[PATCH -v7 1/3] x86 boot: setup data

[PATCH -v7 1/3] x86 boot: setup data

[Huang, Ying]

This patch add a field of 64-bit physical pointer to NULL terminated
single linked list of struct setup_data to real-mode kernel
header. This is used as a more extensible boot parameters passing
mechanism.

Signed-off-by: Huang Ying <ying.huang@intel.com>

---

 arch/x86/boot/header.S      |    6 +++++-
 arch/x86/kernel/e820_64.c   |    6 +++---
 arch/x86/kernel/head64.c    |   26 ++++++++++++++++++++++++++
 arch/x86/kernel/head_32.S   |   37 ++++++++++++++++++++++++++++++++++++-
 arch/x86/kernel/setup_32.c  |   25 +++++++++++++++++++++++--
 arch/x86/kernel/setup_64.c  |   22 ++++++++++++++++++++--
 arch/x86/mm/discontig_32.c  |    3 ++-
 include/asm-x86/bootparam.h |   12 ++++++++++++
 include/asm-x86/e820_64.h   |    1 +
 include/asm-x86/setup_32.h  |    7 +++++++
 include/asm-x86/setup_64.h  |    2 ++
 11 files changed, 137 insertions(+), 10 deletions(-)

Index: linux-2.6/include/asm-x86/bootparam.h
===================================================================
--- linux-2.6.orig/include/asm-x86/bootparam.h	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/include/asm-x86/bootparam.h	2007-10-23 10:48:48.000000000 +0800
@@ -9,6 +9,17 @@
 #include <asm/ist.h>
 #include <video/edid.h>
 
+/* setup data types */
+#define SETUP_NONE			0
+
+/* extensible setup data list node */
+struct setup_data {
+	u64 next;
+	u32 type;
+	u32 len;
+	u8 data[0];
+};
+
 struct setup_header {
 	u8	setup_sects;
 	u16	root_flags;
@@ -46,6 +57,7 @@
 	u32	cmdline_size;
 	u32	hardware_subarch;
 	u64	hardware_subarch_data;
+	u64	setup_data;
 } __attribute__((packed));
 
 struct sys_desc_table {
Index: linux-2.6/arch/x86/boot/header.S
===================================================================
--- linux-2.6.orig/arch/x86/boot/header.S	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/arch/x86/boot/header.S	2007-10-23 13:51:29.000000000 +0800
@@ -119,7 +119,7 @@
 	# Part 2 of the header, from the old setup.S
 
 		.ascii	"HdrS"		# header signature
-		.word	0x0207		# header version number (>= 0x0105)
+		.word	0x0208		# header version number (>= 0x0105)
 					# or else old loadlin-1.5 will fail)
 		.globl realmode_swtch
 realmode_swtch:	.word	0, 0		# default_switch, SETUPSEG
@@ -219,6 +219,10 @@
 
 hardware_subarch_data:	.quad 0
 
+setup_data:		.quad 0			# 64-bit physical pointer to
+						# single linked list of
+						# struct setup_data
+
 # End of setup header #####################################################
 
 	.section ".inittext", "ax"
Index: linux-2.6/arch/x86/kernel/setup_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup_64.c	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/arch/x86/kernel/setup_64.c	2007-10-23 10:48:48.000000000 +0800
@@ -247,6 +247,22 @@
 		ebda_size = 64*1024;
 }
 
+static void __init parse_setup_data(void)
+{
+	struct setup_data *data;
+
+	if (boot_params.hdr.version < 0x0207)
+		return;
+	for (data = __va(boot_params.hdr.setup_data);
+	     data != __va(0);
+	     data = __va(data->next)) {
+		switch (data->type) {
+		default:
+			break;
+		}
+	}
+}
+
 void __init setup_arch(char **cmdline_p)
 {
 	printk(KERN_INFO "Command line: %s\n", boot_command_line);
@@ -282,6 +298,8 @@
 	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
 	*cmdline_p = command_line;
 
+	parse_setup_data();
+
 	parse_early_param();
 
 	finish_e820_parsing();
@@ -340,9 +358,9 @@
 	reserve_bootmem_generic(table_start << PAGE_SHIFT, 
 				(table_end - table_start) << PAGE_SHIFT);
 
-	/* reserve kernel */
+	/* reserve kernel and setup data */
 	reserve_bootmem_generic(__pa_symbol(&_text),
-				__pa_symbol(&_end) - __pa_symbol(&_text));
+				setup_data_end - __pa_symbol(&_text));
 
 	/*
 	 * reserve physical page 0 - it's a special BIOS page on many boxes,
Index: linux-2.6/arch/x86/kernel/setup_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup_32.c	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/arch/x86/kernel/setup_32.c	2007-10-23 13:51:05.000000000 +0800
@@ -66,6 +66,8 @@
    address, and must not be in the .bss segment! */
 unsigned long init_pg_tables_end __initdata = ~0UL;
 
