_count
+	.long		0
+	.long		0
+	.long		0
+	.short		.Lsection_table - .Loptional_header
+	.short		IMAGE_FILE_DEBUG_STRIPPED | \
+			IMAGE_FILE_EXECUTABLE_IMAGE | \
+			IMAGE_FILE_LINE_NUMS_STRIPPED
+
+.Loptional_header:
+#ifdef CONFIG_64BIT
+	.short		PE_OPT_MAGIC_PE32PLUS
+#else
+	.short		PE_OPT_MAGIC_PE32
+#endif
+	.byte		0, 0
+	.long		_etext - .Lefi_header_end
+	.long		__data_size
+	.long		0
+	.long		__efistub_efi_zboot_entry - .Ldoshdr
+	.long		.Lefi_header_end - .Ldoshdr
+
+#ifdef CONFIG_64BIT
+	.quad		0
+#else
+	.long		_etext - .Lhead
+	.long		0
+#endif
+	.long		4096
+	.long		512
+	.short		0, 0, 0, 0, 0, 0
+	.long		0
+	.long		_end - .Ldoshdr
+
+	.long		.Lefi_header_end - .Ldoshdr
+	.long		0
+	.short		IMAGE_SUBSYSTEM_EFI_APPLICATION
+	.short		0
+	.quad		0, 0, 0, 0
+	.long		0
+	.long		(.Lsection_table - .) / 8
+	.quad		0, 0, 0, 0, 0, 0
+
+.Lsection_table:
+	.ascii		".text\0\0\0"
+	.long		_etext - .Lefi_header_end
+	.long		.Lefi_header_end - .Ldoshdr
+	.long		_etext - .Lefi_header_end
+	.long		.Lefi_header_end - .Ldoshdr
+
+	.long		0, 0
+	.short		0, 0
+	.long		IMAGE_SCN_CNT_CODE | \
+			IMAGE_SCN_MEM_READ | \
+			IMAGE_SCN_MEM_EXECUTE
+
+	.ascii		".data\0\0\0"
+	.long		__data_size
+	.long		_etext - .Ldoshdr
+	.long		__data_rawsize
+	.long		_etext - .Ldoshdr
+
+	.long		0, 0
+	.short		0, 0
+	.long		IMAGE_SCN_CNT_INITIALIZED_DATA | \
+			IMAGE_SCN_MEM_READ | \
+			IMAGE_SCN_MEM_WRITE
+
+	.set		.Lsection_count, (. - .Lsection_table) / 40
+
+	.align		12
+.Lefi_header_end:
+
diff --git a/drivers/firmware/efi/libstub/zboot.c b/drivers/firmware/efi/libstub/zboot.c
new file mode 100644
index 000000000000..edb3390c808c
--- /dev/null
+++ b/drivers/firmware/efi/libstub/zboot.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+#define STATIC static
+
+static unsigned char zboot_heap[SZ_64K] __aligned(64);
+static unsigned long free_mem_ptr, free_mem_end_ptr;
+
+#ifdef CONFIG_KERNEL_GZIP
+#include "../../../../lib/decompress_inflate.c"
+#endif
+
+const efi_system_table_t *efi_system_table;
+
+extern char _gzdata_start[], _gzdata_end[];
+extern u32 uncompressed_size __aligned(1);
+
+static void error(char *x)
+{
+	efi_err("%s\n", x);
+}
+
+efi_status_t __efiapi efi_zboot_entry(efi_handle_t handle,
+				      efi_system_table_t *systab)
+{
+	efi_guid_t loaded_image = LOADED_IMAGE_PROTOCOL_GUID;
+	efi_loaded_image_t *parent, *child;
+	efi_handle_t child_handle = NULL;
+	unsigned long image_buffer;
+	efi_status_t status;
+
+	free_mem_ptr = (unsigned long)&zboot_heap;
+	free_mem_end_ptr = free_mem_ptr + sizeof(zboot_heap);
+
+	efi_system_table = systab;
+
+	efi_info("Entering EFI decompressor\n");
+
+	status = efi_bs_call(handle_protocol, handle, &loaded_image,
+			     (void **)&parent);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to locate parent's loaded image protocol\n");
+		return status;
+	}
+
+	status = efi_allocate_pages(uncompressed_size, &image_buffer, ULONG_MAX);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to allocate memory\n");
+		return status;
+	}
+
+	if (__decompress(_gzdata_start, _gzdata_end - _gzdata_start, NULL,
+			 NULL, (unsigned char *)image_buffer, 0, NULL,
+			 error) < 0)
+		return EFI_LOAD_ERROR;
+
+	status = efi_bs_call(load_image, true, handle, NULL,
+			     (void *)image_buffer, uncompressed_size,
+			     &child_handle);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to load image: %lx\n", status);
+		return status;
+	}
+
+	status = efi_bs_call(handle_protocol, child_handle, &loaded_image,
+			     (void **)&child);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to locate child's loaded image protocol\n");
+		return status;
+	}
+
+	// Copy the kernel command line
+	child->load_options = parent->load_options;
+	child->load_options_size = parent->load_options_size;
+
+	status = efi_bs_call(start_image, child_handle, NULL, NULL);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to start image: %lx\n", status);
+		return status;
+	}
+	return EFI_SUCCESS;
+}
diff --git a/drivers/firmware/efi/libstub/zboot.lds b/drivers/firmware/efi/libstub/zboot.lds
new file mode 100644
index 000000000000..56777b5f2668
--- /dev/null
+++ b/drivers/firmware/efi/libstub/zboot.lds
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+ENTRY(__efistub_efi_zboot_header);
+
+SECTIONS
+{
+	.text : ALIGN(4096) {
+		*(.head)
+		*(.text* .init.text*)
+	}
+
+	.rodata : ALIGN(8) {
+		__efistub__gzdata_start = .;
+		*(.gzdata)
+		__efistub__gzdata_end = . - 4;
+		__efistub_uncompressed_size = . - 4;
+		*(.rodata* .init.rodata*)
+		_etext = ALIGN(4096);
+		. = _etext;
+	}
+
+	.data : ALIGN(4096) {
+		*(.data* .init.data*)
+		_edata = ALIGN(512);
+		. = _edata;
+	}
+
+	.bss : {
+		*(.bss* .init.bss*)
+		_end = ALIGN(512);
+		. = _end;
+	}
+
+	/DISCARD/ : {
+		*(__ksymtab_strings ___ksymtab+*)
+	}
+}
+
+PROVIDE(__data_rawsize = ABSOLUTE(_edata - _etext));
+PROVIDE(__data_size = ABSOLUTE(_end - _etext));
+
+PROVIDE(__efistub_memcpy = __pi_memcpy);
+PROVIDE(__efistub_memset = __pi_memset);
+PROVIDE(__efistub_strnlen = __pi_strnlen);
-- 
2.30.2

