Commit 38418404 authored by Juergen Gross's avatar Juergen Gross Committed by Ingo Molnar
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x86/boot: Mostly revert commit ae7e1238 ("Add ACPI RSDP address to setup_header") 



Peter Anvin pointed out that commit:

  ae7e1238 ("x86/boot: Add ACPI RSDP address to setup_header")

should be reverted as setup_header should only contain items set by the
legacy BIOS.

So revert said commit. Instead of fully reverting the dependent commit
of:

  e7b66d16 ("x86/acpi, x86/boot: Take RSDP address for boot params if available")

just remove the setup_header reference in order to replace it by
a boot_params in a followup patch.

Suggested-by: default avatar"H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: bp@alien8.de
Cc: daniel.kiper@oracle.com
Cc: sstabellini@kernel.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20181120072529.5489-2-jgross@suse.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent d19f9130

Documentation/x86/boot.txt

+1 −31
Original line number Diff line number Diff line
@@ -61,18 +61,6 @@ Protocol 2.12: (Kernel 3.8) Added the xloadflags field and extension fields 
	 	to struct boot_params for loading bzImage and ramdisk

		above 4G in 64bit.



Protocol 2.13:	(Kernel 3.14) Support 32- and 64-bit flags being set in

		xloadflags to support booting a 64-bit kernel from 32-bit

		EFI



Protocol 2.14:	(Kernel 4.20) Added acpi_rsdp_addr holding the physical

		address of the ACPI RSDP table.

		The bootloader updates version with:

		0x8000 | min(kernel-version, bootloader-version)

		kernel-version being the protocol version supported by

		the kernel and bootloader-version the protocol version

		supported by the bootloader.



**** MEMORY LAYOUT



The traditional memory map for the kernel loader, used for Image or
@@ -209,7 +197,6 @@ Offset Proto Name Meaning 
0258/8	2.10+	pref_address	Preferred loading address

0260/4	2.10+	init_size	Linear memory required during initialization

0264/4	2.11+	handover_offset	Offset of handover entry point

0268/8	2.14+	acpi_rsdp_addr	Physical address of RSDP table



(1) For backwards compatibility, if the setup_sects field contains 0, the

    real value is 4.
@@ -322,7 +309,7 @@ Protocol: 2.00+ 
  Contains the magic number "HdrS" (0x53726448).



Field name:	version

Type:		modify

Type:		read

Offset/size:	0x206/2

Protocol:	2.00+
@@ -330,12 +317,6 @@ Protocol: 2.00+ 
  e.g. 0x0204 for version 2.04, and 0x0a11 for a hypothetical version

  10.17.



  Up to protocol version 2.13 this information is only read by the

  bootloader. From protocol version 2.14 onwards the bootloader will

  write the used protocol version or-ed with 0x8000 to the field. The

  used protocol version will be the minimum of the supported protocol

  versions of the bootloader and the kernel.



Field name:	realmode_swtch

Type:		modify (optional)

Offset/size:	0x208/4
@@ -763,17 +744,6 @@ Offset/size: 0x264/4 


  See EFI HANDOVER PROTOCOL below for more details.



Field name:	acpi_rsdp_addr

Type:		write

Offset/size:	0x268/8

Protocol:	2.14+



  This field can be set by the boot loader to tell the kernel the

  physical address of the ACPI RSDP table.



  A value of 0 indicates the kernel should fall back to the standard

  methods to locate the RSDP.





**** THE IMAGE CHECKSUM

arch/x86/boot/header.S

+1 −5
Original line number Diff line number Diff line
@@ -300,7 +300,7 @@ _start: 
	# Part 2 of the header, from the old setup.S



		.ascii	"HdrS"		# header signature

		.word	0x020e		# header version number (>= 0x0105)

		.word	0x020d		# header version number (>= 0x0105)

					# or else old loadlin-1.5 will fail)

		.globl realmode_swtch

realmode_swtch:	.word	0, 0		# default_switch, SETUPSEG
@@ -558,10 +558,6 @@ pref_address: .quad LOAD_PHYSICAL_ADDR # preferred load addr 
init_size:		.long INIT_SIZE		# kernel initialization size

handover_offset:	.long 0			# Filled in by build.c



acpi_rsdp_addr:		.quad 0			# 64-bit physical pointer to the

						# ACPI RSDP table, added with

						# version 2.14



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



	.section ".entrytext", "ax"

arch/x86/include/asm/x86_init.h

+0 −2
Original line number Diff line number Diff line
@@ -303,6 +303,4 @@ extern void x86_init_noop(void); 
extern void x86_init_uint_noop(unsigned int unused);

extern bool x86_pnpbios_disabled(void);



void x86_verify_bootdata_version(void);



#endif

arch/x86/include/uapi/asm/bootparam.h

+0 −4
Original line number Diff line number Diff line
@@ -16,9 +16,6 @@ 
#define RAMDISK_PROMPT_FLAG		0x8000

#define RAMDISK_LOAD_FLAG		0x4000



/* version flags */

#define VERSION_WRITTEN	0x8000



/* loadflags */

#define LOADED_HIGH	(1<<0)

#define KASLR_FLAG	(1<<1)
@@ -89,7 +86,6 @@ struct setup_header { 
	__u64	pref_address;

	__u32	init_size;

	__u32	handover_offset;

	__u64	acpi_rsdp_addr;

} __attribute__((packed));



struct sys_desc_table {

arch/x86/kernel/acpi/boot.c

+1 −1
Original line number Diff line number Diff line
@@ -1776,5 +1776,5 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size) 


u64 x86_default_get_root_pointer(void)

{

	return boot_params.hdr.acpi_rsdp_addr;

	return 0;

}

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