[x86] Support booting a Xen PVH guest via Grub2

tl;dr: Xen PVH is the perfect upgrade path from PV and in combination
with grub2 support, it's the Xen "killer feature" we really should have
in Buster.

    Background info about Xen PVH:
https://wiki.xen.org/wiki/Virtualization_Spectrum#Almost_fully_PV:_PVH_mode

PVH mode in Xen, a.k.a. "HVM without having to run qemu" is a Xen guest
type best supported since Xen 4.11 and Linux kernel 4.17. Just like when
using PV mode, the guest does not have an emulated BIOS and the guest
kernel is directly started by the dom0. Buster will ship with Xen 4.11.

   Why is PVH interesting?

1. When the whole Meltdown/Spectre story started, it quickly became
apparent that 64-bit PV is the most problematic virtualization mode to
protect and to protect from, since address space from the hypervisor and
other guests (including dom0) is reachable from a 64-bit PV domU. To
mitigate this, XPTI (the Xen variant of PTI) has been implemented in the
hypervisor, but with a performance hit. HVM (so, also PVH) guests are
better isolated from the hypervisor and other guests. Inside the guest a
choice can be made about which mitigations to enable or not.  Also see
https://xenbits.xen.org/xsa/advisory-254.html

2. Unlike HVM, it's not needed to have a boot loader/sector, partitions,
and a qemu process in the dom0 (using cpu and memory and having an
attack surface).  Also, when running a largeish amount of domUs on a
physical server, not having all the qemu processes is an advantage.

3. Unlike PV, PVH makes use of all hardware features that accelerate
virtualization.

   The upgrade path from PV to PVH is super optimal. It's just setting
type='pvh' in the guest file and doing a full restart of the domU!

Unless... (insert Monty Python's Dramatic Chord!)

Unless... grub2 was used to boot the PV guests.

   Why is it interesting to be able to use grub?

Without using grub in between, the guest kernel and initrd have to be
copied out of the guest onto the dom0 filesystem, because the guest has
to be booted with them directly.  Currently, we already have the
grub-xen packages in Debian, which provide grub images which can be used
as kernel for a PV guest, after which it can load the actual linux
kernel that is symlinked from /vmlinuz on the guest filesystem at that
moment.

The final changes to the Linux kernel for grub+PVH are in Linux 4.20.
This request, to carry a few patches from Linux 4.20, provides one half
of the dots that need to be connected to make the full thing happen for
Buster.

Since we'll have Xen 4.11 in Buster, PVH is supported. The related grub2
patchset was committed to the grub master branch on Dec 12 2018 (yup,
today). So, I'll also start contacting the debian grub team soon to ask
(and help) to get the current grub-xen functionality in Debian to be
extended with PVH capabilities as well.

Test reports:
https://lists.xenproject.org/archives/html/xen-devel/2018-10/msg01913.html
https://lists.xenproject.org/archives/html/xen-devel/2018-11/msg03312.html
This commit is contained in:
Hans van Kranenburg 2018-12-12 22:12:47 +01:00
parent 79a9cada15
commit 4d63e6ccbb
7 changed files with 681 additions and 0 deletions

1
debian/changelog vendored
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@ -63,6 +63,7 @@ linux (4.19.9-1) UNRELEASED; urgency=medium
[ Hans van Kranenburg ]
* [x86] Add patch to repair booting as Xen dom0 (Closes: #914951)
* [x86] Add patches to support booting a Xen PVH guest via Grub2
[ Christoph Anton Mitterer ]
* crypto: Enable MORUS and AEGIS AEAD ciphers (Closes: #914136)