[RFC PATCH 3/4] efi: stub: implement generic EFI zboot

[Ard Biesheuvel]

Implement a minimal EFI app that decompresses the real kernel image and
launches it using the firmware's LoadImage and StartImage boot services.
This removes the need for any arch-specific hacks.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/firmware/efi/Kconfig                |  6 ++
 drivers/firmware/efi/libstub/Makefile       |  2 +
 drivers/firmware/efi/libstub/zboot-header.S | 88 ++++++++++++++++++++
 drivers/firmware/efi/libstub/zboot.c        | 86 +++++++++++++++++++
 drivers/firmware/efi/libstub/zboot.lds      | 44 ++++++++++
 5 files changed, 226 insertions(+)

diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 4720ba98cec3..5fc986f66505 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -116,6 +116,12 @@ config EFI_RUNTIME_WRAPPERS
 config EFI_GENERIC_STUB
 	bool
 
+config EFI_ZBOOT
+	bool "Enable the generic EFI decompressor"
+	depends on EFI_GENERIC_STUB
+	depends on !ARM && !X86
+	select HAVE_KERNEL_GZIP
+
 config EFI_ARMSTUB_DTB_LOADER
 	bool "Enable the DTB loader"
 	depends on EFI_GENERIC_STUB && !RISCV
diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index 475224be08e1..71bd877077b1 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile
@@ -111,8 +111,10 @@ STUBCOPY_RELOC-$(CONFIG_ARM)	:= R_ARM_ABS
 # a verification pass to see if any absolute relocations exist in any of the
 # object files.
 #
+lib-$(CONFIG_EFI_ZBOOT)		+= zboot.o
 extra-y				:= $(lib-y)
 lib-y				:= $(patsubst %.o,%.stub.o,$(lib-y))
+lib-$(CONFIG_EFI_ZBOOT)		+= zboot-header.o
 
