linux.git/arch/x86/include/uapi/asm/bootparam.h, branch v5.6

Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-11-26T17:52:37+00:00

Pull x86 platform updates from Ingo Molnar:
 "UV platform updates (with a 'hubless' variant) and Jailhouse updates
  for better UART support"

* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/jailhouse: Only enable platform UARTs if available
  x86/jailhouse: Improve setup data version comparison
  x86/platform/uv: Account for UV Hubless in is_uvX_hub Ops
  x86/platform/uv: Check EFI Boot to set reboot type
  x86/platform/uv: Decode UVsystab Info
  x86/platform/uv: Add UV Hubbed/Hubless Proc FS Files
  x86/platform/uv: Setup UV functions for Hubless UV Systems
  x86/platform/uv: Add return code to UV BIOS Init function
  x86/platform/uv: Return UV Hubless System Type
  x86/platform/uv: Save OEM_ID from ACPI MADT probe

x86/boot: Introduce setup_indirect

2019-11-12T15:21:15+00:00

The setup_data is a bit awkward to use for extremely large data objects,
both because the setup_data header has to be adjacent to the data object
and because it has a 32-bit length field. However, it is important that
intermediate stages of the boot process have a way to identify which
chunks of memory are occupied by kernel data. Thus introduce an uniform
way to specify such indirect data as setup_indirect struct and
SETUP_INDIRECT type.

And finally bump setup_header version in arch/x86/boot/header.S.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Acked-by: Konrad Rzeszutek Wilk 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-4-daniel.kiper@oracle.com

x86/boot: Introduce kernel_info.setup_type_max

2019-11-12T15:16:54+00:00

This field contains maximal allowed type for setup_data.

Do not bump setup_header version in arch/x86/boot/header.S because it
will be followed by additional changes coming into the Linux/x86 boot
protocol.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-3-daniel.kiper@oracle.com

x86/boot: Introduce kernel_info

2019-11-12T15:10:34+00:00

The relationships between the headers are analogous to the various data
sections:

  setup_header = .data
  boot_params/setup_data = .bss

What is missing from the above list? That's right:

  kernel_info = .rodata

We have been (ab)using .data for things that could go into .rodata or .bss for
a long time, for lack of alternatives and -- especially early on -- inertia.
Also, the BIOS stub is responsible for creating boot_params, so it isn't
available to a BIOS-based loader (setup_data is, though).

setup_header is permanently limited to 144 bytes due to the reach of the
2-byte jump field, which doubles as a length field for the structure, combined
with the size of the "hole" in struct boot_params that a protected-mode loader
or the BIOS stub has to copy it into. It is currently 119 bytes long, which
leaves us with 25 very precious bytes. This isn't something that can be fixed
without revising the boot protocol entirely, breaking backwards compatibility.

boot_params proper is limited to 4096 bytes, but can be arbitrarily extended
by adding setup_data entries. It cannot be used to communicate properties of
the kernel image, because it is .bss and has no image-provided content.

kernel_info solves this by providing an extensible place for information about
the kernel image. It is readonly, because the kernel cannot rely on a
bootloader copying its contents anywhere, but that is OK; if it becomes
necessary it can still contain data items that an enabled bootloader would be
expected to copy into a setup_data chunk.

Do not bump setup_header version in arch/x86/boot/header.S because it
will be followed by additional changes coming into the Linux/x86 boot
protocol.

Suggested-by: H. Peter Anvin (Intel) 
Signed-off-by: Daniel Kiper 
Signed-off-by: Borislav Petkov 
Reviewed-by: Konrad Rzeszutek Wilk 
Reviewed-by: Ross Philipson 
Reviewed-by: H. Peter Anvin (Intel) 
Cc: Andy Lutomirski 
Cc: ard.biesheuvel@linaro.org
Cc: Boris Ostrovsky 
Cc: dave.hansen@linux.intel.com
Cc: eric.snowberg@oracle.com
Cc: Ingo Molnar 
Cc: Jonathan Corbet 
Cc: Juergen Gross 
Cc: kanth.ghatraju@oracle.com
Cc: linux-doc@vger.kernel.org
Cc: linux-efi 
Cc: Peter Zijlstra 
Cc: rdunlap@infradead.org
Cc: ross.philipson@oracle.com
Cc: Thomas Gleixner 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20191112134640.16035-2-daniel.kiper@oracle.com

x86/jailhouse: Only enable platform UARTs if available

2019-10-10T13:43:59+00:00

ACPI tables aren't available if Linux runs as guest of the hypervisor
Jailhouse. This makes the 8250 driver probe for all platform UARTs as it
assumes that all UARTs are present in case of !ACPI. Jailhouse will stop
execution of Linux guest due to port access violation.