+unsigned long setup_data_len __initdata;
+
 int disable_pse __devinitdata = 0;
 
 /*
@@ -327,7 +329,7 @@
 	 * partially used pages are not usable - thus
 	 * we are rounding upwards:
 	 */
-	min_low_pfn = PFN_UP(init_pg_tables_end);
+	min_low_pfn = PFN_UP(init_pg_tables_end+setup_data_len);
 
 	find_max_pfn();
 
@@ -532,6 +534,22 @@
 	return machine_specific_memory_setup();
 }
 
+static void __init parse_setup_data(void)
+{
+	struct setup_data *data;
+
+	if (boot_params.hdr.version < 0x0207)
+		return;
+	for (data = __va(boot_params.hdr.setup_data);
+	     data != __va(0);
+	     data = __va(data->next)) {
+		switch (data->type) {
+		default:
+			break;
+		}
+	}
+}
+
 /*
  * Determine if we were loaded by an EFI loader.  If so, then we have also been
  * passed the efi memmap, systab, etc., so we should use these data structures
@@ -579,6 +597,9 @@
 	rd_prompt = ((boot_params.hdr.ram_size & RAMDISK_PROMPT_FLAG) != 0);
 	rd_doload = ((boot_params.hdr.ram_size & RAMDISK_LOAD_FLAG) != 0);
 #endif
+
+	parse_setup_data();
+
 	ARCH_SETUP
 	if (efi_enabled)
 		efi_init();
@@ -594,7 +615,7 @@
 	init_mm.start_code = (unsigned long) _text;
 	init_mm.end_code = (unsigned long) _etext;
 	init_mm.end_data = (unsigned long) _edata;
-	init_mm.brk = init_pg_tables_end + PAGE_OFFSET;
+	init_mm.brk = init_pg_tables_end + setup_data_len + PAGE_OFFSET;
 
 	code_resource.start = virt_to_phys(_text);
 	code_resource.end = virt_to_phys(_etext)-1;
Index: linux-2.6/arch/x86/kernel/e820_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/e820_64.c	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/arch/x86/kernel/e820_64.c	2007-10-23 10:01:39.000000000 +0800
@@ -79,9 +79,9 @@
 		}
 	} 
 #endif
-	/* kernel code */
-	if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
-		*addrp = PAGE_ALIGN(__pa_symbol(&_end));
+	/* kernel code and setup data */
+	if (last >= __pa_symbol(&_text) && addr < setup_data_end) {
+		*addrp = PAGE_ALIGN(setup_data_end);
 		return 1;
 	}
 
Index: linux-2.6/arch/x86/kernel/head64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head64.c	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/arch/x86/kernel/head64.c	2007-10-23 10:01:39.000000000 +0800
@@ -19,6 +19,9 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
+#include <asm/io.h>
+
+unsigned long __initdata setup_data_end;
 
 static void __init zap_identity_mappings(void)
 {
@@ -38,12 +41,35 @@
 static void __init copy_bootdata(char *real_mode_data)
 {
 	char * command_line;
+	void *sdata_dst;
+	struct setup_data *sdata;
+	u64 *ppa_next;
+	unsigned long sdata_len;
 
 	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);
 		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
 	}
+
+#define SETUP_DATA_ALIGN(addr) \
+	(((unsigned long)(addr)+(SETUP_DATA_ALIGN_SIZE-1))& \
+	 ~(SETUP_DATA_ALIGN_SIZE-1))
+
+	sdata_dst = __va(SETUP_DATA_ALIGN(__pa_symbol(&_end)));
+	ppa_next = &boot_params.hdr.setup_data;
+	while (*ppa_next) {
+		sdata = early_ioremap(*ppa_next, sizeof(*sdata));
+		sdata_len = sizeof(*sdata) + sdata->len;
+		early_iounmap(sdata, sizeof(*sdata));
+		sdata = early_ioremap(*ppa_next, sdata_len);
+		memcpy(sdata_dst, sdata, sdata_len);
+		early_iounmap(sdata, sdata_len);
+		*ppa_next = __pa(sdata_dst);
+		ppa_next = &((struct setup_data *)sdata_dst)->next;
+		sdata_dst = (void *)SETUP_DATA_ALIGN(sdata_dst+sdata_len);
+	}
+	setup_data_end = __pa(sdata_dst);
 }
 
 void __init x86_64_start_kernel(char * real_mode_data)
Index: linux-2.6/include/asm-x86/e820_64.h
===================================================================
--- linux-2.6.orig/include/asm-x86/e820_64.h	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/include/asm-x86/e820_64.h	2007-10-23 10:01:39.000000000 +0800
@@ -56,6 +56,7 @@
 
 extern unsigned ebda_addr, ebda_size;
 extern unsigned long nodemap_addr, nodemap_size;
+extern unsigned long setup_data_end;
 #endif/*!__ASSEMBLY__*/
 