 STUBCOPY_FLAGS-$(CONFIG_ARM64)	+= --prefix-alloc-sections=.init \
 				   --prefix-symbols=__efistub_
diff --git a/drivers/firmware/efi/libstub/zboot-header.S b/drivers/firmware/efi/libstub/zboot-header.S
new file mode 100644
index 000000000000..8f471866081a
--- /dev/null
+++ b/drivers/firmware/efi/libstub/zboot-header.S
@@ -0,0 +1,88 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/pe.h>
+
+	.section	".head", "a"
+	.globl		__efistub_efi_zboot_header
+__efistub_efi_zboot_header:
+.Ldoshdr:
+	.long		MZ_MAGIC
+	.org		.Ldoshdr + 0x3c
+	.long		.Lpehdr - .Ldoshdr
+
+.Lpehdr:
+	.long		PE_MAGIC
+	.short		pe_machine_type
+	.short		.Lsection_count
+	.long		0
+	.long		0
+	.long		0
+	.short		.Lsection_table - .Loptional_header
+	.short		IMAGE_FILE_DEBUG_STRIPPED | \
+			IMAGE_FILE_EXECUTABLE_IMAGE | \
+			IMAGE_FILE_LINE_NUMS_STRIPPED
+
+.Loptional_header:
+#ifdef CONFIG_64BIT
+	.short		PE_OPT_MAGIC_PE32PLUS
+#else
+	.short		PE_OPT_MAGIC_PE32
+#endif
+	.byte		0, 0
+	.long		_etext - .Lefi_header_end
+	.long		__data_size
+	.long		0
+	.long		__efistub_efi_zboot_entry - .Ldoshdr
+	.long		.Lefi_header_end - .Ldoshdr
+
+#ifdef CONFIG_64BIT
+	.quad		0
+#else
+	.long		_etext - .Lhead
+	.long		0
+#endif
+	.long		4096
+	.long		512
+	.short		0, 0, 0, 0, 0, 0
+	.long		0
+	.long		_end - .Ldoshdr
+
+	.long		.Lefi_header_end - .Ldoshdr
+	.long		0
+	.short		IMAGE_SUBSYSTEM_EFI_APPLICATION
+	.short		0
+	.quad		0, 0, 0, 0
+	.long		0
+	.long		(.Lsection_table - .) / 8
+	.quad		0, 0, 0, 0, 0, 0
+
+.Lsection_table:
+	.ascii		".text\0\0\0"
+	.long		_etext - .Lefi_header_end
+	.long		.Lefi_header_end - .Ldoshdr
+	.long		_etext - .Lefi_header_end
+	.long		.Lefi_header_end - .Ldoshdr
+
+	.long		0, 0
+	.short		0, 0
+	.long		IMAGE_SCN_CNT_CODE | \
+			IMAGE_SCN_MEM_READ | \
+			IMAGE_SCN_MEM_EXECUTE
+
+	.ascii		".data\0\0\0"
+	.long		__data_size
+	.long		_etext - .Ldoshdr
+	.long		__data_rawsize
+	.long		_etext - .Ldoshdr
+
+	.long		0, 0
+	.short		0, 0
+	.long		IMAGE_SCN_CNT_INITIALIZED_DATA | \
+			IMAGE_SCN_MEM_READ | \
+			IMAGE_SCN_MEM_WRITE
+
+	.set		.Lsection_count, (. - .Lsection_table) / 40
+
+	.align		12
+.Lefi_header_end:
+
diff --git a/drivers/firmware/efi/libstub/zboot.c b/drivers/firmware/efi/libstub/zboot.c
new file mode 100644
index 000000000000..edb3390c808c
--- /dev/null
+++ b/drivers/firmware/efi/libstub/zboot.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/efi.h>
+#include <asm/efi.h>
+
+#include "efistub.h"
+
+#define STATIC static
+
+static unsigned char zboot_heap[SZ_64K] __aligned(64);
+static unsigned long free_mem_ptr, free_mem_end_ptr;
+
+#ifdef CONFIG_KERNEL_GZIP
+#include "../../../../lib/decompress_inflate.c"
+#endif
+
+const efi_system_table_t *efi_system_table;
+
+extern char _gzdata_start[], _gzdata_end[];
+extern u32 uncompressed_size __aligned(1);
+
+static void error(char *x)
+{
+	efi_err("%s\n", x);
+}
+
