linux.git/arch/x86/boot/memory.c, branch v4.18

x86/boot/e820: Separate the E820 ABI structures from the in-kernel structures

2017-01-29T12:39:32+00:00

Linus pointed out that relying on the compiler to pack structures with
enums is fragile not just for the kernel, but for external tooling as
well which might rely on our UAPI headers.

So separate the two from each other: introduce 'struct boot_e820_entry',
which is the boot protocol entry format.

This actually simplifies the code, as e820__update_table() is now never
called directly with boot protocol table entries - we can rely on
append_e820_table() and do a e820__update_table() call afterwards.

( This will allow further simplifications of __e820__update_table(),
  but that will be done in a separate patch. )

This change also has the side effect of not modifying the bootparams structure
anymore - which might be useful for debugging. In theory we could even constify
the boot_params structure - at least from the E820 code's point of view.

Remove the uapi/asm/e820/types.h file, as it's not used anymore - all
kernel side E820 types are defined in asm/e820/types.h.

Reported-by: Linus Torvalds 
Cc: Alex Thorlton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dan Williams 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Huang, Ying 
Cc: Josh Poimboeuf 
Cc: Juergen Gross 
Cc: Paul Jackson 
Cc: Peter Zijlstra 
Cc: Rafael J. Wysocki 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Wei Yang 
Cc: Yinghai Lu 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

x86/boot/e820: Rename everything to e820_table

2017-01-28T08:33:16+00:00

No change in functionality.

Cc: Alex Thorlton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dan Williams 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Huang, Ying 
Cc: Josh Poimboeuf 
Cc: Juergen Gross 
Cc: Linus Torvalds 
Cc: Paul Jackson 
Cc: Peter Zijlstra 
Cc: Rafael J. Wysocki 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Wei Yang 
Cc: Yinghai Lu 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

x86/boot/e820: Rename 'e820_map' variables to 'e820_array'

2017-01-28T08:33:15+00:00

In line with the rename to 'struct e820_array', harmonize the naming of common e820
table variable names as well:

 e820          =>  e820_array
 e820_saved    =>  e820_array_saved
 e820_map      =>  e820_array
 initial_e820  =>  e820_array_init

This makes the variable names more consistent  and easier to grep for.

No change in functionality.

Cc: Alex Thorlton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dan Williams 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Huang, Ying 
Cc: Josh Poimboeuf 
Cc: Juergen Gross 
Cc: Linus Torvalds 
Cc: Paul Jackson 
Cc: Peter Zijlstra 
Cc: Rafael J. Wysocki 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Wei Yang 
Cc: Yinghai Lu 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

x86/boot/e820: Rename the basic e820 data types to 'struct e820_entry' and 'struct e820_array'

2017-01-28T08:33:14+00:00

The 'e820entry' and 'e820map' names have various annoyances:

 - the missing underscore departs from the usual kernel style
   and makes the code look weird,

 - in the past I kept confusing the 'map' with the 'entry', because
   a 'map' is ambiguous in that regard,

 - it's not really clear from the 'e820map' that this is a regular
   C array.

Rename them to 'struct e820_entry' and 'struct e820_array' accordingly.

( Leave the legacy UAPI header alone but do the rename in the bootparam.h
  and e820/types.h file - outside tools relying on these defines should
  either adjust their code, or should use the legacy header, or should
  create their private copies for the definitions. )

No change in functionality.

Cc: Alex Thorlton 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dan Williams 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Huang, Ying 
Cc: Josh Poimboeuf 
Cc: Juergen Gross 
Cc: Linus Torvalds 
Cc: Paul Jackson 
Cc: Peter Zijlstra 
Cc: Rafael J. Wysocki 
Cc: Tejun Heo 
Cc: Thomas Gleixner 
Cc: Wei Yang 
Cc: Yinghai Lu 
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar

x86, setup: When probing memory with e801, use ax/bx as a pair

2011-04-25T21:52:37+00:00

When we use BIOS function e801 to probe memory, we should use ax/bx
(or cx/dx) as a pair, not mix and match.  This was a typo during the
translation from assembly code, and breaks at least one set of
machines in the field (which return cx = dx = 0).

Reported-and-tested-by: Chris Samuel 
Fix-proposed-by: Thomas Meyer 
Link: http://lkml.kernel.org/r/1303566747.12067.10.camel@localhost.localdomain

Merge branch 'x86/urgent' into x86/setup

2009-05-23T23:42:19+00:00

Resolved conflicts:
	arch/x86/boot/memory.c

Signed-off-by: H. Peter Anvin

x86, setup: revert ACPI 3 E820 extended attributes support

2009-05-22T18:14:02+00:00

Remove ACPI 3 E820 extended memory attributes support.  At least one
vendor actively set all the flags to zero, but left ECX on return at
24.  This bug may be present in other BIOSes.

The breakage functionally means the ACPI 3 flags are probably
completely useless, and that no OS any time soon is going to rely on
their existence.  Therefore, drop support completely.  We may want to
revisit this question in the future, if we find ourselves actually
needing the flags.

This reverts all or part of the following checkins:

     cd670599b7b00d9263f6f11a05c0edeb9cbedaf3
     c549e71d073a6e9a4847497344db28a784061455

However, retain the part from the latter commit that copies e820 into
a temporary buffer; that is an unrelated BIOS workaround.  Put in a
comment to explain that part.

See https://bugzilla.redhat.com/show_bug.cgi?id=499396 for some
additional information.

[ Impact: detect all memory on affected machines ]

Reported-by: Thomas J. Baker 
Signed-off-by: H. Peter Anvin 
Acked-by: Len Brown 
Cc: Chuck Ebbert 
Cc: Kyle McMartin 
Cc: Matt Domsch

x86, setup: "glove box" BIOS interrupts in the core boot code

2009-04-09T23:08:11+00:00

Impact: BIOS proofing

"Glove box" off BIOS interrupts in the core boot code.

LKML-Reference: <49DE7F79.4030106@zytor.com>
Signed-off-by: H. Peter Anvin

x86, setup: guard against pre-ACPI 3 e820 code not updating %ecx

2009-04-01T18:35:00+00:00

Impact: BIOS bug safety

For pre-ACPI 3 BIOSes, pre-initialize the end of the e820 buffer just
in case the BIOS returns an unchanged %ecx but without actually
touching the ACPI 3 extended flags field.

Signed-off-by: H. Peter Anvin

x86, setup: ACPI 3, BIOS workaround for E820-probing code

2009-03-29T01:20:07+00:00

Impact: ACPI 3 spec compliance, BIOS bug workaround

The ACPI 3 spec added another field to the E820 buffer -- which is
backwards incompatible, since it contains a validity bit.
Furthermore, there has been at least one report of a BIOS which
assumes that the buffer it is pointed at is the same buffer as for the
previous E820 call.  Therefore, read the data into a temporary buffer
and copy the standard part of it if and only if the valid bit is set.

Signed-off-by: H. Peter Anvin