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2009-08-21x86, mtrr: make mtrr_aps_delayed_init static boolH. Peter Anvin
mtr_aps_delayed_init was declared u32 and made global, but it only ever takes boolean values and is only ever used in arch/x86/kernel/cpu/mtrr/main.c. Declare it "static bool" and remove external references. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Suresh Siddha <suresh.b.siddha@intel.com>
2009-08-21x86, pat/mtrr: Rendezvous all the cpus for MTRR/PAT initSuresh Siddha
SDM Vol 3a section titled "MTRR considerations in MP systems" specifies the need for synchronizing the logical cpu's while initializing/updating MTRR. Currently Linux kernel does the synchronization of all cpu's only when a single MTRR register is programmed/updated. During an AP online (during boot/cpu-online/resume) where we initialize all the MTRR/PAT registers, we don't follow this synchronization algorithm. This can lead to scenarios where during a dynamic cpu online, that logical cpu is initializing MTRR/PAT with cache disabled (cr0.cd=1) etc while other logical HT sibling continue to run (also with cache disabled because of cr0.cd=1 on its sibling). Starting from Westmere, VMX transitions with cr0.cd=1 don't work properly (because of some VMX performance optimizations) and the above scenario (with one logical cpu doing VMX activity and another logical cpu coming online) can result in system crash. Fix the MTRR initialization by doing rendezvous of all the cpus. During boot and resume, we delay the MTRR/PAT init for APs till all the logical cpu's come online and the rendezvous process at the end of AP's bringup, will initialize the MTRR/PAT for all AP's. For dynamic single cpu online, we synchronize all the logical cpus and do the MTRR/PAT init on the AP that is coming online. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-07-04x86: Clean up mtrr/main.cJaswinder Singh Rajput
Fix following trivial style problems: ERROR: trailing whitespace X 25 WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h> WARNING: Use #include <linux/kvm_para.h> instead of <asm/kvm_para.h> ERROR: do not initialise externals to 0 or NULL X 2 ERROR: "foo * bar" should be "foo *bar" X 5 ERROR: do not use assignment in if condition X 2 WARNING: line over 80 characters X 8 ERROR: return is not a function, parentheses are not required WARNING: braces {} are not necessary for any arm of this statement ERROR: space required before the open parenthesis '(' X 2 ERROR: open brace '{' following function declarations go on the next line ERROR: space required after that ',' (ctx:VxV) X 8 ERROR: space required before the open parenthesis '(' X 3 ERROR: else should follow close brace '}' WARNING: space prohibited between function name and open parenthesis '(' WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable X 2 Also use pr_debug and pr_warning where possible. total: 50 errors, 14 warnings arch/x86/kernel/cpu/mtrr/main.o: text data bss dec hex filename 3668 116 4156 7940 1f04 main.o.before 3668 116 4156 7940 1f04 main.o.after md5: e01af2fd28deef77c8d01e71acfbd365 main.o.before.asm e01af2fd28deef77c8d01e71acfbd365 main.o.after.asm Suggested-by: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <20090703164225.GA21447@elte.hu> Cc: Avi Kivity <avi@redhat.com> # Avi, please have a look at the kvm_para.h bit [ More cleanups ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-15x86, mtrr: replace MTRRcap_MSR with msr-index's MSR_MTRRcapJaswinder Singh Rajput
Use standard msr-index.h's MSR declaration and no need to declare again. [ Impact: cleanup, no object code change ] Signed-off-by: Jaswinder Singh Rajput <jaswinderrajput@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-03-17x86: MTRR workaround for system with stange var MTRRsYinghai Lu
Impact: don't trim e820 according to wrong mtrr Ozan reports that his server emits strange warning. it turns out the BIOS sets the MTRRs incorrectly. Ignore those strange ranges, and don't trim e820, just emit one warning about BIOS Reported-by: Ozan Çağlayan <ozan@pardus.org.tr> Signed-off-by: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <49BEE1E7.7020706@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-13x86: separate mtrr cleanup/mtrr_e820 trim to separate fileYinghai Lu
