Commit faa4602e authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

x86, perf, bts, mm: Delete the never used BTS-ptrace code



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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Markus Metzger <markus.t.metzger@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <20100325135413.938004390@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7c5ecaf7
......@@ -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.
......@@ -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
......
/*
* Debug Store (DS) support
*
* This provides a low-level interface to the hardware's Debug Store
* feature that is used for branch trace store (BTS) and
* precise-event based sampling (PEBS).
*
* It manages:
* - DS and BTS hardware configuration
* - buffer overflow handling (to be done)
* - buffer access
*
* It does not do:
* - security checking (is the caller allowed to trace the task)
* - buffer allocation (memory accounting)
*
*
* Copyright (C) 2007-2009 Intel Corporation.
* Markus Metzger <markus.t.metzger@intel.com>, 2007-2009
*/
#ifndef _ASM_X86_DS_H
#define _ASM_X86_DS_H
#include <linux/types.h>
#include <linux/init.h>
#include <linux/err.h>
#ifdef CONFIG_X86_DS
struct task_struct;
struct ds_context;
struct ds_tracer;
struct bts_tracer;
struct pebs_tracer;
typedef void (*bts_ovfl_callback_t)(struct bts_tracer *);
typedef void (*pebs_ovfl_callback_t)(struct pebs_tracer *);
/*
* A list of features plus corresponding macros to talk about them in
* the ds_request function's flags parameter.
*
* We use the enum to index an array of corresponding control bits;
* we use the macro to index a flags bit-vector.
*/
enum ds_feature {
dsf_bts = 0,
dsf_bts_kernel,
#define BTS_KERNEL (1 << dsf_bts_kernel)
/* trace kernel-mode branches */
dsf_bts_user,
#define BTS_USER (1 << dsf_bts_user)
/* trace user-mode branches */
dsf_bts_overflow,
dsf_bts_max,
dsf_pebs = dsf_bts_max,
dsf_pebs_max,
dsf_ctl_max = dsf_pebs_max,
dsf_bts_timestamps = dsf_ctl_max,
#define BTS_TIMESTAMPS (1 << dsf_bts_timestamps)
/* add timestamps into BTS trace */
#define BTS_USER_FLAGS (BTS_KERNEL | BTS_USER | BTS_TIMESTAMPS)
};
/*
* Request BTS or PEBS
*
* Due to alignement constraints, the actual buffer may be slightly
* smaller than the requested or provided buffer.
*
* Returns a pointer to a tracer structure on success, or
* ERR_PTR(errcode) on failure.
*
* The interrupt threshold is independent from the overflow callback
* to allow users to use their own overflow interrupt handling mechanism.
*
* The function might sleep.
*
* task: the task to request recording for
* cpu: the cpu to request recording for
* base: the base pointer for the (non-pageable) buffer;
* size: the size of the provided buffer in bytes
* ovfl: pointer to a function to be called on buffer overflow;
* NULL if cyclic buffer requested
* th: the interrupt threshold in records from the end of the buffer;
* -1 if no interrupt threshold is requested.
* flags: a bit-mask of the above flags
*/
extern struct bts_tracer *ds_request_bts_task(struct task_struct *task,
void *base, size_t size,
bts_ovfl_callback_t ovfl,
size_t th, unsigned int flags);
extern struct bts_tracer *ds_request_bts_cpu(int cpu, void *base, size_t size,
bts_ovfl_callback_t ovfl,
size_t th, unsigned int flags);
extern struct pebs_tracer *ds_request_pebs_task(struct task_struct *task,
void *base, size_t size,
pebs_ovfl_callback_t ovfl,
size_t th, unsigned int flags);
extern struct pebs_tracer *ds_request_pebs_cpu(int cpu,
void *base, size_t size,
pebs_ovfl_callback_t ovfl,
size_t th, unsigned int flags);
/*
* Release BTS or PEBS resources
* Suspend and resume BTS or PEBS tracing
*
* Must be called with irq's enabled.
