linux-kernel - [PATCH 0/2] Refactor MTRR and PAT initializations

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Message-Id: <1457671546-13486-1-git-send-email-toshi.kani@hpe.com>
Date:	Thu, 10 Mar 2016 21:45:44 -0700
From:	Toshi Kani <toshi.kani@....com>
To:	mingo@...nel.org, bp@...e.de, hpa@...or.com, tglx@...utronix.de
Cc:	mcgrof@...e.com, jgross@...e.com, paul.gortmaker@...driver.com,
	x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 0/2] Refactor MTRR and PAT initializations

Since 'commit 9cd25aac1f44 ("x86/mm/pat: Emulate PAT when it
is disabled")', we emulate a PAT table when PAT is disabled.
This requires pat_init() be called even if PAT is disabled,
which revealed a long standing issue that PAT is left enabled
without calling pat_init() at all.

pat_init() is called from MTRR code since it relies on MTRR's
rendezvous handler to initialize PAT for all APs .  However,
when CPU does not support MTRR, ex. qemu32's virtual CPU, MTRR
is set disabled and does not call pat_init().  There is no
interface available for MTRR to disable PAT, either.

This patch-set refactors MTRR and PAT initializations to make
sure that PAT is properly initialized in all cases.

---
Toshi Kani (2):
 1/2 x86/mm/pat: Change pat_disable() to emulate PAT table
 2/2 x86/mtrr: Refactor PAT initialization code 

---
 arch/x86/include/asm/mtrr.h        |  6 ++-
 arch/x86/include/asm/pat.h         |  1 +
 arch/x86/kernel/cpu/mtrr/generic.c | 24 ++++++-----
 arch/x86/kernel/cpu/mtrr/main.c    | 13 +++++-
 arch/x86/kernel/cpu/mtrr/mtrr.h    |  1 +
 arch/x86/mm/pat.c                  | 84 +++++++++++++++++++++++---------------
 6 files changed, 84 insertions(+), 45 deletions(-)