 #endif/*__E820_HEADER*/
Index: linux-2.6/arch/x86/kernel/head_32.S
===================================================================
--- linux-2.6.orig/arch/x86/kernel/head_32.S	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/arch/x86/kernel/head_32.S	2007-10-23 10:01:39.000000000 +0800
@@ -135,6 +135,21 @@
 	rep
 	movsl
 1:
+	movl boot_params - __PAGE_OFFSET + SETUP_DATA_POINTER,%ebp
+	xorl %ecx,%ecx
+2:
+	andl %ebp,%ebp
+	jz 1f
+	movl $(SETUP_DATA_HEADER_LEN+SETUP_DATA_ALIGN_SIZE-1),%eax
+	addl (SETUP_DATA_LEN)(%ebp),%eax
+	andl $~(SETUP_DATA_ALIGN_SIZE-1),%eax
+	addl %eax, %ecx
+	movl SETUP_DATA_NEXT(%ebp),%ebp
+	jmp 2b
+1:
+	addl $(PAGE_SIZE_asm-1),%ecx
+	andl $~(PAGE_SIZE_asm-1),%ecx
+	movl %ecx,(setup_data_len - __PAGE_OFFSET)
 
 #ifdef CONFIG_PARAVIRT
 	cmpw $0x207, (boot_params + BP_version - __PAGE_OFFSET)
@@ -191,13 +206,33 @@
 	stosl
 	addl $0x1000,%eax
 	loop 11b
-	/* End condition: we must map up to and including INIT_MAP_BEYOND_END */
+	/* End condition: we must map up to and including INIT_MAP_BEYOND_END + setup_data_len */
 	/* bytes beyond the end of our own page tables; the +0x007 is the attribute bits */
 	leal (INIT_MAP_BEYOND_END+0x007)(%edi),%ebp
+	addl (setup_data_len - __PAGE_OFFSET),%ebp
 	cmpl %ebp,%eax
 	jb 10b
 	movl %edi,(init_pg_tables_end - __PAGE_OFFSET)
 
+	/* Copy setup data */
+	leal (boot_params - __PAGE_OFFSET + SETUP_DATA_POINTER),%ebx
+2:
+	movl (%ebx),%ebp
+	andl %ebp,%ebp
+	jz 1f
+	movl $SETUP_DATA_HEADER_LEN,%ecx
+	addl SETUP_DATA_LEN(%ebp),%ecx
+	addl $(SETUP_DATA_ALIGN_SIZE-1),%edi
+	andl $~(SETUP_DATA_ALIGN_SIZE-1),%edi
+	movl %edi,(%ebx)
+	movl %ebp,%esi
+	rep
+	movsb
+	movl (%ebx),%ebx
+	leal SETUP_DATA_NEXT(%ebx),%ebx
+	jmp 2b
+1:
+
 	xorl %ebx,%ebx				/* This is the boot CPU (BSP) */
 	jmp 3f
 /*
Index: linux-2.6/arch/x86/mm/discontig_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/discontig_32.c	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/arch/x86/mm/discontig_32.c	2007-10-23 10:01:39.000000000 +0800
@@ -282,7 +282,8 @@
 	kva_pages = calculate_numa_remap_pages();
 
 	/* partially used pages are not usable - thus round upwards */
-	system_start_pfn = min_low_pfn = PFN_UP(init_pg_tables_end);
+	system_start_pfn = min_low_pfn = PFN_UP(init_pg_tables_end +
+						setup_data_len);
 
 	kva_start_pfn = find_max_low_pfn() - kva_pages;
 
Index: linux-2.6/include/asm-x86/setup_32.h
===================================================================
--- linux-2.6.orig/include/asm-x86/setup_32.h	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/include/asm-x86/setup_32.h	2007-10-23 10:01:39.000000000 +0800
@@ -25,6 +25,13 @@
 #define OLD_CL_OFFSET		0x90022
 #define NEW_CL_POINTER		0x228	/* Relative to real mode data */
 
+#define SETUP_DATA_POINTER	0x248	/* Relative to real mode data */
+
+#define SETUP_DATA_NEXT		0x0
+#define SETUP_DATA_LEN		0xc
+#define SETUP_DATA_HEADER_LEN	0x10
+#define SETUP_DATA_ALIGN_SIZE	0x8
+
 #ifndef __ASSEMBLY__
 
 #include <asm/bootparam.h>
Index: linux-2.6/include/asm-x86/setup_64.h
===================================================================
--- linux-2.6.orig/include/asm-x86/setup_64.h	2007-10-23 10:01:35.000000000 +0800
+++ linux-2.6/include/asm-x86/setup_64.h	2007-10-23 10:03:25.000000000 +0800
@@ -4,7 +4,9 @@
 #define COMMAND_LINE_SIZE	2048
 
 #ifdef __KERNEL__
+#include <linux/const.h>
 
+#define SETUP_DATA_ALIGN_SIZE	__AC(0x8, UL)
 #ifndef __ASSEMBLY__
 #include <asm/bootparam.h>
 

Re: [PATCH -v7 1/3] x86 boot: setup data

[Jeremy Fitzhardinge]

Huang, Ying wrote:
> This patch add a field of 64-bit physical pointer to NULL terminated
> single linked list of struct setup_data to real-mode kernel
> header. This is used as a more extensible boot parameters passing
> mechanism.
>   

As a general comment, I can't say I'm thrilled about sticking the copied
setup data at the end of the initial pagetables.  This is already a
fairly complex area, and changing it touches a surprisingly large number
of places.  I wonder if there isn't a better way to deal with this
(possibly by fixing up the generation of the initial pagetables in the
process).

