parisc: Include compressed vmlinux file in vmlinuz boot kernel

Change the parisc vmlinuz boot code to include and process the real
compressed vmlinux.gz ELF file instead of a compressed memory dump.
This brings parisc in sync on how it's done on x86_64.

The benefit of this change is that, e.g. for debugging purposes, one can
then extract the vmlinux file out of the vmlinuz which was booted which
wasn't possible before. This can be archieved with the existing
scripts/extract-vmlinux script, which just needs a small tweak to prefer
to extract a compressed file before trying the existing given binary.

The downside of this approach is that due to the extra round of
decompression/ELF processing we need more physical memory installed to
be able to boot a kernel.

Signed-off-by: Helge Deller <[e-mail]>

arch/parisc/boot/compressed/Makefile

···
 
 KBUILD_CFLAGS := -D__KERNEL__ -O2 -DBOOTLOADER
 KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
-KBUILD_CFLAGS += $(cflags-y) -fno-delete-null-pointer-checks
+KBUILD_CFLAGS += $(cflags-y) -fno-delete-null-pointer-checks -fno-builtin-printf
 KBUILD_CFLAGS += -fno-PIE -mno-space-regs -mdisable-fpregs -Os
 ifndef CONFIG_64BIT
 KBUILD_CFLAGS += -mfast-indirect-calls
···
 
 OBJECTS += $(obj)/head.o $(obj)/real2.o $(obj)/firmware.o $(obj)/misc.o $(obj)/piggy.o
 
-# LDFLAGS_vmlinux := -X --whole-archive -e startup -T
 LDFLAGS_vmlinux := -X -e startup --as-needed -T
 $(obj)/vmlinux: $(obj)/vmlinux.lds $(OBJECTS) $(LIBGCC)
 	$(call if_changed,ld)
···
 CPPFLAGS_vmlinux.lds += -I$(objtree)/$(obj) -DBOOTLOADER
 $(obj)/vmlinux.lds: $(obj)/sizes.h
 
-OBJCOPYFLAGS_vmlinux.bin := -O binary -R .comment -S
 $(obj)/vmlinux.bin: vmlinux
 	$(call if_changed,objcopy)
 

arch/parisc/boot/compressed/misc.c

···
  */
 
 #include <linux/uaccess.h>
+#include <linux/elf.h>
 #include <asm/unaligned.h>
 #include <asm/page.h>
 #include "sizes.h"
···
 	asm ("sync");
 }
 
+static void parse_elf(void *output)
+{
+#ifdef CONFIG_64BIT
+	Elf64_Ehdr ehdr;
+	Elf64_Phdr *phdrs, *phdr;
+#else
+	Elf32_Ehdr ehdr;
+	Elf32_Phdr *phdrs, *phdr;
+#endif
+	void *dest;
+	int i;
+
+	memcpy(&ehdr, output, sizeof(ehdr));
+	if (ehdr.e_ident[EI_MAG0] != ELFMAG0 ||
+	   ehdr.e_ident[EI_MAG1] != ELFMAG1 ||
+	   ehdr.e_ident[EI_MAG2] != ELFMAG2 ||
+	   ehdr.e_ident[EI_MAG3] != ELFMAG3) {
+		error("Kernel is not a valid ELF file");
+		return;
+	}
+
+#ifdef DEBUG
+	printf("Parsing ELF... ");
+#endif
+
+	phdrs = malloc(sizeof(*phdrs) * ehdr.e_phnum);
+	if (!phdrs)
+		error("Failed to allocate space for phdrs");
+
+	memcpy(phdrs, output + ehdr.e_phoff, sizeof(*phdrs) * ehdr.e_phnum);
+
+	for (i = 0; i < ehdr.e_phnum; i++) {
+		phdr = &phdrs[i];
+
+		switch (phdr->p_type) {
+		case PT_LOAD:
+			dest = (void *)((unsigned long) phdr->p_paddr &
+					(__PAGE_OFFSET_DEFAULT-1));
+			memmove(dest, output + phdr->p_offset, phdr->p_filesz);
+			break;
+		default:
+			break;
+		}
+	}
+
+	free(phdrs);
+}
+
 unsigned long decompress_kernel(unsigned int started_wide,
 		unsigned int command_line,
 		const unsigned int rd_start,
 		const unsigned int rd_end)
 {
 	char *output;
-	unsigned long len, len_all;
+	unsigned long vmlinux_addr, vmlinux_len;
+	unsigned long kernel_addr, kernel_len;
 
 #ifdef CONFIG_64BIT
 	parisc_narrow_firmware = 0;
···
 
 	set_firmware_width_unlocked();
 
-	putchar('U');	/* if you get this p and no more, string storage */
+	putchar('D');	/* if you get this D and no more, string storage */
 			/* in $GLOBAL$ is wrong or %dp is wrong */
-	puts("ncompressing ...\n");
+	puts("ecompressing Linux... ");
 