+efi_status_t __efiapi efi_zboot_entry(efi_handle_t handle,
+				      efi_system_table_t *systab)
+{
+	efi_guid_t loaded_image = LOADED_IMAGE_PROTOCOL_GUID;
+	efi_loaded_image_t *parent, *child;
+	efi_handle_t child_handle = NULL;
+	unsigned long image_buffer;
+	efi_status_t status;
+
+	free_mem_ptr = (unsigned long)&zboot_heap;
+	free_mem_end_ptr = free_mem_ptr + sizeof(zboot_heap);
+
+	efi_system_table = systab;
+
+	efi_info("Entering EFI decompressor\n");
+
+	status = efi_bs_call(handle_protocol, handle, &loaded_image,
+			     (void **)&parent);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to locate parent's loaded image protocol\n");
+		return status;
+	}
+
+	status = efi_allocate_pages(uncompressed_size, &image_buffer, ULONG_MAX);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to allocate memory\n");
+		return status;
+	}
+
+	if (__decompress(_gzdata_start, _gzdata_end - _gzdata_start, NULL,
+			 NULL, (unsigned char *)image_buffer, 0, NULL,
+			 error) < 0)
+		return EFI_LOAD_ERROR;
+
+	status = efi_bs_call(load_image, true, handle, NULL,
+			     (void *)image_buffer, uncompressed_size,
+			     &child_handle);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to load image: %lx\n", status);
+		return status;
+	}
+
+	status = efi_bs_call(handle_protocol, child_handle, &loaded_image,
+			     (void **)&child);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to locate child's loaded image protocol\n");
+		return status;
+	}
+
+	// Copy the kernel command line
+	child->load_options = parent->load_options;
+	child->load_options_size = parent->load_options_size;
+
+	status = efi_bs_call(start_image, child_handle, NULL, NULL);
+	if (status != EFI_SUCCESS) {
+		efi_err("Failed to start image: %lx\n", status);
+		return status;
+	}
+	return EFI_SUCCESS;
+}
diff --git a/drivers/firmware/efi/libstub/zboot.lds b/drivers/firmware/efi/libstub/zboot.lds
new file mode 100644
index 000000000000..56777b5f2668
--- /dev/null
+++ b/drivers/firmware/efi/libstub/zboot.lds
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+ENTRY(__efistub_efi_zboot_header);
+
+SECTIONS
+{
+	.text : ALIGN(4096) {
+		*(.head)
+		*(.text* .init.text*)
+	}
+
+	.rodata : ALIGN(8) {
+		__efistub__gzdata_start = .;
+		*(.gzdata)
+		__efistub__gzdata_end = . - 4;
+		__efistub_uncompressed_size = . - 4;
+		*(.rodata* .init.rodata*)
+		_etext = ALIGN(4096);
+		. = _etext;
+	}
+
+	.data : ALIGN(4096) {
+		*(.data* .init.data*)
+		_edata = ALIGN(512);
+		. = _edata;
+	}
+
+	.bss : {
+		*(.bss* .init.bss*)
+		_end = ALIGN(512);
+		. = _end;
+	}
+
+	/DISCARD/ : {
+		*(__ksymtab_strings ___ksymtab+*)
+	}
+}
+
+PROVIDE(__data_rawsize = ABSOLUTE(_edata - _etext));
+PROVIDE(__data_size = ABSOLUTE(_end - _etext));
+
+PROVIDE(__efistub_memcpy = __pi_memcpy);
+PROVIDE(__efistub_memset = __pi_memset);
+PROVIDE(__efistub_strnlen = __pi_strnlen);
-- 
2.30.2


