[PATCH v4 00/11] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G

[PATCH v4 00/11] x86, boot, 64bit: Add support for loading ramdisk and bzImage above 4G

[Yinghai Lu]

Now we have limit kdump reseved under 896M, because kexec has the limitation.
and also bzImage need to stay under 4g.

To make kexec/kdump could use range above 4g, we need to make bzImage and
ramdisk could be loaded above 4g.
During booting bzImage will be unpacked on same postion and stay high.

The patches add fields in setup_header and boot_params to
1. get info about ramdisk position info above 4g from bootloader/kexec
2. get info about cmd_line_ptr info above 4g from bootloader/kexec
2. set xloadflags bit0 in header for bzImage and bootloader/kexec load
   could check that to decide if it could to put bzImage high.

This patches is tested with kexec tools with local changes and they are sent
to kexec list.

could be found at:

        git://git.kernel.org/pub/scm/linux/kernel/git/yinghai/linux-yinghai.git for-x86-boot

and it is on top of for-x86-mm

-v2: add ext_cmd_line_ptr support, and handle boot_param/cmd_line is above
     4G case.
-v3: according to hpa, use xloadflags instead code32_start_offset.
     0x200 will not be changed...
-v4: move ext_ramdisk_image/ext_ramdisk_size/ext_cmd_line_ptr to boot_params.
     add handling cross GB boundary case.

Thanks

Yinghai

Yinghai Lu (11):
  x86, boot: move verify_cpu.S after 0x200
  x86, boot: Move lldt/ltr out of 64bit code section
  x86, 64bit: Set extra ident mapping for whole kernel range
  x86: Merge early_reserve_initrd for 32bit and 64bit
  x86: add get_ramdisk_image/size()
  x86, boot: add get_cmd_line_ptr()
  x86, boot: move checking of cmd_line_ptr out of common path
  x86, boot: update cmd_line_ptr to unsigned long
  x86: use io_remap to access real_mode_data
  x86, boot: add fields to support load bzImage and ramdisk above 4G
  x86: remove 1024G limitation for kexec buffer on 64bit

 Documentation/x86/boot.txt         |   15 +++-
 Documentation/x86/zero-page.txt    |    3 +
 arch/x86/boot/boot.h               |   18 +++-
 arch/x86/boot/cmdline.c            |   12 ++--
 arch/x86/boot/compressed/cmdline.c |   12 +++-
 arch/x86/boot/compressed/head_64.S |   14 ++-
 arch/x86/boot/header.S             |   12 +++-
 arch/x86/include/asm/bootparam.h   |    8 ++-
 arch/x86/include/asm/kexec.h       |    6 +-
 arch/x86/kernel/head32.c           |   11 ---
 arch/x86/kernel/head64.c           |   41 ++++++----
 arch/x86/kernel/head_64.S          |  153 +++++++++++++++++++++++++++++++++---
 arch/x86/kernel/setup.c            |   53 ++++++++++---
 13 files changed, 285 insertions(+), 73 deletions(-)

-- 
1.7.7

[PATCH v4 01/11] x86, boot: move verify_cpu.S after 0x200

[Yinghai Lu]

We are short of space before 0x200 that is entry for startup_64.

According to hpa, we can not change startup_64 to other offset and
that become ABI now.

We could move function verify_cpu down, and that could avoid extra
code of jmp back and forth if we would move other lines.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Matt Fleming <matt.fleming@intel.com>
---
 arch/x86/boot/compressed/head_64.S |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 2c4b171..2c3cee4 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -182,8 +182,6 @@ no_longmode:
 	hlt
 	jmp     1b
 
-#include "../../kernel/verify_cpu.S"
-
 	/*
 	 * Be careful here startup_64 needs to be at a predictable
 	 * address so I can export it in an ELF header.  Bootloaders
@@ -349,6 +347,9 @@ relocated:
  */
 	jmp	*%rbp
 
+	.code32
+#include "../../kernel/verify_cpu.S"
+
 	.data
 gdt:
 	.word	gdt_end - gdt
-- 
1.7.7

[PATCH v4 02/11] x86, boot: Move lldt/ltr out of 64bit code section

[Yinghai Lu]

commit 08da5a2ca

    x86_64: Early segment setup for VT

add lldt/ltr to clean more segments.

Those code are put in code64, and it is using gdt that is only
loaded from code32 path.

That breaks booting with 64bit bootloader that does not go through
code32 path. It get at startup_64 directly,  and it has different
gdt.

Move those lines into code32 after their gdt is loaded.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Zachary Amsden <zamsden@gmail.com>
Cc: Matt Fleming <matt.fleming@intel.com>
---
 arch/x86/boot/compressed/head_64.S |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/boot/compressed/head_64.S b/arch/x86/boot/compressed/head_64.S
index 2c3cee4..375af23 100644
--- a/arch/x86/boot/compressed/head_64.S
+++ b/arch/x86/boot/compressed/head_64.S
@@ -154,6 +154,12 @@ ENTRY(startup_32)
 	btsl	$_EFER_LME, %eax
 	wrmsr
 
+	/* After gdt is loaded */
+	xorl	%eax, %eax
+	lldt	%ax
+	movl    $0x20, %eax
+	ltr	%ax
+
 	/*
 	 * Setup for the jump to 64bit mode
 	 *
@@ -245,9 +251,6 @@ preferred_addr:
 	movl	%eax, %ss
 	movl	%eax, %fs
 	movl	%eax, %gs
-	lldt	%ax
-	movl    $0x20, %eax
-	ltr	%ax
 
 	/*
 	 * Compute the decompressed kernel start address.  It is where
-- 
1.7.7

[PATCH v4 03/11] x86, 64bit: Set extra ident mapping for whole kernel range

[Yinghai Lu]

Current when kernel is loaded above 1G, only [_text, _text+2M] is set
up with extra ident page table.
That is not enough, some variables that could be used early are out of
that range, like BRK for early page table.
Need to set map for [_text, _end] include text/data/bss/brk...

Also current kernel is not allowed to be loaded above 512g, it thinks
that address is too big.
We need to add one extra spare page for level3 to point that 512g range.
Need to check _text range and set level4 pg with that spare level3 page,
and set level3 with level2 page to cover [_text, _end] with extra mapping.

At last, to handle crossing GB boundary, we need to add another
level2 spare page. To handle crossing 512GB boundary, we need to
add another level3 spare page to next 512G range.

Test on with kexec-tools with local test code to force loading kernel
cross 1G, 5G, 512g, 513g.

We need this to put relocatable 64bit bzImage high above 1g.

