kaiser: delete KAISER_REAL_SWITCH option

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>
Gbp-Pq: Topic features/all/kpti
Gbp-Pq: Name kaiser-delete-kaiser_real_switch-option.patch

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 42ee56eb7d941cc6d06fdf185a918273077e8edf..b61dfbe1c3e8b380c1adf126159a57a9b227812e 100644 (file)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1331,9 +1331,7 @@ 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
@@ -1574,9 +1572,7 @@ 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
 

diff --git a/arch/x86/include/asm/kaiser.h b/arch/x86/include/asm/kaiser.h
index 051acf678cda3761c893ddc501b46ea3c93801a9..e0fc45e77aeeb4bab9d88f624a365f459498ca06 100644 (file)
--- 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/security/Kconfig b/security/Kconfig
index e0751bf0efb7bb98999789e97d928cd941270b6c..93b4e24f142de9021db038c24c82d25cbc9fda6b 100644 (file)
--- a/security/Kconfig
+++ b/security/Kconfig
@@ -50,10 +50,6 @@ 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