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Message-ID: <1335575969.28106.243.camel@gandalf.stny.rr.com>
Date: Fri, 27 Apr 2012 21:19:29 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Ingo Molnar <mingo@...e.hu>,
"H. Peter Anvin" <hpa@...ux.intel.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
Frederic Weisbecker <fweisbec@...il.com>
Subject: [PATCH v3][GIT PULL] tracing: updates for 3.5
Ingo, Peter,
This is the same as the last patch pull request, with the exception that
I added the Acked-by from Masami in the change log of patch 4. The
patches are the same.
-- Steve
Please pull the latest tip/perf/core-3 tree, which can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
tip/perf/core-3
Head SHA1: 4a6d70c9505fef1d8906b1d61db3de5d8ecf9454
Dan Carpenter (1):
tracing: Remove an unneeded check in trace_seq_buffer()
Steven Rostedt (3):
tracing: Add percpu buffers for trace_printk()
ftrace/x86: Have arch x86_64 use breakpoints instead of stop machine
ftrace/x86: Remove the complex ftrace NMI handling code
Vaibhav Nagarnaik (1):
ring-buffer: Add per_cpu ring buffer control files
----
arch/x86/Kconfig | 1 -
arch/x86/include/asm/ftrace.h | 3 +
arch/x86/kernel/ftrace.c | 511 +++++++++++++++++++++++++++--------------
arch/x86/kernel/nmi.c | 10 +-
arch/x86/kernel/traps.c | 8 +-
include/linux/ftrace.h | 6 +
include/linux/kernel.h | 13 +-
include/linux/ring_buffer.h | 6 +-
kernel/trace/ring_buffer.c | 248 +++++++++++---------
kernel/trace/trace.c | 379 ++++++++++++++++++++++--------
kernel/trace/trace.h | 4 +-
kernel/trace/trace_printk.c | 4 +
12 files changed, 810 insertions(+), 383 deletions(-)
---------------------------
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1d14cc6..1324139 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -40,7 +40,6 @@ config X86
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_GRAPH_FP_TEST
select HAVE_FUNCTION_TRACE_MCOUNT_TEST
- select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_KVM
select HAVE_ARCH_KGDB
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index 268c783..18d9005 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -34,6 +34,7 @@
#ifndef __ASSEMBLY__
extern void mcount(void);
+extern int modifying_ftrace_code;
static inline unsigned long ftrace_call_adjust(unsigned long addr)
{
@@ -50,6 +51,8 @@ struct dyn_arch_ftrace {
/* No extra data needed for x86 */
};
+int ftrace_int3_handler(struct pt_regs *regs);
+
#endif /* CONFIG_DYNAMIC_FTRACE */
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_FUNCTION_TRACER */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index c9a281f..cf2d03e 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -20,44 +20,25 @@
#include <linux/init.h>
#include <linux/list.h>
#include <linux/module.h>
+#include <linux/kprobes.h>
#include <trace/syscall.h>
#include <asm/cacheflush.h>
#include <asm/ftrace.h>
#include <asm/nops.h>
-#include <asm/nmi.h>
-
#ifdef CONFIG_DYNAMIC_FTRACE
-/*
- * modifying_code is set to notify NMIs that they need to use
- * memory barriers when entering or exiting. But we don't want
- * to burden NMIs with unnecessary memory barriers when code
- * modification is not being done (which is most of the time).
- *
- * A mutex is already held when ftrace_arch_code_modify_prepare
- * and post_process are called. No locks need to be taken here.
- *
- * Stop machine will make sure currently running NMIs are done
- * and new NMIs will see the updated variable before we need
- * to worry about NMIs doing memory barriers.
- */
-static int modifying_code __read_mostly;
-static DEFINE_PER_CPU(int, save_modifying_code);
-
int ftrace_arch_code_modify_prepare(void)
{
set_kernel_text_rw();
set_all_modules_text_rw();
- modifying_code = 1;
return 0;
}
int ftrace_arch_code_modify_post_process(void)
{
- modifying_code = 0;
set_all_modules_text_ro();
set_kernel_text_ro();
return 0;
@@ -90,134 +71,6 @@ static unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr)
return calc.code;
}
-/*
- * Modifying code must take extra care. On an SMP machine, if
- * the code being modified is also being executed on another CPU
- * that CPU will have undefined results and possibly take a GPF.
- * We use kstop_machine to stop other CPUS from exectuing code.
- * But this does not stop NMIs from happening. We still need
- * to protect against that. We separate out the modification of
- * the code to take care of this.
- *
- * Two buffers are added: An IP buffer and a "code" buffer.
- *
- * 1) Put the instruction pointer into the IP buffer
- * and the new code into the "code" buffer.
- * 2) Wait for any running NMIs to finish and set a flag that says
- * we are modifying code, it is done in an atomic operation.
- * 3) Write the code
- * 4) clear the flag.
- * 5) Wait for any running NMIs to finish.
- *
- * If an NMI is executed, the first thing it does is to call
- * "ftrace_nmi_enter". This will check if the flag is set to write
- * and if it is, it will write what is in the IP and "code" buffers.
- *
- * The trick is, it does not matter if everyone is writing the same
- * content to the code location. Also, if a CPU is executing code
- * it is OK to write to that code location if the contents being written
- * are the same as what exists.
- */
-
-#define MOD_CODE_WRITE_FLAG (1 << 31) /* set when NMI should do the write */
-static atomic_t nmi_running = ATOMIC_INIT(0);
-static int mod_code_status; /* holds return value of text write */
-static void *mod_code_ip; /* holds the IP to write to */
-static const void *mod_code_newcode; /* holds the text to write to the IP */
-
-static unsigned nmi_wait_count;
-static atomic_t nmi_update_count = ATOMIC_INIT(0);
-
-int ftrace_arch_read_dyn_info(char *buf, int size)
-{
- int r;
-
- r = snprintf(buf, size, "%u %u",
- nmi_wait_count,
- atomic_read(&nmi_update_count));
- return r;
-}
-
-static void clear_mod_flag(void)
-{
- int old = atomic_read(&nmi_running);
-
- for (;;) {
- int new = old & ~MOD_CODE_WRITE_FLAG;
-
- if (old == new)
- break;
-
- old = atomic_cmpxchg(&nmi_running, old, new);
- }
-}
-
-static void ftrace_mod_code(void)
-{
- /*
- * Yes, more than one CPU process can be writing to mod_code_status.
- * (and the code itself)
- * But if one were to fail, then they all should, and if one were
- * to succeed, then they all should.