-v4: add crossing GB boundary handling.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/x86/kernel/head_64.S |  149 ++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 139 insertions(+), 10 deletions(-)

diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 94bf9cc..036dd0e 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -78,12 +78,6 @@ startup_64:
 	testl	%eax, %eax
 	jnz	bad_address
 
-	/* Is the address too large? */
-	leaq	_text(%rip), %rdx
-	movq	$PGDIR_SIZE, %rax
-	cmpq	%rax, %rdx
-	jae	bad_address
-
 	/* Fixup the physical addresses in the page table
 	 */
 	addq	%rbp, init_level4_pgt + 0(%rip)
@@ -97,25 +91,153 @@ startup_64:
 
 	addq	%rbp, level2_fixmap_pgt + (506*8)(%rip)
 
-	/* Add an Identity mapping if I am above 1G */
+	/* Add an Identity mapping if _end is above 1G */
+	leaq	_end(%rip), %r9
+	decq	%r9
+	cmp	$PUD_SIZE, %r9
+	jl	ident_complete
+
+	/* get end */
+	andq	$PMD_PAGE_MASK, %r9
+	/* round start to 1G if it is below 1G */
 	leaq	_text(%rip), %rdi
 	andq	$PMD_PAGE_MASK, %rdi
+	cmp	$PUD_SIZE, %rdi
+	jg	1f
+	movq	$PUD_SIZE, %rdi
+1:
+	/* get 512G index */
+	movq	%r9, %r8
+	shrq	$PGDIR_SHIFT, %r8
+	andq	$(PTRS_PER_PGD - 1), %r8
+	movq	%rdi, %rax
+	shrq	$PGDIR_SHIFT, %rax
+	andq	$(PTRS_PER_PGD - 1), %rax
+
+	/* cross two 512G ? */
+	cmp	%r8, %rax
+	jne	set_level3_other_512g
+
+	/* all in first 512G ? */
+	cmp	$0, %rax
+	je	skip_level3_spare
+
+	/* same 512G other than first 512g */
+	leaq    (level3_spare_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
+	leaq    init_level4_pgt(%rip), %rbx
+	movq    %rdx, 0(%rbx, %rax, 8)
+	addq    $L4_PAGE_OFFSET, %rax
+	movq    %rdx, 0(%rbx, %rax, 8)
+
+	/* get 1G index */
+	movq    %r9, %r8
+	shrq    $PUD_SHIFT, %r8
+	andq    $(PTRS_PER_PUD - 1), %r8
+	movq    %rdi, %rax
+	shrq    $PUD_SHIFT, %rax
+	andq    $(PTRS_PER_PUD - 1), %rax
+
+	/* same 1G ? */
+	cmp     %r8, %rax
+	je	set_level2_start_only_not_first_512g
+
+	/* set level2 for end */
+	leaq    level3_spare_pgt(%rip), %rbx
+	leaq    (level2_spare2_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
+	movq    %rdx, 0(%rbx, %r8, 8)
 
+set_level2_start_only_not_first_512g:
+	leaq    level3_spare_pgt(%rip), %rbx
+	leaq    (level2_spare_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
+	movq    %rdx, 0(%rbx, %rax, 8)
+
+	jmp	set_level2_spare
+
+set_level3_other_512g:
+	/* for level2 last on first 512g */
+	leaq	level3_ident_pgt(%rip), %rcx
+	/* start is in first 512G ? */
+	cmp	$0, %rax
+	je	set_level2_start_other_512g
+
+	/* Set level3 for _text */
+	leaq	(level3_spare_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
+	leaq	init_level4_pgt(%rip), %rbx
+	movq	%rdx, 0(%rbx, %rax, 8)
+	addq	$L4_PAGE_OFFSET, %rax
+	movq	%rdx, 0(%rbx, %rax, 8)
+
+	/* for level2 last not on first 512G */
+	leaq	level3_spare_pgt(%rip), %rcx
+
+set_level2_start_other_512g:
+	/* always need to set level2 */
 	movq	%rdi, %rax
 	shrq	$PUD_SHIFT, %rax
 	andq	$(PTRS_PER_PUD - 1), %rax
-	jz	ident_complete
-
+	movq	%rcx, %rbx    /* %rcx has level3_spare_pgt or level3_ident_pgt */
 	leaq	(level2_spare_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
+	movq	%rdx, 0(%rbx, %rax, 8)
+
+set_level3_end_other_512g:
+	leaq	(level3_spare2_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
+	leaq	init_level4_pgt(%rip), %rbx
+	movq	%rdx, 0(%rbx, %r8, 8)
+	addq	$L4_PAGE_OFFSET, %r8
+	movq	%rdx, 0(%rbx, %r8, 8)
+
+	/* always need to set level2 */
+	movq	%r9, %r8
+	shrq	$PUD_SHIFT, %r8
+	andq	$(PTRS_PER_PUD - 1), %r8
+	leaq	level3_spare2_pgt(%rip), %rbx
+	leaq	(level2_spare2_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
+	movq	%rdx, 0(%rbx, %r8, 8)
+
+	jmp	set_level2_spare
+
+skip_level3_spare:
+	/* get 1G index */
+	movq	%r9, %r8
+	shrq	$PUD_SHIFT, %r8
+	andq	$(PTRS_PER_PUD - 1), %r8
+	movq	%rdi, %rax
+	shrq	$PUD_SHIFT, %rax
+	andq	$(PTRS_PER_PUD - 1), %rax
+
+	/* same 1G ? */
+	cmp	%r8, %rax
+	je	set_level2_start_only_first_512g
+
+	/* set level2 without level3 spare */
 	leaq	level3_ident_pgt(%rip), %rbx
+	leaq	(level2_spare2_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
+	movq	%rdx, 0(%rbx, %r8, 8)
+
+set_level2_start_only_first_512g:
+	/*  set level2 without level3 spare */
+	leaq	level3_ident_pgt(%rip), %rbx
+	leaq	(level2_spare_pgt - __START_KERNEL_map + _KERNPG_TABLE)(%rbp), %rdx
 	movq	%rdx, 0(%rbx, %rax, 8)
 
