Added Sapan's real-time clock patch.

9 files changed, 176 insertions, 28 deletions

diff --git a/Documentation/Configure.help b/Documentation/Configure.help
index 96669d2..d17d25c 100644
--- a/Documentation/Configure.help
+++ b/Documentation/Configure.help
@@ -15699,6 +15699,15 @@ CONFIG_TTY_LOG
   Say 'N' unless you are setting up a UML honeypot or otherwise know that
   you want this option.
 
+UML real-time clock support
+CONFIG_UML_REAL_TIME_CLOCK
+  This option ties the UML clock to the host clock, so that time passes at
+  the same rate as on the host, regardless of how much CPU time the UML is
+  getting.  This should normally be enabled.  The exception would be if you're
+  debugging UML.  In this case, time spent staring at the debugger with UML
+  stopped will cause lots of timer ticks to be backed up, and UML will spent
+  lots of time calling the timer when it is finally continued.
+
 Microtek USB scanner support
 CONFIG_USB_MICROTEK
   Say Y here if you want support for the Microtek X6USB and
diff --git a/arch/um/config.in b/arch/um/config.in
index e738e57..a28534b 100644
--- a/arch/um/config.in
+++ b/arch/um/config.in
@@ -49,6 +49,7 @@ int 'Kernel address space size (in .5G units)' CONFIG_KERNEL_HALF_GIGS 1
 bool 'Highmem support' CONFIG_HIGHMEM
 bool '/proc/mm' CONFIG_PROC_MM
 int 'Kernel stack size order' CONFIG_KERNEL_STACK_ORDER 2
+bool 'Real-time Clock' CONFIG_UML_REAL_TIME_CLOCK
 endmenu
 
 mainmenu_option next_comment
diff --git a/arch/um/include/kern_util.h b/arch/um/include/kern_util.h
index 26627ee..6c39cfd 100644
--- a/arch/um/include/kern_util.h
+++ b/arch/um/include/kern_util.h
@@ -107,6 +107,8 @@ extern void arch_switch(void);
 extern void free_irq(unsigned int, void *);
 extern int um_in_interrupt(void);
 extern int cpu(void);
+extern unsigned long long time_stamp(void);
+
 #endif
 
 /*
diff --git a/arch/um/include/user_util.h b/arch/um/include/user_util.h
index 929576b..a94c461 100644
--- a/arch/um/include/user_util.h
+++ b/arch/um/include/user_util.h
@@ -83,6 +83,7 @@ extern void check_sigio(void);
 extern int run_kernel_thread(int (*fn)(void *), void *arg, void **jmp_ptr);
 extern void write_sigio_workaround(void);
 extern void arch_check_bugs(void);
+extern int cpu_feature(char *what, char *buf, int len);
 extern int arch_handle_signal(int sig, union uml_pt_regs *regs);
 extern int arch_fixup(unsigned long address, void *sc_ptr);
 extern int can_do_skas(void);
diff --git a/arch/um/kernel/skas/trap_user.c b/arch/um/kernel/skas/trap_user.c
index 0906f65..ef45cb9 100644
--- a/arch/um/kernel/skas/trap_user.c
+++ b/arch/um/kernel/skas/trap_user.c
@@ -1,5 +1,5 @@
 /* 
- * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
+ * Copyright (C) 2002 - 2003 Jeff Dike (jdike@addtoit.com)
  * Licensed under the GPL
  */
 
@@ -41,8 +41,6 @@ void user_signal(int sig, union uml_pt_regs *regs)
 {
 	struct signal_info *info;
 
-	if(sig == SIGVTALRM)
-		missed_ticks[cpu()]++;
 	regs->skas.is_user = 1;
 	regs->skas.fault_addr = 0;
 	regs->skas.fault_type = 0;
diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c
index 34e16dc..7a6f766 100644
--- a/arch/um/kernel/time.c
+++ b/arch/um/kernel/time.c
@@ -4,6 +4,7 @@
  */
 
 #include <stdio.h>
+#include <stdlib.h>
 #include <unistd.h>
 #include <time.h>
 #include <sys/time.h>
@@ -78,8 +79,44 @@ void idle_timer(void)
 	set_interval(ITIMER_REAL);
 }
 
