[PATCH] LTT for 2.5.46 5/10: i386 trace support

Karim Yaghmour (karim@opersys.com)
Mon, 04 Nov 2002 21:08:07 -0500


D: This patch adds the bare-minimum i386-specific low-level trace
D: statements.

diffstat:
arch/i386/kernel/entry.S | 23 +++++++
arch/i386/kernel/irq.c | 6 ++
arch/i386/kernel/process.c | 5 +
arch/i386/kernel/sys_i386.c | 4 +
arch/i386/kernel/traps.c | 104 ++++++++++++++++++++++++++++++++++
arch/i386/mm/fault.c | 11 +++
include/asm-i386/trace.h | 131 ++++++++++++++++++++++++++++++++++++++++++++
include/asm-i386/unistd.h | 1
8 files changed, 284 insertions(+), 1 deletion(-)

diff -urpN linux-2.5.46/arch/i386/kernel/entry.S linux-2.5.46-ltt/arch/i386/kernel/entry.S
--- linux-2.5.46/arch/i386/kernel/entry.S Mon Nov 4 17:30:15 2002
+++ linux-2.5.46-ltt/arch/i386/kernel/entry.S Mon Nov 4 19:05:28 2002
@@ -233,9 +233,27 @@ ENTRY(system_call)
testb $_TIF_SYSCALL_TRACE,TI_FLAGS(%ebx)
jnz syscall_trace_entry
syscall_call:
+#if (CONFIG_TRACE)
+ movl syscall_entry_trace_active, %eax
+ cmpl $1, %eax # are we tracing system call entries
+ jne no_syscall_entry_trace
+ movl %esp, %eax # copy the stack pointer
+ pushl %eax # pass the stack pointer copy
+ call trace_real_syscall_entry
+ addl $4,%esp # return stack to state before pass
+no_syscall_entry_trace:
+ movl ORIG_EAX(%esp),%eax # restore eax to it's original content
+#endif
call *sys_call_table(,%eax,4)
movl %eax,EAX(%esp) # store the return value
syscall_exit:
+#if (CONFIG_TRACE)
+ movl syscall_exit_trace_active, %eax
+ cmpl $1, %eax # are we tracing system call exits
+ jne no_syscall_exit_trace
+ call trace_real_syscall_exit
+no_syscall_exit_trace:
+#endif
cli # make sure we don't miss an interrupt
# setting need_resched or sigpending
# between sampling and the iret
@@ -741,6 +759,11 @@ ENTRY(sys_call_table)
.long sys_epoll_ctl /* 255 */
.long sys_epoll_wait
.long sys_remap_file_pages
+#if CONFIG_TRACE
+ .long sys_trace
+#else
+ .long sys_ni_syscall
+#endif


.rept NR_syscalls-(.-sys_call_table)/4
diff -urpN linux-2.5.46/arch/i386/kernel/irq.c linux-2.5.46-ltt/arch/i386/kernel/irq.c
--- linux-2.5.46/arch/i386/kernel/irq.c Mon Nov 4 17:30:05 2002
+++ linux-2.5.46-ltt/arch/i386/kernel/irq.c Mon Nov 4 19:01:57 2002
@@ -33,6 +33,8 @@
#include <linux/proc_fs.h>
#include <linux/seq_file.h>

+#include <linux/trace.h>
+
#include <asm/atomic.h>
#include <asm/io.h>
#include <asm/smp.h>
@@ -202,6 +204,8 @@ int handle_IRQ_event(unsigned int irq, s
{
int status = 1; /* Force the "do bottom halves" bit */

+ TRACE_IRQ_ENTRY(irq, !(user_mode(regs)));
+
if (!(action->flags & SA_INTERRUPT))
local_irq_enable();

@@ -214,6 +218,8 @@ int handle_IRQ_event(unsigned int irq, s
add_interrupt_randomness(irq);
local_irq_disable();

+ TRACE_IRQ_EXIT();
+
return status;
}

diff -urpN linux-2.5.46/arch/i386/kernel/process.c linux-2.5.46-ltt/arch/i386/kernel/process.c
--- linux-2.5.46/arch/i386/kernel/process.c Mon Nov 4 17:30:02 2002
+++ linux-2.5.46-ltt/arch/i386/kernel/process.c Mon Nov 4 19:06:21 2002
@@ -34,6 +34,7 @@
#include <linux/init.h>
#include <linux/mc146818rtc.h>
#include <linux/module.h>
+#include <linux/trace.h>

