[PATCH 10/16] UML - Make syscall debugging code configurable

From: Jeff Dike
Date: Mon Mar 07 2005 - 13:19:11 EST

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This patch makes some debug code in the system call path configurable.

Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>

Index: linux-2.6.11/arch/um/Kconfig.debug
===================================================================
--- linux-2.6.11.orig/arch/um/Kconfig.debug 2005-03-05 12:07:34.000000000 -0500
+++ linux-2.6.11/arch/um/Kconfig.debug 2005-03-05 12:18:28.000000000 -0500
@@ -40,4 +40,14 @@
If you're involved in UML kernel development and want to use gcov,
say Y. If you're unsure, say N.

+config SYSCALL_DEBUG
+ bool "Enable system call debugging"
+ default N
+ depends on DEBUG_INFO
+ help
+ This adds some system debugging to UML, including keeping a ring buffer
+ with recent system calls and some global and per-task statistics.
+
+ If unsure, say N
+
endmenu
Index: linux-2.6.11/arch/um/defconfig
===================================================================
--- linux-2.6.11.orig/arch/um/defconfig 2005-03-05 12:07:41.000000000 -0500
+++ linux-2.6.11/arch/um/defconfig 2005-03-05 12:18:28.000000000 -0500
@@ -52,7 +52,6 @@
# CONFIG_BSD_PROCESS_ACCT_V3 is not set
CONFIG_SYSCTL=y
# CONFIG_AUDIT is not set
-CONFIG_LOG_BUF_SHIFT=14
# CONFIG_HOTPLUG is not set
CONFIG_KOBJECT_UEVENT=y
CONFIG_IKCONFIG=y
@@ -61,9 +60,10 @@
CONFIG_KALLSYMS=y
# CONFIG_KALLSYMS_ALL is not set
CONFIG_KALLSYMS_EXTRA_PASS=y
+CONFIG_BASE_FULL=y
+CONFIG_BASE_SMALL=0
CONFIG_FUTEX=y
CONFIG_EPOLL=y
-# CONFIG_CC_OPTIMIZE_FOR_SIZE is not set
CONFIG_SHMEM=y
CONFIG_CC_ALIGN_FUNCTIONS=0
CONFIG_CC_ALIGN_LABELS=0
@@ -241,6 +241,11 @@
# CONFIG_NET_PCMCIA is not set

#
+# PCMCIA network device support
+#
+# CONFIG_NET_PCMCIA is not set
+
+#
# Wan interfaces
#
# CONFIG_WAN is not set
@@ -437,3 +442,4 @@
CONFIG_PT_PROXY=y
# CONFIG_GPROF is not set
# CONFIG_GCOV is not set
+# CONFIG_SYSCALL_DEBUG is not set
Index: linux-2.6.11/arch/um/kernel/Makefile
===================================================================
--- linux-2.6.11.orig/arch/um/kernel/Makefile 2005-03-05 12:14:17.000000000 -0500
+++ linux-2.6.11/arch/um/kernel/Makefile 2005-03-05 12:18:28.000000000 -0500
@@ -18,6 +18,7 @@
obj-$(CONFIG_GPROF) += gprof_syms.o
obj-$(CONFIG_GCOV) += gmon_syms.o
obj-$(CONFIG_TTY_LOG) += tty_log.o
+obj-$(CONFIG_SYSCALL_DEBUG) += syscall_user.o