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[RFC PATCH 4/4] arm64: efi: enable generic EFI compressed boot

[Ard Biesheuvel]

Wire up the generic EFI zboot support for arm64.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/Makefile      |  5 +++++
 arch/arm64/boot/Makefile | 17 ++++++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 2f1de88651e6..c9580f78439f 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -162,6 +162,11 @@ Image: vmlinux
 Image.%: Image
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 
+ifneq ($(CONFIG_EFI_ZBOOT),)
+zImage.efi: Image
+	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+endif
+
 install: install-image := Image
 zinstall: install-image := Image.gz
 install zinstall:
diff --git a/arch/arm64/boot/Makefile b/arch/arm64/boot/Makefile
index ebe80faab883..81500267ab79 100644
--- a/arch/arm64/boot/Makefile
+++ b/arch/arm64/boot/Makefile
@@ -16,7 +16,7 @@
 
 OBJCOPYFLAGS_Image :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
 
-targets := Image Image.bz2 Image.gz Image.lz4 Image.lzma Image.lzo
+targets := Image Image.bz2 Image.gz Image.lz4 Image.lzma Image.lzo zImage.efi
 
 $(obj)/Image: vmlinux FORCE
 	$(call if_changed,objcopy)
@@ -35,3 +35,18 @@ $(obj)/Image.lzma: $(obj)/Image FORCE
 
 $(obj)/Image.lzo: $(obj)/Image FORCE
 	$(call if_changed,lzo)
+
+OBJCOPYFLAGS_Image.gz.o := -O elf64-littleaarch64 -I binary \
+			   --rename-section .data=.gzdata,load,alloc,readonly,contents
+$(obj)/Image.gz.o: $(obj)/Image.gz FORCE
+	$(call if_changed,objcopy)
+
+ZBOOT_DEPS := memcpy.o memset.o strnlen.o
+$(obj)/zImage.efi.elf: $(obj)/Image.gz.o $(addprefix $(objtree)/arch/arm64/lib/,$(ZBOOT_DEPS))
+	$(Q)$(LD) -T $(srctree)/drivers/firmware/efi/libstub/zboot.lds \
+		-o $@ $^ $(objtree)/drivers/firmware/efi/libstub/lib.a \
+		--defsym=pe_machine_type=0xaa64
+
+$(obj)/zImage.efi: OBJCOPYFLAGS := -O binary
+$(obj)/zImage.efi: $(obj)/zImage.efi.elf FORCE
+	$(call if_changed,objcopy)
-- 
2.30.2

[RFC PATCH 4/4] arm64: efi: enable generic EFI compressed boot

[Ard Biesheuvel]

Wire up the generic EFI zboot support for arm64.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/Makefile      |  5 +++++
 arch/arm64/boot/Makefile | 17 ++++++++++++++++-
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 2f1de88651e6..c9580f78439f 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -162,6 +162,11 @@ Image: vmlinux
 Image.%: Image
 	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
 
+ifneq ($(CONFIG_EFI_ZBOOT),)
+zImage.efi: Image
+	$(Q)$(MAKE) $(build)=$(boot) $(boot)/$@
+endif
+
 install: install-image := Image
 zinstall: install-image := Image.gz
 install zinstall:
diff --git a/arch/arm64/boot/Makefile b/arch/arm64/boot/Makefile
index ebe80faab883..81500267ab79 100644
--- a/arch/arm64/boot/Makefile
+++ b/arch/arm64/boot/Makefile
@@ -16,7 +16,7 @@
 
 OBJCOPYFLAGS_Image :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
 
-targets := Image Image.bz2 Image.gz Image.lz4 Image.lzma Image.lzo
+targets := Image Image.bz2 Image.gz Image.lz4 Image.lzma Image.lzo zImage.efi
 
 $(obj)/Image: vmlinux FORCE
 	$(call if_changed,objcopy)
@@ -35,3 +35,18 @@ $(obj)/Image.lzma: $(obj)/Image FORCE
 
 $(obj)/Image.lzo: $(obj)/Image FORCE
 	$(call if_changed,lzo)
+
+OBJCOPYFLAGS_Image.gz.o := -O elf64-littleaarch64 -I binary \
+			   --rename-section .data=.gzdata,load,alloc,readonly,contents
+$(obj)/Image.gz.o: $(obj)/Image.gz FORCE
+	$(call if_changed,objcopy)
+
+ZBOOT_DEPS := memcpy.o memset.o strnlen.o
+$(obj)/zImage.efi.elf: $(obj)/Image.gz.o $(addprefix $(objtree)/arch/arm64/lib/,$(ZBOOT_DEPS))
+	$(Q)$(LD) -T $(srctree)/drivers/firmware/efi/libstub/zboot.lds \
+		-o $@ $^ $(objtree)/drivers/firmware/efi/libstub/lib.a \
+		--defsym=pe_machine_type=0xaa64
+
+$(obj)/zImage.efi: OBJCOPYFLAGS := -O binary
+$(obj)/zImage.efi: $(obj)/zImage.efi.elf FORCE
+	$(call if_changed,objcopy)
-- 
2.30.2


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