linux-toradex.git/arch/x86/kernel/trampoline.c, branch v3.2.18 Linux kernel for Apalis and Colibri modules x86, trampoline: Common infrastructure for low memory trampolines 2011-02-18T05:02:43+00:00 H. Peter Anvin hpa@linux.intel.com 2011-02-14T23:34:57+00:00 4822b7fc6d4870685a9feadfc348d48f5e47460a Common infrastructure for low memory trampolines. This code installs the trampolines permanently in low memory very early. It also permits multiple pieces of code to be used for this purpose. This code also introduces a standard infrastructure for computing symbol addresses in the trampoline code. The only change to the actual SMP trampolines themselves is that the 64-bit trampoline has been made reusable -- the previous version would overwrite the code with a status variable; this moves the status variable to a separate location. Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> LKML-Reference: <4D5DFBE4.7090104@intel.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Matthieu Castet <castet.matthieu@free.fr> Cc: Stephen Rothwell <sfr@canb.auug.org.au> 
Common infrastructure for low memory trampolines.  This code installs
the trampolines permanently in low memory very early.  It also permits
multiple pieces of code to be used for this purpose.

This code also introduces a standard infrastructure for computing
symbol addresses in the trampoline code.

The only change to the actual SMP trampolines themselves is that the
64-bit trampoline has been made reusable -- the previous version would
overwrite the code with a status variable; this moves the status
variable to a separate location.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LKML-Reference: <4D5DFBE4.7090104@intel.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Matthieu Castet <castet.matthieu@free.fr>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Merge branch 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-10-23T03:37:50+00:00 Linus Torvalds torvalds@linux-foundation.org 2010-10-23T03:37:50+00:00 10f2a2b0f68abf39c06cf519cbc1740fa50f900b * 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86-32, mm: Add an initial page table for core bootstrapping 
* 'x86-trampoline-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86-32, mm: Add an initial page table for core bootstrapping
x86-32, mm: Add an initial page table for core bootstrapping 2010-10-20T21:23:55+00:00 Borislav Petkov bp@alien8.de 2010-08-28T13:58:33+00:00 b40827fa7268fda8a62490728a61c2856f33830b This patch adds an initial page table with low mappings used exclusively for booting APs/resuming after ACPI suspend/machine restart. After this, there's no need to add low mappings to swapper_pg_dir and zap them later or create own swsusp PGD page solely for ACPI sleep needs - we have initial_page_table for that. Signed-off-by: Borislav Petkov <bp@alien8.de> LKML-Reference: <20101020070526.GA9588@liondog.tnic> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> 
This patch adds an initial page table with low mappings used exclusively
for booting APs/resuming after ACPI suspend/machine restart. After this,
there's no need to add low mappings to swapper_pg_dir and zap them later
or create own swsusp PGD page solely for ACPI sleep needs - we have
initial_page_table for that.

Signed-off-by: Borislav Petkov <bp@alien8.de>
LKML-Reference: <20101020070526.GA9588@liondog.tnic>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Merge commit 'v2.6.36-rc7' into core/memblock 2010-10-08T07:15:00+00:00 Ingo Molnar mingo@elte.hu 2010-10-08T07:14:51+00:00 153db80f8cf74e8700cac96305b6c0b92918f17c Merge reason: Update from -rc3 to -rc7. Signed-off-by: Ingo Molnar <mingo@elte.hu> 
Merge reason: Update from -rc3 to -rc7.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Merge commit 'v2.6.36-rc3' into x86/memblock 2010-08-31T07:45:46+00:00 Ingo Molnar mingo@elte.hu 2010-08-31T07:45:21+00:00 daab7fc734a53fdeaf844b7c03053118ad1769da Conflicts: arch/x86/kernel/trampoline.c mm/memblock.c Merge reason: Resolve the conflicts, update to latest upstream. Signed-off-by: Ingo Molnar <mingo@elte.hu> 
Conflicts:
	arch/x86/kernel/trampoline.c
	mm/memblock.c

Merge reason: Resolve the conflicts, update to latest upstream.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
x86, memblock: Replace e820_/_early string with memblock_ 2010-08-27T18:13:47+00:00 Yinghai Lu yinghai@kernel.org 2010-08-25T20:39:17+00:00 a9ce6bc15100023b411f8117e53a016d61889800 1.include linux/memblock.h directly. so later could reduce e820.h reference. 2 this patch is done by sed scripts mainly -v2: use MEMBLOCK_ERROR instead of -1ULL or -1UL Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: H. Peter Anvin <hpa@zytor.com> 
1.include linux/memblock.h directly. so later could reduce e820.h reference.
2 this patch is done by sed scripts mainly