+static long get_host_hz(void)
+{
+	char mhzline[16], *end;
+	int ret, mult, mhz, rest, len;
+
+	ret = cpu_feature("cpu MHz", mhzline, 
+			  sizeof(mhzline) / sizeof(mhzline[0]));
+	if(!ret)
+		panic ("Could not get host MHZ");
+
+	mhz = strtoul(mhzline, &end, 10);
+
+	/* This business is to parse a floating point number without using
+	 * floating types.
+	 */
+
+	rest = 0;
+	mult = 0;
+	if(*end == '.'){
+		end++;
+		len = strlen(end);
+		if(len < 6)
+			mult = 6 - len;
+		else if(len > 6)
+			end[6] = '\0';
+		rest = strtoul(end, NULL, 10);
+		while(mult-- > 0)
+			rest *= 10;
+	}
+
+	return(1000000 * mhz + rest);
+}
+
+int host_hz = 0;
+
 void time_init(void)
 {
+	host_hz = get_host_hz();
 	if(signal(SIGVTALRM, boot_timer_handler) == SIG_ERR)
 		panic("Couldn't set SIGVTALRM handler");
 	set_interval(ITIMER_VIRTUAL);
diff --git a/arch/um/kernel/time_kern.c b/arch/um/kernel/time_kern.c
index b45f75f..8570a03 100644
--- a/arch/um/kernel/time_kern.c
+++ b/arch/um/kernel/time_kern.c
@@ -35,13 +35,47 @@ int timer_irq_inited = 0;
  */
 int __attribute__ ((__section__ (".unprotected"))) missed_ticks[NR_CPUS];
 
+static int first_tick;
+static unsigned long long prev_tsc;
+static long long delta;   		/* Deviation per interval */
+
+extern int host_hz;
+
 void timer_irq(union uml_pt_regs *regs)
 {
-	int cpu = current->processor, ticks = missed_ticks[cpu];
+	unsigned long long ticks = 0;
 
-        if(!timer_irq_inited) return;
-	missed_ticks[cpu] = 0;
-	while(ticks--) do_IRQ(TIMER_IRQ, regs);
+        if(!timer_irq_inited){
+		/* This is to ensure that ticks don't pile up when
+		 * the timer handler is suspended */
+		first_tick = 0;
+		return;
+	}
+	
+	if(first_tick){
+#if defined(CONFIG_UML_REAL_TIME_CLOCK)
+		unsigned long long tsc;
+		 /* We've had 1 tick */
+		tsc = time_stamp();
+
+		delta += tsc - prev_tsc;
+		prev_tsc = tsc;
+
+		ticks += (delta * HZ) / host_hz;
+		delta -= (ticks * host_hz) / HZ;
+#else
+		ticks = 1;
+#endif
+	}
+	else {
+		prev_tsc = time_stamp();
+		first_tick = 1;
+	}
+
+	while(ticks > 0){
+		do_IRQ(TIMER_IRQ, regs);
+		ticks--;
+	}
 }
 
 void boot_timer_handler(int sig)
@@ -159,7 +193,6 @@ int __init timer_init(void)
 
 __initcall(timer_init);
 
-
 /*
  * Overrides for Emacs so that we follow Linus's tabbing style.
  * Emacs will notice this stuff at the end of the file and automatically
diff --git a/arch/um/sys-i386/bugs.c b/arch/um/sys-i386/bugs.c
index fe4cbdb..d39750a 100644
--- a/arch/um/sys-i386/bugs.c
+++ b/arch/um/sys-i386/bugs.c
@@ -48,44 +48,79 @@ static char token(int fd, char *buf, int len, char stop)
 	return(c);
 }
 
-static int check_cpu_feature(char *feature, int *have_it)
+static int find_cpuinfo_line(int fd, char *key, char *scratch, int len)
 {
-	char buf[MAXTOKEN], c;
-	int fd, len = sizeof(buf)/sizeof(buf[0]), n;
-
-	printk("Checking for host processor %s support...", feature);
-	fd = os_open_file("/proc/cpuinfo", of_read(OPENFLAGS()), 0);
-	if(fd < 0){
-		printk("Couldn't open /proc/cpuinfo, err = %d\n", -fd);
-		return(0);
-	}
+	int n;
+	char c;
 
