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2008-10-10x86, pat: cleanupsIngo Molnar
clean up recently added code to be more consistent with other x86 code. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-10x86: track memtype for RAM in page structSuresh Siddha
Track the memtype for RAM pages in page struct instead of using the memtype list. This avoids the explosion in the number of entries in memtype list (of the order of 20,000 with AGP) and makes the PAT tracking simpler. We are using PG_arch_1 bit in page->flags. We still use the memtype list for non RAM pages. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-22Merge branch 'x86/urgent' into x86/patIngo Molnar
Conflicts: arch/x86/mm/pageattr.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21devmem, x86: PAT Change /dev/mem mmap with O_SYNC to use UC_MINUSvenkatesh.pallipadi@intel.com
All kernel mappings like ioremap(), etc uses UC_MINUS as the type. /dev/mem mappings with /dev/mem being opened with O_SYNC however was using UC, resulting in a conflict with /dev/mem mmap failing. This seems to be affecting some apps (one being flashrom) which are using O_SYNC and which were working before. Switch /dev/mem with O_SYNC also to UC_MINUS. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-20x86: fix Xorg startup/shutdown slowdown with PATVenki Pallipadi
Rene Herman reported significant Xorg startup/shutdown slowdown due to PAT. It turns out that the memtype list has thousands of entries. Add cached_entry to list add routine, in order to speed up the lookup for sequential reserve_memtype calls. Reported-by: Rene Herman <rene.herman@keyaccess.nl> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-11x86: compile pat debugfs interface only if CONFIG_X86_PAT is setAndreas Herrmann
Recently I've run a kernel w/o PAT support and wondered why there was a file "x86/pat_memtype_list" in debugfs. Of course it's empty if PAT is disabled ... so just get rid of this interface if PAT is disabled. Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-21Merge branches 'x86/urgent', 'x86/amd-iommu', 'x86/apic', 'x86/cleanups', ↵Ingo Molnar
'x86/core', 'x86/cpu', 'x86/fixmap', 'x86/gart', 'x86/kprobes', 'x86/memtest', 'x86/modules', 'x86/nmi', 'x86/pat', 'x86/reboot', 'x86/setup', 'x86/step', 'x86/unify-pci', 'x86/uv', 'x86/xen' and 'xen-64bit' into x86/for-linus
2008-07-20Subject: devmem, x86: fix rename of CONFIG_NONPROMISC_DEVMEMIngo Molnar
From: Arjan van de Ven <arjan@infradead.org> Date: Sat, 19 Jul 2008 15:47:17 -0700 CONFIG_NONPROMISC_DEVMEM was a rather confusing name - but renaming it to CONFIG_PROMISC_DEVMEM causes problems on architectures that do not support this feature; this patch renames it to CONFIG_STRICT_DEVMEM, so that architectures can opt-in into it. ( the polarity of the option is still the same as it was originally; it needs to be for now to not break architectures that don't have the infastructure yet to support this feature) Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: "V.Radhakrishnan" <rk@atr-labs.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> ---
2008-07-18x86: Add a debugfs interface to dump PAT memtypevenkatesh.pallipadi@intel.com
Add a debugfs interface to list out all the PAT memtype reservations. Appears at debugfs x86/pat_memtype_list and output format is type @ <start addr>-<end addr> We do not hold the lock while printing the entire list. So, the list may not be a consistent copy in case where regions are getting added or deleted at the same time. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-07-18x86: rename CONFIG_NONPROMISC_DEVMEM to CONFIG_PROMISC_DEVMEMIngo Molnar
Linus observed: > The real bug is that we shouldn't have "double negatives", and > certainly not negative config options. Making that "promiscuous > /dev/mem" option a negated thing as a config option was bad. right ... lets rename this option. There should never be a negation in config options. [ that reminds me of CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER, but that is for another commit ;-) ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-13x86: max_low_pfn_mapped fix, #2Yinghai Lu
tighten the boundary checks around max_low_pfn_mapped - dont overmap nor undermap into holes. also print out tseg for AMD cpus, for diagnostic purposes. (this is an SMM area, and we split up any big mappings around that area) Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-11x86: introduce max_low_pfn_mapped for 64-bitYinghai Lu
when more than 4g memory is installed, don't map the big hole below 4g. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24x86: pat.c final cleanup of loop body in reserve_memtypeAndreas Herrmann
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh B Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24x86: pat.c introduce function to check for conflicts with existing memtypesAndreas Herrmann
