Commit 784a4661 authored by Dave Hansen's avatar Dave Hansen Committed by Borislav Petkov
Browse files

x86/pkeys: Move read_pkru() and write_pkru() 



write_pkru() was originally used just to write to the PKRU register.  It
was mercifully short and sweet and was not out of place in pgtable.h with
some other pkey-related code.

But, later work included a requirement to also modify the task XSAVE
buffer when updating the register.  This really is more related to the
XSAVE architecture than to paging.

Move the read/write_pkru() to asm/pkru.h.  pgtable.h won't miss them.

Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121455.102647114@linutronix.de
parent a75c5289

arch/x86/include/asm/fpu/xstate.h

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



#include <asm/processor.h>

#include <asm/fpu/api.h>

#include <asm/user.h>



/* Bit 63 of XCR0 is reserved for future expansion */

arch/x86/include/asm/pgtable.h

+1 −56
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ 


#ifndef __ASSEMBLY__

#include <asm/x86_init.h>

#include <asm/fpu/xstate.h>

#include <asm/pkru.h>

#include <asm/fpu/api.h>

#include <asm-generic/pgtable_uffd.h>
@@ -126,35 +126,6 @@ static inline int pte_dirty(pte_t pte) 
	return pte_flags(pte) & _PAGE_DIRTY;

}





static inline u32 read_pkru(void)

{

	if (boot_cpu_has(X86_FEATURE_OSPKE))

		return rdpkru();

	return 0;

}



static inline void write_pkru(u32 pkru)

{

	struct pkru_state *pk;



	if (!boot_cpu_has(X86_FEATURE_OSPKE))

		return;



	pk = get_xsave_addr(&current->thread.fpu.state.xsave, XFEATURE_PKRU);



	/*

	 * The PKRU value in xstate needs to be in sync with the value that is

	 * written to the CPU. The FPU restore on return to userland would

	 * otherwise load the previous value again.

	 */

	fpregs_lock();

	if (pk)

		pk->pkru = pkru;

	__write_pkru(pkru);

	fpregs_unlock();

}



static inline int pte_young(pte_t pte)

{

	return pte_flags(pte) & _PAGE_ACCESSED;
@@ -1360,32 +1331,6 @@ static inline pmd_t pmd_swp_clear_uffd_wp(pmd_t pmd) 
}

#endif /* CONFIG_HAVE_ARCH_USERFAULTFD_WP */



#define PKRU_AD_BIT 0x1

#define PKRU_WD_BIT 0x2

#define PKRU_BITS_PER_PKEY 2



#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS

extern u32 init_pkru_value;

#else

#define init_pkru_value	0

#endif



static inline bool __pkru_allows_read(u32 pkru, u16 pkey)

{

	int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;

	return !(pkru & (PKRU_AD_BIT << pkru_pkey_bits));

}



static inline bool __pkru_allows_write(u32 pkru, u16 pkey)

{

	int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;

	/*

	 * Access-disable disables writes too so we need to check

	 * both bits here.

	 */

	return !(pkru & ((PKRU_AD_BIT|PKRU_WD_BIT) << pkru_pkey_bits));

}



static inline u16 pte_flags_pkey(unsigned long pte_flags)

{

#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS

arch/x86/include/asm/pkru.h

0 → 100644
+61 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _ASM_X86_PKRU_H

#define _ASM_X86_PKRU_H



#include <asm/fpu/xstate.h>



#define PKRU_AD_BIT 0x1

#define PKRU_WD_BIT 0x2

#define PKRU_BITS_PER_PKEY 2



#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS

extern u32 init_pkru_value;

#else

#define init_pkru_value	0

#endif



static inline bool __pkru_allows_read(u32 pkru, u16 pkey)

{

	int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;

	return !(pkru & (PKRU_AD_BIT << pkru_pkey_bits));

}



static inline bool __pkru_allows_write(u32 pkru, u16 pkey)

{

	int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY;

	/*

	 * Access-disable disables writes too so we need to check

	 * both bits here.

	 */

	return !(pkru & ((PKRU_AD_BIT|PKRU_WD_BIT) << pkru_pkey_bits));

}



static inline u32 read_pkru(void)

{

	if (boot_cpu_has(X86_FEATURE_OSPKE))

		return rdpkru();

	return 0;

}



static inline void write_pkru(u32 pkru)

{

	struct pkru_state *pk;



	if (!boot_cpu_has(X86_FEATURE_OSPKE))

		return;



	pk = get_xsave_addr(&current->thread.fpu.state.xsave, XFEATURE_PKRU);



	/*

	 * The PKRU value in xstate needs to be in sync with the value that is

	 * written to the CPU. The FPU restore on return to userland would

	 * otherwise load the previous value again.

	 */

	fpregs_lock();

	if (pk)

		pk->pkru = pkru;

	__write_pkru(pkru);

	fpregs_unlock();

}



#endif

arch/x86/kernel/process_64.c

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#include <linux/syscalls.h>



#include <asm/processor.h>

#include <asm/pkru.h>

#include <asm/fpu/internal.h>

#include <asm/mmu_context.h>

#include <asm/prctl.h>

arch/x86/kvm/svm/sev.c

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/trace_events.h>

#include <asm/fpu/internal.h>



#include <asm/pkru.h>

#include <asm/trapnr.h>



#include "x86.h"