Commit ea4654e0 authored by Breno Leitao's avatar Breno Leitao Committed by Ingo Molnar
Browse files

x86/bugs: Rename CONFIG_PAGE_TABLE_ISOLATION => CONFIG_MITIGATION_PAGE_TABLE_ISOLATION 



Step 4/10 of the namespace unification of CPU mitigations related Kconfig options.

[ mingo: Converted new uses that got added since the series was posted. ]

Suggested-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: default avatarBreno Leitao <leitao@debian.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarJosh Poimboeuf <jpoimboe@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20231121160740.1249350-5-leitao@debian.org
parent 5fa31af3

Documentation/arch/x86/pti.rst

+3 −3
Original line number Diff line number Diff line
@@ -26,9 +26,9 @@ comments in pti.c). 


This approach helps to ensure that side-channel attacks leveraging

the paging structures do not function when PTI is enabled.  It can be

enabled by setting CONFIG_PAGE_TABLE_ISOLATION=y at compile time.

Once enabled at compile-time, it can be disabled at boot with the

'nopti' or 'pti=' kernel parameters (see kernel-parameters.txt).

enabled by setting CONFIG_MITIGATION_PAGE_TABLE_ISOLATION=y at compile

time.  Once enabled at compile-time, it can be disabled at boot with

the 'nopti' or 'pti=' kernel parameters (see kernel-parameters.txt).



Page Table Management

=====================

arch/x86/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -2484,7 +2484,7 @@ menuconfig SPECULATION_MITIGATIONS 


if SPECULATION_MITIGATIONS



config PAGE_TABLE_ISOLATION

config MITIGATION_PAGE_TABLE_ISOLATION

	bool "Remove the kernel mapping in user mode"

	default y

	depends on (X86_64 || X86_PAE)

arch/x86/boot/compressed/ident_map_64.c

+2 −2
Original line number Diff line number Diff line
@@ -8,8 +8,8 @@ 
 * Copyright (C)      2016  Kees Cook

 */



/* No PAGE_TABLE_ISOLATION support needed either: */

#undef CONFIG_PAGE_TABLE_ISOLATION

/* No MITIGATION_PAGE_TABLE_ISOLATION support needed either: */

#undef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION



#include "error.h"

#include "misc.h"

arch/x86/entry/calling.h

+4 −4
Original line number Diff line number Diff line
@@ -142,10 +142,10 @@ For 32-bit we have the following conventions - kernel is built with 
	.endif

.endm



#ifdef CONFIG_PAGE_TABLE_ISOLATION

#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION



/*

 * PAGE_TABLE_ISOLATION PGDs are 8k.  Flip bit 12 to switch between the two

 * MITIGATION_PAGE_TABLE_ISOLATION PGDs are 8k.  Flip bit 12 to switch between the two

 * halves:

 */

#define PTI_USER_PGTABLE_BIT		PAGE_SHIFT
@@ -160,7 +160,7 @@ For 32-bit we have the following conventions - kernel is built with 


.macro ADJUST_KERNEL_CR3 reg:req

	ALTERNATIVE "", "SET_NOFLUSH_BIT \reg", X86_FEATURE_PCID

	/* Clear PCID and "PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */

	/* Clear PCID and "MITIGATION_PAGE_TABLE_ISOLATION bit", point CR3 at kernel pagetables: */

	andq    $(~PTI_USER_PGTABLE_AND_PCID_MASK), \reg

.endm
@@ -275,7 +275,7 @@ For 32-bit we have the following conventions - kernel is built with 
.Lend_\@:

.endm



#else /* CONFIG_PAGE_TABLE_ISOLATION=n: */

#else /* CONFIG_MITIGATION_PAGE_TABLE_ISOLATION=n: */



.macro SWITCH_TO_KERNEL_CR3 scratch_reg:req

.endm

arch/x86/entry/entry_64.S

+3 −3
Original line number Diff line number Diff line
@@ -562,7 +562,7 @@ SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL) 
#ifdef CONFIG_XEN_PV

	ALTERNATIVE "", "jmp xenpv_restore_regs_and_return_to_usermode", X86_FEATURE_XENPV

#endif

#ifdef CONFIG_PAGE_TABLE_ISOLATION

#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION

	ALTERNATIVE "", "jmp .Lpti_restore_regs_and_return_to_usermode", X86_FEATURE_PTI

#endif
@@ -578,7 +578,7 @@ SYM_INNER_LABEL(swapgs_restore_regs_and_return_to_usermode, SYM_L_GLOBAL) 
	jnz	.Lnative_iret

	ud2



#ifdef CONFIG_PAGE_TABLE_ISOLATION

#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION

.Lpti_restore_regs_and_return_to_usermode:

	POP_REGS pop_rdi=0
@@ -1096,7 +1096,7 @@ SYM_CODE_END(error_return) 
 *

 * Registers:

 *	%r14: Used to save/restore the CR3 of the interrupted context

 *	      when PAGE_TABLE_ISOLATION is in use.  Do not clobber.

 *	      when MITIGATION_PAGE_TABLE_ISOLATION is in use.  Do not clobber.

 */

SYM_CODE_START(asm_exc_nmi)

	UNWIND_HINT_IRET_ENTRY