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authorToshi Kani <toshi.kani@hpe.com>2016-03-23 15:42:02 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-08-16 09:30:49 +0200
commit26b340ea33f49af99449607c20c97fa3f499c5fa (patch)
tree93df5edff313a37bb066e0fa4e87e313aa5fd1f6
parenta23b299b4a7d0083a3bdb61d1586956f817e8961 (diff)
x86/xen, pat: Remove PAT table init code from Xen
commit 88ba281108ed0c25c9d292b48bd3f272fcb90dd0 upstream. 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: Toshi Kani <toshi.kani@hpe.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Juergen 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: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/x86/include/asm/pat.h1
-rw-r--r--arch/x86/mm/pat.c2
-rw-r--r--arch/x86/xen/enlighten.c9
3 files changed, 1 insertions, 11 deletions
diff --git a/arch/x86/include/asm/pat.h b/arch/x86/include/asm/pat.h
index 0ad356c066ef..0b1ff4c1c14e 100644
--- a/arch/x86/include/asm/pat.h
+++ b/arch/x86/include/asm/pat.h
@@ -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);
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 869bb3f03a2c..9222e6ae449a 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -191,7 +191,7 @@ 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];
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index cf8d1bcabc56..ffa41591bff9 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -74,7 +74,6 @@
#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
@@ -1519,7 +1518,6 @@ 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)
@@ -1627,13 +1625,6 @@ 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