iscsi_ibft: Fix finding the iBFT under Xen Dom 0

To facilitate diskless iSCSI boot, the firmware can place a table of
configuration details in memory called the iBFT. The presence of this
table is not specified, nor is the precise location (and it's not in the
E820) so the kernel has to search for a magic marker to find it.

When running under Xen, Dom 0 does not have access to the entire host's
memory, only certain regions which are identity-mapped which means that
the pseudo-physical address in Dom0 == real host physical address.
Add the iBFT search bounds as a reserved region which causes it to be
identity-mapped in xen_set_identity_and_remap_chunk() which allows Dom0
access to the specific physical memory to correctly search for the iBFT
magic marker (and later access the full table).

This necessitates moving the call to reserve_ibft_region() somewhat
later so that it is called after e820__memory_setup() which is when the
Xen identity mapping adjustments are applied. The precise location of
the call is not too important so I've put it alongside dmi_setup() which
does similar scanning of memory for configuration tables.

Finally in the iBFT find code, instead of using isa_bus_to_virt() which
doesn't do the right thing under Xen, use early_memremap() like the
dmi_setup() code does.

The result of these changes is that it is possible to boot a diskless
Xen + Dom0 running off an iSCSI disk whereas previously it would fail to
find the iBFT and consequently, the iSCSI root disk.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Konrad Rzeszutek Wilk <konrad@darnok.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com> # for x86
Link: https://lore.kernel.org/r/20230605102840.1521549-1-ross.lagerwall@citrix.com
Signed-off-by: Juergen Gross <jgross@suse.com>

iscsi_ibft: fix crash due to KASLR physical memory remapping

Starting with commit a799c2bd29d1
("x86/setup: Consolidate early memory reservations")
memory reservations have been moved earlier during the boot process,
before the execution of the Kernel Address Space Layout Randomization code.

setup_arch() calls the iscsi_ibft's find_ibft_region() function
to find and reserve the memory dedicated to the iBFT and this function
also saves a virtual pointer to the iBFT table for later use.

The problem is that if KALSR is active, the physical memory gets
remapped somewhere else in the virtual address space and the pointer is
no longer valid, this will cause a kernel panic when the iscsi driver tries
to dereference it.

iBFT detected.
BUG: unable to handle page fault for address: ffff888000099fd8
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 0 P4D 0
Oops: 0000 [#1] SMP PTI

..snip..

Call Trace:
? ibft_create_kobject+0x1d2/0x1d2 [iscsi_ibft]
do_one_initcall+0x44/0x1d0
? kmem_cache_alloc_trace+0x119/0x220
do_init_module+0x5c/0x270
__do_sys_init_module+0x12e/0x1b0
do_syscall_64+0x40/0x80
entry_SYSCALL_64_after_hwframe+0x44/0xae

Fix this bug by saving the address of the physical location
of the ibft; later the driver will use isa_bus_to_virt() to get
the correct virtual address.

N.B. On each reboot KASLR randomizes the virtual addresses so
assuming phys_to_virt before KASLR does its deed is incorrect.

Simplify the code by renaming find_ibft_region()
to reserve_ibft_region() and remove all the wrappers.

Signed-off-by: Maurizio Lombardi <mlombard@redhat.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 287

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license v2 0 as
published by the free software foundation this program is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 23 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.115786599@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ACPI / IBFT: Fix incorrect <acpi/acpi.h> inclusion in iSCSI boot firmware module

To avoid build problems and breaking dependencies between ACPI header
files, <acpi/acpi.h> should not be included directly by code outside
of the ACPI core subsystem, but this is done by the ACPI iSCSI
Boot Firmware code.

The iBFT specification doesn't mention whether or not it can appear
on a non-ACPI platform, but is says that ACPI 3.0b defines the
mechanism. The current CONFIG_ISCSI_IBFT_FIND code doesn't use the
ACPI tables API to locate the table, so it doesn't rely on CONFIG_ACPI
directly.

However, since iBFT is is an ACPI-based mechanism (please refer to
the documentation link below for more information), it should be
correct to make CONFIG_ISCSI_IBFT_FIND depend on CONFIG_ACPI (even
though the table location can be implemented without using ACPI
tables API).

After that change, include/linux/iscsi_ibft.h can be modified to
include <linux/acpi.h> instead of <acpi/acpi.h> as appropriate.

