linux_dsm_epyc7002/arch/x86
Tom Lendacky f23d74f6c6 x86/mm: Rework wbinvd, hlt operation in stop_this_cpu()
Some issues have been reported with the for loop in stop_this_cpu() that
issues the 'wbinvd; hlt' sequence.  Reverting this sequence to halt()
has been shown to resolve the issue.

However, the wbinvd is needed when running with SME.  The reason for the
wbinvd is to prevent cache flush races between encrypted and non-encrypted
entries that have the same physical address.  This can occur when
kexec'ing from memory encryption active to inactive or vice-versa.  The
important thing is to not have outside of kernel text memory references
(such as stack usage), so the usage of the native_*() functions is needed
since these expand as inline asm sequences.  So instead of reverting the
change, rework the sequence.

Move the wbinvd instruction outside of the for loop as native_wbinvd()
and make its execution conditional on X86_FEATURE_SME.  In the for loop,
change the asm 'wbinvd; hlt' sequence back to a halt sequence but use
the native_halt() call.

Fixes: bba4ed011a ("x86/mm, kexec: Allow kexec to be used with SME")
Reported-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Dave Young <dyoung@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yu Chen <yu.c.chen@intel.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: kexec@lists.infradead.org
Cc: ebiederm@redhat.com
Cc: Borislav Petkov <bp@alien8.de>
Cc: Rui Zhang <rui.zhang@intel.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180117234141.21184.44067.stgit@tlendack-t1.amdoffice.net
2018-01-18 11:48:59 +01:00
..
boot Merge branch 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-31 13:13:56 -08:00
configs x86/unwind: Rename unwinder config options to 'CONFIG_UNWINDER_*' 2017-10-14 10:12:12 +02:00
crypto Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-14 09:51:25 -08:00
entry Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-17 11:54:56 -08:00
events Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-17 12:26:37 -08:00
hyperv Char/Misc patches for 4.15-rc1 2017-11-16 09:10:59 -08:00
ia32 License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
include Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-17 12:30:06 -08:00
kernel x86/mm: Rework wbinvd, hlt operation in stop_this_cpu() 2018-01-18 11:48:59 +01:00
kvm Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-14 09:51:25 -08:00
lib Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-14 09:51:25 -08:00
math-emu License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mm Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-17 12:30:06 -08:00
net bpf: fix bpf_tail_call() x64 JIT 2017-10-03 16:04:44 -07:00
oprofile Modules updates for v4.15 2017-11-15 13:46:33 -08:00
pci x86/PCI: Move and shrink AMD 64-bit window to avoid conflict 2018-01-11 12:01:58 -06:00
platform Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-14 09:51:25 -08:00
power Merge branch 'WIP.x86-pti.entry-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-12-18 08:59:15 -08:00
purgatory License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ras License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
realmode x86/realmode: Don't decrypt trampoline area under SEV 2017-11-07 15:35:55 +01:00
tools License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
um Merge commit 'upstream-x86-entry' into WIP.x86/mm 2017-12-17 12:58:53 +01:00
video
xen xen: fixes for 4.15-rc8 2018-01-12 10:00:15 -08:00
.gitignore
Kbuild Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-09-07 09:25:15 -07:00
Kconfig Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-14 09:51:25 -08:00
Kconfig.cpu License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig.debug Merge commit 'upstream-x86-entry' into WIP.x86/mm 2017-12-17 12:58:53 +01:00
Makefile Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-01-14 15:30:02 -08:00
Makefile_32.cpu License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Makefile.um License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00