From 9962eea9e55f797f05f20ba6448929cab2a9f018 Mon Sep 17 00:00:00 2001 From: Minfei Huang Date: Sun, 12 Jul 2015 20:18:42 +0800 Subject: x86/mm: Initialize pmd_idx in page_table_range_init_count() The variable pmd_idx is not initialized for the first iteration of the for loop. Assign the proper value which indexes the start address. Fixes: 719272c45b82 'x86, mm: only call early_ioremap_page_table_range_init() once' Signed-off-by: Minfei Huang Cc: tony.luck@intel.com Cc: wangnan0@huawei.com Cc: david.vrabel@citrix.com Reviewed-by: yinghai@kernel.org Link: http://lkml.kernel.org/r/1436703522-29552-1-git-send-email-mhuang@redhat.com Signed-off-by: Thomas Gleixner --- arch/x86/mm/init_32.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch') diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index c8140e12816a..c23ab1ee3a9a 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -137,6 +137,7 @@ page_table_range_init_count(unsigned long start, unsigned long end) vaddr = start; pgd_idx = pgd_index(vaddr); + pmd_idx = pmd_index(vaddr); for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd_idx++) { for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); -- cgit v1.2.3 From 8c7ea50c010b2f1e006ad37c43f98202a31de2cb Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Thu, 9 Jul 2015 17:28:16 -0700 Subject: x86/mm, asm-generic: Add IOMMU ioremap_uc() variant default We currently have no safe way of currently defining architecture agnostic IOMMU ioremap_*() variants. The trend is for folks to *assume* that ioremap_nocache() should be the default everywhere and then add this mapping on each architectures -- this is not correct today for a variety of reasons. We have two options: 1) Sit and wait for every architecture in Linux to get a an ioremap_*() variant defined before including it upstream. 2) Gather consensus on a safe architecture agnostic ioremap_*() default. Approach 1) introduces development latencies, and since 2) will take time and work on clarifying semantics the only remaining sensible thing to do to avoid issues is returning NULL on ioremap_*() variants. In order for this to work we must have all architectures declare their own ioremap_*() variants as defined. This will take some work, do this for ioremp_uc() to set the example as its only currently implemented on x86. Document all this. We only provide implementation support for ioremap_uc() as the other ioremap_*() variants are well defined all over the kernel for other architectures already. Signed-off-by: Luis R. Rodriguez Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: arnd@arndb.de Cc: benh@kernel.crashing.org Cc: bp@suse.de Cc: dan.j.williams@intel.com Cc: geert@linux-m68k.org Cc: hch@lst.de Cc: hmh@hmh.eng.br Cc: jgross@suse.com Cc: linux-mm@kvack.org Cc: luto@amacapital.net Cc: mpe@ellerman.id.au Cc: mst@redhat.com Cc: ralf@linux-mips.org Cc: ross.zwisler@linux.intel.com Cc: stefan.bader@canonical.com Cc: tj@kernel.org Cc: tomi.valkeinen@ti.com Cc: toshi.kani@hp.com Link: http://lkml.kernel.org/r/1436488096-3165-1-git-send-email-mcgrof@do-not-panic.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/io.h | 2 ++ include/asm-generic/io.h | 30 +++++++++++++++++++++++++++++- 2 files changed, 31 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 83ec9b1d77cc..de25aad07853 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -180,6 +180,8 @@ static inline unsigned int isa_virt_to_bus(volatile void *address) */ extern void __iomem *ioremap_nocache(resource_size_t offset, unsigned long size); extern void __iomem *ioremap_uc(resource_size_t offset, unsigned long size); +#define ioremap_uc ioremap_uc + extern void __iomem *ioremap_cache(resource_size_t offset, unsigned