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Arvind Sankar 262bd5724a x86/cpu/amd: Remove dead code for TSEG region remapping 
Commit

  26bfa5f894 ("x86, amd: Cleanup init_amd")

moved the code that remaps the TSEG region using 4k pages from
init_amd() to bsp_init_amd().

However, bsp_init_amd() is executed well before the direct mapping is
actually created:

  setup_arch()
    -> early_cpu_init()
      -> early_identify_cpu()
        -> this_cpu->c_bsp_init()
	  -> bsp_init_amd()
    ...
    -> init_mem_mapping()

So the change effectively disabled the 4k remapping, because
pfn_range_is_mapped() is always false at this point.

It has been over six years since the commit, and no-one seems to have
noticed this, so just remove the code. The original code was also
incomplete, since it doesn't check how large the TSEG address range
actually is, so it might remap only part of it in any case.

Hygon has copied the incorrect version, so the code has never run on it
since the cpu support was added two years ago. Remove it from there as
well.

Committer notes:

This workaround is incomplete anyway:

1. The code must check MSRC001_0113.TValid (SMM TSeg Mask MSR) first, to
check whether the TSeg address range is enabled.

2. The code must check whether the range is not 2M aligned - if it is,
there's nothing to work around.

3. In all the BIOSes tested, the TSeg range is in a e820 reserved area
and those are not mapped anymore, after

  66520ebc2d ("x86, mm: Only direct map addresses that are marked as E820_RAM")

which means, there's nothing to be worked around either.

So let's rip it out.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20201127171324.1846019-1-nivedita@alum.mit.edu
 		2020-12-08 18:45:21 +01:00
Documentation x86/CPU/AMD: Save AMD NodeId as cpu_die_id 2020-11-19 11:43:13 +01:00
LICENSES LICENSES/deprecated: add Zlib license text 2020-09-16 14:33:49 +02:00
arch x86/cpu/amd: Remove dead code for TSEG region remapping 2020-12-08 18:45:21 +01:00
block block: add a return value to set_capacity_revalidate_and_notify 2020-11-12 13:59:04 -07:00
certs .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
crypto drivers-5.10-2020-10-12 2020-10-13 13:04:41 -07:00
drivers EDAC/mce_amd: Use struct cpuinfo_x86.cpu_die_id for AMD NodeId 2020-11-19 11:43:21 +01:00
fs Merge branch 'akpm' (patches from Andrew) 2020-11-14 12:35:11 -08:00
include A set of fixes for perf: 2020-11-15 09:46:36 -08:00
init bootconfig: Extend the magic check range to the preceding 3 bytes 2020-11-12 20:36:52 -05:00
ipc ipc: adjust proc_ipc_sem_dointvec definition to match prototype 2020-09-05 12:14:29 -07:00
kernel A set of fixes for perf: 2020-11-15 09:46:36 -08:00
lib drm fixes for 5.10-rc3 2020-11-06 12:54:00 -08:00
mm Merge branch 'for-5.10-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu 2020-11-15 08:57:19 -08:00
net Networking fixes for 5.10-rc4, including fixes from the bpf subtree. 2020-11-12 14:02:04 -08:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-11-06 17:49:34 -08:00
scripts Networking fixes for 5.10-rc4, including fixes from the bpf subtree. 2020-11-12 14:02:04 -08:00
security selinux/stable-5.10 PR 20201113 2020-11-14 12:04:02 -08:00
sound ASoC: Fixes for v5.10 2020-11-05 18:19:32 +01:00
tools Networking fixes for 5.10-rc4, including fixes from the bpf subtree. 2020-11-12 14:02:04 -08:00
usr Merge branch 'work.fdpic' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2020-08-07 13:29:39 -07:00
virt kvm: x86/mmu: Support dirty logging for the TDP MMU 2020-10-23 03:42:13 -04:00
.clang-format RDMA 5.10 pull request 2020-10-17 11:18:18 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: docs: ignore sphinx_*/ directories 2020-09-10 10:44:31 -06:00
.mailmap mailmap: fix entry for Dmitry Baryshkov/Eremin-Solenikov 2020-11-14 11:26:03 -08:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Sangbeom Kim to credits 2020-10-26 10:11:18 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS USB/Thunderbolt fixes for 5.10-rc4 2020-11-15 10:02:41 -08:00
Makefile Linux 5.10-rc4 2020-11-15 16:44:31 -08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.