*
* tracer: the tracer handle returned from ds_request_~()
*/
extern void ds_release_bts(struct bts_tracer *tracer);
extern void ds_suspend_bts(struct bts_tracer *tracer);
extern void ds_resume_bts(struct bts_tracer *tracer);
extern void ds_release_pebs(struct pebs_tracer *tracer);
extern void ds_suspend_pebs(struct pebs_tracer *tracer);
extern void ds_resume_pebs(struct pebs_tracer *tracer);
/*
* Release BTS or PEBS resources
* Suspend and resume BTS or PEBS tracing
*
* Cpu tracers must call this on the traced cpu.
* Task tracers must call ds_release_~_noirq() for themselves.
*
* May be called with irq's disabled.
*
* Returns 0 if successful;
* -EPERM if the cpu tracer does not trace the current cpu.
* -EPERM if the task tracer does not trace itself.
*
* tracer: the tracer handle returned from ds_request_~()
*/
extern int ds_release_bts_noirq(struct bts_tracer *tracer);
extern int ds_suspend_bts_noirq(struct bts_tracer *tracer);
extern int ds_resume_bts_noirq(struct bts_tracer *tracer);
extern int ds_release_pebs_noirq(struct pebs_tracer *tracer);
extern int ds_suspend_pebs_noirq(struct pebs_tracer *tracer);
extern int ds_resume_pebs_noirq(struct pebs_tracer *tracer);
/*
* The raw DS buffer state as it is used for BTS and PEBS recording.
*
* This is the low-level, arch-dependent interface for working
* directly on the raw trace data.
*/
struct ds_trace {
/* the number of bts/pebs records */
size_t n;
/* the size of a bts/pebs record in bytes */
size_t size;
/* pointers into the raw buffer:
- to the first entry */
void *begin;
/* - one beyond the last entry */
void *end;
/* - one beyond the newest entry */
void *top;
/* - the interrupt threshold */
void *ith;
/* flags given on ds_request() */
unsigned int flags;
};
/*
* An arch-independent view on branch trace data.
*/
enum bts_qualifier {
bts_invalid,
#define BTS_INVALID bts_invalid
bts_branch,
#define BTS_BRANCH bts_branch
bts_task_arrives,
#define BTS_TASK_ARRIVES bts_task_arrives
bts_task_departs,
#define BTS_TASK_DEPARTS bts_task_departs
bts_qual_bit_size = 4,
bts_qual_max = (1 << bts_qual_bit_size),
};
struct bts_struct {
__u64 qualifier;
union {
/* BTS_BRANCH */
struct {
__u64 from;
__u64 to;
} lbr;
/* BTS_TASK_ARRIVES or BTS_TASK_DEPARTS */
struct {
__u64 clock;
pid_t pid;
} event;
} variant;
};
/*
* The BTS state.
*
* This gives access to the raw DS state and adds functions to provide
* an arch-independent view of the BTS data.
*/
struct bts_trace {
struct ds_trace ds;
int (*read)(struct bts_tracer *tracer, const void *at,
struct bts_struct *out);
int (*write)(struct bts_tracer *tracer, const struct bts_struct *in);
};
/*
* The PEBS state.
*
* This gives access to the raw DS state and the PEBS-specific counter
* reset value.
*/
struct pebs_trace {
struct ds_trace ds;
/* the number of valid counters in the below array */
unsigned int counters;
#define MAX_PEBS_COUNTERS 4
/* the counter reset value */
unsigned long long counter_reset[MAX_PEBS_COUNTERS];
};
/*
* Read the BTS or PEBS trace.
*
* Returns a view on the trace collected for the parameter tracer.
*
* The view remains valid as long as the traced task is not running or
* the tracer is suspended.
* Writes into the trace buffer are not reflected.