Impact: cleanup mtrr main.c is too big, seperate mtrr cleanup and mtrr e820 trim code to another file. Signed-off-by: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <49B87C7B.80809@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-13x86: print out mtrr_range_state when user specify sizeYinghai Lu
Impact: print more debug info Keep it consistent with autodetect version. Signed-off-by: Yinghai Lu <yinghai@kernel.org> LKML-Reference: <49B87C0A.4010105@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-29x86: tone down mtrr_trim_uncached_memory() warningIngo Molnar
kerneloops.org is reporting a lot of these warnings that come due to vmware not setting up any MTRRs for emulated CPUs: | Reported 709 times (14696 total reports) | BIOS bug (often in VMWare) where the MTRR's are set up incorrectly | or not at all | | This warning was last seen in version 2.6.29-rc2-git1, and first | seen in 2.6.24. | | More info: | http://www.kerneloops.org/searchweek.php?search=mtrr_trim_uncached_memory Keep a one-liner KERN_INFO about it - so that we have so notice if empty MTRRs are caused by native hardware/BIOS weirdness. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-02Merge branch 'linus' into x86/cleanupsIngo Molnar
Conflicts: arch/x86/kernel/reboot.c
2008-12-31x86: Rename mtrr_state struct and macro namesSheng Yang
Prepare for exporting them. Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
2008-12-27Merge branch 'x86/core' into x86/cleanupsIngo Molnar
2008-12-25x86: remove impossible test in mtrr/main.cRusty Russell
Impact: cleanup enable_mtrr_cleanup is static, and is never set to anything but 0 or 1. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-28x86: break up mtrr_cleanup() into several small functions.Yinghai Lu
Ingo said mtrr_cleanup() is big and ugly. so break it up into more functions and make it more readable. Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-06Merge branches 'x86/alternatives', 'x86/cleanups', 'x86/commandline', ↵Ingo Molnar
'x86/crashdump', 'x86/debug', 'x86/defconfig', 'x86/doc', 'x86/exports', 'x86/fpu', 'x86/gart', 'x86/idle', 'x86/mm', 'x86/mtrr', 'x86/nmi-watchdog', 'x86/oprofile', 'x86/paravirt', 'x86/reboot', 'x86/sparse-fixes', 'x86/tsc', 'x86/urgent' and 'x86/vmalloc' into x86-v28-for-linus-phase1
2008-10-06Merge branch 'x86/prototypes' into x86-v28-for-linus-phase1Ingo Molnar
Conflicts: arch/x86/kernel/process_32.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-04x86: mtrr_cleanup: treat WRPROT as UNCACHEABLEYinghai Lu
For the purpose of MTRR canonicalization, treat WRPROT as UNCACHEABLE. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-04x86: mtrr_cleanup: first 1M may be covered in var mtrrsYinghai Lu
The first 1M is don't care when it comes to the variables MTRRs. Cover it as WB as a heuristic approximation; this is generally what we want to minimize the number of registers. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-04x86: mtrr_cleanup: print out correct type v2Yinghai Lu
Print out the correct type when the Write Protected (WP) type is seen. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-03x86, debug: mtrr_cleanup print out var mtrr before change itYinghai Lu
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-03x86: mtrr_cleanup try gran_size to less than 1M, v3Yinghai Lu
J.A. Magallón reported: >> Also, on a 64 bit box with 4Gb, it gives this: >> >> cicely:~# cat /proc/mtrr >> reg00: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1 >> reg01: base=0x100000000 (4096MB), size=1024MB: write-back, count=1 >> reg02: base=0x140000000 (5120MB), size= 512MB: write-back, count=1 >> reg03: base=0x160000000 (5632MB), size= 256MB: write-back, count=1 >> reg04: base=0x80000000 (2048MB), size=2048MB: uncachable, count=1 boundary handling has a problem ... fix it. Reported-by: J.A. Magallón <jamagallon@ono.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-30x86: fix typo in enable_mtrr_cleanup early parameterJ.A. Magallón
Correct typo for 'enable_mtrr_cleanup' early boot param name. Signed-off-by: J.A. Magallon <jamagallon@ono.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-29x86: mtrr_cleanup try gran_size to less than 1MYinghai Lu