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@ -0,0 +1,104 @@
From: Juergen Gross <jgross@suse.com>
Date: Wed, 10 Oct 2018 08:14:56 +0200
Subject: x86/acpi, x86/boot: Take RSDP address for boot params if available
Origin: https://git.kernel.org/linus/e7b66d16fe41722350ba87f5788052ef53ee28bb
In case the RSDP address in struct boot_params is specified don't try
to find the table by searching, but take the address directly as set
by the boot loader.
Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jia Zhang <qianyue.zj@alibaba-inc.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boris.ostrovsky@oracle.com
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20181010061456.22238-4-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/acpi.h | 7 +++++++
arch/x86/kernel/acpi/boot.c | 6 ++++++
arch/x86/kernel/x86_init.c | 3 +--
3 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
index a303d7b7d763..2f01eb4d6208 100644
--- a/arch/x86/include/asm/acpi.h
+++ b/arch/x86/include/asm/acpi.h
@@ -142,6 +142,8 @@ static inline u64 acpi_arch_get_root_pointer(void)
void acpi_generic_reduced_hw_init(void);
+u64 x86_default_get_root_pointer(void);
+
#else /* !CONFIG_ACPI */
#define acpi_lapic 0
@@ -153,6 +155,11 @@ static inline void disable_acpi(void) { }
static inline void acpi_generic_reduced_hw_init(void) { }
+static inline u64 x86_default_get_root_pointer(void)
+{
+ return 0;
+}
+
#endif /* !CONFIG_ACPI */
#define ARCH_HAS_POWER_INIT 1
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 3b20607d581b..e8fea7ffa306 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -48,6 +48,7 @@
#include <asm/mpspec.h>
#include <asm/smp.h>
#include <asm/i8259.h>
+#include <asm/setup.h>
#include "sleep.h" /* To include x86_acpi_suspend_lowlevel */
static int __initdata acpi_force = 0;
@@ -1771,3 +1772,8 @@ void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size)
e820__range_add(addr, size, E820_TYPE_ACPI);
e820__update_table_print();
}
+
+u64 x86_default_get_root_pointer(void)
+{
+ return boot_params.hdr.acpi_rsdp_addr;
+}
diff --git a/arch/x86/kernel/x86_init.c b/arch/x86/kernel/x86_init.c
index 2792b5573818..50a2b492fdd6 100644
--- a/arch/x86/kernel/x86_init.c
+++ b/arch/x86/kernel/x86_init.c
@@ -31,7 +31,6 @@ static int __init iommu_init_noop(void) { return 0; }
static void iommu_shutdown_noop(void) { }
static bool __init bool_x86_init_noop(void) { return false; }
static void x86_op_int_noop(int cpu) { }
-static u64 u64_x86_init_noop(void) { return 0; }
/*
* The platform setup functions are preset with the default functions
@@ -96,7 +95,7 @@ struct x86_init_ops x86_init __initdata = {
},
.acpi = {
- .get_root_pointer = u64_x86_init_noop,
+ .get_root_pointer = x86_default_get_root_pointer,
.reduced_hw_early_init = acpi_generic_reduced_hw_init,
},
};
--
2.19.2

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@ -0,0 +1,54 @@
From: Juergen Gross <jgross@suse.com>
Date: Tue, 20 Nov 2018 08:25:29 +0100
Subject: x86/acpi, x86/boot: Take RSDP address from boot params if available
Origin: https://git.kernel.org/linus/e6e094e053af75cbc164e950814d3d084fb1e698
In case the RSDP address in struct boot_params is specified don't try
to find the table by searching, but take the address directly as set
by the boot loader.
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/20181120072529.5489-3-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/uapi/asm/bootparam.h | 3 ++-
arch/x86/kernel/acpi/boot.c | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index a06cbf019744..60733f137e9a 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -155,7 +155,8 @@ struct boot_params {
__u8 _pad2[4]; /* 0x054 */
__u64 tboot_addr; /* 0x058 */
struct ist_info ist_info; /* 0x060 */
- __u8 _pad3[16]; /* 0x070 */
+ __u64 acpi_rsdp_addr; /* 0x070 */
+ __u8 _pad3[8]; /* 0x078 */
__u8 hd0_info[16]; /* obsolete! */ /* 0x080 */
__u8 hd1_info[16]; /* obsolete! */ /* 0x090 */
struct sys_desc_table sys_desc_table; /* obsolete! */ /* 0x0a0 */
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index fb3b1f3a5aba..06635fbca81c 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -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 0;
+ return boot_params.acpi_rsdp_addr;
}
--
2.19.2

