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  1. 23 7月, 2014 1 次提交
    • P
      x86, cpu: Fix cache topology for early P4-SMT · 2a226155
      由 Peter Zijlstra 提交于 
      P4 systems with cpuid level < 4 can have SMT, but the cache topology
description available (cpuid2) does not include SMP information.

Now we know that SMT shares all cache levels, and therefore we can
mark all available cache levels as shared.

We do this by setting cpu_llc_id to ->phys_proc_id, since that's
the same for each SMT thread. We can do this unconditional since if
there's no SMT its still true, the one CPU shares cache with only
itself.

This fixes a problem where such CPUs report an incorrect LLC CPU mask.

This in turn fixes a crash in the scheduler where the topology was
build wrong, it assumes the LLC mask to include at least the SMT CPUs.

Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Tested-by: NBruno Wolff III <bruno@wolff.to>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140722133514.GM12054@laptop.lanSigned-off-by: NH. Peter Anvin <hpa@zytor.com>
      2a226155
  3. 22 7月, 2014 1 次提交
    • S
      x86_32, entry: Store badsys error code in %eax · 8142b215
      由 Sven Wegener 提交于 
      Commit 554086d8 ("x86_32, entry: Do syscall exit work on badsys
(CVE-2014-4508)") introduced a regression in the x86_32 syscall entry
code, resulting in syscall() not returning proper errors for undefined
syscalls on CPUs supporting the sysenter feature.

The following code:

> int result = syscall(666);
> printf("result=%d errno=%d error=%s\n", result, errno, strerror(errno));

results in:

> result=666 errno=0 error=Success

Obviously, the syscall return value is the called syscall number, but it
should have been an ENOSYS error. When run under ptrace it behaves
correctly, which makes it hard to debug in the wild:

> result=-1 errno=38 error=Function not implemented

The %eax register is the return value register. For debugging via ptrace
the syscall entry code stores the complete register context on the
stack. The badsys handlers only store the ENOSYS error code in the
ptrace register set and do not set %eax like a regular syscall handler
would. The old resume_userspace call chain contains code that clobbers
%eax and it restores %eax from the ptrace registers afterwards. The same
goes for the ptrace-enabled call chain. When ptrace is not used, the
syscall return value is the passed-in syscall number from the untouched
%eax register.

Use %eax as the return value register in syscall_badsys and
sysenter_badsys, like a real syscall handler does, and have the caller
push the value onto the stack for ptrace access.
Signed-off-by: NSven Wegener <sven.wegener@stealer.net>
Link: http://lkml.kernel.org/r/alpine.LNX.2.11.1407221022380.31021@titan.int.lan.stealer.netReviewed-and-tested-by: NAndy Lutomirski <luto@amacapital.net>
Cc: <stable@vger.kernel.org> # If 554086d8 is backported
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>
      8142b215
  5. 21 7月, 2014 9 次提交
  7. 20 7月, 2014 11 次提交
  9. 19 7月, 2014 18 次提交