+set_level2_spare:
 	movq	%rdi, %rax
 	shrq	$PMD_SHIFT, %rax
 	andq	$(PTRS_PER_PMD - 1), %rax
 	leaq	__PAGE_KERNEL_IDENT_LARGE_EXEC(%rdi), %rdx
 	leaq	level2_spare_pgt(%rip), %rbx
-	movq	%rdx, 0(%rbx, %rax, 8)
+	movq	%r9, %r8
+	shrq	$PMD_SHIFT, %r8
+	andq	$(PTRS_PER_PMD - 1), %r8
+	cmp	%r8, %rax
+	jl	1f
+	addq	$PTRS_PER_PMD, %r8
+1:	movq	%rdx, 0(%rbx, %rax, 8)
+	addq	$PMD_SIZE, %rdx
+	incq	%rax
+	cmp	%r8, %rax
+	jle	1b
+
 ident_complete:
 
 	/*
@@ -426,8 +548,15 @@ NEXT_PAGE(level2_kernel_pgt)
 	PMDS(0, __PAGE_KERNEL_LARGE_EXEC,
 		KERNEL_IMAGE_SIZE/PMD_SIZE)
 
+NEXT_PAGE(level3_spare_pgt)
+	.fill   512, 8, 0
+NEXT_PAGE(level3_spare2_pgt)
+	.fill   512, 8, 0
+
 NEXT_PAGE(level2_spare_pgt)
 	.fill   512, 8, 0
+NEXT_PAGE(level2_spare2_pgt)
+	.fill   512, 8, 0
 
 #undef PMDS
 #undef NEXT_PAGE
-- 
1.7.7

[PATCH v4 04/11] x86: Merge early_reserve_initrd for 32bit and 64bit

[Yinghai Lu]

They are the same, could move them out from head32/64.c to setup.c.

We are using memblock, and it could handle overlapping properly, so
we don't need to reserve some at first to hold the location, and just
need to make sure we reserve them before we are using memblock to find
free mem to use.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
---
 arch/x86/kernel/head32.c |   11 -----------
 arch/x86/kernel/head64.c |   11 -----------
 arch/x86/kernel/setup.c  |   22 ++++++++++++++++++----
 3 files changed, 18 insertions(+), 26 deletions(-)

diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index c18f59d..4c52efc 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -33,17 +33,6 @@ void __init i386_start_kernel(void)
 	memblock_reserve(__pa_symbol(&_text),
 			 __pa_symbol(&__bss_stop) - __pa_symbol(&_text));
 
-#ifdef CONFIG_BLK_DEV_INITRD
-	/* Reserve INITRD */
-	if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
-		/* Assume only end is not page aligned */
-		u64 ramdisk_image = boot_params.hdr.ramdisk_image;
-		u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
-		u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
-		memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
-	}
-#endif
-
 	/* Call the subarch specific early setup function */
 	switch (boot_params.hdr.hardware_subarch) {
 	case X86_SUBARCH_MRST:
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 037df57..00e612a 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -100,17 +100,6 @@ void __init x86_64_start_reservations(char *real_mode_data)
 	memblock_reserve(__pa_symbol(&_text),
 			 __pa_symbol(&__bss_stop) - __pa_symbol(&_text));
 
-#ifdef CONFIG_BLK_DEV_INITRD
-	/* Reserve INITRD */
-	if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
-		/* Assume only end is not page aligned */
-		unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
-		unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
-		unsigned long ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
-		memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
-	}
-#endif
-
 	reserve_ebda_region();
 
 	/*
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 6d29d1f..ee6d267 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -364,6 +364,19 @@ static u64 __init get_mem_size(unsigned long limit_pfn)
 
 	return mapped_pages << PAGE_SHIFT;
 }
+static void __init early_reserve_initrd(void)
+{
+	/* Assume only end is not page aligned */
+	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
+	u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
+	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
+
+	if (!boot_params.hdr.type_of_loader ||
+	    !ramdisk_image || !ramdisk_size)
+		return;		/* No initrd provided by bootloader */
+
+	memblock_reserve(ramdisk_image, ramdisk_end - ramdisk_image);
+}
 static void __init reserve_initrd(void)
 {
 	/* Assume only end is not page aligned */
@@ -390,10 +403,6 @@ static void __init reserve_initrd(void)
 	if (pfn_range_is_mapped(PFN_DOWN(ramdisk_image),
 				PFN_DOWN(ramdisk_end))) {
 		/* All are mapped, easy case */
-		/*
-		 * don't need to reserve again, already reserved early
-		 * in i386_start_kernel
-		 */
 		initrd_start = ramdisk_image + PAGE_OFFSET;
 		initrd_end = initrd_start + ramdisk_size;
 		return;
@@ -404,6 +413,9 @@ static void __init reserve_initrd(void)
 	memblock_free(ramdisk_image, ramdisk_end - ramdisk_image);
 }
 #else
+static void __init early_reserve_initrd(void)
+{
+}
 static void __init reserve_initrd(void)
 {
 }
@@ -665,6 +677,8 @@ early_param("reservelow", parse_reservelow);
 
 void __init setup_arch(char **cmdline_p)
 {
+	early_reserve_initrd();
+
 #ifdef CONFIG_X86_32
 	memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
 	visws_early_detect();
-- 
1.7.7

[PATCH v4 05/11] x86: add get_ramdisk_image/size()

[Yinghai Lu]

There several places to find ramdisk information early for reserving
and relocating.

Use functions to make code more readable and consistent.

Later will add ext_ramdisk_image/size in those functions to support
loading ramdisk above 4g.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/x86/kernel/setup.c |   29 +++++++++++++++++++++--------
 1 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index ee6d267..194e151 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -298,12 +298,25 @@ static void __init reserve_brk(void)
 
 #ifdef CONFIG_BLK_DEV_INITRD
 
+static u64 __init get_ramdisk_image(void)
+{
+	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
+
+	return ramdisk_image;
+}
+static u64 __init get_ramdisk_size(void)
+{
+	u64 ramdisk_size = boot_params.hdr.ramdisk_size;
+
+	return ramdisk_size;
+}
+
 #define MAX_MAP_CHUNK	(NR_FIX_BTMAPS << PAGE_SHIFT)
 static void __init relocate_initrd(void)
 {
 	/* Assume only end is not page aligned */
-	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
-	u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
+	u64 ramdisk_image = get_ramdisk_image();
+	u64 ramdisk_size  = get_ramdisk_size();
 	u64 area_size     = PAGE_ALIGN(ramdisk_size);
 	u64 ramdisk_here;
 	unsigned long slop, clen, mapaddr;
@@ -342,8 +355,8 @@ static void __init relocate_initrd(void)
 		ramdisk_size  -= clen;
 	}
 