- */
- mod_code_status = probe_kernel_write(mod_code_ip, mod_code_newcode,
- MCOUNT_INSN_SIZE);
-
- /* if we fail, then kill any new writers */
- if (mod_code_status)
- clear_mod_flag();
-}
-
-void ftrace_nmi_enter(void)
-{
- __this_cpu_write(save_modifying_code, modifying_code);
-
- if (!__this_cpu_read(save_modifying_code))
- return;
-
- if (atomic_inc_return(&nmi_running) & MOD_CODE_WRITE_FLAG) {
- smp_rmb();
- ftrace_mod_code();
- atomic_inc(&nmi_update_count);
- }
- /* Must have previous changes seen before executions */
- smp_mb();
-}
-
-void ftrace_nmi_exit(void)
-{
- if (!__this_cpu_read(save_modifying_code))
- return;
-
- /* Finish all executions before clearing nmi_running */
- smp_mb();
- atomic_dec(&nmi_running);
-}
-
-static void wait_for_nmi_and_set_mod_flag(void)
-{
- if (!atomic_cmpxchg(&nmi_running, 0, MOD_CODE_WRITE_FLAG))
- return;
-
- do {
- cpu_relax();
- } while (atomic_cmpxchg(&nmi_running, 0, MOD_CODE_WRITE_FLAG));
-
- nmi_wait_count++;
-}
-
-static void wait_for_nmi(void)
-{
- if (!atomic_read(&nmi_running))
- return;
-
- do {
- cpu_relax();
- } while (atomic_read(&nmi_running));
-
- nmi_wait_count++;
-}
-
static inline int
within(unsigned long addr, unsigned long start, unsigned long end)
{
@@ -238,26 +91,7 @@ do_ftrace_mod_code(unsigned long ip, const void *new_code)
if (within(ip, (unsigned long)_text, (unsigned long)_etext))
ip = (unsigned long)__va(__pa(ip));
- mod_code_ip = (void *)ip;
- mod_code_newcode = new_code;
-
- /* The buffers need to be visible before we let NMIs write them */
- smp_mb();
-
- wait_for_nmi_and_set_mod_flag();
-
- /* Make sure all running NMIs have finished before we write the code */
- smp_mb();
-
- ftrace_mod_code();
-
- /* Make sure the write happens before clearing the bit */
- smp_mb();
-
- clear_mod_flag();
- wait_for_nmi();
-
- return mod_code_status;
+ return probe_kernel_write((void *)ip, new_code, MCOUNT_INSN_SIZE);
}
static const unsigned char *ftrace_nop_replace(void)
@@ -334,6 +168,347 @@ int ftrace_update_ftrace_func(ftrace_func_t func)
return ret;
}
+int modifying_ftrace_code __read_mostly;
+
+/*
+ * A breakpoint was added to the code address we are about to
+ * modify, and this is the handle that will just skip over it.
+ * We are either changing a nop into a trace call, or a trace
+ * call to a nop. While the change is taking place, we treat
+ * it just like it was a nop.
+ */
+int ftrace_int3_handler(struct pt_regs *regs)
+{
+ if (WARN_ON_ONCE(!regs))
+ return 0;
+
+ if (!ftrace_location(regs->ip - 1))
+ return 0;
+
+ regs->ip += MCOUNT_INSN_SIZE - 1;
+
+ return 1;
+}
+
+static int ftrace_write(unsigned long ip, const char *val, int size)
+{
+ /*
+ * On x86_64, kernel text mappings are mapped read-only with
+ * CONFIG_DEBUG_RODATA. So we use the kernel identity mapping instead
+ * of the kernel text mapping to modify the kernel text.
+ *
+ * For 32bit kernels, these mappings are same and we can use
+ * kernel identity mapping to modify code.
+ */
+ if (within(ip, (unsigned long)_text, (unsigned long)_etext))
+ ip = (unsigned long)__va(__pa(ip));
+
+ return probe_kernel_write((void *)ip, val, size);
+}
+
+static int add_break(unsigned long ip, const char *old)
+{
+ unsigned char replaced[MCOUNT_INSN_SIZE];
+ unsigned char brk = BREAKPOINT_INSTRUCTION;
+
+ if (probe_kernel_read(replaced, (void *)ip, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ /* Make sure it is what we expect it to be */
+ if (memcmp(replaced, old, MCOUNT_INSN_SIZE) != 0)
+ return -EINVAL;
+
+ if (ftrace_write(ip, &brk, 1))
+ return -EPERM;
+
+ return 0;
+}
+
+static int add_brk_on_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned const char *old;
+ unsigned long ip = rec->ip;
+
+ old = ftrace_call_replace(ip, addr);
+
+ return add_break(rec->ip, old);
+}
+
+
+static int add_brk_on_nop(struct dyn_ftrace *rec)
+{
+ unsigned const char *old;
+
+ old = ftrace_nop_replace();
+
+ return add_break(rec->ip, old);
+}
+
+static int add_breakpoints(struct dyn_ftrace *rec, int enable)
+{
+ unsigned long ftrace_addr;
+ int ret;
+
+ ret = ftrace_test_record(rec, enable);
+
+ ftrace_addr = (unsigned long)FTRACE_ADDR;
+
+ switch (ret) {
+ case FTRACE_UPDATE_IGNORE:
+ return 0;
+
+ case FTRACE_UPDATE_MAKE_CALL:
+ /* converting nop to call */
+ return add_brk_on_nop(rec);
+
+ case FTRACE_UPDATE_MAKE_NOP:
+ /* converting a call to a nop */
+ return add_brk_on_call(rec, ftrace_addr);
+ }
+ return 0;
+}
+
+/*
+ * On error, we need to remove breakpoints. This needs to
+ * be done caefully. If the address does not currently have a
+ * breakpoint, we know we are done. Otherwise, we look at the
+ * remaining 4 bytes of the instruction. If it matches a nop
+ * we replace the breakpoint with the nop. Otherwise we replace
+ * it with the call instruction.
+ */
+static int remove_breakpoint(struct dyn_ftrace *rec)
+{
+ unsigned char ins[MCOUNT_INSN_SIZE];
+ unsigned char brk = BREAKPOINT_INSTRUCTION;
+ const unsigned char *nop;
+ unsigned long ftrace_addr;
+ unsigned long ip = rec->ip;
+
+ /* If we fail the read, just give up */
+ if (probe_kernel_read(ins, (void *)ip, MCOUNT_INSN_SIZE))
+ return -EFAULT;
+
+ /* If this does not have a breakpoint, we are done */
+ if (ins[0] != brk)
+ return -1;
+
+ nop = ftrace_nop_replace();
+
+ /*
+ * If the last 4 bytes of the instruction do not match
+ * a nop, then we assume that this is a call to ftrace_addr.
+ */
+ if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0) {
+ /*
+ * For extra paranoidism, we check if the breakpoint is on
+ * a call that would actually jump to the ftrace_addr.
+ * If not, don't touch the breakpoint, we make just create
+ * a disaster.