long size); extern void __iomem *ioremap_prot(resource_size_t offset, unsigned long size, unsigned long prot_val); diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h index f56094cfdeff..eed3bbe88c8a 100644 --- a/include/asm-generic/io.h +++ b/include/asm-generic/io.h @@ -736,6 +736,35 @@ static inline void *phys_to_virt(unsigned long address) } #endif +/** + * DOC: ioremap() and ioremap_*() variants + * + * If you have an IOMMU your architecture is expected to have both ioremap() + * and iounmap() implemented otherwise the asm-generic helpers will provide a + * direct mapping. + * + * There are ioremap_*() call variants, if you have no IOMMU we naturally will + * default to direct mapping for all of them, you can override these defaults. + * If you have an IOMMU you are highly encouraged to provide your own + * ioremap variant implementation as there currently is no safe architecture + * agnostic default. To avoid possible improper behaviour default asm-generic + * ioremap_*() variants all return NULL when an IOMMU is available. If you've + * defined your own ioremap_*() variant you must then declare your own + * ioremap_*() variant as defined to itself to avoid the default NULL return. + */ + +#ifdef CONFIG_MMU + +#ifndef ioremap_uc +#define ioremap_uc ioremap_uc +static inline void __iomem *ioremap_uc(phys_addr_t offset, size_t size) +{ + return NULL; +} +#endif + +#else /* !CONFIG_MMU */ + /* * Change "struct page" to physical address. * @@ -743,7 +772,6 @@ static inline void *phys_to_virt(unsigned long address) * you'll need to provide your own definitions. */ -#ifndef CONFIG_MMU #ifndef ioremap #define ioremap ioremap static inline void __iomem *ioremap(phys_addr_t offset, size_t size) -- cgit v1.2.3 From 4c73e8926623ca0f64c2c6111289ab8096fa647a Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Tue, 28 Jul 2015 20:17:13 +0200 Subject: arch/*/io.h: Add ioremap_uc() to all architectures This adds ioremap_uc() only for architectures that do not include asm-generic.h/io.h as that already provides a default definition for them for both cases where you have CONFIG_MMU and you do not, and because of this, the number of architectures this patch address is less than the architectures that the ioremap_wt() patch addressed, "arch/*/io.h: Add ioremap_wt() to all architectures"). In order to reduce the number of architectures we have to modify by adding new architecture IO APIs we'll have to review the architectures in this patch, see why they can't add asm-generic.h/io.h or issues that would be created by doing so and then spread a consistent inclusion of this header towards the end of their own header. For instance arch/metag includes the asm-generic/io.h *before* the ioremap*() definitions, this should be the other way around but only once we have guard wrappers for the non-MMU case also for asm-generic/io.h. Reported-by: Stephen Rothwell Signed-off-by: Luis R. Rodriguez Cc: Abhilash Kesavan Cc: Benjamin Herrenschmidt Cc: Borislav Petkov Cc: Chris Metcalf Cc: David Howells Cc: Fengguang Wu Cc: Geert Uytterhoeven Cc: Greg Kroah-Hartman Cc: Greg Ungerer Cc: Guenter Roeck Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Koichi Yasutake Cc: Kyle McMartin Cc: Linus Torvalds Cc: Michael Ellerman Cc: Paul Mackerras Cc: Peter Hurley Cc: Peter Zijlstra Cc: Rob Herring Cc: Thomas Gleixner Cc: Toshi Kani Cc: Will Deacon Cc: linux-am33-list@redhat.com Cc: linux-arch@vger.kernel.org Cc: linux-m68k@lists.linux-m68k.org Cc: linux-sh@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/20150728181713.GB30479@wotan.suse.de Signed-off-by: Ingo Molnar --- arch/avr32/include/asm/io.h | 1 + arch/frv/include/asm/io.h | 1 + arch/m32r/include/asm/io.h | 1 + arch/m68k/include/asm/io_mm.h | 1 + arch/mn10300/include/asm/io.h | 1 + arch/powerpc/include/asm/io.h | 1 + arch/sh/include/asm/io.h | 1 + arch/tile/include/asm/io.h | 1 + 8 files changed, 8 insertions(+) (limited to 'arch') diff --git a/arch/avr32/include/asm/io.h b/arch/avr32/include/asm/io.h index e998ff5d8e1a..f855646e0db7 100644 --- a/arch/avr32/include/asm/io.h +++ b/arch/avr32/include/asm/io.h @@ -297,6 +297,7 @@ extern void __iounmap(void __iomem *addr); #define ioremap_wc ioremap_nocache #define ioremap_wt ioremap_nocache +#define ioremap_uc ioremap_nocache #define cached(addr) P1SEGADDR(addr) #define uncached(addr) P2SEGADDR(addr) diff --git a/arch/frv/include/asm/io.h b/arch/frv/include/asm/io.h index a31b63ec4930..70dfbea8c8d7 100644 --- a/arch/frv/include/asm/io.h +++ b/arch/frv/include/asm/io.h @@ -278,6 +278,7 @@ static inline void __iomem *ioremap_fullcache(unsigned long physaddr, unsigned l } #define ioremap_wc ioremap_nocache +#define ioremap_uc ioremap_nocache extern void iounmap(void volatile __iomem *addr); diff --git a/arch/m32r/include/asm/io.h b/arch/m32r/include/asm/io.h index 0c3f25ee3381..4c4982af6fbd 100644 --- a/arch/m32r/include/asm/io.h +++ b/arch/m32r/include/asm/io.h @@ -69,6 +69,7 @@ extern void iounmap(volatile void __iomem *addr); #define ioremap_nocache(off,size) ioremap(off,size) #define ioremap_wc ioremap_nocache #define ioremap_wt ioremap_nocache +#define ioremap_uc ioremap_nocache /* * IO bus memory addresses are also 1:1 with the physical address diff --git a/arch/m68k/include/asm/io_mm.h b/arch/m68k/include/asm/io_mm.h index 618c85d3c786..a0fce34029b3 100644 --- a/arch/m68k/include/asm/io_mm.h +++ b/arch/m68k/include/asm/io_mm.h @@ -467,6 +467,7 @@ static inline void __iomem *ioremap_nocache(unsigned long physaddr, unsigned lon { return __ioremap(physaddr, size, IOMAP_NOCACHE_SER); } +#define ioremap_uc ioremap_nocache static inline void __iomem *ioremap_wt(unsigned long physaddr, unsigned long size) { diff --git a/arch/mn10300/include/asm/io.h b/arch/mn10300/include/asm/io.h index 07c5b4a3903b..62189353d2f6 100644 --- a/arch/mn10300/include/asm/io.h +++ b/arch/mn10300/include/asm/io.h @@ -283,6 +283,7 @@ static inline void __iomem *ioremap_nocache(unsigned long offset, unsigned long #define ioremap_wc ioremap_nocache #define ioremap_wt ioremap_nocache +#define ioremap_uc ioremap_nocache static inline void iounmap(void __iomem *addr) { diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h index a8d2ef30d473..5879fde56f3c 100644 --- a/arch/powerpc/include/asm/io.h +++ b/arch/powerpc/include/asm/io.h @@ -721,6 +721,7 @@ extern void __iomem *ioremap_prot(phys_addr_t address, unsigned long size, unsigned long flags); extern void __iomem *ioremap_wc(phys_addr_t address, unsigned long size); #define ioremap_nocache(addr, size) ioremap((addr), (size)) +#define ioremap_uc(addr, size) ioremap((addr), (size)) extern void iounmap(volatile void __iomem *addr); diff --git a/arch/sh/include/asm/io.h b/arch/sh/include/asm/io.h index 728c4c571f40..93ec9066dbef 100644 --- a/arch/sh/include/asm/io.h +++ b/arch/sh/include/asm/io.h @@ -368,6 +368,7 @@ static inline int iounmap_fixed(void __iomem *addr) { return -EINVAL; } #endif #define ioremap_nocache ioremap +#define ioremap_uc ioremap #define iounmap __iounmap /* diff --git a/arch/tile/include/asm/io.h b/arch/tile/include/asm/io.h index dc61de15c1f9..322b5fe94781 100644 --- a/arch/tile/include/asm/io.h +++ b/arch/tile/include/asm/io.h @@ -55,6 +55,7 @@ extern void iounmap(volatile void __iomem *addr); #define ioremap_nocache(physaddr, size) ioremap(physaddr, size) #define ioremap_wc(physaddr, size) ioremap(physaddr, size) #define