Or more simply, define a max size for this data, and copy it into an
initdata area (which, being initdata, can be quite large without wasting
lots of memory).

> Signed-off-by: Huang Ying <ying.huang@intel.com>
>
> ---
>
>  arch/x86/boot/header.S      |    6 +++++-
>  arch/x86/kernel/e820_64.c   |    6 +++---
>  arch/x86/kernel/head64.c    |   26 ++++++++++++++++++++++++++
>  arch/x86/kernel/head_32.S   |   37 ++++++++++++++++++++++++++++++++++++-
>  arch/x86/kernel/setup_32.c  |   25 +++++++++++++++++++++++--
>  arch/x86/kernel/setup_64.c  |   22 ++++++++++++++++++++--
>  arch/x86/mm/discontig_32.c  |    3 ++-
>  include/asm-x86/bootparam.h |   12 ++++++++++++
>  include/asm-x86/e820_64.h   |    1 +
>  include/asm-x86/setup_32.h  |    7 +++++++
>  include/asm-x86/setup_64.h  |    2 ++
>  11 files changed, 137 insertions(+), 10 deletions(-)
>
> Index: linux-2.6/include/asm-x86/bootparam.h
> ===================================================================
> --- linux-2.6.orig/include/asm-x86/bootparam.h	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/include/asm-x86/bootparam.h	2007-10-23 10:48:48.000000000 +0800
> @@ -9,6 +9,17 @@
>  #include <asm/ist.h>
>  #include <video/edid.h>
>  
> +/* setup data types */
> +#define SETUP_NONE			0
> +
> +/* extensible setup data list node */
> +struct setup_data {
> +	u64 next;
> +	u32 type;
> +	u32 len;
> +	u8 data[0];
> +};
>   

What are the alignment rules for this structure?  Is it always 64-bit
aligned?  What about the relationship of len and data?

> +
>  struct setup_header {
>  	u8	setup_sects;
>  	u16	root_flags;
> @@ -46,6 +57,7 @@
>  	u32	cmdline_size;
>  	u32	hardware_subarch;
>  	u64	hardware_subarch_data;
> +	u64	setup_data;
>  } __attribute__((packed));
>  
>  struct sys_desc_table {
> Index: linux-2.6/arch/x86/boot/header.S
> ===================================================================
> --- linux-2.6.orig/arch/x86/boot/header.S	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/arch/x86/boot/header.S	2007-10-23 13:51:29.000000000 +0800
> @@ -119,7 +119,7 @@
>  	# Part 2 of the header, from the old setup.S
>  
>  		.ascii	"HdrS"		# header signature
> -		.word	0x0207		# header version number (>= 0x0105)
> +		.word	0x0208		# header version number (>= 0x0105)
>  					# or else old loadlin-1.5 will fail)
>  		.globl realmode_swtch
>  realmode_swtch:	.word	0, 0		# default_switch, SETUPSEG
> @@ -219,6 +219,10 @@
>  
>  hardware_subarch_data:	.quad 0
>  
> +setup_data:		.quad 0			# 64-bit physical pointer to
> +						# single linked list of
> +						# struct setup_data
> +
>  # End of setup header #####################################################
>  
>  	.section ".inittext", "ax"
> Index: linux-2.6/arch/x86/kernel/setup_64.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/setup_64.c	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/arch/x86/kernel/setup_64.c	2007-10-23 10:48:48.000000000 +0800
> @@ -247,6 +247,22 @@
>  		ebda_size = 64*1024;
>  }
>  
> +static void __init parse_setup_data(void)
> +{
> +	struct setup_data *data;
> +
> +	if (boot_params.hdr.version < 0x0207)
> +		return;
> +	for (data = __va(boot_params.hdr.setup_data);
> +	     data != __va(0);
> +	     data = __va(data->next)) {
> +		switch (data->type) {
> +		default:
> +			break;
> +		}
> +	}
> +}
> +
>  void __init setup_arch(char **cmdline_p)
>  {
>  	printk(KERN_INFO "Command line: %s\n", boot_command_line);
> @@ -282,6 +298,8 @@
>  	strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
>  	*cmdline_p = command_line;
>  
> +	parse_setup_data();
> +
>  	parse_early_param();
>  
>  	finish_e820_parsing();
> @@ -340,9 +358,9 @@
>  	reserve_bootmem_generic(table_start << PAGE_SHIFT, 
>  				(table_end - table_start) << PAGE_SHIFT);
>  
> -	/* reserve kernel */
> +	/* reserve kernel and setup data */
>  	reserve_bootmem_generic(__pa_symbol(&_text),
> -				__pa_symbol(&_end) - __pa_symbol(&_text));
> +				setup_data_end - __pa_symbol(&_text));
>  
>  	/*
>  	 * reserve physical page 0 - it's a special BIOS page on many boxes,
> Index: linux-2.6/arch/x86/kernel/setup_32.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/setup_32.c	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/arch/x86/kernel/setup_32.c	2007-10-23 13:51:05.000000000 +0800
> @@ -66,6 +66,8 @@
>     address, and must not be in the .bss segment! */
>  unsigned long init_pg_tables_end __initdata = ~0UL;
>  
> +unsigned long setup_data_len __initdata;
> +
>  int disable_pse __devinitdata = 0;
>  
>  /*
> @@ -327,7 +329,7 @@
>  	 * partially used pages are not usable - thus
>  	 * we are rounding upwards:
>  	 */
> -	min_low_pfn = PFN_UP(init_pg_tables_end);
> +	min_low_pfn = PFN_UP(init_pg_tables_end+setup_data_len);
>  
>  	find_max_pfn();
>  
> @@ -532,6 +534,22 @@
>  	return machine_specific_memory_setup();
>  }
>  
> +static void __init parse_setup_data(void)
> +{
> +	struct setup_data *data;
> +
> +	if (boot_params.hdr.version < 0x0207)
> +		return;
> +	for (data = __va(boot_params.hdr.setup_data);
> +	     data != __va(0);
> +	     data = __va(data->next)) {
> +		switch (data->type) {
> +		default:
> +			break;
> +		}
> +	}
> +}
>   