+ */
+ ftrace_addr = (unsigned long)FTRACE_ADDR;
+ nop = ftrace_call_replace(ip, ftrace_addr);
+
+ if (memcmp(&ins[1], &nop[1], MCOUNT_INSN_SIZE - 1) != 0)
+ return -EINVAL;
+ }
+
+ return probe_kernel_write((void *)ip, &nop[0], 1);
+}
+
+static int add_update_code(unsigned long ip, unsigned const char *new)
+{
+ /* skip breakpoint */
+ ip++;
+ new++;
+ if (ftrace_write(ip, new, MCOUNT_INSN_SIZE - 1))
+ return -EPERM;
+ return 0;
+}
+
+static int add_update_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned long ip = rec->ip;
+ unsigned const char *new;
+
+ new = ftrace_call_replace(ip, addr);
+ return add_update_code(ip, new);
+}
+
+static int add_update_nop(struct dyn_ftrace *rec)
+{
+ unsigned long ip = rec->ip;
+ unsigned const char *new;
+
+ new = ftrace_nop_replace();
+ return add_update_code(ip, new);
+}
+
+static int add_update(struct dyn_ftrace *rec, int enable)
+{
+ unsigned long ftrace_addr;
+ int ret;
+
+ ret = ftrace_test_record(rec, enable);
+
+ ftrace_addr = (unsigned long)FTRACE_ADDR;
+
+ switch (ret) {
+ case FTRACE_UPDATE_IGNORE:
+ return 0;
+
+ case FTRACE_UPDATE_MAKE_CALL:
+ /* converting nop to call */
+ return add_update_call(rec, ftrace_addr);
+
+ case FTRACE_UPDATE_MAKE_NOP:
+ /* converting a call to a nop */
+ return add_update_nop(rec);
+ }
+
+ return 0;
+}
+
+static int finish_update_call(struct dyn_ftrace *rec, unsigned long addr)
+{
+ unsigned long ip = rec->ip;
+ unsigned const char *new;
+
+ new = ftrace_call_replace(ip, addr);
+
+ if (ftrace_write(ip, new, 1))
+ return -EPERM;
+
+ return 0;
+}
+
+static int finish_update_nop(struct dyn_ftrace *rec)
+{
+ unsigned long ip = rec->ip;
+ unsigned const char *new;
+
+ new = ftrace_nop_replace();
+
+ if (ftrace_write(ip, new, 1))
+ return -EPERM;
+ return 0;
+}
+
+static int finish_update(struct dyn_ftrace *rec, int enable)
+{
+ unsigned long ftrace_addr;
+ int ret;
+
+ ret = ftrace_update_record(rec, enable);
+
+ ftrace_addr = (unsigned long)FTRACE_ADDR;
+
+ switch (ret) {
+ case FTRACE_UPDATE_IGNORE:
+ return 0;
+
+ case FTRACE_UPDATE_MAKE_CALL:
+ /* converting nop to call */
+ return finish_update_call(rec, ftrace_addr);
+
+ case FTRACE_UPDATE_MAKE_NOP:
+ /* converting a call to a nop */
+ return finish_update_nop(rec);
+ }
+
+ return 0;
+}
+
+static void do_sync_core(void *data)
+{
+ sync_core();
+}
+
+static void run_sync(void)
+{
+ int enable_irqs = irqs_disabled();
+
+ /* We may be called with interrupts disbled (on bootup). */
+ if (enable_irqs)
+ local_irq_enable();
+ on_each_cpu(do_sync_core, NULL, 1);
+ if (enable_irqs)
+ local_irq_disable();
+}
+
+static void ftrace_replace_code(int enable)
+{
+ struct ftrace_rec_iter *iter;
+ struct dyn_ftrace *rec;
+ const char *report = "adding breakpoints";
+ int count = 0;
+ int ret;
+
+ for_ftrace_rec_iter(iter) {
+ rec = ftrace_rec_iter_record(iter);
+
+ ret = add_breakpoints(rec, enable);
+ if (ret)
+ goto remove_breakpoints;
+ count++;
+ }
+
+ run_sync();
+
+ report = "updating code";
+
+ for_ftrace_rec_iter(iter) {
+ rec = ftrace_rec_iter_record(iter);
+
+ ret = add_update(rec, enable);
+ if (ret)
+ goto remove_breakpoints;
+ }
+
+ run_sync();
+
+ report = "removing breakpoints";
+
+ for_ftrace_rec_iter(iter) {
+ rec = ftrace_rec_iter_record(iter);
+
+ ret = finish_update(rec, enable);
+ if (ret)
+ goto remove_breakpoints;
+ }
+
+ run_sync();
+
+ return;
+
+ remove_breakpoints:
+ ftrace_bug(ret, rec ? rec->ip : 0);
+ printk(KERN_WARNING "Failed on %s (%d):\n", report, count);
+ for_ftrace_rec_iter(iter) {
+ rec = ftrace_rec_iter_record(iter);
+ remove_breakpoint(rec);
+ }
+}
+
+void arch_ftrace_update_code(int command)
+{
+ modifying_ftrace_code++;
+
+ if (command & FTRACE_UPDATE_CALLS)
+ ftrace_replace_code(1);
+ else if (command & FTRACE_DISABLE_CALLS)
+ ftrace_replace_code(0);
+
+ if (command & FTRACE_UPDATE_TRACE_FUNC)
+ ftrace_update_ftrace_func(ftrace_trace_function);
+
+ if (command & FTRACE_START_FUNC_RET)
+ ftrace_enable_ftrace_graph_caller();
+ else if (command & FTRACE_STOP_FUNC_RET)
+ ftrace_disable_ftrace_graph_caller();
+
+ modifying_ftrace_code--;
+}
+
int __init ftrace_dyn_arch_init(void *data)
{
/* The return code is retured via data */
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 47acaf3..eb1539e 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -84,7 +84,7 @@ __setup("unknown_nmi_panic", setup_unknown_nmi_panic);
#define nmi_to_desc(type) (&nmi_desc[type])
-static int notrace __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, bool b2b)
+static int __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, bool b2b)
{
struct nmi_desc *desc = nmi_to_desc(type);
struct nmiaction *a;
@@ -209,7 +209,7 @@ void unregister_nmi_handler(unsigned int type, const char *name)
EXPORT_SYMBOL_GPL(unregister_nmi_handler);
-static notrace __kprobes void
+static __kprobes void
pci_serr_error(unsigned char reason, struct pt_regs *regs)
{
pr_emerg("NMI: PCI system error (SERR) for reason %02x on CPU %d.\n",
@@ -236,7 +236,7 @@ pci_serr_error(unsigned char reason, struct pt_regs *regs)
outb(reason, NMI_REASON_PORT);
}
-static notrace __kprobes void
+static __kprobes void
io_check_error(unsigned char reason, struct pt_regs *regs)
{
unsigned long i;
@@ -263,7 +263,7 @@ io_check_error(unsigned char reason, struct pt_regs *regs)
outb(reason, NMI_REASON_PORT);
}
-static notrace __kprobes void
+static __kprobes void
unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
{
int handled;
@@ -305,7 +305,7 @@ unknown_nmi_error(unsigned char reason, struct pt_regs *regs)
static DEFINE_PER_CPU(bool, swallow_nmi);
static DEFINE_PER_CPU(unsigned long, last_nmi_rip);
-static notrace __kprobes void default_do_nmi(struct pt_regs *regs)
+static __kprobes void default_do_nmi(struct pt_regs *regs)
{
unsigned char reason = 0;
int handled;
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index ff9281f1..92d5756 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -50,6 +50,7 @@
#include <asm/processor.h>
#include <asm/debugreg.h>
#include <linux/atomic.h>
+#include <asm/ftrace.h>
#include <asm/traps.h>
#include <asm/desc.h>
#include <asm/i387.h>
@@ -303,8 +304,13 @@ gp_in_kernel:
}
/* May run on IST stack. */
-dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
+dotraplinkage void __kprobes notrace do_int3(struct pt_regs *regs, long error_code)
{
+#ifdef CONFIG_DYNAMIC_FTRACE
+ /* ftrace must be first, everything else may cause a recursive crash */
+ if (unlikely(modifying_ftrace_code) && ftrace_int3_handler(regs))
+ return;
+#endif
#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, X86_TRAP_BP,
SIGTRAP) == NOTIFY_STOP)
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 72a6cab..0b55903 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -286,6 +286,12 @@ struct ftrace_rec_iter *ftrace_rec_iter_start(void);
struct ftrace_rec_iter *ftrace_rec_iter_next(struct ftrace_rec_iter *iter);
struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter);
+#define for_ftrace_rec_iter(iter) \
+ for (iter = ftrace_rec_iter_start(); \
+ iter; \
+ iter = ftrace_rec_iter_next(iter))
+
+
int ftrace_update_record(struct dyn_ftrace *rec, int enable);
int ftrace_test_record(struct dyn_ftrace *rec, int enable);
void ftrace_run_stop_machine(int command);
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 645231c..c0d3442 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -480,15 +480,16 @@ do { \
#define trace_printk(fmt, args...) \
do { \
+ static const char *trace_printk_fmt \
+ __attribute__((section("__trace_printk_fmt"))) = \
+ __builtin_constant_p(fmt) ? fmt : NULL; \
+ \
__trace_printk_check_format(fmt, ##args); \
- if (__builtin_constant_p(fmt)) { \
- static const char *trace_printk_fmt \
- __attribute__((section("__trace_printk_fmt"))) = \
- __builtin_constant_p(fmt) ? fmt : NULL; \
\
+ if (__builtin_constant_p(fmt)) \
__trace_bprintk(_THIS_IP_, trace_printk_fmt, ##args); \
- } else \
- __trace_printk(_THIS_IP_, fmt, ##args); \