References: http://www.microsoft.com/whdc/system/platform/firmware/ibft.mspx
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
Cc: Peter Jones <pjones@redhat.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
[rjw: Subject and changelog]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ACPI: Clean up inclusions of ACPI header files

Replace direct inclusions of <acpi/acpi.h>, <acpi/acpi_bus.h> and
<acpi/acpi_drivers.h>, which are incorrect, with <linux/acpi.h>
inclusions and remove some inclusions of those files that aren't
necessary.

First of all, <acpi/acpi.h>, <acpi/acpi_bus.h> and <acpi/acpi_drivers.h>
should not be included directly from any files that are built for
CONFIG_ACPI unset, because that generally leads to build warnings about
undefined symbols in !CONFIG_ACPI builds. For CONFIG_ACPI set,
<linux/acpi.h> includes those files and for CONFIG_ACPI unset it
provides stub ACPI symbols to be used in that case.

Second, there are ordering dependencies between those files that always
have to be met. Namely, it is required that <acpi/acpi_bus.h> be included
prior to <acpi/acpi_drivers.h> so that the acpi_pci_root declarations the
latter depends on are always there. And <acpi/acpi.h> which provides
basic ACPICA type declarations should always be included prior to any other
ACPI headers in CONFIG_ACPI builds. That also is taken care of including
<linux/acpi.h> as appropriate.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> (drivers/pci stuff)
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> (Xen stuff)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

ibft: Update iBFT handling for v1.03 of the spec.

- Use struct acpi_table_ibft instead of struct ibft_table_header
- Don't do reserve_ibft_region() on UEFI machines (section 1.4.3.1)
- If ibft_addr isn't initialized when ibft_init() is called, check for
ACPI-based tables.
- Fix compiler error when CONFIG_ACPI is not defined.

Signed-off-by: Konrad Rzeszutek Wilk <konrad@kernel.org>
Signed-off-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>

ibft, x86: Change reserve_ibft_region() to find_ibft_region()

This allows arch code could decide the way to reserve the ibft.

And we should reserve ibft as early as possible, instead of BOOTMEM
stage, in case the table is in RAM range and is not reserved by BIOS
(this will often be the case.)

Move to just after find_smp_config().

Also when CONFIG_NO_BOOTMEM=y, We will not have reserve_bootmem() anymore.

-v2: fix typo about ibft pointed by Konrad Rzeszutek Wilk <konrad@darnok.org>

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4BB510FB.80601@kernel.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Peter Jones <pjones@redhat.com>
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
CC: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

Firmware: add iSCSI iBFT Support

Add /sysfs/firmware/ibft/[initiator|targetX|ethernetX] directories along with
text properties which export the the iSCSI Boot Firmware Table (iBFT)
structure.

What is iSCSI Boot Firmware Table? It is a mechanism for the iSCSI tools to
extract from the machine NICs the iSCSI connection information so that they
can automagically mount the iSCSI share/target. Currently the iSCSI
information is hard-coded in the initrd. The /sysfs entries are read-only
one-name-and-value fields.

The usual set of data exposed is:

# for a in `find /sys/firmware/ibft/ -type f -print`; do echo -n "$a: "; cat $a; done
/sys/firmware/ibft/target0/target-name: iqn.2007.com.intel-sbx44:storage-10gb
/sys/firmware/ibft/target0/nic-assoc: 0
/sys/firmware/ibft/target0/chap-type: 0
/sys/firmware/ibft/target0/lun: 00000000
/sys/firmware/ibft/target0/port: 3260
/sys/firmware/ibft/target0/ip-addr: 192.168.79.116
/sys/firmware/ibft/target0/flags: 3
/sys/firmware/ibft/target0/index: 0
/sys/firmware/ibft/ethernet0/mac: 00:11:25:9d:8b:01
/sys/firmware/ibft/ethernet0/vlan: 0
/sys/firmware/ibft/ethernet0/gateway: 192.168.79.254
/sys/firmware/ibft/ethernet0/origin: 0
/sys/firmware/ibft/ethernet0/subnet-mask: 255.255.252.0
/sys/firmware/ibft/ethernet0/ip-addr: 192.168.77.41
/sys/firmware/ibft/ethernet0/flags: 7
/sys/firmware/ibft/ethernet0/index: 0
/sys/firmware/ibft/initiator/initiator-name: iqn.2007-07.com:konrad.initiator
/sys/firmware/ibft/initiator/flags: 3
/sys/firmware/ibft/initiator/index: 0

For full details of the IBFT structure please take a look at:
ftp://ftp.software.ibm.com/systems/support/system_x_pdf/ibm_iscsi_boot_firmware_table_v1.02.pdf

[akpm@linux-foundation.org: fix build]
Signed-off-by: Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Peter Jones <pjones@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>