[PATCH v3 14/24] x86/boot: Add EFI kernel extraction interface

[Evgeniy Baskov]

To enable extraction of kernel image from EFI stub code directly
extraction code needs to have separate interface that avoid part
of low level initialization logic, i.e. serial port setup.

Add kernel extraction function callable from libstub as a part
of preparation for extracting the kernel directly from EFI environment.

Tested-by: Mario Limonciello <mario.limonciello@xxxxxxx>
Signed-off-by: Evgeniy Baskov <baskov@xxxxxxxxx>
---
 arch/x86/boot/compressed/head_32.S    |   3 +-
 arch/x86/boot/compressed/head_64.S    |   2 +-
 arch/x86/boot/compressed/misc.c       | 100 +++++++++++++++++---------
 arch/x86/boot/compressed/misc.h       |   1 +
 arch/x86/include/asm/shared/extract.h |  26 +++++++
 5 files changed, 96 insertions(+), 36 deletions(-)
 create mode 100644 arch/x86/include/asm/shared/extract.h

diff --git a/arch/x86/boot/compressed/head_32.S b/arch/x86/boot/compressed/head_32.S
index 3b354eb9516d..b46a1c4109cf 100644
--- a/arch/x86/boot/compressed/head_32.S
+++ b/arch/x86/boot/compressed/head_32.S
@@ -217,8 +217,7 @@ SYM_DATA(image_offset, .long 0)
  */
 	.bss
 	.balign 4
-boot_heap:
-	.fill BOOT_HEAP_SIZE, 1, 0
+SYM_DATA(boot_heap,	.fill BOOT_HEAP_SIZE, 1, 0)
 boot_stack:
 	.fill BOOT_STACK_SIZE, 1, 0
 boot_stack_end:
diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 73a2ac2b063d..6cfcdeb4531b 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -1006,7 +1006,7 @@ SYM_FUNC_END(startup32_check_sev_cbit)
  */
 	.bss
 	.balign 4
-SYM_DATA_LOCAL(boot_heap,	.fill BOOT_HEAP_SIZE, 1, 0)
+SYM_DATA(boot_heap,	.fill BOOT_HEAP_SIZE, 1, 0)
 
 SYM_DATA_START_LOCAL(boot_stack)
 	.fill BOOT_STACK_SIZE, 1, 0
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index c9c235d65d16..ebf229c38b3b 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -308,11 +308,11 @@ static inline unsigned long kernel_add_identity_map_dummy(unsigned long start,
  *             |-------uncompressed kernel image---------|
  *
  */
-asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
-				  unsigned char *input_data,
-				  unsigned long input_len,
-				  unsigned char *output,
-				  unsigned long output_len)
+static void *do_extract_kernel(void *rmode,
+			       unsigned char *input_data,
+			       unsigned long input_len,
+			       unsigned char *output,
+			       unsigned long output_len)
 {
 	const unsigned long kernel_total_size = VO__end - VO__text;
 	unsigned long virt_addr = LOAD_PHYSICAL_ADDR;
@@ -326,26 +326,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 
 	sanitize_boot_params(boot_params);
 
-	init_default_io_ops();
-
-	/*
-	 * On 64-bit this pointer is set during page table uninitialization,
-	 * but on 32-bit it remains uninitialized, since paging is disabled.
-	 */
-	if (IS_ENABLED(CONFIG_X86_32))
-		kernel_add_identity_map = kernel_add_identity_map_dummy;
-
-
-	/*
-	 * Detect TDX guest environment.
-	 *
-	 * It has to be done before console_init() in order to use
-	 * paravirtualized port I/O operations if needed.
-	 */
-	early_tdx_detect();
-
-	init_bare_console();
-
 	/*
 	 * Save RSDP address for later use. Have this after console_init()
 	 * so that early debugging output from the RSDP parsing code can be
@@ -353,11 +333,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	 */
 	boot_params->acpi_rsdp_addr = get_rsdp_addr();
 