+ else \
+ __trace_printk(_THIS_IP_, fmt, ##args); \
} while (0)
extern __printf(2, 3)
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 7be2e88..6c8835f 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -96,9 +96,11 @@ __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *k
__ring_buffer_alloc((size), (flags), &__key); \
})
+#define RING_BUFFER_ALL_CPUS -1
+
void ring_buffer_free(struct ring_buffer *buffer);
-int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
+int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, int cpu);
void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val);
@@ -129,7 +131,7 @@ ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
-unsigned long ring_buffer_size(struct ring_buffer *buffer);
+unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu);
void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_reset(struct ring_buffer *buffer);
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index cf8d11e..2d5eb33 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -449,6 +449,7 @@ struct ring_buffer_per_cpu {
raw_spinlock_t reader_lock; /* serialize readers */
arch_spinlock_t lock;
struct lock_class_key lock_key;
+ unsigned int nr_pages;
struct list_head *pages;
struct buffer_page *head_page; /* read from head */
struct buffer_page *tail_page; /* write to tail */
@@ -466,10 +467,12 @@ struct ring_buffer_per_cpu {
unsigned long read_bytes;
u64 write_stamp;
u64 read_stamp;
+ /* ring buffer pages to update, > 0 to add, < 0 to remove */
+ int nr_pages_to_update;
+ struct list_head new_pages; /* new pages to add */
};
struct ring_buffer {
- unsigned pages;
unsigned flags;
int cpus;
atomic_t record_disabled;
@@ -963,14 +966,10 @@ static int rb_check_pages(struct ring_buffer_per_cpu *cpu_buffer)
return 0;
}
-static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
- unsigned nr_pages)
+static int __rb_allocate_pages(int nr_pages, struct list_head *pages, int cpu)
{
+ int i;
struct buffer_page *bpage, *tmp;
- LIST_HEAD(pages);
- unsigned i;
-
- WARN_ON(!nr_pages);
for (i = 0; i < nr_pages; i++) {
struct page *page;
@@ -981,15 +980,13 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
*/
bpage = kzalloc_node(ALIGN(sizeof(*bpage), cache_line_size()),
GFP_KERNEL | __GFP_NORETRY,
- cpu_to_node(cpu_buffer->cpu));
+ cpu_to_node(cpu));
if (!bpage)
goto free_pages;
- rb_check_bpage(cpu_buffer, bpage);
+ list_add(&bpage->list, pages);
- list_add(&bpage->list, &pages);
-
- page = alloc_pages_node(cpu_to_node(cpu_buffer->cpu),
+ page = alloc_pages_node(cpu_to_node(cpu),
GFP_KERNEL | __GFP_NORETRY, 0);
if (!page)
goto free_pages;
@@ -997,6 +994,27 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
rb_init_page(bpage->page);
}
+ return 0;
+
+free_pages:
+ list_for_each_entry_safe(bpage, tmp, pages, list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
+ }
+
+ return -ENOMEM;
+}
+
+static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
+ unsigned nr_pages)
+{
+ LIST_HEAD(pages);
+
+ WARN_ON(!nr_pages);
+
+ if (__rb_allocate_pages(nr_pages, &pages, cpu_buffer->cpu))
+ return -ENOMEM;
+
/*
* The ring buffer page list is a circular list that does not
* start and end with a list head. All page list items point to
@@ -1005,20 +1023,15 @@ static int rb_allocate_pages(struct ring_buffer_per_cpu *cpu_buffer,
cpu_buffer->pages = pages.next;
list_del(&pages);
+ cpu_buffer->nr_pages = nr_pages;
+
rb_check_pages(cpu_buffer);
return 0;
-
- free_pages:
- list_for_each_entry_safe(bpage, tmp, &pages, list) {
- list_del_init(&bpage->list);
- free_buffer_page(bpage);
- }
- return -ENOMEM;
}
static struct ring_buffer_per_cpu *
-rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
+rb_allocate_cpu_buffer(struct ring_buffer *buffer, int nr_pages, int cpu)
{
struct ring_buffer_per_cpu *cpu_buffer;
struct buffer_page *bpage;
@@ -1052,7 +1065,7 @@ rb_allocate_cpu_buffer(struct ring_buffer *buffer, int cpu)
INIT_LIST_HEAD(&cpu_buffer->reader_page->list);
- ret = rb_allocate_pages(cpu_buffer, buffer->pages);
+ ret = rb_allocate_pages(cpu_buffer, nr_pages);
if (ret < 0)
goto fail_free_reader;
@@ -1113,7 +1126,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
{
struct ring_buffer *buffer;
int bsize;
- int cpu;
+ int cpu, nr_pages;
/* keep it in its own cache line */
buffer = kzalloc(ALIGN(sizeof(*buffer), cache_line_size()),
@@ -1124,14 +1137,14 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
goto fail_free_buffer;
- buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
+ nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
buffer->flags = flags;
buffer->clock = trace_clock_local;
buffer->reader_lock_key = key;
/* need at least two pages */
- if (buffer->pages < 2)
- buffer->pages = 2;
+ if (nr_pages < 2)
+ nr_pages = 2;
/*
* In case of non-hotplug cpu, if the ring-buffer is allocated
@@ -1154,7 +1167,7 @@ struct ring_buffer *__ring_buffer_alloc(unsigned long size, unsigned flags,
for_each_buffer_cpu(buffer, cpu) {
buffer->buffers[cpu] =
- rb_allocate_cpu_buffer(buffer, cpu);
+ rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
if (!buffer->buffers[cpu])
goto fail_free_buffers;
}
@@ -1276,6 +1289,18 @@ out:
raw_spin_unlock_irq(&cpu_buffer->reader_lock);
}
+static void update_pages_handler(struct ring_buffer_per_cpu *cpu_buffer)
+{
+ if (cpu_buffer->nr_pages_to_update > 0)
+ rb_insert_pages(cpu_buffer, &cpu_buffer->new_pages,
+ cpu_buffer->nr_pages_to_update);
+ else
+ rb_remove_pages(cpu_buffer, -cpu_buffer->nr_pages_to_update);
+ cpu_buffer->nr_pages += cpu_buffer->nr_pages_to_update;
+ /* reset this value */
+ cpu_buffer->nr_pages_to_update = 0;
+}
+
/**
* ring_buffer_resize - resize the ring buffer
* @buffer: the buffer to resize.
@@ -1285,14 +1310,12 @@ out:
*
* Returns -1 on failure.
*/
-int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
+int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
+ int cpu_id)
{
struct ring_buffer_per_cpu *cpu_buffer;
- unsigned nr_pages, rm_pages, new_pages;
- struct buffer_page *bpage, *tmp;
- unsigned long buffer_size;
- LIST_HEAD(pages);
- int i, cpu;
+ unsigned nr_pages;
+ int cpu;
/*
* Always succeed at resizing a non-existent buffer:
@@ -1302,15 +1325,11 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
size *= BUF_PAGE_SIZE;
- buffer_size = buffer->pages * BUF_PAGE_SIZE;
/* we need a minimum of two pages */
if (size < BUF_PAGE_SIZE * 2)
size = BUF_PAGE_SIZE * 2;
- if (size == buffer_size)
- return size;
-
atomic_inc(&buffer->record_disabled);
/* Make sure all writers are done with this buffer. */
@@ -1321,68 +1340,56 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
nr_pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
- if (size < buffer_size) {
-
- /* easy case, just free pages */
- if (RB_WARN_ON(buffer, nr_pages >= buffer->pages))
- goto out_fail;
-
- rm_pages = buffer->pages - nr_pages;
-
+ if (cpu_id == RING_BUFFER_ALL_CPUS) {
+ /* calculate the pages to update */
for_each_buffer_cpu(buffer, cpu) {
cpu_buffer = buffer->buffers[cpu];
- rb_remove_pages(cpu_buffer, rm_pages);
- }
- goto out;
- }
- /*
- * This is a bit more difficult. We only want to add pages
- * when we can allocate enough for all CPUs. We do this
- * by allocating all the pages and storing them on a local
- * link list. If we succeed in our allocation, then we
- * add these pages to the cpu_buffers. Otherwise we just free
- * them all and return -ENOMEM;
- */
- if (RB_WARN_ON(buffer, nr_pages <= buffer->pages))
- goto out_fail;
+ cpu_buffer->nr_pages_to_update = nr_pages -
+ cpu_buffer->nr_pages;
- new_pages = nr_pages - buffer->pages;
+ /*
+ * nothing more to do for removing pages or no update
+ */
+ if (cpu_buffer->nr_pages_to_update <= 0)
+ continue;
- for_each_buffer_cpu(buffer, cpu) {
- for (i = 0; i < new_pages; i++) {
- struct page *page;
/*
- * __GFP_NORETRY flag makes sure that the allocation
- * fails gracefully without invoking oom-killer and
- * the system is not destabilized.