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@ -0,0 +1,235 @@
From: Juergen Gross <jgross@suse.com>
Date: Wed, 10 Oct 2018 08:14:55 +0200
Subject: x86/boot: Add ACPI RSDP address to setup_header
Origin: https://git.kernel.org/linus/ae7e1238e68f2a472a125673ab506d49158c1889
Xen PVH guests receive the address of the RSDP table from Xen. In order
to support booting a Xen PVH guest via Grub2 using the standard x86
boot entry we need a way for Grub2 to pass the RSDP address to the
kernel.
For this purpose expand the struct setup_header to hold the physical
address of the RSDP address. Being zero means it isn't specified and
has to be located the legacy way (searching through low memory or
EBDA).
While documenting the new setup_header layout and protocol version
2.14 add the missing documentation of protocol version 2.13.
There are Grub2 versions in several distros with a downstream patch
violating the boot protocol by writing past the end of setup_header.
This requires another update of the boot protocol to enable the kernel
to distinguish between a specified RSDP address and one filled with
garbage by such a broken Grub2.
From protocol 2.14 on Grub2 will write the version it is supporting
(but never a higher value than found to be supported by the kernel)
ored with 0x8000 to the version field of setup_header. This enables
the kernel to know up to which field Grub2 has written information
to. All fields after that are supposed to be clobbered.
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: corbet@lwn.net
Cc: linux-doc@vger.kernel.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20181010061456.22238-3-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/head32.c | 1 +
arch/x86/kernel/head64.c | 2 ++
arch/x86/kernel/setup.c | 17 ++++++++++++++
7 files changed, 62 insertions(+), 2 deletions(-)
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index 5e9b826b5f62..7727db8f94bc 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -61,6 +61,18 @@ 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
@@ -197,6 +209,7 @@ 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.
@@ -309,7 +322,7 @@ Protocol: 2.00+
Contains the magic number "HdrS" (0x53726448).
Field name: version
-Type: read
+Type: modify
Offset/size: 0x206/2
Protocol: 2.00+
@@ -317,6 +330,12 @@ 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
@@ -744,6 +763,17 @@ 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
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 850b8762e889..4c881c850125 100644
--- a/arch/x86/boot/header.S
+++ b/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 0x020d # header version number (>= 0x0105)
+ .word 0x020e # header version number (>= 0x0105)
# or else old loadlin-1.5 will fail)
.globl realmode_swtch
realmode_swtch: .word 0, 0 # default_switch, SETUPSEG
@@ -558,6 +558,10 @@ 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"
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index b85a7c54c6a1..0f842104862c 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/arch/x86/include/asm/x86_init.h
@@ -303,4 +303,6 @@ 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
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index a06cbf019744..22f89d040ddd 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -16,6 +16,9 @@
#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)
@@ -86,6 +89,7 @@ struct setup_header {
__u64 pref_address;
__u32 init_size;
__u32 handover_offset;
+ __u64 acpi_rsdp_addr;
} __attribute__((packed));
struct sys_desc_table {
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index ec6fefbfd3c0..76fa3b836598 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -37,6 +37,7 @@ asmlinkage __visible void __init i386_start_kernel(void)
cr4_init_shadow();
sanitize_boot_params(&boot_params);
+ x86_verify_bootdata_version();
x86_early_init_platform_quirks();
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index ddee1f0870c4..5dc377dc9d7b 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -457,6 +457,8 @@ void __init x86_64_start_reservations(char *real_mode_data)
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) {
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index b4866badb235..8e226b7a1753 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1281,6 +1281,23 @@ 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 = {
--
2.19.2