Please don't add new duplicated code.  Put this into a common place.

> +
>  /*
>   * Determine if we were loaded by an EFI loader.  If so, then we have also been
>   * passed the efi memmap, systab, etc., so we should use these data structures
> @@ -579,6 +597,9 @@
>  	rd_prompt = ((boot_params.hdr.ram_size & RAMDISK_PROMPT_FLAG) != 0);
>  	rd_doload = ((boot_params.hdr.ram_size & RAMDISK_LOAD_FLAG) != 0);
>  #endif
> +
> +	parse_setup_data();
> +
>  	ARCH_SETUP
>  	if (efi_enabled)
>  		efi_init();
> @@ -594,7 +615,7 @@
>  	init_mm.start_code = (unsigned long) _text;
>  	init_mm.end_code = (unsigned long) _etext;
>  	init_mm.end_data = (unsigned long) _edata;
> -	init_mm.brk = init_pg_tables_end + PAGE_OFFSET;
> +	init_mm.brk = init_pg_tables_end + setup_data_len + PAGE_OFFSET;
>  
>  	code_resource.start = virt_to_phys(_text);
>  	code_resource.end = virt_to_phys(_etext)-1;
> Index: linux-2.6/arch/x86/kernel/e820_64.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/e820_64.c	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/arch/x86/kernel/e820_64.c	2007-10-23 10:01:39.000000000 +0800
> @@ -79,9 +79,9 @@
>  		}
>  	} 
>  #endif
> -	/* kernel code */
> -	if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
> -		*addrp = PAGE_ALIGN(__pa_symbol(&_end));
> +	/* kernel code and setup data */
> +	if (last >= __pa_symbol(&_text) && addr < setup_data_end) {
> +		*addrp = PAGE_ALIGN(setup_data_end);
>  		return 1;
>  	}
>  
> Index: linux-2.6/arch/x86/kernel/head64.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/head64.c	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/arch/x86/kernel/head64.c	2007-10-23 10:01:39.000000000 +0800
> @@ -19,6 +19,9 @@
>  #include <asm/pgtable.h>
>  #include <asm/tlbflush.h>
>  #include <asm/sections.h>
> +#include <asm/io.h>
> +
> +unsigned long __initdata setup_data_end;
>  
>  static void __init zap_identity_mappings(void)
>  {
> @@ -38,12 +41,35 @@
>  static void __init copy_bootdata(char *real_mode_data)
>  {
>  	char * command_line;
> +	void *sdata_dst;
> +	struct setup_data *sdata;
> +	u64 *ppa_next;
> +	unsigned long sdata_len;
>  
>  	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);
>  		memcpy(boot_command_line, command_line, COMMAND_LINE_SIZE);
>  	}
> +
> +#define SETUP_DATA_ALIGN(addr) \
> +	(((unsigned long)(addr)+(SETUP_DATA_ALIGN_SIZE-1))& \
> +	 ~(SETUP_DATA_ALIGN_SIZE-1))
> +
> +	sdata_dst = __va(SETUP_DATA_ALIGN(__pa_symbol(&_end)));
> +	ppa_next = &boot_params.hdr.setup_data;
> +	while (*ppa_next) {
> +		sdata = early_ioremap(*ppa_next, sizeof(*sdata));
> +		sdata_len = sizeof(*sdata) + sdata->len;
> +		early_iounmap(sdata, sizeof(*sdata));
> +		sdata = early_ioremap(*ppa_next, sdata_len);
> +		memcpy(sdata_dst, sdata, sdata_len);
> +		early_iounmap(sdata, sdata_len);
> +		*ppa_next = __pa(sdata_dst);
> +		ppa_next = &((struct setup_data *)sdata_dst)->next;
> +		sdata_dst = (void *)SETUP_DATA_ALIGN(sdata_dst+sdata_len);
> +	}
> +	setup_data_end = __pa(sdata_dst);
>  }
>  
>  void __init x86_64_start_kernel(char * real_mode_data)
> Index: linux-2.6/include/asm-x86/e820_64.h
> ===================================================================
> --- linux-2.6.orig/include/asm-x86/e820_64.h	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/include/asm-x86/e820_64.h	2007-10-23 10:01:39.000000000 +0800
> @@ -56,6 +56,7 @@
>  
>  extern unsigned ebda_addr, ebda_size;
>  extern unsigned long nodemap_addr, nodemap_size;
> +extern unsigned long setup_data_end;
>  #endif/*!__ASSEMBLY__*/
>  
>  #endif/*__E820_HEADER*/
> Index: linux-2.6/arch/x86/kernel/head_32.S
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/head_32.S	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/arch/x86/kernel/head_32.S	2007-10-23 10:01:39.000000000 +0800
> @@ -135,6 +135,21 @@
>  	rep
>  	movsl
>  1:
> +	movl boot_params - __PAGE_OFFSET + SETUP_DATA_POINTER,%ebp
>   

