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  1. 17 Mar, 2009 1 commit
  3. 14 Mar, 2009 2 commits
  5. 13 Mar, 2009 4 commits
    • Andreas Herrmann's avatar
      x86: mtrr: don't modify RdDram/WrDram bits of fixed MTRRs · 3ff42da5
      Andreas Herrmann authored 
      Impact: bug fix + BIOS workaround

BIOS is expected to clear the SYSCFG[MtrrFixDramModEn] on AMD CPUs
after fixed MTRRs are configured.

Some BIOSes do not clear SYSCFG[MtrrFixDramModEn] on BP (and on APs).

This can lead to obfuscation in Linux when this bit is not cleared on
BP but cleared on APs. A consequence of this is that the saved
fixed-MTRR state (from BP) differs from the fixed-MTRRs of APs --
because RdDram/WrDram bits are read as zero when
SYSCFG[MtrrFixDramModEn] is cleared -- and Linux tries to sync
fixed-MTRR state from BP to AP. This implies that Linux sets
SYSCFG[MtrrFixDramEn] and activates those bits.

More important is that (some) systems change these bits in SMM when
ACPI is enabled. Hence it is racy if Linux modifies RdMem/WrMem bits,
too.

(1) The patch modifies an old fix from Bernhard Kaindl to get
    suspend/resume working on some Acer Laptops. Bernhard's patch
    tried to sync RdMem/WrMem bits of fixed MTRR registers and that
    helped on those old Laptops. (Don't ask me why -- can't test it
    myself). But this old problem was not the motivation for the
    patch. (See http://lkml.org/lkml/2007/4/3/110)

(2) The more important effect is to fix issues on some more current systems.

    On those systems Linux panics or just freezes, see

    http://bugzilla.kernel.org/show_bug.cgi?id=11541
    (and also duplicates of this bug:
    http://bugzilla.kernel.org/show_bug.cgi?id=11737
    http://bugzilla.kernel.org/show_bug.cgi?id=11714)

    The affected systems boot only using acpi=ht, acpi=off or
    when the kernel is built with CONFIG_MTRR=n.

    The acpi options prevent full enablement of ACPI.  Obviously when
    ACPI is enabled the BIOS/SMM modfies RdMem/WrMem bits.  When
    CONFIG_MTRR=y Linux also accesses and modifies those bits when it
    needs to sync fixed-MTRRs across cores (Bernhard's fix, see (1)).
    How do you synchronize that? You can't. As a consequence Linux
    shouldn't touch those bits at all (Rationale are AMD's BKDGs which
    recommend to clear the bit that makes RdMem/WrMem accessible).
    This is the purpose of this patch. And (so far) this suffices to
    fix (1) and (2).

I suggest not to touch RdDram/WrDram bits of fixed-MTRRs and
SYSCFG[MtrrFixDramEn] and to clear SYSCFG[MtrrFixDramModEn] as
suggested by AMD K8, and AMD family 10h/11h BKDGs.
BIOS is expected to do this anyway. This should avoid that
Linux and SMM tread on each other's toes ...
Signed-off-by: default avatarAndreas Herrmann <andreas.herrmann3@amd.com>
Cc: trenn@suse.de
Cc: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <20090312163937.GH20716@alberich.amd.com>
Cc: <stable@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      3ff42da5
    • Yinghai Lu's avatar
      x86: separate mtrr cleanup/mtrr_e820 trim to separate file · 0d890355
      Yinghai Lu authored 
      Impact: cleanup

mtrr main.c is too big, seperate mtrr cleanup and mtrr e820 trim
code to another file.
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
LKML-Reference: <49B87C7B.80809@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      0d890355
    • Yinghai Lu's avatar
      x86: print out mtrr_range_state when user specify size · c1ab7e93
      Yinghai Lu authored 
      Impact: print more debug info

Keep it consistent with autodetect version.
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
LKML-Reference: <49B87C0A.4010105@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      c1ab7e93
    • Yinghai Lu's avatar
      x86: more MTRR debug printouts · 8ad97905
      Yinghai Lu authored 
      Impact: improve MTRR debugging messages

There's still inefficiencies suspected with the MTRR sanitizing
code, so make sure we get all the info we need from a dmesg.

- Remove unneeded mtrr_show

 (It will only printout one time by first cpu, so it is no big deal.)

- Also print out directly from get_mtrr, because it doesn't update mtrr_state.
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
LKML-Reference: <49B9BA5A.40108@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      8ad97905
  7. 12 Mar, 2009 1 commit
  9. 11 Mar, 2009 25 commits
  11. 10 Mar, 2009 7 commits