#include <asm/uaccess.h>
#include <asm/pgtable.h>
@@ -225,6 +226,10 @@ int kernel_thread(int (*fn)(void *), voi

/* Ok, create the new process.. */
p = do_fork(flags | CLONE_VM | CLONE_UNTRACED, 0, &regs, 0, NULL);
+#if (CONFIG_TRACE)
+ if(!IS_ERR(p))
+ TRACE_PROCESS(TRACE_EV_PROCESS_KTHREAD, p->pid, (int) fn);
+#endif
return IS_ERR(p) ? PTR_ERR(p) : p->pid;
}

diff -urpN linux-2.5.46/arch/i386/kernel/sys_i386.c linux-2.5.46-ltt/arch/i386/kernel/sys_i386.c
--- linux-2.5.46/arch/i386/kernel/sys_i386.c Mon Nov 4 17:30:52 2002
+++ linux-2.5.46-ltt/arch/i386/kernel/sys_i386.c Mon Nov 4 19:01:57 2002
@@ -20,6 +20,8 @@
#include <linux/file.h>
#include <linux/utsname.h>

+#include <linux/trace.h>
+
#include <asm/uaccess.h>
#include <asm/ipc.h>

@@ -138,6 +140,8 @@ asmlinkage int sys_ipc (uint call, int f
version = call >> 16; /* hack for backward compatibility */
call &= 0xffff;

+ TRACE_IPC(TRACE_EV_IPC_CALL, call, first);
+
switch (call) {
case SEMOP:
return sys_semop (first, (struct sembuf *)ptr, second);
diff -urpN linux-2.5.46/arch/i386/kernel/traps.c linux-2.5.46-ltt/arch/i386/kernel/traps.c
--- linux-2.5.46/arch/i386/kernel/traps.c Mon Nov 4 17:30:10 2002
+++ linux-2.5.46-ltt/arch/i386/kernel/traps.c Mon Nov 4 19:01:57 2002
@@ -28,6 +28,8 @@
#include <linux/ioport.h>
#endif

+#include <linux/trace.h>
+
#ifdef CONFIG_MCA
#include <linux/mca.h>
#include <asm/processor.h>
@@ -285,6 +287,76 @@ bug:
printk("Kernel BUG\n");
}

+/* Trace related code */
+#if (CONFIG_TRACE)
+asmlinkage void trace_real_syscall_entry(struct pt_regs *regs)
+{
+ int use_depth;
+ int use_bounds;
+ int depth = 0;
+ int seek_depth;
+ unsigned long lower_bound;
+ unsigned long upper_bound;
+ unsigned long addr;
+ unsigned long *stack;
+ trace_syscall_entry trace_syscall_event;
+
+ /* Set the syscall ID */
+ trace_syscall_event.syscall_id = (uint8_t) regs->orig_eax;
+
+ /* Set the address in any case */
+ trace_syscall_event.address = regs->eip;
+
+ /* Are we in the kernel (This is a kernel thread)? */
+ if (!(regs->xcs & 3))
+ /* Don't go digining anywhere */
+ goto trace_syscall_end;
+
+ /* Get the trace configuration */
+ if (trace_get_config(&use_depth,
+ &use_bounds,
+ &seek_depth,
+ (void *) &lower_bound,
+ (void *) &upper_bound) < 0)
+ goto trace_syscall_end;
+
+ /* Do we have to search for an eip address range */
+ if ((use_depth == 1) || (use_bounds == 1)) {
+ /* Start at the top of the stack (bottom address since stacks grow downward) */
+ stack = (unsigned long *) regs->esp;
+
+ /* Keep on going until we reach the end of the process' stack limit (wherever it may be) */
+ while (!get_user(addr, stack)) {
+ /* Does this LOOK LIKE an address in the program */
+ if ((addr > current->mm->start_code)
+ && (addr < current->mm->end_code)) {
+ /* Does this address fit the description */
+ if (((use_depth == 1) && (depth == seek_depth))
+ || ((use_bounds == 1) && (addr > lower_bound) && (addr < upper_bound))) {
+ /* Set the address */
+ trace_syscall_event.address = addr;
+
+ /* We're done */
+ goto trace_syscall_end;
+ } else
+ /* We're one depth more */
+ depth++;
+ }
+ /* Go on to the next address */
+ stack++;
+ }
+ }
+trace_syscall_end:
+ /* Trace the event */
+ trace_event(TRACE_EV_SYSCALL_ENTRY, &trace_syscall_event);
+}
+
+asmlinkage void trace_real_syscall_exit(void)
+{
+ trace_event(TRACE_EV_SYSCALL_EXIT, NULL);
+}
+#endif /* (CONFIG_TRACE) */
+
spinlock_t die_lock = SPIN_LOCK_UNLOCKED;