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@ -0,0 +1,43 @@
From: Juergen Gross <jgross@suse.com>
Date: Mon, 3 Dec 2018 11:38:11 +0100
Subject: x86/boot: Clear RSDP address in boot_params for broken loaders
Origin: https://git.kernel.org/linus/182ddd16194cd082f25fa1b063dae3c7c5cce384
Gunnar Krueger reported a systemd-boot failure and bisected it down to:
e6e094e053af75 ("x86/acpi, x86/boot: Take RSDP address from boot params if available")
In case a broken boot loader doesn't clear its 'struct boot_params', clear
rsdp_addr in sanitize_boot_params().
Reported-by: Gunnar Krueger <taijian@posteo.de>
Tested-by: Gunnar Krueger <taijian@posteo.de>
Signed-off-by: Juergen Gross <jgross@suse.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bp@alien8.de
Cc: sstabellini@kernel.org
Fixes: e6e094e053af75 ("x86/acpi, x86/boot: Take RSDP address from boot params if available")
Link: http://lkml.kernel.org/r/20181203103811.17056-1-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/bootparam_utils.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/include/asm/bootparam_utils.h b/arch/x86/include/asm/bootparam_utils.h
index a07ffd23e4dd..f6f6ef436599 100644
--- a/arch/x86/include/asm/bootparam_utils.h
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -36,6 +36,7 @@ static void sanitize_boot_params(struct boot_params *boot_params)
*/
if (boot_params->sentinel) {
/* fields in boot_params are left uninitialized, clear them */
+ boot_params->acpi_rsdp_addr = 0;
memset(&boot_params->ext_ramdisk_image, 0,
(char *)&boot_params->efi_info -
(char *)&boot_params->ext_ramdisk_image);
--
2.19.2

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@ -0,0 +1,239 @@
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(-)
diff --git a/Documentation/x86/boot.txt b/Documentation/x86/boot.txt
index 7727db8f94bc..5e9b826b5f62 100644
--- a/Documentation/x86/boot.txt
+++ b/Documentation/x86/boot.txt
@@ -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
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 4c881c850125..850b8762e889 100644
--- a/arch/x86/boot/header.S
+++ b/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 # 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"
diff --git a/arch/x86/include/asm/x86_init.h b/arch/x86/include/asm/x86_init.h
index 0f842104862c..b85a7c54c6a1 100644
--- a/arch/x86/include/asm/x86_init.h
+++ b/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
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index 22f89d040ddd..a06cbf019744 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/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 {
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index 92c76bf97ad8..fb3b1f3a5aba 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -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;
}
diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
index 76fa3b836598..ec6fefbfd3c0 100644
--- a/arch/x86/kernel/head32.c
+++ b/arch/x86/kernel/head32.c
@@ -37,7 +37,6 @@ asmlinkage __visible void __init i386_start_kernel(void)
cr4_init_shadow();
sanitize_boot_params(&boot_params);
- x86_verify_bootdata_version();
x86_early_init_platform_quirks();
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 7663a8eb602b..16b1cbd3a61e 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -457,8 +457,6 @@ void __init x86_64_start_reservations(char *real_mode_data)
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) {
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index b74e7bfed6ab..d494b9bfe618 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1280,23 +1280,6 @@ 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 = {
--
2.19.2

View File

@ -84,6 +84,11 @@ features/mips/MIPS-increase-MAX-PHYSMEM-BITS-on-Loongson-3-only.patch
features/mips/MIPS-Loongson-3-Add-Loongson-LS3A-RS780E-1-way-machi.patch
features/x86/x86-memtest-WARN-if-bad-RAM-found.patch
features/x86/x86-make-x32-syscall-support-conditional.patch
features/x86/x86-boot-Add-ACPI-RSDP-address-to-setup_header.patch
features/x86/x86-acpi-x86-boot-Take-RSDP-address-for-boot-params-.patch
features/x86/x86-boot-Mostly-revert-commit-ae7e1238e68f2a-Add-ACP.patch
features/x86/x86-acpi-x86-boot-Take-RSDP-address-from-boot-params.patch
features/x86/x86-boot-Clear-RSDP-address-in-boot_params-for-broke.patch
# Miscellaneous bug fixes
bugfix/all/kbuild-use-nostdinc-in-compile-tests.patch