... to strip down loop body in reserve_memtype. Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh B Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24x86: pat.c consolidate list_add handling in reserve_memtypeAndreas Herrmann
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh B Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24x86: pat.c consolidate error/debug messages in reserve_memtypeAndreas Herrmann
... and move last debug message out of locked section. Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh B Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24x86: pat.c more trivial changesAndreas Herrmann
- add BUG statement to catch invalid start and end parameters - No need to track the actual type in both req_type and actual_type -- keep req_type unchanged. - removed (IMHO) superfluous comments Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh B Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24x86: pat.c choose more crisp variable namesAndreas Herrmann
- parse/ml => entry (within list_for_each and friends) - new_entry => new - ret_type => new_type (to avoid confusion with req_type) (... to make it more readable...) Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh B Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-24x86: introduce macro to check whether an address range is in the ISA rangeAndreas Herrmann
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh B Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-19x86: shrink pat_x_mtrr_type to its essentialsAndreas Herrmann
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Suresh B Siddha <suresh.b.siddha@intel.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-18x86: PAT: make pat_x_mtrr_type() more readableHugh Dickins
Clean up over-complications in pat_x_mtrr_type(). And if reserve_memtype() ignores stray req_type bits when pat_enabled, it's better to mask them off when not also. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-16Merge branch 'linus' into x86/patIngo Molnar
2008-06-12x86: rename pat_wc_enabled to pat_enabledAndreas Herrmann
BTW, what does pat_wc_enabled stand for? Does it mean "write-combining"? Currently it is used to globally switch on or off PAT support. Thus I renamed it to pat_enabled. I think this increases readability (and hope that I didn't miss something). Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-12x86: PAT: fixed checkpatch errors (and whitespaces)Andreas Herrmann
x86: PAT: fixed checkpatch errors (and whitespaces) Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-12x86: PAT: fix ambiguous paranoia check in pat_init()Andreas Herrmann
Starting with commit 8d4a4300854f3971502e81dacd930704cb88f606 (x86: cleanup PAT cpu validation) the PAT CPU feature flag is not cleared anymore. Now the error message "PAT enabled, but CPU feature cleared" in pat_init() is misleading. Furthermore the current code does not check for existence of the PAT CPU feature flag if a CPU is whitelisted in validate_pat_support. This patch clears pat_wc_enabled if boot CPU has no PAT feature flag and adapts the paranoia check. Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-12x86: fix Xorg crash with xf86MapVidMem errorVenki Pallipadi
Clarify the usage of mtrr_lookup() in PAT code, and to make PAT code resilient to mtrr lookup problems. Specifically, pat_x_mtrr_type() is restructured to highlight, under what conditions we look for mtrr hint. pat_x_mtrr_type() uses a default type when there are any errors in mtrr lookup (still maintaining the pat consistency). And, reserve_memtype() highlights its usage ot mtrr_lookup for request type of '-1' and also defaults in a sane way on any mtrr lookup failure. pat.c looks at mtrr type of a range to get a hint on what mapping type to request when user/API: (1) hasn't specified any type (/dev/mem mapping) and we do not want to take performance hit by always mapping UC_MINUS. This will be the case for /dev/mem mappings used to map BIOS area or ACPI region which are WB'able. In this case, as long as MTRR is not WB, PAT will request UC_MINUS for such mappings. (2) user/API requests WB mapping while in reality MTRR may have UC or WC. In this case, PAT can map as WB (without checking MTRR) and still effective type will be UC or WC. But, a subsequent request to map same region as UC or WC may fail, as the region will get trackked as WB in PAT list. Looking at MTRR hint helps us to track based on effective type rather than what user requested. Again, here mtrr_lookup is only used as hint and we fallback to WB mapping (as requested by user) as default. In both cases, after using the mtrr hint, we still go through the memtype list to make sure there are no inconsistencies among multiple users. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Tested-by: Rufus & Azrael <rufus-azrael@numericable.fr> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-04x86: section mismatch fixAndrew Morton
