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Commit b976690f authored by Joerg Roedel's avatar Joerg Roedel Committed by Thomas Gleixner
Browse files

x86/mm/pti: Introduce pti_finalize() 



Introduce a new function to finalize the kernel mappings for the userspace
page-table after all ro/nx protections have been applied to the kernel
mappings.

Also move the call to pti_clone_kernel_text() to that function so that it
will run on 32 bit kernels too.

Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarPavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-30-git-send-email-joro@8bytes.org
parent 1ac228a7

arch/x86/include/asm/pti.h

+1 −2
Original line number Diff line number Diff line
@@ -6,10 +6,9 @@ 
#ifdef CONFIG_PAGE_TABLE_ISOLATION

extern void pti_init(void);

extern void pti_check_boottime_disable(void);

extern void pti_clone_kernel_text(void);

extern void pti_finalize(void);

#else

static inline void pti_check_boottime_disable(void) { }

static inline void pti_clone_kernel_text(void) { }

#endif



#endif /* __ASSEMBLY__ */

arch/x86/mm/init_64.c

+0 −6
Original line number Diff line number Diff line
@@ -1291,12 +1291,6 @@ void mark_rodata_ro(void) 
			(unsigned long) __va(__pa_symbol(_sdata)));



	debug_checkwx();



	/*

	 * Do this after all of the manipulation of the

	 * kernel text page tables are complete.

	 */

	pti_clone_kernel_text();

}



int kern_addr_valid(unsigned long addr)

arch/x86/mm/pti.c

+13 −1
Original line number Diff line number Diff line
@@ -462,7 +462,7 @@ static inline bool pti_kernel_image_global_ok(void) 
 * For some configurations, map all of kernel text into the user page

 * tables.  This reduces TLB misses, especially on non-PCID systems.

 */

void pti_clone_kernel_text(void)

static void pti_clone_kernel_text(void)

{

	/*

	 * rodata is part of the kernel image and is normally
@@ -526,3 +526,15 @@ void __init pti_init(void) 
	pti_setup_espfix64();

	pti_setup_vsyscall();

}



/*

 * Finalize the kernel mappings in the userspace page-table.

 */

void pti_finalize(void)

{

	/*

	 * Do this after all of the manipulation of the

	 * kernel text page tables are complete.

	 */

	pti_clone_kernel_text();

}

include/linux/pti.h

+1 −0
Original line number Diff line number Diff line
@@ -6,6 +6,7 @@ 
#include <asm/pti.h>

#else

static inline void pti_init(void) { }

static inline void pti_finalize(void) { }

#endif



#endif

init/main.c

+7 −0
Original line number Diff line number Diff line
@@ -1065,6 +1065,13 @@ static int __ref kernel_init(void *unused) 
	jump_label_invalidate_initmem();

	free_initmem();

	mark_readonly();



	/*

	 * Kernel mappings are now finalized - update the userspace page-table

	 * to finalize PTI.

	 */

	pti_finalize();



	system_state = SYSTEM_RUNNING;

	numa_default_policy();