-	ramdisk_image = boot_params.hdr.ramdisk_image;
-	ramdisk_size  = boot_params.hdr.ramdisk_size;
+	ramdisk_image = get_ramdisk_image();
+	ramdisk_size  = get_ramdisk_size();
 	printk(KERN_INFO "Move RAMDISK from [mem %#010llx-%#010llx] to"
 		" [mem %#010llx-%#010llx]\n",
 		ramdisk_image, ramdisk_image + ramdisk_size - 1,
@@ -367,8 +380,8 @@ static u64 __init get_mem_size(unsigned long limit_pfn)
 static void __init early_reserve_initrd(void)
 {
 	/* Assume only end is not page aligned */
-	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
-	u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
+	u64 ramdisk_image = get_ramdisk_image();
+	u64 ramdisk_size  = get_ramdisk_size();
 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
 
 	if (!boot_params.hdr.type_of_loader ||
@@ -380,8 +393,8 @@ static void __init early_reserve_initrd(void)
 static void __init reserve_initrd(void)
 {
 	/* Assume only end is not page aligned */
-	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
-	u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
+	u64 ramdisk_image = get_ramdisk_image();
+	u64 ramdisk_size  = get_ramdisk_size();
 	u64 ramdisk_end   = PAGE_ALIGN(ramdisk_image + ramdisk_size);
 	u64 mapped_size;
 
-- 
1.7.7

[PATCH v4 06/11] x86, boot: add get_cmd_line_ptr()

[Yinghai Lu]

later will check ext_cmd_line_ptr at the same time.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/x86/boot/compressed/cmdline.c |   10 ++++++++--
 arch/x86/kernel/head64.c           |   13 +++++++++++--
 2 files changed, 19 insertions(+), 4 deletions(-)

diff --git a/arch/x86/boot/compressed/cmdline.c b/arch/x86/boot/compressed/cmdline.c
index 10f6b11..b4c913c 100644
--- a/arch/x86/boot/compressed/cmdline.c
+++ b/arch/x86/boot/compressed/cmdline.c
@@ -13,13 +13,19 @@ static inline char rdfs8(addr_t addr)
 	return *((char *)(fs + addr));
 }
 #include "../cmdline.c"
+static unsigned long get_cmd_line_ptr(void)
+{
+	unsigned long cmd_line_ptr = real_mode->hdr.cmd_line_ptr;
+
+	return cmd_line_ptr;
+}
 int cmdline_find_option(const char *option, char *buffer, int bufsize)
 {
-	return __cmdline_find_option(real_mode->hdr.cmd_line_ptr, option, buffer, bufsize);
+	return __cmdline_find_option(get_cmd_line_ptr(), option, buffer, bufsize);
 }
 int cmdline_find_option_bool(const char *option)
 {
-	return __cmdline_find_option_bool(real_mode->hdr.cmd_line_ptr, option);
+	return __cmdline_find_option_bool(get_cmd_line_ptr(), option);
 }
 
 #endif
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 00e612a..3ac6cad 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -41,13 +41,22 @@ static void __init clear_bss(void)
 	       (unsigned long) __bss_stop - (unsigned long) __bss_start);
 }
 
+static unsigned long get_cmd_line_ptr(void)
+{
+	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+
+	return cmd_line_ptr;
+}
+
 static void __init copy_bootdata(char *real_mode_data)
 {
 	char * command_line;
+	unsigned long cmd_line_ptr;
 
 	memcpy(&boot_params, real_mode_data, sizeof boot_params);
-	if (boot_params.hdr.cmd_line_ptr) {
-		command_line = __va(boot_params.hdr.cmd_line_ptr);
+	cmd_line_ptr = get_cmd_line_ptr();
+	if (cmd_line_ptr) {
+		command_line = __va(cmd_line_ptr);
 		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 	}
 }
-- 
1.7.7

[PATCH v4 07/11] x86, boot: move checking of cmd_line_ptr out of common path

[Yinghai Lu]

cmdline.c::__cmdline_find_option... are shared between
16-bit setup code and 32/64 bit decompressor code.

for 32/64 only path via kexec, we should not check if ptr less 1M.
as those cmdline could be put above 1M, or even 4G.

Move out accessible checking out of __cmdline_find_option()
So decompressor in misc.c can parse cmdline correctly.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/x86/boot/boot.h    |   14 ++++++++++++--
 arch/x86/boot/cmdline.c |    8 ++++----
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index 18997e5..7fadf80 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -289,12 +289,22 @@ int __cmdline_find_option(u32 cmdline_ptr, const char *option, char *buffer, int
 int __cmdline_find_option_bool(u32 cmdline_ptr, const char *option);
 static inline int cmdline_find_option(const char *option, char *buffer, int bufsize)
 {
-	return __cmdline_find_option(boot_params.hdr.cmd_line_ptr, option, buffer, bufsize);
+	u32 cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+
+	if (cmd_line_ptr >= 0x100000)
+		return -1;      /* inaccessible */
+
+	return __cmdline_find_option(cmd_line_ptr, option, buffer, bufsize);
 }
 
 static inline int cmdline_find_option_bool(const char *option)
 {
-	return __cmdline_find_option_bool(boot_params.hdr.cmd_line_ptr, option);
+	u32 cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+
+	if (cmd_line_ptr >= 0x100000)
+		return -1;      /* inaccessible */
+
+	return __cmdline_find_option_bool(cmd_line_ptr, option);
 }
 
 
diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c
index 6b3b6f7..768f00f 100644
--- a/arch/x86/boot/cmdline.c
+++ b/arch/x86/boot/cmdline.c
@@ -41,8 +41,8 @@ int __cmdline_find_option(u32 cmdline_ptr, const char *option, char *buffer, int
 		st_bufcpy	/* Copying this to buffer */
 	} state = st_wordstart;
 
-	if (!cmdline_ptr || cmdline_ptr >= 0x100000)
-		return -1;	/* No command line, or inaccessible */
+	if (!cmdline_ptr)
+		return -1;      /* No command line */
 
 	cptr = cmdline_ptr & 0xf;
 	set_fs(cmdline_ptr >> 4);
@@ -111,8 +111,8 @@ int __cmdline_find_option_bool(u32 cmdline_ptr, const char *option)
 		st_wordskip,	/* Miscompare, skip */
 	} state = st_wordstart;
 
-	if (!cmdline_ptr || cmdline_ptr >= 0x100000)
-		return -1;	/* No command line, or inaccessible */
+	if (!cmdline_ptr)
+		return -1;      /* No command line */
 
 	cptr = cmdline_ptr & 0xf;
 	set_fs(cmdline_ptr >> 4);
-- 
1.7.7

[PATCH v4 08/11] x86, boot: update cmd_line_ptr to unsigned long

[Yinghai Lu]

boot/compressed/misc.c could be with 64 bit, and cmd_line_ptr could
above 4g.

