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x86, perf, bts, mm: Delete the never used BTS-ptrace code
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Support for the PMU's BTS features has been upstreamed in
v2.6.32, but we still have the old and disabled ptrace-BTS,
as Linus noticed it not so long ago.

It's buggy: TIF_DEBUGCTLMSR is trampling all over that MSR without
regard for other uses (perf) and doesn't provide the flexibility
needed for perf either.

Its users are ptrace-block-step and ptrace-bts, since ptrace-bts
was never used and ptrace-block-step can be implemented using a
much simpler approach.

So axe all 3000 lines of it. That includes the *locked_memory*()
APIs in mm/mlock.c as well.

Reported-by: Linus Torvalds <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Roland McGrath <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Markus Metzger <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Andrew Morton <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
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Peter Zijlstra authored and Ingo Molnar committed Mar 26, 2010
1 parent 7c5ecaf commit faa4602
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Showing 34 changed files with 9 additions and 3,269 deletions.
20 changes: 0 additions & 20 deletions arch/x86/Kconfig.cpu
Original file line number Diff line number Diff line change
Expand Up @@ -502,23 +502,3 @@ config CPU_SUP_UMC_32
CPU might render the kernel unbootable.

If unsure, say N.

config X86_DS
def_bool X86_PTRACE_BTS
depends on X86_DEBUGCTLMSR
select HAVE_HW_BRANCH_TRACER

config X86_PTRACE_BTS
bool "Branch Trace Store"
default y
depends on X86_DEBUGCTLMSR
depends on BROKEN
---help---
This adds a ptrace interface to the hardware's branch trace store.

Debuggers may use it to collect an execution trace of the debugged
application in order to answer the question 'how did I get here?'.
Debuggers may trace user mode as well as kernel mode.

Say Y unless there is no application development on this machine
and you want to save a small amount of code size.
9 changes: 0 additions & 9 deletions arch/x86/Kconfig.debug
Original file line number Diff line number Diff line change
Expand Up @@ -174,15 +174,6 @@ config IOMMU_LEAK
Add a simple leak tracer to the IOMMU code. This is useful when you
are debugging a buggy device driver that leaks IOMMU mappings.

config X86_DS_SELFTEST
bool "DS selftest"
default y
depends on DEBUG_KERNEL
depends on X86_DS
---help---
Perform Debug Store selftests at boot time.
If in doubt, say "N".

config HAVE_MMIOTRACE_SUPPORT
def_bool y

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302 changes: 0 additions & 302 deletions arch/x86/include/asm/ds.h

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