obj-$(CONFIG_MODE_TT) += tt/
obj-$(CONFIG_MODE_SKAS) += skas/
Index: linux-2.6.11/arch/um/kernel/skas/syscall_user.c
===================================================================
--- linux-2.6.11.orig/arch/um/kernel/skas/syscall_user.c 2005-03-05 12:14:17.000000000 -0500
+++ linux-2.6.11/arch/um/kernel/skas/syscall_user.c 2005-03-05 12:18:28.000000000 -0500
@@ -6,6 +6,7 @@
#include <stdlib.h>
#include <signal.h>
#include "kern_util.h"
+#include "uml-config.h"
#include "syscall_user.h"
#include "sysdep/ptrace.h"
#include "sysdep/sigcontext.h"
@@ -14,6 +15,11 @@
void handle_syscall(union uml_pt_regs *regs)
{
long result;
+#if UML_CONFIG_SYSCALL_DEBUG
+ int index;
+
+ index = record_syscall_start(UPT_SYSCALL_NR(regs));
+#endif

syscall_trace(regs, 0);
result = execute_syscall_skas(regs);
@@ -21,6 +27,9 @@
REGS_SET_SYSCALL_RETURN(regs->skas.regs, result);

syscall_trace(regs, 1);
+#if UML_CONFIG_SYSCALL_DEBUG
+ record_syscall_end(index, result);
+#endif
}

/*
Index: linux-2.6.11/arch/um/kernel/syscall_kern.c
===================================================================
--- linux-2.6.11.orig/arch/um/kernel/syscall_kern.c 2005-03-05 12:14:17.000000000 -0500
+++ linux-2.6.11/arch/um/kernel/syscall_kern.c 2005-03-05 12:18:28.000000000 -0500
@@ -154,6 +154,22 @@
return error;
}

+DEFINE_SPINLOCK(syscall_lock);
+
+static int syscall_index = 0;
+
+int next_syscall_index(int limit)
+{
+ int ret;
+
+ spin_lock(&syscall_lock);
+ ret = syscall_index;
+ if(++syscall_index == limit)
+ syscall_index = 0;
+ spin_unlock(&syscall_lock);
+ return(ret);
+}
+
/*
* Overrides for Emacs so that we follow Linus's tabbing style.
* Emacs will notice this stuff at the end of the file and automatically
Index: linux-2.6.11/arch/um/kernel/syscall_user.c
===================================================================
--- linux-2.6.11.orig/arch/um/kernel/syscall_user.c 2005-03-05 12:07:34.000000000 -0500
+++ linux-2.6.11/arch/um/kernel/syscall_user.c 2005-03-05 12:18:28.000000000 -0500
@@ -46,3 +46,51 @@
* c-file-style: "linux"
* End:
*/
+/*
+ * Copyright (C) 2002 Jeff Dike (jdike@xxxxxxxxxx)
+ * Licensed under the GPL
+ */
+
+#include <stdlib.h>
+#include <sys/time.h>
+#include "kern_util.h"
+#include "syscall_user.h"
+
+struct {
+ int syscall;
+ int pid;
+ long result;
+ struct timeval start;
+ struct timeval end;
+} syscall_record[1024];
+
+int record_syscall_start(int syscall)
+{
+ int max, index;
+
+ max = sizeof(syscall_record)/sizeof(syscall_record[0]);
+ index = next_syscall_index(max);
+
+ syscall_record[index].syscall = syscall;
+ syscall_record[index].pid = current_pid();
+ syscall_record[index].result = 0xdeadbeef;
+ gettimeofday(&syscall_record[index].start, NULL);
+ return(index);
+}
+
+void record_syscall_end(int index, long result)
+{
+ syscall_record[index].result = result;
+ gettimeofday(&syscall_record[index].end, NULL);
+}
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only. This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-file-style: "linux"
+ * End:
+ */
Index: linux-2.6.11/arch/um/kernel/tt/syscall_kern.c
===================================================================
--- linux-2.6.11.orig/arch/um/kernel/tt/syscall_kern.c 2005-03-05 12:07:34.000000000 -0500
+++ linux-2.6.11/arch/um/kernel/tt/syscall_kern.c 2005-03-05 12:18:28.000000000 -0500
@@ -22,8 +22,10 @@
long res;
int syscall;