You need to check the boot protocol version before looking at this pointer.

> +	xorl %ecx,%ecx
> +2:
> +	andl %ebp,%ebp
> +	jz 1f
> +	movl $(SETUP_DATA_HEADER_LEN+SETUP_DATA_ALIGN_SIZE-1),%eax
> +	addl (SETUP_DATA_LEN)(%ebp),%eax
> +	andl $~(SETUP_DATA_ALIGN_SIZE-1),%eax
> +	addl %eax, %ecx
> +	movl SETUP_DATA_NEXT(%ebp),%ebp
> +	jmp 2b
> +1:
> +	addl $(PAGE_SIZE_asm-1),%ecx
> +	andl $~(PAGE_SIZE_asm-1),%ecx
> +	movl %ecx,(setup_data_len - __PAGE_OFFSET)
>  
>  #ifdef CONFIG_PARAVIRT
>  	cmpw $0x207, (boot_params + BP_version - __PAGE_OFFSET)
> @@ -191,13 +206,33 @@
>  	stosl
>  	addl $0x1000,%eax
>  	loop 11b
> -	/* End condition: we must map up to and including INIT_MAP_BEYOND_END */
> +	/* End condition: we must map up to and including INIT_MAP_BEYOND_END + setup_data_len */
>  	/* bytes beyond the end of our own page tables; the +0x007 is the attribute bits */
>  	leal (INIT_MAP_BEYOND_END+0x007)(%edi),%ebp
> +	addl (setup_data_len - __PAGE_OFFSET),%ebp
>  	cmpl %ebp,%eax
>  	jb 10b
>  	movl %edi,(init_pg_tables_end - __PAGE_OFFSET)
>  
> +	/* Copy setup data */
> +	leal (boot_params - __PAGE_OFFSET + SETUP_DATA_POINTER),%ebx
> +2:
> +	movl (%ebx),%ebp
> +	andl %ebp,%ebp
> +	jz 1f
> +	movl $SETUP_DATA_HEADER_LEN,%ecx
> +	addl SETUP_DATA_LEN(%ebp),%ecx
> +	addl $(SETUP_DATA_ALIGN_SIZE-1),%edi
> +	andl $~(SETUP_DATA_ALIGN_SIZE-1),%edi
> +	movl %edi,(%ebx)
> +	movl %ebp,%esi
> +	rep
> +	movsb
> +	movl (%ebx),%ebx
> +	leal SETUP_DATA_NEXT(%ebx),%ebx
> +	jmp 2b
> +1:
> +
>  	xorl %ebx,%ebx				/* This is the boot CPU (BSP) */
>  	jmp 3f
>  /*
> Index: linux-2.6/arch/x86/mm/discontig_32.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/mm/discontig_32.c	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/arch/x86/mm/discontig_32.c	2007-10-23 10:01:39.000000000 +0800
> @@ -282,7 +282,8 @@
>  	kva_pages = calculate_numa_remap_pages();
>  
>  	/* partially used pages are not usable - thus round upwards */
> -	system_start_pfn = min_low_pfn = PFN_UP(init_pg_tables_end);
> +	system_start_pfn = min_low_pfn = PFN_UP(init_pg_tables_end +
> +						setup_data_len);
>  
>  	kva_start_pfn = find_max_low_pfn() - kva_pages;
>  
> Index: linux-2.6/include/asm-x86/setup_32.h
> ===================================================================
> --- linux-2.6.orig/include/asm-x86/setup_32.h	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/include/asm-x86/setup_32.h	2007-10-23 10:01:39.000000000 +0800
> @@ -25,6 +25,13 @@
>  #define OLD_CL_OFFSET		0x90022
>  #define NEW_CL_POINTER		0x228	/* Relative to real mode data */
>  
> +#define SETUP_DATA_POINTER	0x248	/* Relative to real mode data */
> +
> +#define SETUP_DATA_NEXT		0x0
> +#define SETUP_DATA_LEN		0xc
> +#define SETUP_DATA_HEADER_LEN	0x10
> +#define SETUP_DATA_ALIGN_SIZE	0x8
>   