*
* tracer: the tracer handle returned from ds_request_~()
*/
extern const struct bts_trace *ds_read_bts(struct bts_tracer *tracer);
extern const struct pebs_trace *ds_read_pebs(struct pebs_tracer *tracer);
/*
* Reset the write pointer of the BTS/PEBS buffer.
*
* Returns 0 on success; -Eerrno on error
*
* tracer: the tracer handle returned from ds_request_~()
*/
extern int ds_reset_bts(struct bts_tracer *tracer);
extern int ds_reset_pebs(struct pebs_tracer *tracer);
/*
* Set the PEBS counter reset value.
*
* Returns 0 on success; -Eerrno on error
*
* tracer: the tracer handle returned from ds_request_pebs()
* counter: the index of the counter
* value: the new counter reset value
*/
extern int ds_set_pebs_reset(struct pebs_tracer *tracer,
unsigned int counter, u64 value);
/*
* Initialization
*/
struct cpuinfo_x86;
extern void __cpuinit ds_init_intel(struct cpuinfo_x86 *);
/*
* Context switch work
*/
extern void ds_switch_to(struct task_struct *prev, struct task_struct *next);
#else /* CONFIG_X86_DS */
struct cpuinfo_x86;
static inline void __cpuinit ds_init_intel(struct cpuinfo_x86 *ignored) {}
static inline void ds_switch_to(struct task_struct *prev,
struct task_struct *next) {}
#endif /* CONFIG_X86_DS */
#endif /* _ASM_X86_DS_H */
......@@ -21,7 +21,6 @@ struct mm_struct;
#include <asm/msr.h>
#include <asm/desc_defs.h>
#include <asm/nops.h>
#include <asm/ds.h>
#include <linux/personality.h>
#include <linux/cpumask.h>
......@@ -29,6 +28,7 @@ struct mm_struct;
#include <linux/threads.h>
#include <linux/math64.h>
#include <linux/init.h>
#include <linux/err.h>
#define HBP_NUM 4
/*
......@@ -473,10 +473,6 @@ struct thread_struct {
unsigned long iopl;
/* Max allowed port in the bitmap, in bytes: */
unsigned io_bitmap_max;
/* MSR_IA32_DEBUGCTLMSR value to switch in if TIF_DEBUGCTLMSR is set. */
unsigned long debugctlmsr;
/* Debug Store context; see asm/ds.h */
struct ds_context *ds_ctx;
};
static inline unsigned long native_get_debugreg(int regno)
......@@ -814,21 +810,6 @@ static inline unsigned long get_debugctlmsr(void)
return debugctlmsr;
}
static inline unsigned long get_debugctlmsr_on_cpu(int cpu)
{
u64 debugctlmsr = 0;
u32 val1, val2;
#ifndef CONFIG_X86_DEBUGCTLMSR
if (boot_cpu_data.x86 < 6)
return 0;
#endif
rdmsr_on_cpu(cpu, MSR_IA32_DEBUGCTLMSR, &val1, &val2);
debugctlmsr = val1 | ((u64)val2 << 32);
return debugctlmsr;
}
static inline void update_debugctlmsr(unsigned long debugctlmsr)
{
#ifndef CONFIG_X86_DEBUGCTLMSR
......@@ -838,18 +819,6 @@ static inline void update_debugctlmsr(unsigned long debugctlmsr)
wrmsrl(MSR_IA32_DEBUGCTLMSR, debugctlmsr);
}
static inline void update_debugctlmsr_on_cpu(int cpu,
unsigned long debugctlmsr)
{
#ifndef CONFIG_X86_DEBUGCTLMSR
if (boot_cpu_data.x86 < 6)
return;
#endif
wrmsr_on_cpu(cpu, MSR_IA32_DEBUGCTLMSR,
(u32)((u64)debugctlmsr),
(u32)((u64)debugctlmsr >> 32));
}
/*
* from system description table in BIOS. Mostly for MCA use, but
* others may find it useful:
......