Fix this: WARNING: vmlinux.o(.text+0x114bb): Section mismatch in reference from the function nopat() to the function .cpuinit.text:pat_disable() The function nopat() references the function __cpuinit pat_disable(). This is often because nopat lacks a __cpuinit annotation or the annotation of pat_disable is wrong. Reported-by: "Fabio Comolli" <fabio.comolli@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-04x86: fix Xorg crash with xf86MapVidMem errorVenki Pallipadi
Clarify the usage of mtrr_lookup() in PAT code, and to make PAT code resilient to mtrr lookup problems. Specifically, pat_x_mtrr_type() is restructured to highlight, under what conditions we look for mtrr hint. pat_x_mtrr_type() uses a default type when there are any errors in mtrr lookup (still maintaining the pat consistency). And, reserve_memtype() highlights its usage ot mtrr_lookup for request type of '-1' and also defaults in a sane way on any mtrr lookup failure. pat.c looks at mtrr type of a range to get a hint on what mapping type to request when user/API: (1) hasn't specified any type (/dev/mem mapping) and we do not want to take performance hit by always mapping UC_MINUS. This will be the case for /dev/mem mappings used to map BIOS area or ACPI region which are WB'able. In this case, as long as MTRR is not WB, PAT will request UC_MINUS for such mappings. (2) user/API requests WB mapping while in reality MTRR may have UC or WC. In this case, PAT can map as WB (without checking MTRR) and still effective type will be UC or WC. But, a subsequent request to map same region as UC or WC may fail, as the region will get trackked as WB in PAT list. Looking at MTRR hint helps us to track based on effective type rather than what user requested. Again, here mtrr_lookup is only used as hint and we fallback to WB mapping (as requested by user) as default. In both cases, after using the mtrr hint, we still go through the memtype list to make sure there are no inconsistencies among multiple users. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Tested-by: Rufus & Azrael <rufus-azrael@numericable.fr> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-25arch/x86/mm/pat.c: use boot_cpu_has()Andrew Morton
arch/x86/mm/pat.c: In function 'phys_mem_access_prot_allowed': arch/x86/mm/pat.c:526: warning: passing argument 2 of 'constant_test_bit' from incompatible pointer type arch/x86/mm/pat.c:526: warning: passing argument 2 of 'variable_test_bit' from incompatible pointer type arch/x86/mm/pat.c:527: warning: passing argument 2 of 'constant_test_bit' from incompatible pointer type arch/x86/mm/pat.c:527: warning: passing argument 2 of 'variable_test_bit' from incompatible pointer type arch/x86/mm/pat.c:528: warning: passing argument 2 of 'constant_test_bit' from incompatible pointer type arch/x86/mm/pat.c:528: warning: passing argument 2 of 'variable_test_bit' from incompatible pointer type arch/x86/mm/pat.c:529: warning: passing argument 2 of 'constant_test_bit' from incompatible pointer type arch/x86/mm/pat.c:529: warning: passing argument 2 of 'variable_test_bit' from incompatible pointer type Don't open-code test_bit() on a __u32 Cc: Andrea Arcangeli <andrea@qumranet.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-19Merge branch 'linus' into x86/patIngo Molnar
2008-05-18Merge branch 'linus' into x86/patThomas Gleixner
2008-05-17x86: fix crash on cpu hotplug on pat-incapable machinesAvi Kivity
pat_disable() is __init, which means it goes away after booting is complete. Unfortunately it is used by the hotplug code if the machine is not pat-capable, causing a crash. Fix by marking pat_disable() as __cpuinit. Signed-off-by: Avi Kivity <avi@qumranet.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-13x86: arch/x86/mm/pat.c - fix warningPranith Kumar
fix this warning: arch/x86/mm/pat.c: In function `phys_mem_access_prot_allowed': arch/x86/mm/pat.c:558: warning: long long unsigned int format, long unsigned int arg (arg 6) arch/x86/mm/pat.c: In function `map_devmem': arch/x86/mm/pat.c:580: warning: long long unsigned int format, long unsigned int arg (arg 6) Signed-off-by: D Pranith Kumar <bobby.prani@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-12x86: add "debugpat" boot optionVenki Pallipadi
enable debug messages by a boot option "debugpat". Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-08x86: cleanup PAT cpu validationThomas Gleixner
Move the scattered checks for PAT support to a single function. Its moved to addon_cpuid_features.c as this file is shared between 32 and 64 bit. Remove the manipulation of the PAT feature bit and just disable PAT in the PAT layer, based on the PAT bit provided by the CPU and the current CPU version/model white list. Change the boot CPU check so it works on Voyager somewhere in the future as well :) Also panic, when a secondary has PAT disabled but the primary one has alrady switched to PAT. We have no way to undo that. The white list is kept for now to ensure that we can rely on known to work CPU types and concentrate on the software induced problems instead of fighthing CPU erratas and subtle wreckage caused by not yet verified CPUs. Once the PAT code has stabilized enough, we can remove the white list and open the can of worms. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-28x86: PAT fixIngo Molnar
