[uml-devel] [PATCH] - fix for 2.4.22-7um RTC on CPUs faster than 2.1 GHz

["Christopher S. Aker" <caker@theshore.net>]

Enabling the RTC in 2.4.22-7um produced a hang very soon after INIT at boot time.

I discovered host_hz as an int overflows past 2.1 Ghz (2147483647 hz).  An
unsigned int/long would only work for up to ~ 4.3 Ghz (4294967295 hz) or so, which
isn't that far off, imo...  So -- Below is a patch that changes the type of
host_hz to unsigned long long.  Also, I believe some casting was taking place with
the return value of get_host_hz, so mhz is also redefined as an unsigned long
long.

-Chris


diff -Naur orig/arch/um/kernel/time.c mine/arch/um/kernel/time.c
--- orig/arch/um/kernel/time.c  2003-12-18 02:30:20.000000000 -0500
+++ mine/arch/um/kernel/time.c  2003-12-18 02:32:38.000000000 -0500
@@ -79,10 +79,11 @@
        set_interval(ITIMER_REAL);
 }

-static long get_host_hz(void)
+static unsigned long long get_host_hz(void)
 {
        char mhzline[16], *end;
-       int ret, mult, mhz, rest, len;
+       int ret, mult, rest, len;
+       unsigned long long mhz;

        ret = cpu_feature("cpu MHz", mhzline,
                          sizeof(mhzline) / sizeof(mhzline[0]));
@@ -112,7 +113,7 @@
        return(1000000 * mhz + rest);
 }

-int host_hz = 0;
+unsigned long long host_hz = 0;

 void time_init(void)
 {
diff -Naur orig/arch/um/kernel/time_kern.c mine/arch/um/kernel/time_kern.c
--- orig/arch/um/kernel/time_kern.c     2003-12-18 02:30:20.000000000 -0500
+++ mine/arch/um/kernel/time_kern.c     2003-12-18 02:34:58.000000000 -0500
@@ -39,7 +39,7 @@
 static unsigned long long prev_tsc;
 static long long delta;                /* Deviation per interval */

-extern int host_hz;
+extern unsigned long long host_hz;

 void timer_irq(union uml_pt_regs *regs)
 {



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