void die(const char * str, struct pt_regs * regs, long err)
@@ -318,6 +390,8 @@ static inline unsigned long get_cr2(void
static void inline do_trap(int trapnr, int signr, char *str, int vm86,
struct pt_regs * regs, long error_code, siginfo_t *info)
{
+ TRACE_TRAP_ENTRY(trapnr, regs->eip);
+
if (vm86 && regs->eflags & VM_MASK)
goto vm86_trap;

@@ -332,6 +406,7 @@ static void inline do_trap(int trapnr, i
force_sig_info(signr, info, tsk);
else
force_sig(signr, tsk);
+ TRACE_TRAP_EXIT();
return;
}

@@ -357,14 +432,17 @@ static void inline do_trap(int trapnr, i
regs->eip = fixup;
else
die(str, regs, error_code);
+ TRACE_TRAP_EXIT();
return;
}

vm86_trap: {
int ret = handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, trapnr);
if (ret) goto trap_signal;
+ TRACE_TRAP_EXIT();
return;
}
+ TRACE_TRAP_EXIT();
}

#define DO_ERROR(trapnr, signr, str, name) \
@@ -424,11 +502,15 @@ asmlinkage void do_general_protection(st

current->thread.error_code = error_code;
current->thread.trap_no = 13;
+ TRACE_TRAP_ENTRY(13, regs->eip);
force_sig(SIGSEGV, current);
+ TRACE_TRAP_EXIT();
return;

gp_in_vm86:
+ TRACE_TRAP_ENTRY(13, regs->eip);
handle_vm86_fault((struct kernel_vm86_regs *) regs, error_code);
+ TRACE_TRAP_EXIT();
return;

gp_in_kernel:
@@ -489,6 +571,12 @@ static void default_do_nmi(struct pt_reg
{
unsigned char reason = inb(0x61);

+#ifndef CONFIG_X86_LOCAL_APIC
+/* On an machines with APIC enabled, NMIs are used to implement a watchdog
+and will hang the machine if traced. */
+ TRACE_TRAP_ENTRY(2, regs->eip);
+#endif
+
if (!(reason & 0xc0)) {
#if CONFIG_X86_LOCAL_APIC
/*
@@ -501,6 +589,9 @@ static void default_do_nmi(struct pt_reg
}
#endif
unknown_nmi_error(reason, regs);
+#ifndef CONFIG_X86_LOCAL_APIC
+ TRACE_TRAP_EXIT();
+#endif
return;
}
if (reason & 0x80)
@@ -515,6 +606,10 @@ static void default_do_nmi(struct pt_reg
inb(0x71); /* dummy */
outb(0x0f, 0x70);
inb(0x71); /* dummy */
+
+#ifndef CONFIG_X86_LOCAL_APIC
+ TRACE_TRAP_EXIT();
+#endif
}

static int dummy_nmi_callback(struct pt_regs * regs, int cpu)
@@ -615,7 +710,9 @@ asmlinkage void do_debug(struct pt_regs
*/
info.si_addr = ((regs->xcs & 3) == 0) ? (void *)tsk->thread.eip :
(void *)regs->eip;
+ TRACE_TRAP_ENTRY(1, regs->eip);
force_sig_info(SIGTRAP, &info, tsk);
+ TRACE_TRAP_EXIT();

/* Disable additional traps. They'll be re-enabled when
* the signal is delivered.
@@ -627,7 +724,9 @@ clear_dr7:
return;

debug_vm86:
+ TRACE_TRAP_ENTRY(1, regs->eip);
handle_vm86_trap((struct kernel_vm86_regs *) regs, error_code, 1);
+ TRACE_TRAP_EXIT();
return;

clear_TF:
@@ -776,10 +875,12 @@ asmlinkage void do_simd_coprocessor_erro
asmlinkage void do_spurious_interrupt_bug(struct pt_regs * regs,
long error_code)
{
+ TRACE_TRAP_ENTRY(16, regs->eip);
#if 0
/* No need to warn about this any longer. */
printk("Ignoring P6 Local APIC Spurious Interrupt Bug...\n");
#endif
+ TRACE_TRAP_EXIT();
}