......@@ -82,61 +82,6 @@
#ifndef __ASSEMBLY__
#include <linux/types.h>
/* configuration/status structure used in PTRACE_BTS_CONFIG and
PTRACE_BTS_STATUS commands.
*/
struct ptrace_bts_config {
/* requested or actual size of BTS buffer in bytes */
__u32 size;
/* bitmask of below flags */
__u32 flags;
/* buffer overflow signal */
__u32 signal;
/* actual size of bts_struct in bytes */
__u32 bts_size;
};
#endif /* __ASSEMBLY__ */
#define PTRACE_BTS_O_TRACE 0x1 /* branch trace */
#define PTRACE_BTS_O_SCHED 0x2 /* scheduling events w/ jiffies */
#define PTRACE_BTS_O_SIGNAL 0x4 /* send SIG<signal> on buffer overflow
instead of wrapping around */
#define PTRACE_BTS_O_ALLOC 0x8 /* (re)allocate buffer */
#define PTRACE_BTS_CONFIG 40
/* Configure branch trace recording.
ADDR points to a struct ptrace_bts_config.
DATA gives the size of that buffer.
A new buffer is allocated, if requested in the flags.
An overflow signal may only be requested for new buffers.
Returns the number of bytes read.
*/
#define PTRACE_BTS_STATUS 41
/* Return the current configuration in a struct ptrace_bts_config
pointed to by ADDR; DATA gives the size of that buffer.
Returns the number of bytes written.
*/
#define PTRACE_BTS_SIZE 42
/* Return the number of available BTS records for draining.
DATA and ADDR are ignored.
*/
#define PTRACE_BTS_GET 43
/* Get a single BTS record.
DATA defines the index into the BTS array, where 0 is the newest
entry, and higher indices refer to older entries.
ADDR is pointing to struct bts_struct (see asm/ds.h).
*/
#define PTRACE_BTS_CLEAR 44
/* Clear the BTS buffer.
DATA and ADDR are ignored.
*/
#define PTRACE_BTS_DRAIN 45
/* Read all available BTS records and clear the buffer.
ADDR points to an array of struct bts_struct.
DATA gives the size of that buffer.
BTS records are read from oldest to newest.
Returns number of BTS records drained.
*/
#endif
#endif /* _ASM_X86_PTRACE_ABI_H */
......@@ -289,12 +289,6 @@ extern int do_get_thread_area(struct task_struct *p, int idx,
extern int do_set_thread_area(struct task_struct *p, int idx,
struct user_desc __user *info, int can_allocate);
#ifdef CONFIG_X86_PTRACE_BTS
extern void ptrace_bts_untrace(struct task_struct *tsk);
#define arch_ptrace_untrace(tsk) ptrace_bts_untrace(tsk)
#endif /* CONFIG_X86_PTRACE_BTS */
#endif /* __KERNEL__ */
#endif /* !__ASSEMBLY__ */
......
......@@ -92,8 +92,6 @@ struct thread_info {
#define TIF_IO_BITMAP 22 /* uses I/O bitmap */
#define TIF_FREEZE 23 /* is freezing for suspend */
#define TIF_FORCED_TF 24 /* true if TF in eflags artificially */
#define TIF_DEBUGCTLMSR 25 /* uses thread_struct.debugctlmsr */
#define TIF_DS_AREA_MSR 26 /* uses thread_struct.ds_area_msr */
#define TIF_LAZY_MMU_UPDATES 27 /* task is updating the mmu lazily */
#define TIF_SYSCALL_TRACEPOINT 28 /* syscall tracepoint instrumentation */
......@@ -115,8 +113,6 @@ struct thread_info {
#define _TIF_IO_BITMAP (1 << TIF_IO_BITMAP)
#define _TIF_FREEZE (1 << TIF_FREEZE)
#define _TIF_FORCED_TF (1 << TIF_FORCED_TF)
#define _TIF_DEBUGCTLMSR (1 << TIF_DEBUGCTLMSR)
#define _TIF_DS_AREA_MSR (1 << TIF_DS_AREA_MSR)
#define _TIF_LAZY_MMU_UPDATES (1 << TIF_LAZY_MMU_UPDATES)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
......@@ -147,7 +143,7 @@ struct thread_info {
/* flags to check in __switch_to() */
#define _TIF_WORK_CTXSW \
(_TIF_IO_BITMAP|_TIF_DEBUGCTLMSR|_TIF_DS_AREA_MSR|_TIF_NOTSC)
(_TIF_IO_BITMAP|_TIF_NOTSC)
#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW|_TIF_DEBUG)
......