one have gran < 1M reg00: base=0xd8000000 (3456MB), size= 128MB: uncachable, count=1 reg01: base=0xe0000000 (3584MB), size= 512MB: uncachable, count=1 reg02: base=0x00000000 ( 0MB), size=4096MB: write-back, count=1 reg03: base=0x100000000 (4096MB), size= 512MB: write-back, count=1 reg04: base=0x120000000 (4608MB), size= 128MB: write-back, count=1 reg05: base=0xd7f80000 (3455MB), size= 512KB: uncachable, count=1 will get Found optimal setting for mtrr clean up gran_size: 512K chunk_size: 2M num_reg: 7 lose RAM: 0G range0: 0000000000000000 - 00000000d8000000 Setting variable MTRR 0, base: 0GB, range: 2GB, type WB Setting variable MTRR 1, base: 2GB, range: 1GB, type WB Setting variable MTRR 2, base: 3GB, range: 256MB, type WB Setting variable MTRR 3, base: 3328MB, range: 128MB, type WB hole: 00000000d7f00000 - 00000000d7f80000 Setting variable MTRR 4, base: 3455MB, range: 512KB, type UC rangeX: 0000000100000000 - 0000000128000000 Setting variable MTRR 5, base: 4GB, range: 512MB, type WB Setting variable MTRR 6, base: 4608MB, range: 128MB, type WB so start from 64k instead of 1M Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-09-29x86: mtrr_cleanup prepare to make gran_size to less 1MYinghai Lu
make the print out right with size < 1M Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-09-29x86: mtrr_cleanup safe to get more spare regs nowYinghai Lu
Delay exit to make sure we can actually get the optimal result in as many cases as possible. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-09-28x86: mtrr_cleanup hole size should be less than half of chunk_size, v2Yinghai Lu
v2: should check with half of range0 size instead of chunk_size So don't have silly big hole. in hpa's case we could auto detect instead of adding mtrr_chunk_size in command line. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-27x86: add mtrr_cleanup_debug command lineYinghai Lu
add mtrr_cleanup_debug to print out more info about layout Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-27x86: mtrr_cleanup optimization, v2Yinghai Lu
fix hpa's t61 with 4g ram: change layout from (n - 1)*chunksize + chunk_size - NC to n*chunksize - NC Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-27x86: don't need to go to chunksize to 4GYinghai Lu
change back chunksize max to 2g otherwise will get strange layout in 2G ram system like 0 - 4g WB, 2040M - 2048M UC, 2048M - 4G NC instead of 0 - 2g WB, 2040M - 2048M UC Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-19x86: fix arch/x86/kernel/cpu/mtrr/main.c warningYinghai Lu
fix this warning reported by Andrew Morton: > arch/x86/kernel/cpu/mtrr/main.c: In function 'mtrr_bp_init': > arch/x86/kernel/cpu/mtrr/main.c:1170: warning: 'extra_remove_base' may be used uninitialized in this function the warning is bogus but the logic that prevents uninitialized use is a bit convoluted so simplify it all. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21x86: use WARN() in arch/x86/kernelArjan van de Ven
Use WARN() instead of a printk+WARN_ON() pair; this way the message becomes part of the warning section for better reporting/collection. This also allowed the folding of some if()'s into the WARN() Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: akpm@linux-foundation.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-22x86: mtrr/main.c declare range_state as staticJaswinder Singh
Signed-off-by: Jaswinder Singh <jaswinder@infradead.org>
2008-07-15Merge branch 'generic-ipi' into generic-ipi-for-linusIngo Molnar
Conflicts: arch/powerpc/Kconfig arch/s390/kernel/time.c arch/x86/kernel/apic_32.c arch/x86/kernel/cpu/perfctr-watchdog.c arch/x86/kernel/i8259_64.c arch/x86/kernel/ldt.c arch/x86/kernel/nmi_64.c arch/x86/kernel/smpboot.c arch/x86/xen/smp.c include/asm-x86/hw_irq_32.h include/asm-x86/hw_irq_64.h include/asm-x86/mach-default/irq_vectors.h include/asm-x86/mach-voyager/irq_vectors.h include/asm-x86/smp.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-08x86: rename two e820 related functionsYinghai Lu
rename update_memory_range to e820_update_range rename add_memory_region to e820_add_region to make it more clear that they are about e820 map operations. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-06-26smp_call_function: get rid of the unused nonatomic/retry argumentJens Axboe