So change to unsigned long instead, that will be 64bit in 64bit path
and 32bit in 32bit path.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/x86/boot/boot.h    |    8 ++++----
 arch/x86/boot/cmdline.c |    4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index 7fadf80..5b75319 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -285,11 +285,11 @@ struct biosregs {
 void intcall(u8 int_no, const struct biosregs *ireg, struct biosregs *oreg);
 
 /* cmdline.c */
-int __cmdline_find_option(u32 cmdline_ptr, const char *option, char *buffer, int bufsize);
-int __cmdline_find_option_bool(u32 cmdline_ptr, const char *option);
+int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *buffer, int bufsize);
+int __cmdline_find_option_bool(unsigned long cmdline_ptr, const char *option);
 static inline int cmdline_find_option(const char *option, char *buffer, int bufsize)
 {
-	u32 cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
 
 	if (cmd_line_ptr >= 0x100000)
 		return -1;      /* inaccessible */
@@ -299,7 +299,7 @@ static inline int cmdline_find_option(const char *option, char *buffer, int bufs
 
 static inline int cmdline_find_option_bool(const char *option)
 {
-	u32 cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
+	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
 
 	if (cmd_line_ptr >= 0x100000)
 		return -1;      /* inaccessible */
diff --git a/arch/x86/boot/cmdline.c b/arch/x86/boot/cmdline.c
index 768f00f..625d21b 100644
--- a/arch/x86/boot/cmdline.c
+++ b/arch/x86/boot/cmdline.c
@@ -27,7 +27,7 @@ static inline int myisspace(u8 c)
  * Returns the length of the argument (regardless of if it was
  * truncated to fit in the buffer), or -1 on not found.
  */
-int __cmdline_find_option(u32 cmdline_ptr, const char *option, char *buffer, int bufsize)
+int __cmdline_find_option(unsigned long cmdline_ptr, const char *option, char *buffer, int bufsize)
 {
 	addr_t cptr;
 	char c;
@@ -99,7 +99,7 @@ int __cmdline_find_option(u32 cmdline_ptr, const char *option, char *buffer, int
  * Returns the position of that option (starts counting with 1)
  * or 0 on not found
  */
-int __cmdline_find_option_bool(u32 cmdline_ptr, const char *option)
+int __cmdline_find_option_bool(unsigned long cmdline_ptr, const char *option)
 {
 	addr_t cptr;
 	char c;
-- 
1.7.7

[PATCH v4 09/11] x86: use io_remap to access real_mode_data

[Yinghai Lu]

When 64bit bootloader put real mode data above 4g, We can not
access real mode data directly yet.

because in arch/x86/kernel/head_64.S, only set ident mapping
for 0-1g, and kernel code/data/bss.

So need to move early_ioremap_init() calling early from setup_arch()
to x86_64_start_kernel().

Also use rsi/rdi instead of esi/edi for real_data pointer passing
between asm code and c code.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
---
 arch/x86/kernel/head64.c  |   17 ++++++++++++++---
 arch/x86/kernel/head_64.S |    4 ++--
 arch/x86/kernel/setup.c   |    2 ++
 3 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 3ac6cad..735cd47 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -52,12 +52,21 @@ static void __init copy_bootdata(char *real_mode_data)
 {
 	char * command_line;
 	unsigned long cmd_line_ptr;
+	char *p;
 
-	memcpy(&boot_params, real_mode_data, sizeof boot_params);
+	/*
+	 * for 64bit bootload path, those data could be above 4G,
+	 * and we do set ident mapping for them in head_64.S.
+	 * So need to ioremap to access them.
+	 */
+	p = early_memremap((unsigned long)real_mode_data, sizeof(boot_params));
+	memcpy(&boot_params, p, sizeof(boot_params));
+	early_iounmap(p, sizeof(boot_params));
 	cmd_line_ptr = get_cmd_line_ptr();
 	if (cmd_line_ptr) {
-		command_line = __va(cmd_line_ptr);
+		command_line = early_memremap(cmd_line_ptr, COMMAND_LINE_SIZE);
 		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
+		early_iounmap(command_line, COMMAND_LINE_SIZE);
 	}
 }
 
@@ -104,7 +113,9 @@ void __init x86_64_start_kernel(char * real_mode_data)
 
 void __init x86_64_start_reservations(char *real_mode_data)
 {
-	copy_bootdata(__va(real_mode_data));
+	early_ioremap_init();
+
+	copy_bootdata(real_mode_data);
 
 	memblock_reserve(__pa_symbol(&_text),
 			 __pa_symbol(&__bss_stop) - __pa_symbol(&_text));
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 036dd0e..4e90af7 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -358,9 +358,9 @@ ENTRY(secondary_startup_64)
 	movl	initial_gs+4(%rip),%edx
 	wrmsr	
 
-	/* esi is pointer to real mode structure with interesting info.
+	/* rsi is pointer to real mode structure with interesting info.
 	   pass it to C */
-	movl	%esi, %edi
+	movq	%rsi, %rdi
 	
 	/* Finally jump to run C code and to be on real kernel address
 	 * Since we are running on identity-mapped space we have to jump
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 194e151..573fa7d7 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -718,7 +718,9 @@ void __init setup_arch(char **cmdline_p)
 
 	early_trap_init();
 	early_cpu_init();
+#ifdef CONFIG_X86_32
 	early_ioremap_init();
+#endif
 
 	setup_olpc_ofw_pgd();
 
-- 
1.7.7

[PATCH v4 10/11] x86, boot: add fields to support load bzImage and ramdisk above 4G

[Yinghai Lu]

ext_ramdisk_image/size will record high 32bits for ramdisk info.

xloadflags bit0 will be set if relocatable with 64bit.

Let get_ramdisk_image/size to use ext_ramdisk_image/size to get
right positon for ramdisk.

bootloader will fill value to ext_ramdisk_image/size when it load
ramdisk above 4G.

Also bootloader will check if xloadflags bit0 is set to decicde if
it could load ramdisk high above 4G.

Update header version to 2.12.

