linux-kernel - [PATCH 4.1 40/65] kaiser: delete KAISER_REAL

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Date:   Mon,  5 Mar 2018 19:25:13 -0500
From:   Pavel Tatashin <pasha.tatashin@...cle.com>
To:     steven.sistare@...cle.com, daniel.m.jordan@...cle.com,
        linux-kernel@...r.kernel.org, Alexander.Levin@...rosoft.com,
        dan.j.williams@...el.com, sathyanarayanan.kuppuswamy@...el.com,
        pankaj.laxminarayan.bharadiya@...el.com, akuster@...sta.com,
        cminyard@...sta.com, pasha.tatashin@...cle.com,
        gregkh@...uxfoundation.org, stable@...r.kernel.org
Subject: [PATCH 4.1 40/65] kaiser: delete KAISER_REAL_SWITCH option

From: Hugh Dickins <hughd@...gle.com>

We fail to see what CONFIG_KAISER_REAL_SWITCH is for: it seems to be
left over from early development, and now just obscures tricky parts
of the code.  Delete it before adding PCIDs, or nokaiser boot option.

(Or if there is some good reason to keep the option, then it needs
a help text - and a "depends on KAISER", so that all those without
KAISER are not asked the question.)

Signed-off-by: Hugh Dickins <hughd@...gle.com>
Acked-by: Jiri Kosina <jkosina@...e.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
(cherry picked from commit b9d2ccc54e17b5aa50dd0c036d3f4fb4e5248d54)
Signed-off-by: Pavel Tatashin <pasha.tatashin@...cle.com>

Conflicts:
	arch/x86/entry/entry_64.S (not in this tree)
	arch/x86/kernel/entry_64.S (patched instead of that)
---
 arch/x86/include/asm/kaiser.h | 4 ----
 arch/x86/kernel/entry_64.S    | 4 ----
 security/Kconfig              | 4 ----
 3 files changed, 12 deletions(-)

diff --git a/arch/x86/include/asm/kaiser.h b/arch/x86/include/asm/kaiser.h
index 051acf678cda..e0fc45e77aee 100644
--- a/arch/x86/include/asm/kaiser.h
+++ b/arch/x86/include/asm/kaiser.h
@@ -21,17 +21,13 @@
 
 .macro _SWITCH_TO_KERNEL_CR3 reg
 movq %cr3, \reg
-#ifdef CONFIG_KAISER_REAL_SWITCH
 andq $(~KAISER_SHADOW_PGD_OFFSET), \reg
-#endif
 movq \reg, %cr3
 .endm
 
 .macro _SWITCH_TO_USER_CR3 reg
 movq %cr3, \reg
-#ifdef CONFIG_KAISER_REAL_SWITCH
 orq $(KAISER_SHADOW_PGD_OFFSET), \reg
-#endif
 movq \reg, %cr3
 .endm
 
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 5c6c11d9d779..d2b2372e01c6 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -1541,9 +1541,7 @@ ENTRY(nmi)
 	/* %rax is saved above, so OK to clobber here */
 	movq	%cr3, %rax
 	pushq	%rax
-#ifdef CONFIG_KAISER_REAL_SWITCH
 	andq	$(~KAISER_SHADOW_PGD_OFFSET), %rax
-#endif
 	movq	%rax, %cr3
 #endif
 	call	do_nmi
@@ -1779,9 +1777,7 @@ end_repeat_nmi:
 	/* %rax is saved above, so OK to clobber here */
 	movq	%cr3, %rax
 	pushq	%rax
-#ifdef CONFIG_KAISER_REAL_SWITCH
 	andq	$(~KAISER_SHADOW_PGD_OFFSET), %rax
-#endif
 	movq	%rax, %cr3
 #endif
 	DEFAULT_FRAME 0				/* XXX: Do we need this? */
diff --git a/security/Kconfig b/security/Kconfig
index 5f4b656bfa4c..9d63046e4794 100644
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -41,10 +41,6 @@ config KAISER
 
 	  If you are unsure how to answer this question, answer Y.
 
-config KAISER_REAL_SWITCH
-	bool "KAISER: actually switch page tables"
-	default y
-
 config SECURITYFS
 	bool "Enable the securityfs filesystem"
 	help
-- 
2.16.2