+#ifdef CONFIG_SYSCALL_DEBUG
current->thread.nsyscalls++;
nsyscalls++;
+#endif
syscall = UPT_SYSCALL_NR(&regs->regs);

if((syscall >= NR_syscalls) || (syscall < 0))
Index: linux-2.6.11/arch/um/kernel/tt/syscall_user.c
===================================================================
--- linux-2.6.11.orig/arch/um/kernel/tt/syscall_user.c 2005-03-05 12:14:17.000000000 -0500
+++ linux-2.6.11/arch/um/kernel/tt/syscall_user.c 2005-03-05 12:18:28.000000000 -0500
@@ -23,11 +23,17 @@
void *sc;
long result;
int syscall;
+#ifdef UML_CONFIG_DEBUG_SYSCALL
+ int index;
+#endif

syscall = UPT_SYSCALL_NR(regs);
sc = UPT_SC(regs);
SC_START_SYSCALL(sc);

+#ifdef UML_CONFIG_DEBUG_SYSCALL
+ index = record_syscall_start(syscall);
+#endif
syscall_trace(regs, 0);
result = execute_syscall_tt(regs);

@@ -39,6 +45,9 @@
SC_SET_SYSCALL_RETURN(sc, result);

syscall_trace(regs, 1);
+#ifdef UML_CONFIG_DEBUG_SYSCALL
+ record_syscall_end(index, result);
+#endif
}

void do_sigtrap(void *task)
Index: linux-2.6.11/arch/um/kernel/tt/tracer.c
===================================================================
--- linux-2.6.11.orig/arch/um/kernel/tt/tracer.c 2005-03-05 12:14:17.000000000 -0500
+++ linux-2.6.11/arch/um/kernel/tt/tracer.c 2005-03-05 12:18:28.000000000 -0500
@@ -13,7 +13,6 @@
#include <string.h>
#include <sys/mman.h>
#include <sys/ptrace.h>
-#include <linux/ptrace.h>
#include <sys/time.h>
#include <sys/wait.h>
#include "user.h"
@@ -187,7 +186,10 @@
int status, pid = 0, sig = 0, cont_type, tracing = 0, op = 0;
int proc_id = 0, n, err, old_tracing = 0, strace = 0;
int local_using_sysemu = 0;
-
+#ifdef UML_CONFIG_SYSCALL_DEBUG
+ unsigned long eip = 0;
+ int last_index;
+#endif
signal(SIGPIPE, SIG_IGN);
setup_tracer_winch();
tracing_pid = os_getpid();
@@ -278,6 +280,23 @@
else if(WIFSTOPPED(status)){
proc_id = pid_to_processor_id(pid);
sig = WSTOPSIG(status);
+#ifdef UML_CONFIG_SYSCALL_DEBUG
+ if(signal_index[proc_id] == 1024){
+ signal_index[proc_id] = 0;
+ last_index = 1023;
+ }
+ else last_index = signal_index[proc_id] - 1;
+ if(((sig == SIGPROF) || (sig == SIGVTALRM) ||
+ (sig == SIGALRM)) &&
+ (signal_record[proc_id][last_index].signal == sig)&&
+ (signal_record[proc_id][last_index].pid == pid))
+ signal_index[proc_id] = last_index;
+ signal_record[proc_id][signal_index[proc_id]].pid = pid;
+ gettimeofday(&signal_record[proc_id][signal_index[proc_id]].time, NULL);
+ eip = ptrace(PTRACE_PEEKUSER, pid, PT_IP_OFFSET, 0);
+ signal_record[proc_id][signal_index[proc_id]].addr = eip;
+ signal_record[proc_id][signal_index[proc_id]++].signal = sig;
+#endif
if(proc_id == -1){
sleeping_process_signal(pid, sig);
continue;

-
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Next message: Jeff Dike: "[PATCH 14/16] UML - Fix a compile failure"
Previous message: Jeff Dike: "[PATCH 13/16] UML - Remove mm_indirect reference in modify_ldt"
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