-v2: use MEMBLOCK_ERROR instead of -1ULL or -1UL

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
x86, mm: Fix CONFIG_VMSPLIT_1G and 2G_OPT trampoline 2010-08-25T06:05:17+00:00 Hugh Dickins hughd@google.com 2010-08-25T05:44:12+00:00 b7d460897739e02f186425b7276e3fdb1595cea7 rc2 kernel crashes when booting second cpu on this CONFIG_VMSPLIT_2G_OPT laptop: whereas cloning from kernel to low mappings pgd range does need to limit by both KERNEL_PGD_PTRS and KERNEL_PGD_BOUNDARY, cloning kernel pgd range itself must not be limited by the smaller KERNEL_PGD_BOUNDARY. Signed-off-by: Hugh Dickins <hughd@google.com> LKML-Reference: <alpine.LSU.2.00.1008242235120.2515@sister.anvils> Signed-off-by: H. Peter Anvin <hpa@zytor.com> 
rc2 kernel crashes when booting second cpu on this CONFIG_VMSPLIT_2G_OPT
laptop: whereas cloning from kernel to low mappings pgd range does need
to limit by both KERNEL_PGD_PTRS and KERNEL_PGD_BOUNDARY, cloning kernel
pgd range itself must not be limited by the smaller KERNEL_PGD_BOUNDARY.

Signed-off-by: Hugh Dickins <hughd@google.com>
LKML-Reference: <alpine.LSU.2.00.1008242235120.2515@sister.anvils>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
x86-32: Separate 1:1 pagetables from swapper_pg_dir 2010-08-18T16:17:20+00:00 Joerg Roedel joerg.roedel@amd.com 2010-08-16T12:38:33+00:00 fd89a137924e0710078c3ae855e7cec1c43cb845 This patch fixes machine crashes which occur when heavily exercising the CPU hotplug codepaths on a 32-bit kernel. These crashes are caused by AMD Erratum 383 and result in a fatal machine check exception. Here's the scenario: 1. On 32-bit, the swapper_pg_dir page table is used as the initial page table for booting a secondary CPU. 2. To make this work, swapper_pg_dir needs a direct mapping of physical memory in it (the low mappings). By adding those low, large page (2M) mappings (PAE kernel), we create the necessary conditions for Erratum 383 to occur. 3. Other CPUs which do not participate in the off- and onlining game may use swapper_pg_dir while the low mappings are present (when leave_mm is called). For all steps below, the CPU referred to is a CPU that is using swapper_pg_dir, and not the CPU which is being onlined. 4. The presence of the low mappings in swapper_pg_dir can result in TLB entries for addresses below __PAGE_OFFSET to be established speculatively. These TLB entries are marked global and large. 5. When the CPU with such TLB entry switches to another page table, this TLB entry remains because it is global. 6. The process then generates an access to an address covered by the above TLB entry but there is a permission mismatch - the TLB entry covers a large global page not accessible to userspace. 7. Due to this permission mismatch a new 4kb, user TLB entry gets established. Further, Erratum 383 provides for a small window of time where both TLB entries are present. This results in an uncorrectable machine check exception signalling a TLB multimatch which panics the machine. There are two ways to fix this issue: 1. Always do a global TLB flush when a new cr3 is loaded and the old page table was swapper_pg_dir. I consider this a hack hard to understand and with performance implications 2. Do not use swapper_pg_dir to boot secondary CPUs like 64-bit does. This patch implements solution 2. It introduces a trampoline_pg_dir which has the same layout as swapper_pg_dir with low_mappings. This page table is used as the initial page table of the booting CPU. Later in the bringup process, it switches to swapper_pg_dir and does a global TLB flush. This fixes the crashes in our test cases. -v2: switch to swapper_pg_dir right after entering start_secondary() so that we are able to access percpu data which might not be mapped in the trampoline page table. Signed-off-by: Joerg Roedel <joerg.roedel@amd.com> LKML-Reference: <20100816123833.GB28147@aftab> Signed-off-by: Borislav Petkov <borislav.petkov@amd.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com> 
This patch fixes machine crashes which occur when heavily exercising the
CPU hotplug codepaths on a 32-bit kernel. These crashes are caused by
AMD Erratum 383 and result in a fatal machine check exception. Here's
the scenario:

1. On 32-bit, the swapper_pg_dir page table is used as the initial page
table for booting a secondary CPU.

2. To make this work, swapper_pg_dir needs a direct mapping of physical
memory in it (the low mappings). By adding those low, large page (2M)
mappings (PAE kernel), we create the necessary conditions for Erratum
383 to occur.