It's never used and the comments refer to nonatomic and retry interchangably. So get rid of it. Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-05-25x86: mtrr cleanup for converting continuous to discrete layout - fix #2Yinghai Lu
disable the noisy print out. also use the one the less spare mtrr reg. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-25x86: mtrr cleanup for converting continuous to discrete - auto detect v4Yinghai Lu
Loop through mtrr chunk_size and gran_size from 1M to 2G to find out the optimal value so user does not need to add mtrr_chunk_size and mtrr_gran_size to the kernel command line. If optimal value is not found, print out all list to help select less optimal value. Add mtrr_spare_reg_nr= so user could set 2 instead of 1, if the card need more entries. v2: find the one with more spare entries v3: fix hole_basek offset v4: tight the compare between range and range_new loop stop with 4g Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Gabriel C <nix.or.die@googlemail.com> Cc: Mika Fischer <mika.fischer@zoopnet.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-05-25x86: mtrr cleanup for converting continuous to discrete layout v8 - fixYinghai Lu
v9: address format change requests by Ingo more case handling in range_to_var_with_hole Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-25x86: fix trimming e820 with MTRR holes. - fixYinghai Lu
v2: process hole then end_pfn fix update_memory_range with whole cover comparing Signed-off-by: Yinghai Lu <yinghai.lu@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-25x86: fix trimming e820 with MTRR holes.Yinghai Lu
converting MTRR layout from continous to discrete, some time could run out of MTRRs. So add gran_sizek to prevent that by dumpping small RAM piece less than gran_sizek. previous trimming only can handle highest_pfn from mtrr to end_pfn from e820. when have more than 4g RAM installed, there will be holes below 4g. so need to check ram below 4g is coverred well. need to be applied after [PATCH] x86: mtrr cleanup for converting continuous to discrete layout v7 Signed-off-by: Yinghai Lu <yinghai.lu@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-25x86: mtrr cleanup for converting continuous to discrete layout, v8Yinghai Lu
some BIOS like to use continus MTRR layout, and X driver can not add WB entries for graphical cards when 4g or more RAM installed. the patch will change MTRR to discrete. mtrr_chunk_size= could be used to have smaller continuous block to hold holes. default is 256m, could be set according to size of graphics card memory. mtrr_gran_size= could be used to send smallest mtrr block to avoid run out of MTRRs v2: fix -1 for UC checking v3: default to disable, and need use enable_mtrr_cleanup to enable this feature skip the var state change warning. remove next_basek in range_to_mtrr() v4: correct warning mask. v5: CONFIG_MTRR_SANITIZER v6: fix 1g, 2g, 512 aligment with extra hole v7: gran_sizek to prevent running out of MTRRs. v8: fix hole_basek caculation caused when removing next_basek gran_sizek using when basek is 0. need to apply [PATCH] x86: fix trimming e820 with MTRR holes. right after this one. Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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>
2008-03-21x86: trim mtrr don't close gap for resource allocation.Yinghai Lu
fix the bug reported here: http://bugzilla.kernel.org/show_bug.cgi?id=10232 use update_memory_range() instead of add_memory_range() directly to avoid closing the gap. ( the new code only affects and runs on systems where the MTRR workaround triggers. ) Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-26x86: don't print a warning when MTRR are blank and running in KVMJoerg Roedel
Inside a KVM virtual machine the MTRRs are usually blank. This confuses Linux and causes a warning message at boot. This patch removes that warning message when running Linux as a KVM guest. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-02-26x86/mtrr: fix kernel-doc missing notationRandy Dunlap
Fix mtrr kernel-doc warning: Warning(linux-2.6.24-git12//arch/x86/kernel/cpu/mtrr/main.c:677): No description found for parameter 'end_pfn' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-02-06x86: fix mttr trimmingYinghai Lu