/*
@@ -808,8 +909,10 @@ asmlinkage void math_emulate(long arg)
{
printk("math-emulation not enabled and no coprocessor found.\n");
printk("killing %s.\n",current->comm);
+ TRACE_TRAP_ENTRY(7, 0);
force_sig(SIGFPE,current);
schedule();
+ TRACE_TRAP_EXIT();
}

#endif /* CONFIG_MATH_EMULATION */
@@ -841,7 +944,6 @@ do { \
"3" ((char *) (addr)),"2" (__KERNEL_CS << 16)); \
} while (0)

-
/*
* This needs to use 'idt_table' rather than 'idt', and
* thus use the _nonmapped_ version of the IDT, as the
diff -urpN linux-2.5.46/arch/i386/mm/fault.c linux-2.5.46-ltt/arch/i386/mm/fault.c
--- linux-2.5.46/arch/i386/mm/fault.c Mon Nov 4 17:30:03 2002
+++ linux-2.5.46-ltt/arch/i386/mm/fault.c Mon Nov 4 19:01:57 2002
@@ -20,6 +20,8 @@
#include <linux/tty.h>
#include <linux/vt_kern.h> /* For unblank_screen() */

+#include <linux/trace.h>
+
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
@@ -188,6 +190,8 @@ asmlinkage void do_page_fault(struct pt_
mm = tsk->mm;
info.si_code = SEGV_MAPERR;

+ TRACE_TRAP_ENTRY(14, regs->eip);
+
/*
* If we're in an interrupt, have no user context or are running in an
* atomic region then we must not take the fault..
@@ -272,6 +276,7 @@ good_area:
tsk->thread.screen_bitmap |= 1 << bit;
}
up_read(&mm->mmap_sem);
+ TRACE_TRAP_EXIT();
return;

/*
@@ -291,6 +296,7 @@ bad_area:
/* info.si_code has been set above */
info.si_addr = (void *)address;
force_sig_info(SIGSEGV, &info, tsk);
+ TRACE_TRAP_EXIT();
return;
}

@@ -305,6 +311,7 @@ bad_area:

if (nr == 6) {
do_invalid_op(regs, 0);
+ TRACE_TRAP_EXIT();
return;
}
}
@@ -314,6 +321,7 @@ no_context:
/* Are we prepared to handle this kernel fault? */
if ((fixup = search_exception_table(regs->eip)) != 0) {
regs->eip = fixup;
+ TRACE_TRAP_EXIT();
return;
}

@@ -387,6 +395,7 @@ do_sigbus:
/* Kernel mode? Handle exceptions or die */
if (!(error_code & 4))
goto no_context;
+ TRACE_TRAP_EXIT();
return;

