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From: Juergen Gross <jgross@suse.com>
Date: Tue, 20 Nov 2018 08:25:28 +0100
Subject: x86/boot: Mostly revert commit ae7e1238e68f2a ("Add ACPI RSDP address
to setup_header")
Origin: https://git.kernel.org/linus/3841840449817ba6cf3e636008bc4e1061a03388
Peter Anvin pointed out that commit:
ae7e1238e68f2a ("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:
e7b66d16fe4172 ("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: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Juergen 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: Ingo Molnar <mingo@kernel.org>
---
Documentation/x86/boot.txt | 32 +--------------------------
arch/x86/boot/header.S | 6 +----
arch/x86/include/asm/x86_init.h | 2 --
arch/x86/include/uapi/asm/bootparam.h | 4 ----
arch/x86/kernel/acpi/boot.c | 2 +-
arch/x86/kernel/head32.c | 1 -
arch/x86/kernel/head64.c | 2 --
arch/x86/kernel/setup.c | 17 --------------
8 files changed, 3 insertions(+), 63 deletions(-)
Index: linux/Documentation/x86/boot.txt
===================================================================
--- linux.orig/Documentation/x86/boot.txt
+++ linux/Documentation/x86/boot.txt
@@ -61,18 +61,6 @@ Protocol 2.12: (Kernel 3.8) Added the xl
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
Index: linux/arch/x86/boot/header.S
===================================================================
--- linux.orig/arch/x86/boot/header.S
+++ linux/arch/x86/boot/header.S
@@ -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
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"
Index: linux/arch/x86/include/asm/x86_init.h
===================================================================
--- linux.orig/arch/x86/include/asm/x86_init.h
+++ linux/arch/x86/include/asm/x86_init.h
@@ -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
Index: linux/arch/x86/include/uapi/asm/bootparam.h
===================================================================
--- linux.orig/arch/x86/include/uapi/asm/bootparam.h
+++ linux/arch/x86/include/uapi/asm/bootparam.h
@@ -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 {
Index: linux/arch/x86/kernel/acpi/boot.c
===================================================================
--- linux.orig/arch/x86/kernel/acpi/boot.c
+++ linux/arch/x86/kernel/acpi/boot.c
@@ -1775,5 +1775,5 @@ void __init arch_reserve_mem_area(acpi_p
u64 x86_default_get_root_pointer(void)
{
- return boot_params.hdr.acpi_rsdp_addr;
+ return 0;
}
Index: linux/arch/x86/kernel/head32.c
===================================================================
--- linux.orig/arch/x86/kernel/head32.c
+++ linux/arch/x86/kernel/head32.c
@@ -37,7 +37,6 @@ asmlinkage __visible void __init i386_st
cr4_init_shadow();
sanitize_boot_params(&boot_params);
- x86_verify_bootdata_version();
x86_early_init_platform_quirks();
Index: linux/arch/x86/kernel/head64.c
===================================================================
--- linux.orig/arch/x86/kernel/head64.c
+++ linux/arch/x86/kernel/head64.c
@@ -477,8 +477,6 @@ void __init x86_64_start_reservations(ch
if (!boot_params.hdr.version)
copy_bootdata(__va(real_mode_data));
- x86_verify_bootdata_version();
-
x86_early_init_platform_quirks();
switch (boot_params.hdr.hardware_subarch) {
Index: linux/arch/x86/kernel/setup.c
===================================================================
--- linux.orig/arch/x86/kernel/setup.c
+++ linux/arch/x86/kernel/setup.c
@@ -1281,23 +1281,6 @@ void __init setup_arch(char **cmdline_p)
unwind_init();
}
-/*
- * From boot protocol 2.14 onwards we expect the bootloader to set the
- * version to "0x8000 | <used version>". In case we find a version >= 2.14
- * without the 0x8000 we assume the boot loader supports 2.13 only and
- * reset the version accordingly. The 0x8000 flag is removed in any case.
- */
-void __init x86_verify_bootdata_version(void)
-{
- if (boot_params.hdr.version & VERSION_WRITTEN)
- boot_params.hdr.version &= ~VERSION_WRITTEN;
- else if (boot_params.hdr.version >= 0x020e)
- boot_params.hdr.version = 0x020d;
-
- if (boot_params.hdr.version < 0x020e)
- boot_params.hdr.acpi_rsdp_addr = 0;
-}
-
#ifdef CONFIG_X86_32
static struct resource video_ram_resource = {
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