-v2: add ext_cmd_line_ptr for above 4G support.
-v3: update to xloadflags from HPA.
-v4: use fields from bootparam instead setup_header accoring to HPA.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Rob Landley <rob@landley.net>
Cc: Matt Fleming <matt.fleming@intel.com>
---
 Documentation/x86/boot.txt         |   15 ++++++++++++++-
 Documentation/x86/zero-page.txt    |    3 +++
 arch/x86/boot/compressed/cmdline.c |    2 ++
 arch/x86/boot/header.S             |   12 ++++++++++--
 arch/x86/include/asm/bootparam.h   |    8 ++++++--
 arch/x86/kernel/head64.c           |    2 ++
 arch/x86/kernel/setup.c            |    4 ++++
 7 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index 9efceff..b2d95ae 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -57,6 +57,9 @@ Protocol 2.10:	(Kernel 2.6.31) Added a protocol for relaxed alignment
 Protocol 2.11:	(Kernel 3.6) Added a field for offset of EFI handover
 		protocol entry point.
 
+Protocol 2.12:	(Kernel 3.9) Added three fields for loading bzImage and
+		 ramdisk above 4G with 64bit in bootparam.
+
 **** MEMORY LAYOUT
 
 The traditional memory map for the kernel loader, used for Image or
@@ -182,7 +185,7 @@ Offset	Proto	Name		Meaning
 0230/4	2.05+	kernel_alignment Physical addr alignment required for kernel
 0234/1	2.05+	relocatable_kernel Whether kernel is relocatable or not
 0235/1	2.10+	min_alignment	Minimum alignment, as a power of two
-0236/2	N/A	pad3		Unused
+0236/2	2.12+	xloadflags	Boot protocol option flags
 0238/4	2.06+	cmdline_size	Maximum size of the kernel command line
 023C/4	2.07+	hardware_subarch Hardware subarchitecture
 0240/8	2.07+	hardware_subarch_data Subarchitecture-specific data
@@ -581,6 +584,16 @@ Protocol:	2.10+
   misaligned kernel.  Therefore, a loader should typically try each
   power-of-two alignment from kernel_alignment down to this alignment.
 
+Field name:     xloadflags
+Type:           modify (obligatory)
+Offset/size:    0x236/2
+Protocol:       2.12+
+
+  This field is a bitmask.
+
+  Bit 0 (read): LOADED_ABOVE_4G
+        - If 1, kernel/boot_params/cmdline/ramdisk could be above 4g
+
 Field name:	cmdline_size
 Type:		read
 Offset/size:	0x238/4
diff --git a/Documentation/x86/zero-page.txt b/Documentation/x86/zero-page.txt
index cf5437d..0e19657 100644
--- a/Documentation/x86/zero-page.txt
+++ b/Documentation/x86/zero-page.txt
@@ -19,6 +19,9 @@ Offset	Proto	Name		Meaning
 090/010	ALL	hd1_info	hd1 disk parameter, OBSOLETE!!
 0A0/010	ALL	sys_desc_table	System description table (struct sys_desc_table)
 0B0/010	ALL	olpc_ofw_header	OLPC's OpenFirmware CIF and friends
+0C0/004 ALL	ext_ramdisk_image ramdisk_image high 32bits
+0C4/004 ALL	ext_ramdisk_size  ramdisk_size high 32bits
+0C8/004 ALL	ext_cmd_line_ptr  cmd_line_ptr high 32bits
 140/080	ALL	edid_info	Video mode setup (struct edid_info)
 1C0/020	ALL	efi_info	EFI 32 information (struct efi_info)
 1E0/004	ALL	alk_mem_k	Alternative mem check, in KB
diff --git a/arch/x86/boot/compressed/cmdline.c b/arch/x86/boot/compressed/cmdline.c
index b4c913c..bffd73b 100644
--- a/arch/x86/boot/compressed/cmdline.c
+++ b/arch/x86/boot/compressed/cmdline.c
@@ -17,6 +17,8 @@ static unsigned long get_cmd_line_ptr(void)
 {
 	unsigned long cmd_line_ptr = real_mode->hdr.cmd_line_ptr;
 
+	cmd_line_ptr |= (u64)real_mode->ext_cmd_line_ptr << 32;
+
 	return cmd_line_ptr;
 }
 int cmdline_find_option(const char *option, char *buffer, int bufsize)
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 2a01744..ae5b00d 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -279,7 +279,7 @@ _start:
 	# Part 2 of the header, from the old setup.S
 
 		.ascii	"HdrS"		# header signature
-		.word	0x020b		# header version number (>= 0x0105)
+		.word	0x020c		# header version number (>= 0x0105)
 					# or else old loadlin-1.5 will fail)
 		.globl realmode_swtch
 realmode_swtch:	.word	0, 0		# default_switch, SETUPSEG
@@ -369,7 +369,15 @@ relocatable_kernel:    .byte 1
 relocatable_kernel:    .byte 0
 #endif
 min_alignment:		.byte MIN_KERNEL_ALIGN_LG2	# minimum alignment
-pad3:			.word 0
+
+xloadflags:
+LOADED_ABOVE_4G	= 1			# If set, the kernel/boot_param/
+					# ramdisk could be loaded above 4g
+#if defined(CONFIG_X86_64) && defined(CONFIG_RELOCATABLE)
+			.word LOADED_ABOVE_4G
+#else
+			.word 0
+#endif
 
 cmdline_size:   .long   COMMAND_LINE_SIZE-1     #length of the command line,
                                                 #added with boot protocol
diff --git a/arch/x86/include/asm/bootparam.h b/arch/x86/include/asm/bootparam.h
index 2ad874c..c83ecc8 100644
--- a/arch/x86/include/asm/bootparam.h
+++ b/arch/x86/include/asm/bootparam.h
@@ -57,7 +57,8 @@ struct setup_header {
 	__u32	initrd_addr_max;
 	__u32	kernel_alignment;
 	__u8	relocatable_kernel;
-	__u8	_pad2[3];
+	__u8	min_alignment;
+	__u16	xloadflags;
 	__u32	cmdline_size;
 	__u32	hardware_subarch;
 	__u64	hardware_subarch_data;
@@ -105,7 +106,10 @@ struct boot_params {
 	__u8  hd1_info[16];	/* obsolete! */		/* 0x090 */
 	struct sys_desc_table sys_desc_table;		/* 0x0a0 */
 	struct olpc_ofw_header olpc_ofw_header;		/* 0x0b0 */
-	__u8  _pad4[128];				/* 0x0c0 */
+	__u32 ext_ramdisk_image;			/* 0x0c0 */
+	__u32 ext_ramdisk_size;				/* 0x0c4 */
+	__u32 ext_cmd_line_ptr;				/* 0x0c8 */
+	__u8  _pad4[116];				/* 0x0cc */
 	struct edid_info edid_info;			/* 0x140 */
 	struct efi_info efi_info;			/* 0x1c0 */
 	__u32 alt_mem_k;				/* 0x1e0 */
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 735cd47..7b941be 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -45,6 +45,8 @@ static unsigned long get_cmd_line_ptr(void)
 {
 	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
 
