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Subject[PATCH 4.9 18/39] kaiser: delete KAISER_REAL_SWITCH option
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Hugh Dickins <hughd@google.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. But we'd much rather delete it.)

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/entry/entry_64.S | 4 ----
arch/x86/include/asm/kaiser.h | 4 ----
security/Kconfig | 4 ----
3 files changed, 12 deletions(-)

--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1317,9 +1317,7 @@ 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
@@ -1560,9 +1558,7 @@ 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

--- 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

--- 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

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