-	*have_it = 0;
-	buf[len - 1] = '\0';
+	scratch[len - 1] = '\0';
 	while(1){
-		c = token(fd, buf, len - 1, ':');
-		if(c <= 0) goto out;
+		c = token(fd, scratch, len - 1, ':');
+		if(c <= 0)
+			return(0);
 		else if(c != ':'){
 			printk("Failed to find ':' in /proc/cpuinfo\n");
-			goto out;
+			return(0);
 		}
 
-		if(!strncmp(buf, "flags", strlen("flags"))) break;
+		if(!strncmp(scratch, key, strlen(key))) 
+			return(1);
 
 		do {
 			n = os_read_file(fd, &c, sizeof(c));
 			if(n != sizeof(c)){
 				printk("Failed to find newline in "
 				       "/proc/cpuinfo, err = %d\n", -n);
-				goto out;
+				return(0);
 			}
 		} while(c != '\n');
 	}
+	return(0);
+}
+
+int cpu_feature(char *what, char *buf, int len)
+{
+	int fd, ret = 0;
+
+	fd = os_open_file("/proc/cpuinfo", of_read(OPENFLAGS()), 0);
+	if(fd < 0){
+		printk("Couldn't open /proc/cpuinfo, err = %d\n", -fd);
+		return(0);
+	}
+
+	if(!find_cpuinfo_line(fd, what, buf, len)){
+		printk("Couldn't find '%s' line in /proc/cpuinfo\n", what);
+		goto out_close;
+	}
+
+	token(fd, buf, len, '\n');
+	ret = 1;
+
+ out_close:
+	os_close_file(fd);
+	return(ret);
+}
+
+static int check_cpu_flag(char *feature, int *have_it)
+{
+	char buf[MAXTOKEN], c;
+	int fd, len = sizeof(buf)/sizeof(buf[0]);
+
+	printk("Checking for host processor %s support...", feature);
+	fd = os_open_file("/proc/cpuinfo", of_read(OPENFLAGS()), 0);
+	if(fd < 0){
+		printk("Couldn't open /proc/cpuinfo, err = %d\n", -fd);
+		return(0);
+	}
+
+	*have_it = 0;
+	if(!find_cpuinfo_line(fd, "flags", buf, sizeof(buf) / sizeof(buf[0])))
+		goto out;
 
 	c = token(fd, buf, len - 1, ' ');
 	if(c < 0) goto out;
 	else if(c != ' '){
-		printk("Failed to find ':' in /proc/cpuinfo\n");
+		printk("Failed to find ' ' in /proc/cpuinfo\n");
 		goto out;
 	}
 
@@ -106,6 +141,9 @@ static int check_cpu_feature(char *feature, int *have_it)
 	return(1);
 }
 
+#if 0 /* This doesn't work in tt mode, plus it's causing compilation problems
+       * for some people.
+       */
 static void disable_lcall(void)
 {
 	struct modify_ldt_ldt_s ldt;
@@ -119,10 +157,13 @@ static void disable_lcall(void)
 	if(err)
 		printk("Failed to disable lcall7 - errno = %d\n", errno);
 }
+#endif
 
 void arch_init_thread(void)
 {
+#if 0
 	disable_lcall();
+#endif
 }
 
 void arch_check_bugs(void)
@@ -134,8 +175,10 @@ void arch_check_bugs(void)
 		       "checks\n");
 		return;
 	}
-	if(check_cpu_feature("cmov", &have_it)) cpu_has_cmov = have_it;
-	if(check_cpu_feature("xmm", &have_it)) cpu_has_xmm = have_it;
+	if(check_cpu_flag("cmov", &have_it)) 
+		cpu_has_cmov = have_it;
+	if(check_cpu_flag("xmm", &have_it)) 
+		cpu_has_xmm = have_it;
 }
 
 int arch_handle_signal(int sig, union uml_pt_regs *regs)
diff --git a/arch/um/sys-i386/time.c b/arch/um/sys-i386/time.c
new file mode 100644
index 0000000..a6a5ba7
--- /dev/null
+++ b/arch/um/sys-i386/time.c
@@ -0,0 +1,24 @@
+/*
+ * sys-i386/time.c 
+ * Created 		25.9.2002	Sapan Bhatia
+ *
+ */
+
+unsigned long long time_stamp(void)
+{
+	unsigned long low, high;
+
+	asm("rdtsc" : "=a" (low), "=d" (high));
+	return((((unsigned long long) high) << 32) + low);
+}
+
+/*
+ * 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:
+ */