Pavel Emelyanov reported that his networking card did not work and bisected it down to: " The commit 093af8d7f0ba3c6be1485973508584ef081e9f93 x86_32: trim memory by updating e820 broke my e1000 card: on loading driver says that e1000: probe of 0000:04:03.0 failed with error -5 and the interface doesn't appear. " on a 32-bit kernel, base will overflow when try to do PAGE_SHIFT, and highest_addr will always less 4G. So use pfn instead of address to avoid the overflow when more than 4g RAM is installed on a 32-bit kernel. Many thanks to Pavel Emelyanov for reporting and testing it. Bisected-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Tested-by: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-02-04x86: add cpu mtrr init function definitions to mtrr.hHarvey Harrison
mtrr.h was included everywhere needed. Fixes the following sparse warnings. Also, the return types in the extern definitions were incorrect. arch/x86/kernel/cpu/mtrr/amd.c:113:12: warning: symbol 'amd_init_mtrr' was not declared. Should it be static? arch/x86/kernel/cpu/mtrr/cyrix.c:268:12: warning: symbol 'cyrix_init_mtrr' was not declared. Should it be static? arch/x86/kernel/cpu/mtrr/centaur.c:218:12: warning: symbol 'centaur_init_mtrr' was not declared. Should it be static? Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-04x86: remove long dead cyrix mtrr codeHarvey Harrison
cyrix_arr_init was #if 0 all the way back to at least v2.6.12. This was the only place where arr3_protected was set to anything but zero. Eliminate this variable. Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86: improve MTRR trimming messagesIngo Molnar
improve the MTTR trimming messages and also trigger a WARN_ON() so that kerneloops.org can pick it up and categorize it. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86_32: trim memory by updating e820Yinghai Lu
when MTRRs are not covering the whole e820 table, we need to trim the RAM and need to update e820. reuse some code on 64-bit as well. here need to add early_get_cap and use it in early_cpu_detect, and move mtrr_bp_init early. The code successfully trimmed the memory map on Justin's system: from: [ 0.000000] BIOS-e820: 0000000100000000 - 000000022c000000 (usable) to: [ 0.000000] modified: 0000000100000000 - 0000000228000000 (usable) [ 0.000000] modified: 0000000228000000 - 000000022c000000 (reserved) According to Justin it makes quite a difference: | When I boot the box without any trimming it acts like a 286 or 386, | takes about 10 minutes to boot (using raptor disks). Signed-off-by: Yinghai Lu <yinghai.lu@sun.com> Tested-by: Justin Piszcz <jpiszcz@lucidpixels.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30x86, 32-bit: trim memory not covered by wb mtrrsJesse Barnes
On some machines, buggy BIOSes don't properly setup WB MTRRs to cover all available RAM, meaning the last few megs (or even gigs) of memory will be marked uncached. Since Linux tends to allocate from high memory addresses first, this causes the machine to be unusably slow as soon as the kernel starts really using memory (i.e. right around init time). This patch works around the problem by scanning the MTRRs at boot and figuring out whether the current end_pfn value (setup by early e820 code) goes beyond the highest WB MTRR range, and if so, trimming it to match. A fairly obnoxious KERN_WARNING is printed too, letting the user know that not all of their memory is available due to a likely BIOS bug. Something similar could be done on i386 if needed, but the boot ordering would be slightly different, since the MTRR code on i386 depends on the boot_cpu_data structure being setup. This patch fixes a bug in the last patch that caused the code to run on non-Intel machines (AMD machines apparently don't need it and it's untested on other non-Intel machines, so best keep it off). Further enhancements and fixes from: Yinghai Lu <Yinghai.Lu@Sun.COM> Andi Kleen <ak@suse.de> Signed-off-by: Jesse Barnes <jesse.barnes@intel.com> Tested-by: Justin Piszcz <jpiszcz@lucidpixels.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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