3. Other CPUs which do not participate in the off- and onlining game may
use swapper_pg_dir while the low mappings are present (when leave_mm is
called). For all steps below, the CPU referred to is a CPU that is using
swapper_pg_dir, and not the CPU which is being onlined.

4. The presence of the low mappings in swapper_pg_dir can result
in TLB entries for addresses below __PAGE_OFFSET to be established
speculatively. These TLB entries are marked global and large.

5. When the CPU with such TLB entry switches to another page table, this
TLB entry remains because it is global.

6. The process then generates an access to an address covered by the
above TLB entry but there is a permission mismatch - the TLB entry
covers a large global page not accessible to userspace.

7. Due to this permission mismatch a new 4kb, user TLB entry gets
established. Further, Erratum 383 provides for a small window of time
where both TLB entries are present. This results in an uncorrectable
machine check exception signalling a TLB multimatch which panics the
machine.

There are two ways to fix this issue:

        1. Always do a global TLB flush when a new cr3 is loaded and the
        old page table was swapper_pg_dir. I consider this a hack hard
        to understand and with performance implications

        2. Do not use swapper_pg_dir to boot secondary CPUs like 64-bit
        does.

This patch implements solution 2. It introduces a trampoline_pg_dir
which has the same layout as swapper_pg_dir with low_mappings. This page
table is used as the initial page table of the booting CPU. Later in the
bringup process, it switches to swapper_pg_dir and does a global TLB
flush. This fixes the crashes in our test cases.

-v2: switch to swapper_pg_dir right after entering start_secondary() so
that we are able to access percpu data which might not be mapped in the
trampoline page table.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
LKML-Reference: <20100816123833.GB28147@aftab>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
x86: Use find_e820() instead of hard coded trampoline address 2009-12-11T08:28:22+00:00 Yinghai Lu yinghai@kernel.org 2009-12-10T21:07:22+00:00 893f38d144a4d96d2483cd7c3801d26e1b2c23e9 Jens found the following crash/regression: [ 0.000000] found SMP MP-table at [ffff8800000fdd80] fdd80 [ 0.000000] Kernel panic - not syncing: Overlapping early reservations 12-f011 MP-table mpc to 0-fff BIOS data page and [ 0.000000] Kernel panic - not syncing: Overlapping early reservations 12-f011 MP-table mpc to 6000-7fff TRAMPOLINE and bisected it to b24c2a9 ("x86: Move find_smp_config() earlier and avoid bootmem usage"). It turns out the BIOS is using the first 64k for mptable, without reserving it. So try to find good range for the real-mode trampoline instead of hard coding it, in case some bios tries to use that range for sth. Reported-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Yinghai Lu <yinghai@kernel.org> Tested-by: Jens Axboe <jens.axboe@oracle.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <4B21630A.6000308@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> 
Jens found the following crash/regression:

[    0.000000] found SMP MP-table at [ffff8800000fdd80] fdd80
[    0.000000] Kernel panic - not syncing: Overlapping early reservations 12-f011 MP-table mpc to 0-fff BIOS data page

and

[    0.000000] Kernel panic - not syncing: Overlapping early reservations 12-f011 MP-table mpc to 6000-7fff TRAMPOLINE

and bisected it to b24c2a9 ("x86: Move find_smp_config()
earlier and avoid bootmem usage").

It turns out the BIOS is using the first 64k for mptable,
without reserving it.

So try to find good range for the real-mode trampoline instead of
hard coding it, in case some bios tries to use that range for sth.

Reported-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Tested-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <4B21630A.6000308@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
x86: Fix Suspend to RAM freeze on Acer Aspire 1511Lmi laptop 2009-10-12T16:06:48+00:00 Jan Beulich JBeulich@novell.com 2009-10-06T15:32:43+00:00 7a4b7e5e741fe0a72a517b0367a2659aa53f7c44 Move the trampoline and accessors back out of .cpuinit.* for the case of 64-bits+ACPI_SLEEP. This solves s2ram hangs reported in: http://bugzilla.kernel.org/show_bug.cgi?id=14279 Reported-and-bisected-by: Christian Casteyde <casteyde.christian@free.fr> Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: <bugzilla-daemon@bugzilla.kernel.org> Cc: "Andrew Morton" <akpm@linux-foundation.org> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Ingo Molnar <mingo@elte.hu> 
Move the trampoline and accessors back out of .cpuinit.* for the
case of 64-bits+ACPI_SLEEP.

This solves s2ram hangs reported in:

  http://bugzilla.kernel.org/show_bug.cgi?id=14279

Reported-and-bisected-by: Christian Casteyde <casteyde.christian@free.fr>
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: <bugzilla-daemon@bugzilla.kernel.org>
Cc: "Andrew Morton" <akpm@linux-foundation.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>