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Commit 37ba7ab5 authored by H. Peter Anvin's avatar H. Peter Anvin
Browse files

x86, boot: make kernel_alignment adjustable; new bzImage fields 



Make the kernel_alignment field adjustable; this allows us to set it
to a large value (intended to be 16 MB to avoid ZONE_DMA contention,
memory holes and other weirdness) while a smart bootloader can still
force a loading at a lesser alignment if absolutely necessary.

Also export pref_address (preferred loading address, corresponding to
the link-time address) and init_size, the total amount of linear
memory the kernel will require during initialization.

[ Impact: allows better kernel placement, gives bootloader more info ]

Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 99aa4559

arch/x86/boot/compressed/head_32.S

+5 −2
Original line number Diff line number Diff line
@@ -69,8 +69,11 @@ ENTRY(startup_32) 


#ifdef CONFIG_RELOCATABLE

	movl	%ebp, %ebx

	addl    $(CONFIG_PHYSICAL_ALIGN - 1), %ebx

	andl    $(~(CONFIG_PHYSICAL_ALIGN - 1)), %ebx

	movl	BP_kernel_alignment(%esi), %eax

	decl	%eax

	addl    %eax, %ebx

	notl	%eax

	andl    %eax, %ebx

#else

	movl	$LOAD_PHYSICAL_ADDR, %ebx

#endif

arch/x86/boot/compressed/head_64.S

+10 −4
Original line number Diff line number Diff line
@@ -84,8 +84,11 @@ ENTRY(startup_32) 


#ifdef CONFIG_RELOCATABLE

	movl	%ebp, %ebx

	addl	$(PMD_PAGE_SIZE -1), %ebx

	andl	$PMD_PAGE_MASK, %ebx

	movl	BP_kernel_alignment(%esi), %eax

	decl	%eax

	addl	%eax, %ebx

	notl	%eax

	andl	%eax, %ebx

#else

	movl	$LOAD_PHYSICAL_ADDR, %ebx

#endif
@@ -224,8 +227,11 @@ ENTRY(startup_64) 
	/* Start with the delta to where the kernel will run at. */

#ifdef CONFIG_RELOCATABLE

	leaq	startup_32(%rip) /* - $startup_32 */, %rbp

	addq	$(PMD_PAGE_SIZE - 1), %rbp

	andq	$PMD_PAGE_MASK, %rbp

	movl	BP_kernel_alignment(%rsi), %eax

	decl	%eax

	addq	%rax, %rbp

	notq	%rax

	andq	%rax, %rbp

#else

	movq	$LOAD_PHYSICAL_ADDR, %rbp

#endif

arch/x86/boot/header.S

+13 −2
Original line number Diff line number Diff line
@@ -116,7 +116,7 @@ _start: 
	# Part 2 of the header, from the old setup.S



		.ascii	"HdrS"		# header signature

		.word	0x0209		# header version number (>= 0x0105)

		.word	0x020a		# header version number (>= 0x0105)

					# or else old loadlin-1.5 will fail)

		.globl realmode_swtch

realmode_swtch:	.word	0, 0		# default_switch, SETUPSEG
@@ -201,7 +201,7 @@ relocatable_kernel: .byte 1 
#else

relocatable_kernel:    .byte 0

#endif

pad2:			.byte 0

min_alignment:		.byte MIN_KERNEL_ALIGN_LG2	# minimum alignment

pad3:			.word 0



cmdline_size:   .long   COMMAND_LINE_SIZE-1     #length of the command line,
@@ -220,6 +220,17 @@ setup_data: .quad 0 # 64-bit physical pointer to 
						# single linked list of

						# struct setup_data



pref_address:		.quad LOAD_PHYSICAL_ADDR	# preferred load addr



#define ZO_INIT_SIZE	(ZO__end - ZO_startup_32 + ZO_extract_offset)

#define VO_INIT_SIZE	(VO__end - VO__text)

#if ZO_INIT_SIZE > VO_INIT_SIZE

#define INIT_SIZE ZO_INIT_SIZE

#else

#define INIT_SIZE VO_INIT_SIZE

#endif

init_size:		.long INIT_SIZE		# kernel initialization size



# End of setup header #####################################################



	.section ".inittext", "ax"

arch/x86/include/asm/boot.h

+15 −0
Original line number Diff line number Diff line
@@ -8,11 +8,26 @@ 


#ifdef __KERNEL__



#include <asm/page_types.h>



/* Physical address where kernel should be loaded. */

#define LOAD_PHYSICAL_ADDR ((CONFIG_PHYSICAL_START \

				+ (CONFIG_PHYSICAL_ALIGN - 1)) \

				& ~(CONFIG_PHYSICAL_ALIGN - 1))



/* Minimum kernel alignment, as a power of two */

#ifdef CONFIG_x86_64

#define MIN_KERNEL_ALIGN_LG2	PMD_SHIFT

#else

#define MIN_KERNEL_ALIGN_LG2	(PAGE_SHIFT+1)

#endif

#define MIN_KERNEL_ALIGN	(_AC(1, UL) << MIN_KERNEL_ALIGN_LG2)



#if (CONFIG_PHYSICAL_ALIGN & (CONFIG_PHYSICAL_ALIGN-1)) || \

	(CONFIG_PHYSICAL_ALIGN < (_AC(1, UL) << MIN_KERNEL_ALIGN_LG2))

#error "Invalid value for CONFIG_PHYSICAL_ALIGN"

#endif



#ifdef CONFIG_KERNEL_BZIP2

#define BOOT_HEAP_SIZE             0x400000

#else /* !CONFIG_KERNEL_BZIP2 */

arch/x86/kernel/asm-offsets_32.c

+1 −0
Original line number Diff line number Diff line
@@ -146,4 +146,5 @@ void foo(void) 
	OFFSET(BP_loadflags, boot_params, hdr.loadflags);

	OFFSET(BP_hardware_subarch, boot_params, hdr.hardware_subarch);

	OFFSET(BP_version, boot_params, hdr.version);

	OFFSET(BP_kernel_alignment, boot_params, hdr.kernel_alignment);

}