Adrian Bunk noticed the following Coverity report: > Commit e7f260a276f2c9184fe753732d834b1f6fbe9f17 > (x86: PAT use reserve free memtype in mmap of /dev/mem) > added the following gem to arch/x86/mm/pat.c: > > <-- snip --> > > ... > int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, > unsigned long size, pgprot_t *vma_prot) > { > u64 offset = ((u64) pfn) << PAGE_SHIFT; > unsigned long flags = _PAGE_CACHE_UC_MINUS; > unsigned long ret_flags; > ... > ... (nothing that touches ret_flags) > ... > if (flags != _PAGE_CACHE_UC_MINUS) { > retval = reserve_memtype(offset, offset + size, flags, NULL); > } else { > retval = reserve_memtype(offset, offset + size, -1, &ret_flags); > } > > if (retval < 0) > return 0; > > flags = ret_flags; > > if (pfn <= max_pfn_mapped && > ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) { > free_memtype(offset, offset + size); > printk(KERN_INFO > "%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n", > current->comm, current->pid, > cattr_name(flags), > offset, offset + size); > return 0; > } > > *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) | > flags); > return 1; > } > > <-- snip --> > > If (flags != _PAGE_CACHE_UC_MINUS) we pass garbage from the stack to > ioremap_change_attr() and/or __pgprot(). > > Spotted by the Coverity checker. the fix simplifies the code as we get rid of the 'ret_flags' complication. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-27x86 PAT: tone down debugging messages some moreLinus Torvalds
Ingo already fixed one of these at my request (in "x86 PAT: tone down debugging messages", commit 1ebcc654f010d4a63f3ebf8ddd2cab5a709b1824), but there was another one he missed. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-26x86, PAT: disable /dev/mem mmap RAM with PATVenki Pallipadi
disable /dev/mem mmap of RAM with PAT. It makes things safer and eliminates aliasing. A future improvement would be to avoid the range_is_allowed duplication. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-26x86 PAT: tone down debugging messagesIngo Molnar
Linus reported these excessive debug printouts: > Overlap at 0xe0300000-0xe0400000 > Overlap at 0xe0300000-0xe0380000 > Overlap at 0xe0300000-0xe0400000 > Overlap at 0xe0300000-0xe0400000 > Overlap at 0xe0300000-0xe0400000 > Overlap at 0xe0300000-0xe0400000 > Overlap at 0xe0300000-0xe0400000 turn that into a pr_debug(). Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-24pat: cleanupsIngo Molnar
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-24x86: PAT use reserve free memtype in mmap of /dev/memvenkatesh.pallipadi@intel.com
Use reserve_memtype and free_memtype wrappers for /dev/mem mmaps. The memtype is slightly complicated here, given that we have to support existing X mappings. We fallback on UC_MINUS for that. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-24x86: PAT phys_mem_access_prot_allowed for dev/mem mmapvenkatesh.pallipadi@intel.com
Introduce phys_mem_access_prot_allowed(), which checks whether the mapping is possible, without any conflicts and returns success or failure based on that. phys_mem_access_prot() by itself does not allow failure case. This ability to return error is needed for PAT where we may have aliasing conflicts. x86 setup __HAVE_PHYS_MEM_ACCESS_PROT and move x86 specific code out of /dev/mem into arch specific area. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: pat cpu feature bit setting for known cpusYinghai Lu
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: enable PAT for amd k8 and fam10hYinghai Lu
make known_pat_cpu to think amd k8 and fam10h is ok too. also make tom2 below to be WRBACK Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: add PAT related debug printsvenkatesh.pallipadi@intel.com
Adds debug prints at critical code. Adds enough info in dmesg to allow us to do effective first round of analysis of any issues that may result due to PAT patch series. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-04-17x86: PAT infrastructure patchvenkatesh.pallipadi@intel.com
Sets up pat_init() infrastructure. PAT MSR has following setting. PAT |PCD ||PWT ||| 000 WB _PAGE_CACHE_WB 001 WC _PAGE_CACHE_WC 010 UC- _PAGE_CACHE_UC_MINUS 011 UC _PAGE_CACHE_UC We are effectively changing WT from boot time setting to WC. UC_MINUS is used to provide backward compatibility to existing /dev/mem users(X). reserve_memtype and free_memtype are new interfaces for maintaining alias-free mapping. It is currently implemented in a simple way with a linked list and not optimized. reserve and free tracks the effective memory type, as a result of PAT and MTRR setting rather than what is actually requested in PAT. pat_init piggy backs on mtrr_init as the rules for setting both pat and mtrr are same. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>