-	output = (char *) KERNEL_BINARY_TEXT_START;
-	len_all = __pa(SZ_end) - __pa(SZparisc_kernel_start);
-
-	if ((unsigned long) &_startcode_end > (unsigned long) output)
+	/* where the final bits are stored */
+	kernel_addr = KERNEL_BINARY_TEXT_START;
+	kernel_len = __pa(SZ_end) - __pa(SZparisc_kernel_start);
+	if ((unsigned long) &_startcode_end > kernel_addr)
 		error("Bootcode overlaps kernel code");
 
-	len = get_unaligned_le32(&output_len);
-	if (len > len_all)
-		error("Output len too big.");
-	else
-		memset(&output[len], 0, len_all - len);
+	/*
+	 * Calculate addr to where the vmlinux ELF file shall be decompressed.
+	 * Assembly code in head.S positioned the stack directly behind bss, so
+	 * leave 2 MB for the stack.
+	 */
+	vmlinux_addr = (unsigned long) &_ebss + 2*1024*1024;
+	vmlinux_len = get_unaligned_le32(&output_len);
+	output = (char *) vmlinux_addr;
 
 	/*
 	 * Initialize free_mem_ptr and free_mem_end_ptr.
 	 */
-	free_mem_ptr = (unsigned long) &_ebss;
-	free_mem_ptr += 2*1024*1024;	/* leave 2 MB for stack */
+	free_mem_ptr = vmlinux_addr + vmlinux_len;
 
 	/* Limit memory for bootoader to 1GB */
 	#define ARTIFICIAL_LIMIT (1*1024*1024*1024)
···
 		free_mem_end_ptr = rd_start;
 #endif
 
+	if (free_mem_ptr >= free_mem_end_ptr)
+		error("Kernel too big for machine.");
+
 #ifdef DEBUG
+	printf("\n");
 	printf("startcode_end = %x\n", &_startcode_end);
 	printf("commandline   = %x\n", command_line);
 	printf("rd_start      = %x\n", rd_start);
···
 	printf("input_data    = %x\n", input_data);
 	printf("input_len     = %x\n", input_len);
 	printf("output        = %x\n", output);
-	printf("output_len    = %x\n", len);
-	printf("output_max    = %x\n", len_all);
+	printf("output_len    = %x\n", vmlinux_len);
+	printf("kernel_addr   = %x\n", kernel_addr);
+	printf("kernel_len    = %x\n", kernel_len);
 #endif
 
 	__decompress(input_data, input_len, NULL, NULL,
 			output, 0, NULL, error);
+	parse_elf(output);
 
-	flush_data_cache(output, len);
+	output = (char *) kernel_addr;
+	flush_data_cache(output, kernel_len);
 
-	printf("Booting kernel ...\n\n");
+	printf("done.\nBooting the kernel.\n");
 
 	return (unsigned long) output;
 }

arch/parisc/boot/compressed/vmlinux.lds.S

···
 #endif
 	_startcode_end = .;
 
+	/* vmlinux.bin.gz is here */
+	. = ALIGN(8);
+	.rodata.compressed : {
+		*(.rodata.compressed)
+	}
+
 	/* bootloader code and data starts behind area of extracted kernel */
 	. = (SZ_end - SZparisc_kernel_start + KERNEL_BINARY_TEXT_START);
 
···
 		*(.rodata)	 /* read-only data */
 		*(.rodata.*)
 		_erodata = . ;
-	}
-	. = ALIGN(8);
-	.rodata.compressed : {
-		*(.rodata.compressed)
 	}
 	. = ALIGN(8);
 	.bss : {

arch/parisc/include/asm/page.h

···
 /* This governs the relationship between virtual and physical addresses.
  * If you alter it, make sure to take care of our various fixed mapping
  * segments in fixmap.h */
-#if defined(BOOTLOADER)
-#define __PAGE_OFFSET	(0)		/* bootloader uses physical addresses */
-#else
 #ifdef CONFIG_64BIT
-#define __PAGE_OFFSET	(0x40000000)	/* 1GB */
+#define __PAGE_OFFSET_DEFAULT	(0x40000000)	/* 1GB */
 #else
-#define __PAGE_OFFSET	(0x10000000)	/* 256MB */
+#define __PAGE_OFFSET_DEFAULT	(0x10000000)	/* 256MB */
 #endif
+
+#if defined(BOOTLOADER)
+#define __PAGE_OFFSET	(0)	/* bootloader uses physical addresses */
+#else
+#define __PAGE_OFFSET	__PAGE_OFFSET_DEFAULT
 #endif /* BOOTLOADER */
 
 #define PAGE_OFFSET		((unsigned long)__PAGE_OFFSET)