ioremap_wt(physaddr, size) ioremap(physaddr, size) +#define ioremap_uc(physaddr, size) ioremap(physaddr, size) #define ioremap_fullcache(physaddr, size) ioremap(physaddr, size) #define mmiowb() -- cgit v1.2.3 From d5dc861bd601b546ae6b36af54485142cca36a5e Mon Sep 17 00:00:00 2001 From: Toshi Kani Date: Wed, 22 Jul 2015 12:06:11 -0600 Subject: x86/mm/pat: Add comments to cachemode translation tables Add comments to the cachemode translation tables to clarify that the default values are set as minimal supported mode, which are necessary to handle WC and WT fallback to UC- when they are not enabled. Signed-off-by: Toshi Kani Cc: Jan Beulich Cc: Borislav Petkov Cc: Ingo Molnar Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1437588371-28223-1-git-send-email-toshi.kani@hp.com Signed-off-by: Thomas Gleixner --- arch/x86/mm/init.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch') diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 8533b46e6bee..1d8a83df153a 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -30,8 +30,11 @@ /* * Tables translating between page_cache_type_t and pte encoding. * - * Minimal supported modes are defined statically, they are modified - * during bootup if more supported cache modes are available. + * The default values are defined statically as minimal supported mode; + * WC and WT fall back to UC-. pat_init() updates these values to support + * more cache modes, WC and WT, when it is safe to do so. See pat_init() + * for the details. Note, __early_ioremap() used during early boot-time + * takes pgprot_t (pte encoding) and does not use these tables. * * Index into __cachemode2pte_tbl[] is the cachemode. * -- cgit v1.2.3 From 8f45fe441a9836011672436ef007654969b28ccc Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Mon, 24 Aug 2015 19:34:54 -0400 Subject: x86/mm/pat: Make mm/pageattr[-test].c explicitly non-modular The file pageattr.c is obj-y and it includes pageattr-test.c based on CPA_DEBUG (a bool), meaning that no code here is currently being built as a module by anyone. Lets remove the couple traces of modularity so that when reading the code there is no doubt it is builtin-only. Since module_init translates to device_initcall in the non-modular case, the init ordering remains unchanged with this commit. Signed-off-by: Paul Gortmaker Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1440459295-21814-3-git-send-email-paul.gortmaker@windriver.com Signed-off-by: Ingo Molnar --- arch/x86/mm/pageattr-test.c | 4 ++-- arch/x86/mm/pageattr.c | 1 - 2 files changed, 2 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/x86/mm/pageattr-test.c b/arch/x86/mm/pageattr-test.c index 8ff686aa7e8c..5f169d5d76a8 100644 --- a/arch/x86/mm/pageattr-test.c +++ b/arch/x86/mm/pageattr-test.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include @@ -256,5 +257,4 @@ static int start_pageattr_test(void) return 0; } - -module_init(start_pageattr_test); +device_initcall(start_pageattr_test); diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 727158cb3b3c..2c44c0792301 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -4,7 +4,6 @@ */ #include #include -#include #include #include #include -- cgit v1.2.3 From 13fe86f465b72fc9328d4f5ebc33223c011852ae Mon Sep 17 00:00:00 2001 From: Paul Gortmaker Date: Mon, 24 Aug 2015 19:34:55 -0400 Subject: x86/mm: Make kernel/check.c explicitly non-modular The Kconfig currently controlling compilation of this code is: arch/x86/Kconfig:config X86_CHECK_BIOS_CORRUPTION arch/x86/Kconfig: bool "Check for low memory corruption" ...meaning that it currently is not being built as a module by anyone. Lets remove the couple traces of modularity so that when reading the code there is no doubt it is builtin-only. Since module_init translates to device_initcall in the non-modular case, the init ordering remains unchanged with this commit. Signed-off-by: Paul Gortmaker Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1440459295-21814-4-git-send-email-paul.gortmaker@windriver.