No, use asm-offsets(_32|_64).c

> +
>  #ifndef __ASSEMBLY__
>  
>  #include <asm/bootparam.h>
> Index: linux-2.6/include/asm-x86/setup_64.h
> ===================================================================
> --- linux-2.6.orig/include/asm-x86/setup_64.h	2007-10-23 10:01:35.000000000 +0800
> +++ linux-2.6/include/asm-x86/setup_64.h	2007-10-23 10:03:25.000000000 +0800
> @@ -4,7 +4,9 @@
>  #define COMMAND_LINE_SIZE	2048
>  
>  #ifdef __KERNEL__
> +#include <linux/const.h>
>  
> +#define SETUP_DATA_ALIGN_SIZE	__AC(0x8, UL)
>  #ifndef __ASSEMBLY__
>  #include <asm/bootparam.h>
>  
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/
>   

Re: [PATCH -v7 1/3] x86 boot: setup data

[H. Peter Anvin]

Jeremy Fitzhardinge wrote:
>>  1:
>> +	movl boot_params - __PAGE_OFFSET + SETUP_DATA_POINTER,%ebp
> 
> You need to check the boot protocol version before looking at this pointer.
> 

No, he doesn't.  The boot protocol version is communication between the 
boot loader and the kernel (specifically, it is communication FROM the 
kernel TO the bootloader), not between internal bits of the kernel.  Th

Since the pointer is safely inside the setup template, even if the 
bootloader doesn't understand boot protocol version 2.08 it will have 
copied it.

So this is fine.

	-hpa

Re: [PATCH -v7 1/3] x86 boot: setup data

[Jeremy Fitzhardinge]

H. Peter Anvin wrote:
> No, he doesn't.  The boot protocol version is communication between
> the boot loader and the kernel (specifically, it is communication FROM
> the kernel TO the bootloader), not between internal bits of the
> kernel.  Th

So the bootloader will only fill out fields the kernel claims to understand?

> Since the pointer is safely inside the setup template, even if the
> bootloader doesn't understand boot protocol version 2.08 it will have
> copied it.


OK.

    J

Re: [PATCH -v7 1/3] x86 boot: setup data

[H. Peter Anvin]

Jeremy Fitzhardinge wrote:
> H. Peter Anvin wrote:
>> No, he doesn't.  The boot protocol version is communication between
>> the boot loader and the kernel (specifically, it is communication FROM
>> the kernel TO the bootloader), not between internal bits of the
>> kernel.  Th
> 
> So the bootloader will only fill out fields the kernel claims to understand?
> 

Correct.  If it fails to respect this restriction, it might even 
overwrite kernel code.  To make the bootloader's job easier, we have 
retconned the jump instruction at the beginning of the header to also be 
a limit marker.

	-hpa

Re: [PATCH -v7 1/3] x86 boot: setup data

[H. Peter Anvin]

Jeremy Fitzhardinge wrote:
> 
> As a general comment, I can't say I'm thrilled about sticking the copied
> setup data at the end of the initial pagetables.  This is already a
> fairly complex area, and changing it touches a surprisingly large number
> of places.  I wonder if there isn't a better way to deal with this
> (possibly by fixing up the generation of the initial pagetables in the
> process).
> 
> Or more simply, define a max size for this data, and copy it into an
> initdata area (which, being initdata, can be quite large without wasting
> lots of memory).
> 

The initdata solution is fairly sensible.  It's easy, and this data 
really isn't expected to grow very fast at all.  Unfortunately we don't 
*have* an initdata bss section at the moment, so a large buffer would 
bloat the kernel binary -- at least the uncompressed one.  One school of 
thought says that this should be fixed :) [*]

However, appending to bss (like the pagetables already are) *should* be 
a reasonable option; what really should be done there is instead of 
replacing init_pg_tables_end with setup_data_end we should except 
additional dynamic data items here, and have an initial_data_end 
variable for the extreme end of any initial data no matter the source. 
It still does touch a lot of places, but at least that way they will be 
fixed once and for all.  It's somewhat questionable if it isn't easier 
for this particular job to just fix the initial bss issue.