+ * to add pages, make sure all new pages can be
+ * allocated without receiving ENOMEM
*/
- bpage = kzalloc_node(ALIGN(sizeof(*bpage),
- cache_line_size()),
- GFP_KERNEL | __GFP_NORETRY,
- cpu_to_node(cpu));
- if (!bpage)
- goto free_pages;
- list_add(&bpage->list, &pages);
- page = alloc_pages_node(cpu_to_node(cpu),
- GFP_KERNEL | __GFP_NORETRY, 0);
- if (!page)
- goto free_pages;
- bpage->page = page_address(page);
- rb_init_page(bpage->page);
+ INIT_LIST_HEAD(&cpu_buffer->new_pages);
+ if (__rb_allocate_pages(cpu_buffer->nr_pages_to_update,
+ &cpu_buffer->new_pages, cpu))
+ /* not enough memory for new pages */
+ goto no_mem;
}
- }
- for_each_buffer_cpu(buffer, cpu) {
- cpu_buffer = buffer->buffers[cpu];
- rb_insert_pages(cpu_buffer, &pages, new_pages);
- }
+ /* wait for all the updates to complete */
+ for_each_buffer_cpu(buffer, cpu) {
+ cpu_buffer = buffer->buffers[cpu];
+ if (cpu_buffer->nr_pages_to_update) {
+ update_pages_handler(cpu_buffer);
+ }
+ }
+ } else {
+ cpu_buffer = buffer->buffers[cpu_id];
+ if (nr_pages == cpu_buffer->nr_pages)
+ goto out;
- if (RB_WARN_ON(buffer, !list_empty(&pages)))
- goto out_fail;
+ cpu_buffer->nr_pages_to_update = nr_pages -
+ cpu_buffer->nr_pages;
+
+ INIT_LIST_HEAD(&cpu_buffer->new_pages);
+ if (cpu_buffer->nr_pages_to_update > 0 &&
+ __rb_allocate_pages(cpu_buffer->nr_pages_to_update,
+ &cpu_buffer->new_pages, cpu_id))
+ goto no_mem;
+
+ update_pages_handler(cpu_buffer);
+ }
out:
- buffer->pages = nr_pages;
put_online_cpus();
mutex_unlock(&buffer->mutex);
@@ -1390,25 +1397,24 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
return size;
- free_pages:
- list_for_each_entry_safe(bpage, tmp, &pages, list) {
- list_del_init(&bpage->list);
- free_buffer_page(bpage);
+ no_mem:
+ for_each_buffer_cpu(buffer, cpu) {
+ struct buffer_page *bpage, *tmp;
+ cpu_buffer = buffer->buffers[cpu];
+ /* reset this number regardless */
+ cpu_buffer->nr_pages_to_update = 0;
+ if (list_empty(&cpu_buffer->new_pages))
+ continue;
+ list_for_each_entry_safe(bpage, tmp, &cpu_buffer->new_pages,
+ list) {
+ list_del_init(&bpage->list);
+ free_buffer_page(bpage);
+ }
}
put_online_cpus();
mutex_unlock(&buffer->mutex);
atomic_dec(&buffer->record_disabled);
return -ENOMEM;
-
- /*
- * Something went totally wrong, and we are too paranoid
- * to even clean up the mess.
- */
- out_fail:
- put_online_cpus();
- mutex_unlock(&buffer->mutex);
- atomic_dec(&buffer->record_disabled);
- return -1;
}
EXPORT_SYMBOL_GPL(ring_buffer_resize);
@@ -1510,7 +1516,7 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer)
* assign the commit to the tail.
*/
again:
- max_count = cpu_buffer->buffer->pages * 100;
+ max_count = cpu_buffer->nr_pages * 100;
while (cpu_buffer->commit_page != cpu_buffer->tail_page) {
if (RB_WARN_ON(cpu_buffer, !(--max_count)))
@@ -3588,9 +3594,18 @@ EXPORT_SYMBOL_GPL(ring_buffer_read);
* ring_buffer_size - return the size of the ring buffer (in bytes)
* @buffer: The ring buffer.
*/
-unsigned long ring_buffer_size(struct ring_buffer *buffer)
+unsigned long ring_buffer_size(struct ring_buffer *buffer, int cpu)
{
- return BUF_PAGE_SIZE * buffer->pages;
+ /*
+ * Earlier, this method returned
+ * BUF_PAGE_SIZE * buffer->nr_pages
+ * Since the nr_pages field is now removed, we have converted this to
+ * return the per cpu buffer value.