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/check.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) (limited to 'arch') diff --git a/arch/x86/kernel/check.c b/arch/x86/kernel/check.c index 83a7995625a6..f40cfd12ba66 100644 --- a/arch/x86/kernel/check.c +++ b/arch/x86/kernel/check.c @@ -1,4 +1,4 @@ -#include +#include #include #include #include @@ -162,6 +162,5 @@ static int start_periodic_check_for_corruption(void) schedule_delayed_work(&bios_check_work, 0); return 0; } - -module_init(start_periodic_check_for_corruption); +device_initcall(start_periodic_check_for_corruption); -- cgit v1.2.3 From ee03c5868e74847ba0bd1e6dccbbe26e6504466d Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Wed, 26 Aug 2015 16:34:10 -0700 Subject: s390/io: Add pci_iomap_wc() and pci_iomap_wc_range() The following commit: 1b3d4200c1e0 ("PCI: Add pci_iomap_wc() variants") Introduced pci_iomap_wc() variants but broke the s390 build, because s390 requires its own implementation of pcio_iomap*() calls. The reason for that is that: "BAR spaces are not disjunctive on s390 so we need the bar parameter of pci_iomap to find the corresponding device and create the mapping cookie" so it has its own lookup/lock solution and it does not include asm-generic/pci_iomap.h. Since it currenty maps ioremap_wc() to ioremap_nocache() and that's the architecture default we can easily just map the wc calls to the default calls as well. Reported-by: kbuild test robot Signed-off-by: Luis R. Rodriguez Cc: Andrew Morton Cc: Borislav Petkov Cc: Fengguang Wu Cc: Frank Blaschka Cc: Guenter Roeck Cc: Heiko Carstens Cc: Jean-Christophe Plagniol-Villard Cc: Linus Torvalds Cc: Martin Schwidefsky Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thierry Reding Cc: Thomas Gleixner Cc: Tomi Valkeinen Cc: Toshi Kani Cc: Will Deacon Cc: linux-fbdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linux390@de.ibm.com Link: http://lkml.kernel.org/r/1440632050-23648-1-git-send-email-mcgrof@do-not-panic.com Signed-off-by: Ingo Molnar --- arch/s390/include/asm/io.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch') diff --git a/arch/s390/include/asm/io.h b/arch/s390/include/asm/io.h index cb5fdf3a78fc..437e9af96688 100644 --- a/arch/s390/include/asm/io.h +++ b/arch/s390/include/asm/io.h @@ -57,6 +57,8 @@ static inline void ioport_unmap(void __iomem *p) */ #define pci_iomap pci_iomap #define pci_iounmap pci_iounmap +#define pci_iomap_wc pci_iomap +#define pci_iomap_wc_range pci_iomap_range #define memcpy_fromio(dst, src, count) zpci_memcpy_fromio(dst, src, count) #define memcpy_toio(dst, src, count) zpci_memcpy_toio(dst, src, count) -- cgit v1.2.3 From 2baa891e42d84159b693eadd44f6fe1486285bdc Mon Sep 17 00:00:00 2001 From: "Luis R. Rodriguez" Date: Mon, 24 Aug 2015 12:13:33 -0700 Subject: x86/mm/mtrr: Remove kernel internal MTRR interfaces: unexport mtrr_add() and mtrr_del() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The effort to replace mtrr_add() with architecture agnostic arch_phys_wc_add() is complete, this will ensure write-combining implementations (PAT on x86) is taken advantage instead of using MTRR. With the effort done now, hide direct MTRR access for drivers. The legacy user-space /proc/mtrr ABI is not affected. Update x86 documentation on MTRR to reflect the completion of the phasing out of direct access to MTRR, also add a note on platform firmware code use of MTRRs based on the obituary