......@@ -47,8 +47,6 @@ obj-$(CONFIG_X86_TRAMPOLINE) += trampoline.o
obj-y += process.o
obj-y += i387.o xsave.o
obj-y += ptrace.o
obj-$(CONFIG_X86_DS) += ds.o
obj-$(CONFIG_X86_DS_SELFTEST) += ds_selftest.o
obj-$(CONFIG_X86_32) += tls.o
obj-$(CONFIG_IA32_EMULATION) += tls.o
obj-y += step.o
......
......@@ -12,7 +12,6 @@
#include <asm/processor.h>
#include <asm/pgtable.h>
#include <asm/msr.h>
#include <asm/ds.h>
#include <asm/bugs.h>
#include <asm/cpu.h>
......@@ -367,7 +366,6 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c)
set_cpu_cap(c, X86_FEATURE_BTS);
if (!(l1 & (1<<12)))
set_cpu_cap(c, X86_FEATURE_PEBS);
ds_init_intel(c);
}
if (c->x86 == 6 && c->x86_model == 29 && cpu_has_clflush)
......
This diff is collapsed.
<
/*
* Debug Store support - selftest
*
*
* Copyright (C) 2009 Intel Corporation.
* Markus Metzger <markus.t.metzger@intel.com>, 2009
*/
#include "ds_selftest.h"
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/smp.h>
#include <linux/cpu.h>
#include <asm/ds.h>
#define BUFFER_SIZE 521 /* Intentionally chose an odd size. */
#define SMALL_BUFFER_SIZE 24 /* A single bts entry. */
struct ds_selftest_bts_conf {
struct bts_tracer *tracer;
int error;
int (*suspend)(struct bts_tracer *);
int (*resume)(struct bts_tracer *);
};
static int ds_selftest_bts_consistency(const struct bts_trace *trace)
{
int error = 0;
if (!trace) {
printk(KERN_CONT "failed to access trace...");
/* Bail out. Other tests are pointless. */
return -1;
}
if (!trace->read) {
printk(KERN_CONT "bts read not available...");
error = -1;
}
/* Do some sanity checks on the trace configuration. */
if (!trace->ds.n) {
printk(KERN_CONT "empty bts buffer...");
error = -1;
}
if (!trace->ds.size) {
printk(KERN_CONT "bad bts trace setup...");
error = -1;
}
if (trace->ds.end !=
(char *)trace->ds.begin + (trace->ds.n * trace->ds.size)) {
printk(KERN_CONT "bad bts buffer setup...");
error = -1;
}
/*
* We allow top in [begin; end], since its not clear when the
* overflow adjustment happens: after the increment or before the
* write.
*/
if ((trace->ds.top < trace->ds.begin) ||
(trace->ds.end < trace->ds.top)) {
printk(KERN_CONT "bts top out of bounds...");
error = -1;
}
return error;
}
static int ds_selftest_bts_read(struct bts_tracer *tracer,
const struct bts_trace *trace,
const void *from, const void *to)
{
const unsigned char *at;
/*
* Check a few things which do not belong to this test.
* They should be covered by other tests.
*/
if (!trace)
return -1;
if (!trace->read)
return -1;
if (to < from)
return -1;
if (from < trace->ds.begin)
return -1;