+ */
+ if (!cpumask_test_cpu(cpu, buffer->cpumask))
+ return 0;
+
+ return BUF_PAGE_SIZE * buffer->buffers[cpu]->nr_pages;
}
EXPORT_SYMBOL_GPL(ring_buffer_size);
@@ -3765,8 +3780,11 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
!cpumask_test_cpu(cpu, buffer_b->cpumask))
goto out;
+ cpu_buffer_a = buffer_a->buffers[cpu];
+ cpu_buffer_b = buffer_b->buffers[cpu];
+
/* At least make sure the two buffers are somewhat the same */
- if (buffer_a->pages != buffer_b->pages)
+ if (cpu_buffer_a->nr_pages != cpu_buffer_b->nr_pages)
goto out;
ret = -EAGAIN;
@@ -3780,9 +3798,6 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
if (atomic_read(&buffer_b->record_disabled))
goto out;
- cpu_buffer_a = buffer_a->buffers[cpu];
- cpu_buffer_b = buffer_b->buffers[cpu];
-
if (atomic_read(&cpu_buffer_a->record_disabled))
goto out;
@@ -4071,6 +4086,8 @@ static int rb_cpu_notify(struct notifier_block *self,
struct ring_buffer *buffer =
container_of(self, struct ring_buffer, cpu_notify);
long cpu = (long)hcpu;
+ int cpu_i, nr_pages_same;
+ unsigned int nr_pages;
switch (action) {
case CPU_UP_PREPARE:
@@ -4078,8 +4095,23 @@ static int rb_cpu_notify(struct notifier_block *self,
if (cpumask_test_cpu(cpu, buffer->cpumask))
return NOTIFY_OK;
+ nr_pages = 0;
+ nr_pages_same = 1;
+ /* check if all cpu sizes are same */
+ for_each_buffer_cpu(buffer, cpu_i) {
+ /* fill in the size from first enabled cpu */
+ if (nr_pages == 0)
+ nr_pages = buffer->buffers[cpu_i]->nr_pages;
+ if (nr_pages != buffer->buffers[cpu_i]->nr_pages) {
+ nr_pages_same = 0;
+ break;
+ }
+ }
+ /* allocate minimum pages, user can later expand it */
+ if (!nr_pages_same)
+ nr_pages = 2;
buffer->buffers[cpu] =
- rb_allocate_cpu_buffer(buffer, cpu);
+ rb_allocate_cpu_buffer(buffer, nr_pages, cpu);
if (!buffer->buffers[cpu]) {
WARN(1, "failed to allocate ring buffer on CPU %ld\n",
cpu);
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index ed7b5d1..f11a285 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -629,7 +629,6 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt)
static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
{
int len;
- void *ret;
if (s->len <= s->readpos)
return -EBUSY;
@@ -637,9 +636,7 @@ static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt)
len = s->len - s->readpos;
if (cnt > len)
cnt = len;
- ret = memcpy(buf, s->buffer + s->readpos, cnt);
- if (!ret)
- return -EFAULT;
+ memcpy(buf, s->buffer + s->readpos, cnt);
s->readpos += cnt;
return cnt;
@@ -841,7 +838,8 @@ __acquires(kernel_lock)
/* If we expanded the buffers, make sure the max is expanded too */
if (ring_buffer_expanded && type->use_max_tr)
- ring_buffer_resize(max_tr.buffer, trace_buf_size);
+ ring_buffer_resize(max_tr.buffer, trace_buf_size,
+ RING_BUFFER_ALL_CPUS);
/* the test is responsible for initializing and enabling */
pr_info("Testing tracer %s: ", type->name);
@@ -857,7 +855,8 @@ __acquires(kernel_lock)
/* Shrink the max buffer again */
if (ring_buffer_expanded && type->use_max_tr)
- ring_buffer_resize(max_tr.buffer, 1);
+ ring_buffer_resize(max_tr.buffer, 1,
+ RING_BUFFER_ALL_CPUS);
printk(KERN_CONT "PASSED\n");
}
@@ -1498,25 +1497,119 @@ static void __trace_userstack(struct trace_array *tr, unsigned long flags)
#endif /* CONFIG_STACKTRACE */
+/* created for use with alloc_percpu */
+struct trace_buffer_struct {
+ char buffer[TRACE_BUF_SIZE];
+};
+
+static struct trace_buffer_struct *trace_percpu_buffer;
+static struct trace_buffer_struct *trace_percpu_sirq_buffer;
+static struct trace_buffer_struct *trace_percpu_irq_buffer;
+static struct trace_buffer_struct *trace_percpu_nmi_buffer;
+
+/*
+ * The buffer used is dependent on the context. There is a per cpu
+ * buffer for normal context, softirq contex, hard irq context and
+ * for NMI context. Thise allows for lockless recording.
+ *
+ * Note, if the buffers failed to be allocated, then this returns NULL
+ */
+static char *get_trace_buf(void)
+{
+ struct trace_buffer_struct *percpu_buffer;
+ struct trace_buffer_struct *buffer;
+
+ /*
+ * If we have allocated per cpu buffers, then we do not
+ * need to do any locking.
+ */
+ if (in_nmi())
+ percpu_buffer = trace_percpu_nmi_buffer;
+ else if (in_irq())
+ percpu_buffer = trace_percpu_irq_buffer;
+ else if (in_softirq())
+ percpu_buffer = trace_percpu_sirq_buffer;
+ else
+ percpu_buffer = trace_percpu_buffer;
+
+ if (!percpu_buffer)
+ return NULL;
+
+ buffer = per_cpu_ptr(percpu_buffer, smp_processor_id());
+
+ return buffer->buffer;
+}
+
+static int alloc_percpu_trace_buffer(void)
+{
+ struct trace_buffer_struct *buffers;
+ struct trace_buffer_struct *sirq_buffers;
+ struct trace_buffer_struct *irq_buffers;
+ struct trace_buffer_struct *nmi_buffers;
+
+ buffers = alloc_percpu(struct trace_buffer_struct);
+ if (!buffers)
+ goto err_warn;
+
+ sirq_buffers = alloc_percpu(struct trace_buffer_struct);
+ if (!sirq_buffers)
+ goto err_sirq;
+
+ irq_buffers = alloc_percpu(struct trace_buffer_struct);
+ if (!irq_buffers)
+ goto err_irq;
+
+ nmi_buffers = alloc_percpu(struct trace_buffer_struct);
+ if (!nmi_buffers)
+ goto err_nmi;
+
+ trace_percpu_buffer = buffers;
+ trace_percpu_sirq_buffer = sirq_buffers;
+ trace_percpu_irq_buffer = irq_buffers;
+ trace_percpu_nmi_buffer = nmi_buffers;
+
+ return 0;
+
+ err_nmi:
+ free_percpu(irq_buffers);
+ err_irq:
+ free_percpu(sirq_buffers);
+ err_sirq:
+ free_percpu(buffers);
+ err_warn:
+ WARN(1, "Could not allocate percpu trace_printk buffer");
+ return -ENOMEM;
+}
+
+void trace_printk_init_buffers(void)
+{
+ static int buffers_allocated;
+
+ if (buffers_allocated)
+ return;
+
+ if (alloc_percpu_trace_buffer())
+ return;
+
+ pr_info("ftrace: Allocated trace_printk buffers\n");
+
+ buffers_allocated = 1;
+}
+
/**
* trace_vbprintk - write binary msg to tracing buffer
*
*/
int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
{
- static arch_spinlock_t trace_buf_lock =
- (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
- static u32 trace_buf[TRACE_BUF_SIZE];
-
struct ftrace_event_call *call = &event_bprint;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
struct trace_array *tr = &global_trace;
- struct trace_array_cpu *data;
struct bprint_entry *entry;
unsigned long flags;
- int disable;
- int cpu, len = 0, size, pc;
+ char *tbuffer;
+ int len = 0, size, pc;
if (unlikely(tracing_selftest_running || tracing_disabled))
return 0;
@@ -1526,43 +1619,36 @@ int trace_vbprintk(unsigned long ip, const char *fmt, va_list args)
pc = preempt_count();