vmalloc_fault:
@@ -420,6 +429,8 @@ vmalloc_fault:
pte_k = pte_offset_kernel(pmd_k, address);
if (!pte_present(*pte_k))
goto no_context;
+ TRACE_TRAP_EXIT();
return;
}
+ TRACE_TRAP_EXIT();
}
diff -urpN linux-2.5.46/include/asm-i386/trace.h linux-2.5.46-ltt/include/asm-i386/trace.h
--- linux-2.5.46/include/asm-i386/trace.h Wed Dec 31 19:00:00 1969
+++ linux-2.5.46-ltt/include/asm-i386/trace.h Mon Nov 4 19:01:58 2002
@@ -0,0 +1,131 @@
+/*
+ * linux/include/asm-i386/trace.h
+ *
+ * Copyright (C) 2002, Karim Yaghmour
+ *
+ * i386 definitions for tracing system
+ */
+
+#include <linux/trace.h>
+
+/* Current arch type */
+#define TRACE_ARCH_TYPE TRACE_ARCH_TYPE_I386
+
+/* Current variant type */
+#define TRACE_ARCH_VARIANT TRACE_ARCH_VARIANT_NONE
+
+#ifdef CONFIG_X86_TSC /* Is there x86 TSC support? */
+#include <asm/msr.h>
+
+/**
+ * get_time_delta: - Utility function for getting time delta.
+ * @now: pointer to a timeval struct that may be given current time
+ * @cpu: the associated CPU id
+ *
+ * Returns either the TSC if TSCs are being used, or the time and the
+ * time difference between the current time and the buffer start time
+ * if TSCs are not being used. The time is returned so that callers
+ * can use the do_gettimeofday() result if they need to.
+ */
+static inline trace_time_delta get_time_delta(struct timeval *now, u8 cpu)
+{
+ trace_time_delta time_delta;
+
+ if((using_tsc == 1) && cpu_has_tsc)
+ rdtscl(time_delta);
+ else {
+ do_gettimeofday(now);
+ time_delta = calc_time_delta(now, &buffer_start_time(cpu));
+ }
+
+ return time_delta;
+}
+
+/**
+ * get_timestamp: - Utility function for getting a time and TSC pair.
+ * @now: current time
+ * @tsc: the TSC associated with now
+ *
+ * Sets the value pointed to by now to the current time and the value
+ * pointed to by tsc to the tsc associated with that time, if the
+ * platform supports TSC.
+ */
+static inline void get_timestamp(struct timeval *now,
+ trace_time_delta *tsc)
+{
+ do_gettimeofday(now);
+
+ if((using_tsc == 1) && cpu_has_tsc)
+ rdtscl(*tsc);
+}
+
+/**
+ * get_time_or_tsc: - Utility function for getting a time or a TSC.
+ * @now: current time
+ * @tsc: current TSC
+ *
+ * Sets the value pointed to by now to the current time or the value
+ * pointed to by tsc to the current tsc, depending on whether we're
+ * using TSCs or not.
+ */
+static inline void get_time_or_tsc(struct timeval *now,
+ trace_time_delta *tsc)
+{
+ if((using_tsc == 1) && cpu_has_tsc)
+ rdtscl(*tsc);
+ else
+ do_gettimeofday(now);
+}
+
+/**
+ * switch_time_delta: - Utility function getting buffer switch time delta.
+ * @time_delta: previously calculated or retrieved time delta
+ *
+ * Returns the time_delta passed in if we're using TSC or 0 otherwise.
+ * This function is used only for start/end buffer events.
+ */
+static inline trace_time_delta switch_time_delta(trace_time_delta time_delta)
+{
+ if((using_tsc == 1) && cpu_has_tsc)
+ return time_delta;
+ else
+ return 0;
+}
+
+/**
+ * have_tsc: - Does this platform have a useable TSC?
+ *
+ * Returns 1 if this platform has a useable TSC counter for
+ * timestamping purposes, 0 otherwise.
+ */
+static inline int have_tsc(void)
+{
+ if(cpu_has_tsc)
+ return 1;
+ else
+ return 0;
+}
+
+extern void init_ltt_percpu_timer(void * dummy);
+
+/**
+ * init_percpu_timers: - Initialize per-cpu timers (only if using TSC)
+ *
+ * Sets up the timers needed on each CPU for checking asynchronous
+ * tasks needing attention. This is only the case when TSC timestamping
+ * is being used (TSCs need to be read on the current CPU).
+ */
+static inline void init_percpu_timers(void)
+{
+ if((using_tsc == 1) && cpu_has_tsc) {
+ /* Initialize the timer on this (or the only) CPU */
+ init_ltt_percpu_timer(NULL);
+ /* Initialize the timers on all other CPUs */
+ if(smp_call_function(init_ltt_percpu_timer, NULL, 1, 1) != 0)
+ printk(KERN_ALERT "Tracer: Couldn't initialize all per-CPU timers\n");
+ }
+}
+
+#else /* No TSC support (#ifdef CONFIG_X86_TSC) */
+#include <asm-generic/trace.h>
+#endif /* #ifdef CONFIG_X86_TSC */
diff -urpN linux-2.5.46/include/asm-i386/unistd.h linux-2.5.46-ltt/include/asm-i386/unistd.h
--- linux-2.5.46/include/asm-i386/unistd.h Mon Nov 4 17:30:35 2002
+++ linux-2.5.46-ltt/include/asm-i386/unistd.h Mon Nov 4 19:10:41 2002
@@ -262,6 +262,7 @@
#define __NR_sys_epoll_ctl 255
#define __NR_sys_epoll_wait 256
#define __NR_remap_file_pages 257
+#define __NR_sys_trace 258


/* user-visible error numbers are in the range -1 - -124: see <asm-i386/errno.h> */
-
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