Furthermore, on looking through the code again, I see a bunch of 
"init_pg_tables_end + setup_data_len" which really is ugly.

>> +
>> +/* extensible setup data list node */
>> +struct setup_data {
>> +	u64 next;
>> +	u32 type;
>> +	u32 len;
>> +	u8 data[0];
>> +};
>>   
> 
> What are the alignment rules for this structure?  Is it always 64-bit
> aligned?  What about the relationship of len and data?
> 

It's x86, so alignment is soft - it presumably *should* be 64-bit 
aligned, but nothing break if the boot loader doesn't.

	-hpa

[*] A very clean way to do that is to put said section right at the 
beginning of the bss, and move __init_end after it:

   .bss : AT(ADDR(.bss) - LOAD_OFFSET) {
         __bss_start = .;                /* BSS */
	*(.init.bss)
	. = ALIGN(4096);
         __init_end = .;
         *(.bss.page_aligned)
         *(.bss)
         . = ALIGN(4);
         __bss_stop = .;
         _end = . ;
         /* This is where the kernel creates the early boot page tables */
         . = ALIGN(4096);
         pg0 = . ;
   }

On x86-64, this entails moving .data_nosave; it probably can be moved to 
the same relative position as on i386 (although I have not verified that 
that is true.)

Re: [PATCH -v7 1/3] x86 boot: setup data

[Andi Kleen]

On Wednesday 24 October 2007 00:08:32 Jeremy Fitzhardinge wrote:
> Huang, Ying wrote:
> > This patch add a field of 64-bit physical pointer to NULL terminated
> > single linked list of struct setup_data to real-mode kernel
> > header. This is used as a more extensible boot parameters passing
> > mechanism.
> >   
> 
> As a general comment, I can't say I'm thrilled about sticking the copied
> setup data at the end of the initial pagetables.  This is already a
> fairly complex area, and changing it touches a surprisingly large number
> of places.  I wonder if there isn't a better way to deal with this
> (possibly by fixing up the generation of the initial pagetables in the
> process).

With the early reserve code in 
ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-reserve
and
ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-alloc
this could be likely done cleaner.

-Andi

Re: [PATCH -v7 1/3] x86 boot: setup data

[Jeremy Fitzhardinge]

H. Peter Anvin wrote:
> Furthermore, on looking through the code again, I see a bunch of
> "init_pg_tables_end + setup_data_len" which really is ugly.

Yeah, that's what I'm objecting to.

>> What are the alignment rules for this structure?  Is it always 64-bit
>> aligned?  What about the relationship of len and data?
>>
>
> It's x86, so alignment is soft - it presumably *should* be 64-bit
> aligned, but nothing break if the boot loader doesn't.

This was more or less a rhetorical question - the code spends some
effort in rounding len up to some alignment, so its probably worth
documenting with the structure.


    J

Re: [PATCH -v7 1/3] x86 boot: setup data

[H. Peter Anvin]

Andi Kleen wrote:
> 
> With the early reserve code in 
> ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-reserve
> and
> ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-alloc
> this could be likely done cleaner.
> 

Indeed it could.  For i386, the equivalent code would have another 
significant benefit: reserving memory and then mapping and accessing it 
later would (at least eventually) allow accesses > 4 GB on PAE kernels 
(or with a PSE36 hack, on non-PAE kernels.)

	-hpa

Re: [PATCH -v7 1/3] x86 boot: setup data

[Huang, Ying]

On Tue, 2007-10-23 at 16:55 -0700, H. Peter Anvin wrote:
> Andi Kleen wrote:
> > 
> > With the early reserve code in 
> > ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-reserve
> > and
> > ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-alloc
> > this could be likely done cleaner.
> > 
> 
> Indeed it could.  For i386, the equivalent code would have another 
> significant benefit: reserving memory and then mapping and accessing it 
> later would (at least eventually) allow accesses > 4 GB on PAE kernels 
> (or with a PSE36 hack, on non-PAE kernels.)

For i386, the bootmem allocator covers at most 0~796M memory area. So
some early reserve memory area can not be revered with bootmem allocator
later. Should we fix bootmem allocator firstly?

Best Regards,
Huang Ying

Re: [PATCH -v7 1/3] x86 boot: setup data

[Andrew Morton]

On Tue, 23 Oct 2007 16:55:13 -0700
"H. Peter Anvin" <hpa@zytor.com> wrote:

> Andi Kleen wrote:
> > 
> > With the early reserve code in 
> > ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-reserve
> > and
> > ftp://firstfloor.org/pub/ak/x86_64/quilt/patches/early-alloc
> > this could be likely done cleaner.
> > 
> 
> Indeed it could.  For i386, the equivalent code would have another 
> significant benefit: reserving memory and then mapping and accessing it 
> later would (at least eventually) allow accesses > 4 GB on PAE kernels 
> (or with a PSE36 hack, on non-PAE kernels.)
> 

Cleaner sounds good.  I'll duck these patches for now.

This one doesn't apply, btw: setup_32.h disappeared.