So far, these access violations were solved by tuning the 8250.nr_uarts
cmdline parameter, but this has limitations: Only consecutive platform
UARTs can be mapped to Linux, and only in the sequence 0x3f8, 0x2f8,
0x3e8, 0x2e8.

Beginning from setup_data version 2, Jailhouse will place information of
available platform UARTs in setup_data. This allows for selective
activation of platform UARTs.

Query setup_data version and only activate available UARTS. This
patch comes with backward compatibility, and will still support older
setup_data versions. In case of older setup_data versions, Linux falls
back to the old behaviour.

Signed-off-by: Ralf Ramsauer 
Signed-off-by: Borislav Petkov 
Reviewed-by: Jan Kiszka 
Cc: Baoquan He 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: jailhouse-dev@googlegroups.com
Cc: Juergen Gross 
Cc: "Kirill A. Shutemov" 
Cc: Thomas Gleixner 
Cc: x86-ml 
Link: https://lkml.kernel.org/r/20191010102102.421035-3-ralf.ramsauer@oth-regensburg.de

x86/jailhouse: Improve setup data version comparison

2019-10-10T13:38:30+00:00

Soon, setup_data will contain information on passed-through platform
UARTs. This requires some preparational work for the sanity check of the
header and the check of the version.

Use the following strategy:

  1. Ensure that the header declares at least enough space for the
     version and the compatible_version as it must hold that fields for
     any version. The location and semantics of header+version fields
     will never change.

  2. Copy over data -- as much as as possible. The length is either
     limited by the header length or the length of setup_data.

  3. Things are now in place -- sanity check if the header length
     complies the actual version.

For future versions of the setup_data, only step 3 requires alignment.

Signed-off-by: Ralf Ramsauer 
Signed-off-by: Borislav Petkov 
Reviewed-by: Jan Kiszka 
Cc: Baoquan He 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: jailhouse-dev@googlegroups.com
Cc: Juergen Gross 
Cc: "Kirill A. Shutemov" 
Cc: Thomas Gleixner 
Cc: x86-ml 
Link: https://lkml.kernel.org/r/20191010102102.421035-2-ralf.ramsauer@oth-regensburg.de

x86/boot: Add xloadflags bits to check for 5-level paging support

2019-06-28T05:14:59+00:00

The current kernel supports 5-level paging mode, and supports dynamically
choosing the paging mode during bootup depending on the kernel image,
hardware and kernel parameter settings. This flexibility brings several
issues to kexec/kdump:

1) Dynamic switching between paging modes requires support in the target
   kernel. This means kexec from a 5-level paging kernel into a kernel
   which does not support mode switching is not possible. So the loader
   needs to be able to analyze the supported paging modes of the kexec
   target kernel.

2) If running on a 5-level paging kernel and the kexec target kernel is a
   4-level paging kernel, the target immage cannot be loaded above the 64TB
   address space limit. But the kexec loader searches for a load area from
   top to bottom which would eventually put the target kernel above 64TB
   when the machine has large enough RAM size. So the loader needs to be
   able to analyze the paging mode of the target kernel to load it at a
   suitable spot in the address space.

Solution:

Add two bits XLF_5LEVEL and XLF_5LEVEL_ENABLED:

 - Bit XLF_5LEVEL indicates whether 5-level paging mode switching support
   is available. (Issue #1)

 - Bit XLF_5LEVEL_ENABLED indicates whether the kernel was compiled with
   full 5-level paging support (CONFIG_X86_5LEVEL=y). (Issue #2)

The loader will use these bits to verify whether the target kernel is
suitable to be kexec'ed to from a 5-level paging kernel and to determine
the constraints of the target kernel load address.

The flags will be used by the kernel kexec subsystem and the userspace
kexec tools.

[ tglx: Massaged changelog ]

Signed-off-by: Baoquan He 
Signed-off-by: Thomas Gleixner 
Acked-by: Kirill A. Shutemov 
Cc: bp@alien8.de
Cc: hpa@zytor.com
Cc: dyoung@redhat.com
Link: https://lkml.kernel.org/r/20190524073810.24298-2-bhe@redhat.com

x86/acpi, x86/boot: Take RSDP address from boot params if available

2018-11-20T08:43:11+00:00

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" 
Signed-off-by: Juergen Gross 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
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

x86/boot: Mostly revert commit ae7e1238e68f2a ("Add ACPI RSDP address to setup_header")

2018-11-20T08:43:10+00:00

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" 
Signed-off-by: Juergen Gross 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
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

x86/boot: Add ACPI RSDP address to setup_header

2018-10-10T08:44:22+00:00

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 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
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