preempt_disable_notrace();
- cpu = raw_smp_processor_id();
- data = tr->data[cpu];
- disable = atomic_inc_return(&data->disabled);
- if (unlikely(disable != 1))
+ tbuffer = get_trace_buf();
+ if (!tbuffer) {
+ len = 0;
goto out;
+ }
- /* Lockdep uses trace_printk for lock tracing */
- local_irq_save(flags);
- arch_spin_lock(&trace_buf_lock);
- len = vbin_printf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+ len = vbin_printf((u32 *)tbuffer, TRACE_BUF_SIZE/sizeof(int), fmt, args);
- if (len > TRACE_BUF_SIZE || len < 0)
- goto out_unlock;
+ if (len > TRACE_BUF_SIZE/sizeof(int) || len < 0)
+ goto out;
+ local_save_flags(flags);
size = sizeof(*entry) + sizeof(u32) * len;
buffer = tr->buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_BPRINT, size,
flags, pc);
if (!event)
- goto out_unlock;
+ goto out;
entry = ring_buffer_event_data(event);
entry->ip = ip;
entry->fmt = fmt;
- memcpy(entry->buf, trace_buf, sizeof(u32) * len);
+ memcpy(entry->buf, tbuffer, sizeof(u32) * len);
if (!filter_check_discard(call, entry, buffer, event)) {
ring_buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
}
-out_unlock:
- arch_spin_unlock(&trace_buf_lock);
- local_irq_restore(flags);
-
out:
- atomic_dec_return(&data->disabled);
preempt_enable_notrace();
unpause_graph_tracing();
@@ -1588,58 +1674,53 @@ int trace_array_printk(struct trace_array *tr,
int trace_array_vprintk(struct trace_array *tr,
unsigned long ip, const char *fmt, va_list args)
{
- static arch_spinlock_t trace_buf_lock = __ARCH_SPIN_LOCK_UNLOCKED;
- static char trace_buf[TRACE_BUF_SIZE];
-
struct ftrace_event_call *call = &event_print;
struct ring_buffer_event *event;
struct ring_buffer *buffer;
- struct trace_array_cpu *data;
- int cpu, len = 0, size, pc;
+ int len = 0, size, pc;
struct print_entry *entry;
- unsigned long irq_flags;
- int disable;
+ unsigned long flags;
+ char *tbuffer;
if (tracing_disabled || tracing_selftest_running)
return 0;
+ /* Don't pollute graph traces with trace_vprintk internals */
+ pause_graph_tracing();
+
pc = preempt_count();
preempt_disable_notrace();
- cpu = raw_smp_processor_id();
- data = tr->data[cpu];
- disable = atomic_inc_return(&data->disabled);
- if (unlikely(disable != 1))
+
+ tbuffer = get_trace_buf();
+ if (!tbuffer) {
+ len = 0;
goto out;
+ }
- pause_graph_tracing();
- raw_local_irq_save(irq_flags);
- arch_spin_lock(&trace_buf_lock);
- len = vsnprintf(trace_buf, TRACE_BUF_SIZE, fmt, args);
+ len = vsnprintf(tbuffer, TRACE_BUF_SIZE, fmt, args);
+ if (len > TRACE_BUF_SIZE)
+ goto out;
+ local_save_flags(flags);
size = sizeof(*entry) + len + 1;
buffer = tr->buffer;
event = trace_buffer_lock_reserve(buffer, TRACE_PRINT, size,
- irq_flags, pc);
+ flags, pc);
if (!event)
- goto out_unlock;
+ goto out;
entry = ring_buffer_event_data(event);
entry->ip = ip;
- memcpy(&entry->buf, trace_buf, len);
+ memcpy(&entry->buf, tbuffer, len);
entry->buf[len] = '\0';
if (!filter_check_discard(call, entry, buffer, event)) {
ring_buffer_unlock_commit(buffer, event);
- ftrace_trace_stack(buffer, irq_flags, 6, pc);
+ ftrace_trace_stack(buffer, flags, 6, pc);
}
-
- out_unlock:
- arch_spin_unlock(&trace_buf_lock);
- raw_local_irq_restore(irq_flags);
- unpause_graph_tracing();
out:
- atomic_dec_return(&data->disabled);
preempt_enable_notrace();
+ unpause_graph_tracing();
return len;
}
@@ -2974,7 +3055,14 @@ int tracer_init(struct tracer *t, struct trace_array *tr)
return t->init(tr);
}
-static int __tracing_resize_ring_buffer(unsigned long size)
+static void set_buffer_entries(struct trace_array *tr, unsigned long val)
+{
+ int cpu;
+ for_each_tracing_cpu(cpu)
+ tr->data[cpu]->entries = val;
+}
+
+static int __tracing_resize_ring_buffer(unsigned long size, int cpu)
{
int ret;
@@ -2985,19 +3073,32 @@ static int __tracing_resize_ring_buffer(unsigned long size)
*/
ring_buffer_expanded = 1;
- ret = ring_buffer_resize(global_trace.buffer, size);
+ ret = ring_buffer_resize(global_trace.buffer, size, cpu);
if (ret < 0)
return ret;
if (!current_trace->use_max_tr)
goto out;
- ret = ring_buffer_resize(max_tr.buffer, size);
+ ret = ring_buffer_resize(max_tr.buffer, size, cpu);
if (ret < 0) {
- int r;
+ int r = 0;
+
+ if (cpu == RING_BUFFER_ALL_CPUS) {
+ int i;
+ for_each_tracing_cpu(i) {
+ r = ring_buffer_resize(global_trace.buffer,
+ global_trace.data[i]->entries,
+ i);
+ if (r < 0)
+ break;
+ }
+ } else {
+ r = ring_buffer_resize(global_trace.buffer,
+ global_trace.data[cpu]->entries,
+ cpu);
+ }
- r = ring_buffer_resize(global_trace.buffer,
- global_trace.entries);
if (r < 0) {
/*
* AARGH! We are left with different
@@ -3019,14 +3120,21 @@ static int __tracing_resize_ring_buffer(unsigned long size)
return ret;
}
- max_tr.entries = size;
+ if (cpu == RING_BUFFER_ALL_CPUS)
+ set_buffer_entries(&max_tr, size);
+ else
+ max_tr.data[cpu]->entries = size;
+
out:
- global_trace.entries = size;
+ if (cpu == RING_BUFFER_ALL_CPUS)
+ set_buffer_entries(&global_trace, size);
+ else
+ global_trace.data[cpu]->entries = size;
return ret;
}
-static ssize_t tracing_resize_ring_buffer(unsigned long size)
+static ssize_t tracing_resize_ring_buffer(unsigned long size, int cpu_id)
{
int cpu, ret = size;
@@ -3042,12 +3150,19 @@ static ssize_t tracing_resize_ring_buffer(unsigned long size)
atomic_inc(&max_tr.data[cpu]->disabled);
}
- if (size != global_trace.entries)
- ret = __tracing_resize_ring_buffer(size);
+ if (cpu_id != RING_BUFFER_ALL_CPUS) {
+ /* make sure, this cpu is enabled in the mask */
+ if (!cpumask_test_cpu(cpu_id, tracing_buffer_mask)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+ ret = __tracing_resize_ring_buffer(size, cpu_id);
if (ret < 0)
ret = -ENOMEM;
+out:
for_each_tracing_cpu(cpu) {
if (global_trace.data[cpu])
atomic_dec(&global_trace.data[cpu]->disabled);
@@ -3078,7 +3193,8 @@ int tracing_update_buffers(void)
mutex_lock(&trace_types_lock);
if (!ring_buffer_expanded)
- ret = __tracing_resize_ring_buffer(trace_buf_size);
+ ret = __tracing_resize_ring_buffer(trace_buf_size,
+ RING_BUFFER_ALL_CPUS);
mutex_unlock(&trace_types_lock);
return ret;
@@ -3102,7 +3218,8 @@ static int tracing_set_tracer(const char *buf)
mutex_lock(&trace_types_lock);
if (!ring_buffer_expanded) {
- ret = __tracing_resize_ring_buffer(trace_buf_size);
+ ret = __tracing_resize_ring_buffer(trace_buf_size,
+ RING_BUFFER_ALL_CPUS);
if (ret < 0)
goto out;
ret = 0;
@@ -3128,8 +3245,8 @@ static int tracing_set_tracer(const char *buf)
* The max_tr ring buffer has some state (e.g. ring->clock) and
* we want preserve it.