+	cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
+
 	return cmd_line_ptr;
 }
 
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 573fa7d7..166d30b 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -302,12 +302,16 @@ static u64 __init get_ramdisk_image(void)
 {
 	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
 
+	ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
+
 	return ramdisk_image;
 }
 static u64 __init get_ramdisk_size(void)
 {
 	u64 ramdisk_size = boot_params.hdr.ramdisk_size;
 
+	ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
+
 	return ramdisk_size;
 }
 
-- 
1.7.7

Re: [PATCH v4 10/11] x86, boot: add fields to support load bzImage and ramdisk above 4G

[Yinghai Lu]

[-- Attachment #1: Type: text/plain, Size: 709 bytes --]

On Sat, Nov 24, 2012 at 12:35 PM, Yinghai Lu <yinghai@kernel.org> wrote:
> ext_ramdisk_image/size will record high 32bits for ramdisk info.
>
> xloadflags bit0 will be set if relocatable with 64bit.
>
> Let get_ramdisk_image/size to use ext_ramdisk_image/size to get
> right positon for ramdisk.
>
> bootloader will fill value to ext_ramdisk_image/size when it load
> ramdisk above 4G.
>
> Also bootloader will check if xloadflags bit0 is set to decicde if
> it could load ramdisk high above 4G.
>
> Update header version to 2.12.
>
> -v2: add ext_cmd_line_ptr for above 4G support.
> -v3: update to xloadflags from HPA.
> -v4: use fields from bootparam instead setup_header accoring to HPA.

-v5 attached...

[-- Attachment #2: ext_ramdisk_image_v5.patch --]
[-- Type: application/octet-stream, Size: 7650 bytes --]

Subject: [PATCH v5 10/11] x86, boot: add fields to support load bzImage and ramdisk above 4G

ext_ramdisk_image/size will record high 32bits for ramdisk info.

xloadflags bit0 will be set if relocatable with 64bit.

Let get_ramdisk_image/size to use ext_ramdisk_image/size to get
right positon for ramdisk.

bootloader will fill value to ext_ramdisk_image/size when it load
ramdisk above 4G.

Also bootloader will check if xloadflags bit0 is set to decicde if
it could load ramdisk high above 4G.

Update header version to 2.12.

-v2: add ext_cmd_line_ptr for above 4G support.
-v3: update to xloadflags from HPA.
-v4: use fields from bootparam instead setup_header accoring to HPA.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Rob Landley <rob@landley.net>
Cc: Matt Fleming <matt.fleming@intel.com>

---
 Documentation/x86/boot.txt         |   19 ++++++++++++++++++-
 Documentation/x86/zero-page.txt    |    3 +++
 arch/x86/boot/compressed/cmdline.c |    3 +++
 arch/x86/boot/header.S             |   12 ++++++++++--
 arch/x86/include/asm/bootparam.h   |   10 ++++++++--
 arch/x86/kernel/head64.c           |    3 +++
 arch/x86/kernel/setup.c            |    6 ++++++
 7 files changed, 51 insertions(+), 5 deletions(-)

Index: linux-2.6/Documentation/x86/boot.txt
===================================================================
--- linux-2.6.orig/Documentation/x86/boot.txt
+++ linux-2.6/Documentation/x86/boot.txt
@@ -57,6 +57,9 @@ Protocol 2.10:	(Kernel 2.6.31) Added a p
 Protocol 2.11:	(Kernel 3.6) Added a field for offset of EFI handover
 		protocol entry point.
 
+Protocol 2.12:	(Kernel 3.9) Added three fields for loading bzImage and
+		 ramdisk above 4G with 64bit in bootparam.
+
 **** MEMORY LAYOUT
 
 The traditional memory map for the kernel loader, used for Image or
@@ -182,7 +185,7 @@ Offset	Proto	Name		Meaning
 0230/4	2.05+	kernel_alignment Physical addr alignment required for kernel
 0234/1	2.05+	relocatable_kernel Whether kernel is relocatable or not
 0235/1	2.10+	min_alignment	Minimum alignment, as a power of two
-0236/2	N/A	pad3		Unused
+0236/2	2.12+	xloadflags	Boot protocol option flags
 0238/4	2.06+	cmdline_size	Maximum size of the kernel command line
 023C/4	2.07+	hardware_subarch Hardware subarchitecture
 0240/8	2.07+	hardware_subarch_data Subarchitecture-specific data
@@ -581,6 +584,20 @@ Protocol:	2.10+
   misaligned kernel.  Therefore, a loader should typically try each
   power-of-two alignment from kernel_alignment down to this alignment.
 
+Field name:     xloadflags
+Type:           modify (obligatory)
+Offset/size:    0x236/2
+Protocol:       2.12+
+
+  This field is a bitmask.
+
+  Bit 0 (read): CAN_BE_LOADED_ABOVE_4G
+        - If 1, kernel/boot_params/cmdline/ramdisk can be above 4g,
+
+  Bit 15 (write): USE_EXT_BOOT_PARAMS
+	- If 1, set by bootloader, and kernel could check new fields
+		in boot_params that are added from 2.12 safely.
+
 Field name:	cmdline_size
 Type:		read
 Offset/size:	0x238/4
Index: linux-2.6/arch/x86/boot/header.S
===================================================================
--- linux-2.6.orig/arch/x86/boot/header.S
+++ linux-2.6/arch/x86/boot/header.S
@@ -279,7 +279,7 @@ _start:
 	# Part 2 of the header, from the old setup.S
 