discussion of MTRRs on Linux [0]. [0] http://lkml.kernel.org/r/1438991330.3109.196.camel@hp.com Signed-off-by: Luis R. Rodriguez Cc: Cc: Andy Lutomirski Cc: Andy Walls Cc: Antonino Daplas Cc: Borislav Petkov Cc: Daniel Vetter Cc: Dave Airlie Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Doug Ledford Cc: H. Peter Anvin Cc: Jean-Christophe Plagniol-Villard Cc: Juergen Gross Cc: Linus Torvalds Cc: Mel Gorman Cc: Peter Zijlstra Cc: Suresh Siddha Cc: Thomas Gleixner Cc: Tomi Valkeinen Cc: Toshi Kani Cc: Ville Syrjälä Cc: Vlastimil Babka Cc: airlied@linux.ie Cc: benh@kernel.crashing.org Cc: bhelgaas@google.com Cc: dan.j.williams@intel.com Cc: konrad.wilk@oracle.com Cc: linux-fbdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linux-media@vger.kernel.org Cc: mst@redhat.com Cc: netdev@vger.kernel.org Cc: vinod.koul@intel.com Cc: xen-devel@lists.xensource.com Link: http://lkml.kernel.org/r/1440443613-13696-12-git-send-email-mcgrof@do-not-panic.com Signed-off-by: Ingo Molnar --- Documentation/x86/mtrr.txt | 20 ++++++++++++++++---- arch/x86/kernel/cpu/mtrr/main.c | 2 -- 2 files changed, 16 insertions(+), 6 deletions(-) (limited to 'arch') diff --git a/Documentation/x86/mtrr.txt b/Documentation/x86/mtrr.txt index 860bc3adc223..dc3e703913ac 100644 --- a/Documentation/x86/mtrr.txt +++ b/Documentation/x86/mtrr.txt @@ -6,10 +6,22 @@ Luis R. Rodriguez - April 9, 2015 =============================================================================== Phasing out MTRR use -MTRR use is replaced on modern x86 hardware with PAT. Over time the only type -of effective MTRR that is expected to be supported will be for write-combining. -As MTRR use is phased out device drivers should use arch_phys_wc_add() to make -MTRR effective on non-PAT systems while a no-op on PAT enabled systems. +MTRR use is replaced on modern x86 hardware with PAT. Direct MTRR use by +drivers on Linux is now completely phased out, device drivers should use +arch_phys_wc_add() in combination with ioremap_wc() to make MTRR effective on +non-PAT systems while a no-op but equally effective on PAT enabled systems. + +Even if Linux does not use MTRRs directly, some x86 platform firmware may still +set up MTRRs early before booting the OS. They do this as some platform +firmware may still have implemented access to MTRRs which would be controlled +and handled by the platform firmware directly. An example of platform use of +MTRRs is through the use of SMI handlers, one case could be for fan control, +the platform code would need uncachable access to some of its fan control +registers. Such platform access does not need any Operating System MTRR code in +place other than mtrr_type_lookup() to ensure any OS specific mapping requests +are aligned with platform MTRR setup. If MTRRs are only set up by the platform +firmware code though and the OS does not make any specific MTRR mapping +requests mtrr_type_lookup() should always return MTRR_TYPE_INVALID. For details refer to Documentation/x86/pat.txt. diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c index e7ed0d8ebacb..f891b4750f04 100644 --- a/arch/x86/kernel/cpu/mtrr/main.c +++ b/arch/x86/kernel/cpu/mtrr/main.c @@ -448,7 +448,6 @@ int mtrr_add(unsigned long base, unsigned long size, unsigned int type, return mtrr_add_page(base >> PAGE_SHIFT, size >> PAGE_SHIFT, type, increment); } -EXPORT_SYMBOL(mtrr_add); /** * mtrr_del_page - delete a memory type region @@ -537,7 +536,6 @@ int mtrr_del(int reg, unsigned long base, unsigned long size) return -EINVAL; return mtrr_del_page(reg, base >> PAGE_SHIFT, size >> PAGE_SHIFT); } -EXPORT_SYMBOL(mtrr_del); /** * arch_phys_wc_add - add a WC MTRR and handle errors if PAT is unavailable -- cgit v1.2.3