*/
- ring_buffer_resize(max_tr.buffer, 1);
- max_tr.entries = 1;
+ ring_buffer_resize(max_tr.buffer, 1, RING_BUFFER_ALL_CPUS);
+ set_buffer_entries(&max_tr, 1);
}
destroy_trace_option_files(topts);
@@ -3137,10 +3254,17 @@ static int tracing_set_tracer(const char *buf)
topts = create_trace_option_files(current_trace);
if (current_trace->use_max_tr) {
- ret = ring_buffer_resize(max_tr.buffer, global_trace.entries);
- if (ret < 0)
- goto out;
- max_tr.entries = global_trace.entries;
+ int cpu;
+ /* we need to make per cpu buffer sizes equivalent */
+ for_each_tracing_cpu(cpu) {
+ ret = ring_buffer_resize(max_tr.buffer,
+ global_trace.data[cpu]->entries,
+ cpu);
+ if (ret < 0)
+ goto out;
+ max_tr.data[cpu]->entries =
+ global_trace.data[cpu]->entries;
+ }
}
if (t->init) {
@@ -3642,30 +3766,82 @@ out_err:
goto out;
}
+struct ftrace_entries_info {
+ struct trace_array *tr;
+ int cpu;
+};
+
+static int tracing_entries_open(struct inode *inode, struct file *filp)
+{
+ struct ftrace_entries_info *info;
+
+ if (tracing_disabled)
+ return -ENODEV;
+
+ info = kzalloc(sizeof(*info), GFP_KERNEL);
+ if (!info)
+ return -ENOMEM;
+
+ info->tr = &global_trace;
+ info->cpu = (unsigned long)inode->i_private;
+
+ filp->private_data = info;
+
+ return 0;
+}
+
static ssize_t
tracing_entries_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
{
- struct trace_array *tr = filp->private_data;
- char buf[96];
- int r;
+ struct ftrace_entries_info *info = filp->private_data;
+ struct trace_array *tr = info->tr;
+ char buf[64];
+ int r = 0;
+ ssize_t ret;
mutex_lock(&trace_types_lock);
- if (!ring_buffer_expanded)
- r = sprintf(buf, "%lu (expanded: %lu)\n",
- tr->entries >> 10,
- trace_buf_size >> 10);
- else
- r = sprintf(buf, "%lu\n", tr->entries >> 10);
+
+ if (info->cpu == RING_BUFFER_ALL_CPUS) {
+ int cpu, buf_size_same;
+ unsigned long size;
+
+ size = 0;
+ buf_size_same = 1;
+ /* check if all cpu sizes are same */
+ for_each_tracing_cpu(cpu) {
+ /* fill in the size from first enabled cpu */
+ if (size == 0)
+ size = tr->data[cpu]->entries;
+ if (size != tr->data[cpu]->entries) {
+ buf_size_same = 0;
+ break;
+ }
+ }
+
+ if (buf_size_same) {
+ if (!ring_buffer_expanded)
+ r = sprintf(buf, "%lu (expanded: %lu)\n",
+ size >> 10,
+ trace_buf_size >> 10);
+ else
+ r = sprintf(buf, "%lu\n", size >> 10);
+ } else
+ r = sprintf(buf, "X\n");
+ } else
+ r = sprintf(buf, "%lu\n", tr->data[info->cpu]->entries >> 10);
+
mutex_unlock(&trace_types_lock);
- return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+ ret = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+ return ret;
}
static ssize_t
tracing_entries_write(struct file *filp, const char __user *ubuf,
size_t cnt, loff_t *ppos)
{
+ struct ftrace_entries_info *info = filp->private_data;
unsigned long val;
int ret;
@@ -3680,7 +3856,7 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
/* value is in KB */
val <<= 10;
- ret = tracing_resize_ring_buffer(val);
+ ret = tracing_resize_ring_buffer(val, info->cpu);
if (ret < 0)
return ret;
@@ -3689,6 +3865,16 @@ tracing_entries_write(struct file *filp, const char __user *ubuf,
return cnt;
}
+static int
+tracing_entries_release(struct inode *inode, struct file *filp)
+{
+ struct ftrace_entries_info *info = filp->private_data;
+
+ kfree(info);
+
+ return 0;
+}
+
static ssize_t
tracing_total_entries_read(struct file *filp, char __user *ubuf,
size_t cnt, loff_t *ppos)
@@ -3700,7 +3886,7 @@ tracing_total_entries_read(struct file *filp, char __user *ubuf,
mutex_lock(&trace_types_lock);
for_each_tracing_cpu(cpu) {
- size += tr->entries >> 10;
+ size += tr->data[cpu]->entries >> 10;
if (!ring_buffer_expanded)
expanded_size += trace_buf_size >> 10;
}
@@ -3734,7 +3920,7 @@ tracing_free_buffer_release(struct inode *inode, struct file *filp)
if (trace_flags & TRACE_ITER_STOP_ON_FREE)
tracing_off();
/* resize the ring buffer to 0 */
- tracing_resize_ring_buffer(0);
+ tracing_resize_ring_buffer(0, RING_BUFFER_ALL_CPUS);
return 0;
}
@@ -3933,9 +4119,10 @@ static const struct file_operations tracing_pipe_fops = {
};
static const struct file_operations tracing_entries_fops = {
- .open = tracing_open_generic,
+ .open = tracing_entries_open,
.read = tracing_entries_read,
.write = tracing_entries_write,
+ .release = tracing_entries_release,
.llseek = generic_file_llseek,
};
@@ -4387,6 +4574,9 @@ static void tracing_init_debugfs_percpu(long cpu)
trace_create_file("stats", 0444, d_cpu,
(void *) cpu, &tracing_stats_fops);
+
+ trace_create_file("buffer_size_kb", 0444, d_cpu,
+ (void *) cpu, &tracing_entries_fops);
}
#ifdef CONFIG_FTRACE_SELFTEST
@@ -4716,7 +4906,7 @@ static __init int tracer_init_debugfs(void)
(void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops);
trace_create_file("buffer_size_kb", 0644, d_tracer,
- &global_trace, &tracing_entries_fops);
+ (void *) RING_BUFFER_ALL_CPUS, &tracing_entries_fops);
trace_create_file("buffer_total_size_kb", 0444, d_tracer,
&global_trace, &tracing_total_entries_fops);
@@ -4955,6 +5145,10 @@ __init static int tracer_alloc_buffers(void)
if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
goto out_free_buffer_mask;
+ /* Only allocate trace_printk buffers if a trace_printk exists */
+ if (__stop___trace_bprintk_fmt != __start___trace_bprintk_fmt)
+ trace_printk_init_buffers();
+
/* To save memory, keep the ring buffer size to its minimum */
if (ring_buffer_expanded)
ring_buf_size = trace_buf_size;
@@ -4973,7 +5167,6 @@ __init static int tracer_alloc_buffers(void)
WARN_ON(1);
goto out_free_cpumask;
}
- global_trace.entries = ring_buffer_size(global_trace.buffer);
if (global_trace.buffer_disabled)
tracing_off();
@@ -4986,7 +5179,6 @@ __init static int tracer_alloc_buffers(void)
ring_buffer_free(global_trace.buffer);
goto out_free_cpumask;
}
- max_tr.entries = 1;
#endif
/* Allocate the first page for all buffers */
@@ -4995,6 +5187,11 @@ __init static int tracer_alloc_buffers(void)
max_tr.data[i] = &per_cpu(max_tr_data, i);
}
+ set_buffer_entries(&global_trace, ring_buf_size);
+#ifdef CONFIG_TRACER_MAX_TRACE
+ set_buffer_entries(&max_tr, 1);
+#endif
+
trace_init_cmdlines();
register_tracer(&nop_trace);
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 95059f0..1c8b7c6 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -131,6 +131,7 @@ struct trace_array_cpu {
atomic_t disabled;
void *buffer_page; /* ring buffer spare */
+ unsigned long entries;
unsigned long saved_latency;
unsigned long critical_start;
unsigned long critical_end;
@@ -152,7 +153,6 @@ struct trace_array_cpu {
*/
struct trace_array {
struct ring_buffer *buffer;
- unsigned long entries;
int cpu;
int buffer_disabled;
cycle_t time_start;
@@ -826,6 +826,8 @@ extern struct list_head ftrace_events;
extern const char *__start___trace_bprintk_fmt[];
extern const char *__stop___trace_bprintk_fmt[];
+void trace_printk_init_buffers(void);
+
#undef FTRACE_ENTRY
#define FTRACE_ENTRY(call, struct_name, id, tstruct, print, filter) \
extern struct ftrace_event_call \
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index 6fd4ffd..a9077c1 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -51,6 +51,10 @@ void hold_module_trace_bprintk_format(const char **start, const char **end)
const char **iter;
char *fmt;
+ /* allocate the trace_printk per cpu buffers */
+ if (start != end)
+ trace_printk_init_buffers();
+
mutex_lock(&btrace_mutex);
for (iter = start; iter < end; iter++) {
struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
--
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