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Commit 88ba2811 authored by Toshi Kani's avatar Toshi Kani Committed by Ingo Molnar
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x86/xen, pat: Remove PAT table init code from Xen 



Xen supports PAT without MTRRs for its guests.  In order to
enable WC attribute, it was necessary for xen_start_kernel()
to call pat_init_cache_modes() to update PAT table before
starting guest kernel.

Now that the kernel initializes PAT table to the BIOS handoff
state when MTRR is disabled, this Xen-specific PAT init code
is no longer necessary.  Delete it from xen_start_kernel().

Also change __init_cache_modes() to a static function since
PAT table should not be tweaked by other modules.

Signed-off-by: default avatarToshi Kani <toshi.kani@hpe.com>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarJuergen Gross <jgross@suse.com>
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: Konrad Rzeszutek Wilk <konrad.wilk@oracle.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: paul.gortmaker@windriver.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1458769323-24491-7-git-send-email-toshi.kani@hpe.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent ad025a73

arch/x86/include/asm/pat.h

+0 −1
Original line number Diff line number Diff line
@@ -7,7 +7,6 @@ 
bool pat_enabled(void);

void pat_disable(const char *reason);

extern void pat_init(void);

void __init_cache_modes(u64);



extern int reserve_memtype(u64 start, u64 end,

		enum page_cache_mode req_pcm, enum page_cache_mode *ret_pcm);

arch/x86/mm/pat.c

+1 −1
Original line number Diff line number Diff line
@@ -192,7 +192,7 @@ static enum page_cache_mode pat_get_cache_mode(unsigned pat_val, char *msg) 
 * configuration.

 * Using lower indices is preferred, so we start with highest index.

 */

void __init_cache_modes(u64 pat)

static void __init_cache_modes(u64 pat)

{

	enum page_cache_mode cache;

	char pat_msg[33];

arch/x86/xen/enlighten.c

+0 −9
Original line number Diff line number Diff line
@@ -75,7 +75,6 @@ 
#include <asm/mach_traps.h>

#include <asm/mwait.h>

#include <asm/pci_x86.h>

#include <asm/pat.h>

#include <asm/cpu.h>



#ifdef CONFIG_ACPI
@@ -1511,7 +1510,6 @@ asmlinkage __visible void __init xen_start_kernel(void) 
{

	struct physdev_set_iopl set_iopl;

	unsigned long initrd_start = 0;

	u64 pat;

	int rc;



	if (!xen_start_info)
@@ -1618,13 +1616,6 @@ asmlinkage __visible void __init xen_start_kernel(void) 
				   xen_start_info->nr_pages);

	xen_reserve_special_pages();



	/*

	 * Modify the cache mode translation tables to match Xen's PAT

	 * configuration.

	 */

	rdmsrl(MSR_IA32_CR_PAT, pat);

	__init_cache_modes(pat);



	/* keep using Xen gdt for now; no urgent need to change it */



#ifdef CONFIG_X86_32