4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Toshi Kani <[email protected]> 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 <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Acked-by: Juergen Gross <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Konrad Rzeszutek Wilk <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Luis R. Rodriguez <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Toshi Kani <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/include/asm/pat.h | 1 - arch/x86/mm/pat.c | 2 +- arch/x86/xen/enlighten.c | 9 --------- 3 files changed, 1 insertion(+), 11 deletions(-) --- 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); --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -191,7 +191,7 @@ static enum page_cache_mode pat_get_cach * 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]; --- 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_sta { 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_sta 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
