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Commit ad025a73 authored by Toshi Kani's avatar Toshi Kani Committed by Ingo Molnar
Browse files

x86/mtrr: Fix PAT init handling when MTRR is disabled 



get_mtrr_state() calls pat_init() on BSP even if MTRR is disabled.
This results in calling pat_init() on BSP only since APs do not call
pat_init() when MTRR is disabled.  This inconsistency between BSP
and APs leads to undefined behavior.

Make BSP's calling condition to pat_init() consistent with AP's,
mtrr_ap_init() and mtrr_aps_init().

Signed-off-by: default avatarToshi Kani <toshi.kani@hpe.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: elliott@hpe.com
Cc: konrad.wilk@oracle.com
Cc: paul.gortmaker@windriver.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1458769323-24491-6-git-send-email-toshi.kani@hpe.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent edfe63ec

arch/x86/kernel/cpu/mtrr/generic.c

+14 −10
Original line number Diff line number Diff line
@@ -444,11 +444,24 @@ static void __init print_mtrr_state(void) 
		pr_debug("TOM2: %016llx aka %lldM\n", mtrr_tom2, mtrr_tom2>>20);

}



/* PAT setup for BP. We need to go through sync steps here */

void __init mtrr_bp_pat_init(void)

{

	unsigned long flags;



	local_irq_save(flags);

	prepare_set();



	pat_init();



	post_set();

	local_irq_restore(flags);

}



/* Grab all of the MTRR state for this CPU into *state */

bool __init get_mtrr_state(void)

{

	struct mtrr_var_range *vrs;

	unsigned long flags;

	unsigned lo, dummy;

	unsigned int i;
@@ -481,15 +494,6 @@ bool __init get_mtrr_state(void) 


	mtrr_state_set = 1;



	/* PAT setup for BP. We need to go through sync steps here */

	local_irq_save(flags);

	prepare_set();



	pat_init();



	post_set();

	local_irq_restore(flags);



	return !!(mtrr_state.enabled & MTRR_STATE_MTRR_ENABLED);

}

arch/x86/kernel/cpu/mtrr/main.c

+3 −0
Original line number Diff line number Diff line
@@ -752,6 +752,9 @@ void __init mtrr_bp_init(void) 
			/* BIOS may override */

			__mtrr_enabled = get_mtrr_state();



			if (mtrr_enabled())

				mtrr_bp_pat_init();



			if (mtrr_cleanup(phys_addr)) {

				changed_by_mtrr_cleanup = 1;

				mtrr_if->set_all();

arch/x86/kernel/cpu/mtrr/mtrr.h

+1 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ void set_mtrr_prepare_save(struct set_mtrr_context *ctxt); 
void fill_mtrr_var_range(unsigned int index,

		u32 base_lo, u32 base_hi, u32 mask_lo, u32 mask_hi);

bool get_mtrr_state(void);

void mtrr_bp_pat_init(void);



extern void set_mtrr_ops(const struct mtrr_ops *ops);