-	debug_putstr("early console in extract_kernel\n");
-
-	free_mem_ptr     = heap;	/* Heap */
-	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
-
 	/*
 	 * The memory hole needed for the kernel is the larger of either
 	 * the entire decompressed kernel plus relocation table, or the
@@ -411,12 +386,12 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	if (virt_addr & (MIN_KERNEL_ALIGN - 1))
 		error("Destination virtual address inappropriately aligned");
 #ifdef CONFIG_X86_64
-	if (heap > 0x3fffffffffffUL)
+	if (phys_addr > 0x3fffffffffffUL)
 		error("Destination address too large");
 	if (virt_addr + max(output_len, kernel_total_size) > KERNEL_IMAGE_SIZE)
 		error("Destination virtual address is beyond the kernel mapping area");
 #else
-	if (heap > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
+	if (phys_addr > ((-__PAGE_OFFSET-(128<<20)-1) & 0x7fffffff))
 		error("Destination address too large");
 #endif
 #ifndef CONFIG_RELOCATABLE
@@ -430,12 +405,71 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	parse_elf(output, output_len, virt_addr);
 	debug_putstr("done.\nBooting the kernel.\n");
 
+	return output;
+}
+
+asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
+				  unsigned char *input_data,
+				  unsigned long input_len,
+				  unsigned char *output,
+				  unsigned long output_len)
+{
+	void *entry;
+
+	init_default_io_ops();
+
+	/*
+	 * On 64-bit this pointer is set during page table uninitialization,
+	 * but on 32-bit it remains uninitialized, since paging is disabled.
+	 */
+	if (IS_ENABLED(CONFIG_X86_32))
+		kernel_add_identity_map = kernel_add_identity_map_dummy;
+
+	/*
+	 * Detect TDX guest environment.
+	 *
+	 * It has to be done before console_init() in order to use
+	 * paravirtualized port I/O operations if needed.
+	 */
+	early_tdx_detect();
+
+	init_bare_console();
+
+	debug_putstr("early console in extract_kernel\n");
+
+	free_mem_ptr     = heap;	/* Heap */
+	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
+
+	entry = do_extract_kernel(rmode, input_data,
+				  input_len, output, output_len);
+
 	/* Disable exception handling before booting the kernel */
 	cleanup_exception_handling();
 
-	return output;
+	return entry;
 }
 
+void *efi_extract_kernel(struct boot_params *rmode,
+			 struct efi_extract_callbacks *cb,
+			 unsigned char *input_data,
+			 unsigned long input_len,
+			 unsigned long output_len)
+{
+	extern char boot_heap[BOOT_HEAP_SIZE];
+
+	free_mem_ptr     = (unsigned long)boot_heap;	/* Heap */
+	free_mem_end_ptr = (unsigned long)boot_heap + BOOT_HEAP_SIZE;
+
+	init_console_func(cb->putstr, cb->puthex);
+	kernel_add_identity_map = cb->map_range;
+
+	return do_extract_kernel(rmode, input_data,
+				 input_len, (void *)LOAD_PHYSICAL_ADDR, output_len);
+}
+
+
+
+
 void fortify_panic(const char *name)
 {
 	error("detected buffer overflow");
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 0076b2845b4b..379c4a3ca7dd 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -26,6 +26,7 @@
 #include <asm/boot.h>
 #include <asm/bootparam.h>
 #include <asm/desc_defs.h>
+#include <asm/shared/extract.h>
 
 #include "tdx.h"
 
diff --git a/arch/x86/include/asm/shared/extract.h b/arch/x86/include/asm/shared/extract.h
new file mode 100644
index 000000000000..46bf56348a86
--- /dev/null
+++ b/arch/x86/include/asm/shared/extract.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef ASM_SHARED_EXTRACT_H
+#define ASM_SHARED_EXTRACT_H
+
+#include <asm/bootparam.h>
+
+#define MAP_WRITE	0x02 /* Writable memory */
+#define MAP_EXEC	0x04 /* Executable memory */
+#define MAP_ALLOC	0x10 /* Range needs to be allocated */
+#define MAP_PROTECT	0x20 /* Set exact memory attributes for memory range */
+
+struct efi_extract_callbacks {
+	void (*putstr)(const char *msg);
+	void (*puthex)(unsigned long x);
+	unsigned long (*map_range)(unsigned long start,
+				   unsigned long end,
+				   unsigned int flags);
+};
+
+void *efi_extract_kernel(struct boot_params *rmode,
+			 struct efi_extract_callbacks *cb,
+			 unsigned char *input_data,
+			 unsigned long input_len,
+			 unsigned long output_len);
+
+#endif /* ASM_SHARED_EXTRACT_H */
-- 
2.37.4