 		.ascii	"HdrS"		# header signature
-		.word	0x020b		# header version number (>= 0x0105)
+		.word	0x020c		# header version number (>= 0x0105)
 					# or else old loadlin-1.5 will fail)
 		.globl realmode_swtch
 realmode_swtch:	.word	0, 0		# default_switch, SETUPSEG
@@ -369,7 +369,15 @@ relocatable_kernel:    .byte 1
 relocatable_kernel:    .byte 0
 #endif
 min_alignment:		.byte MIN_KERNEL_ALIGN_LG2	# minimum alignment
-pad3:			.word 0
+
+xloadflags:
+CAN_BE_LOADED_ABOVE_4G	= 1		# If set, the kernel/boot_param/
+					# ramdisk could be loaded above 4g
+#if defined(CONFIG_X86_64) && defined(CONFIG_RELOCATABLE)
+			.word CAN_BE_LOADED_ABOVE_4G
+#else
+			.word 0
+#endif
 
 cmdline_size:   .long   COMMAND_LINE_SIZE-1     #length of the command line,
                                                 #added with boot protocol
Index: linux-2.6/arch/x86/include/asm/bootparam.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/bootparam.h
+++ linux-2.6/arch/x86/include/asm/bootparam.h
@@ -57,7 +57,10 @@ struct setup_header {
 	__u32	initrd_addr_max;
 	__u32	kernel_alignment;
 	__u8	relocatable_kernel;
-	__u8	_pad2[3];
+	__u8	min_alignment;
+	__u16	xloadflags;
+#define CAN_BE_LOADED_ABOVE_4G	(1<<0)
+#define USE_EXT_BOOT_PARAMS		(1<<15)
 	__u32	cmdline_size;
 	__u32	hardware_subarch;
 	__u64	hardware_subarch_data;
@@ -105,7 +108,10 @@ struct boot_params {
 	__u8  hd1_info[16];	/* obsolete! */		/* 0x090 */
 	struct sys_desc_table sys_desc_table;		/* 0x0a0 */
 	struct olpc_ofw_header olpc_ofw_header;		/* 0x0b0 */
-	__u8  _pad4[128];				/* 0x0c0 */
+	__u32 ext_ramdisk_image;			/* 0x0c0 */
+	__u32 ext_ramdisk_size;				/* 0x0c4 */
+	__u32 ext_cmd_line_ptr;				/* 0x0c8 */
+	__u8  _pad4[116];				/* 0x0cc */
 	struct edid_info edid_info;			/* 0x140 */
 	struct efi_info efi_info;			/* 0x1c0 */
 	__u32 alt_mem_k;				/* 0x1e0 */
Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -302,12 +302,18 @@ static u64 __init get_ramdisk_image(void
 {
 	u64 ramdisk_image = boot_params.hdr.ramdisk_image;
 
+	if (boot_params.hdr.xloadflags & USE_EXT_BOOT_PARAMS)
+		ramdisk_image |= (u64)boot_params.ext_ramdisk_image << 32;
+
 	return ramdisk_image;
 }
 static u64 __init get_ramdisk_size(void)
 {
 	u64 ramdisk_size = boot_params.hdr.ramdisk_size;
 
+	if (boot_params.hdr.xloadflags & USE_EXT_BOOT_PARAMS)
+		ramdisk_size |= (u64)boot_params.ext_ramdisk_size << 32;
+
 	return ramdisk_size;
 }
 
Index: linux-2.6/arch/x86/boot/compressed/cmdline.c
===================================================================
--- linux-2.6.orig/arch/x86/boot/compressed/cmdline.c
+++ linux-2.6/arch/x86/boot/compressed/cmdline.c
@@ -17,6 +17,9 @@ static unsigned long get_cmd_line_ptr(vo
 {
 	unsigned long cmd_line_ptr = real_mode->hdr.cmd_line_ptr;
 
+	if (real_mode->hdr.xloadflags & USE_EXT_BOOT_PARAMS)
+		cmd_line_ptr |= (u64)real_mode->ext_cmd_line_ptr << 32;
+
 	return cmd_line_ptr;
 }
 int cmdline_find_option(const char *option, char *buffer, int bufsize)
Index: linux-2.6/arch/x86/kernel/head64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head64.c
+++ linux-2.6/arch/x86/kernel/head64.c
@@ -45,6 +45,9 @@ static unsigned long get_cmd_line_ptr(vo
 {
 	unsigned long cmd_line_ptr = boot_params.hdr.cmd_line_ptr;
 
+	if (boot_params.hdr.xloadflags & USE_EXT_BOOT_PARAMS)
+		cmd_line_ptr |= (u64)boot_params.ext_cmd_line_ptr << 32;
+
 	return cmd_line_ptr;
 }
 
Index: linux-2.6/Documentation/x86/zero-page.txt
===================================================================
--- linux-2.6.orig/Documentation/x86/zero-page.txt
+++ linux-2.6/Documentation/x86/zero-page.txt
@@ -19,6 +19,9 @@ Offset	Proto	Name		Meaning
 090/010	ALL	hd1_info	hd1 disk parameter, OBSOLETE!!
 0A0/010	ALL	sys_desc_table	System description table (struct sys_desc_table)
 0B0/010	ALL	olpc_ofw_header	OLPC's OpenFirmware CIF and friends
+0C0/004 ALL	ext_ramdisk_image ramdisk_image high 32bits
+0C4/004 ALL	ext_ramdisk_size  ramdisk_size high 32bits
+0C8/004 ALL	ext_cmd_line_ptr  cmd_line_ptr high 32bits
 140/080	ALL	edid_info	Video mode setup (struct edid_info)
 1C0/020	ALL	efi_info	EFI 32 information (struct efi_info)
 1E0/004	ALL	alk_mem_k	Alternative mem check, in KB

[PATCH v4 11/11] x86: remove 1024G limitation for kexec buffer on 64bit

[Yinghai Lu]

Now 64bit kernel supports more than 1T ram and kexec tools
could find buffer above 1T, remove that obsolete limitation.
and use MAXMEM instead.

Tested on system more than 1024G ram.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
---
 arch/x86/include/asm/kexec.h |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/kexec.h b/arch/x86/include/asm/kexec.h
index 317ff17..11bfdc5 100644
--- a/arch/x86/include/asm/kexec.h
+++ b/arch/x86/include/asm/kexec.h
@@ -48,11 +48,11 @@
 # define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
 #else
 /* Maximum physical address we can use pages from */
-# define KEXEC_SOURCE_MEMORY_LIMIT      (0xFFFFFFFFFFUL)
+# define KEXEC_SOURCE_MEMORY_LIMIT      (MAXMEM-1)
 /* Maximum address we can reach in physical address mode */
-# define KEXEC_DESTINATION_MEMORY_LIMIT (0xFFFFFFFFFFUL)
+# define KEXEC_DESTINATION_MEMORY_LIMIT (MAXMEM-1)
 /* Maximum address we can use for the control pages */
-# define KEXEC_CONTROL_MEMORY_LIMIT     (0xFFFFFFFFFFUL)
+# define KEXEC_CONTROL_MEMORY_LIMIT     (MAXMEM-1)
 
 /* Allocate one page for the pdp and the second for the code */
 # define KEXEC_CONTROL_PAGE_SIZE  (4096UL + 4096UL)
-- 
1.7.7