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authorAaron Durbin <adurbin@chromium.org>2014-03-28 08:40:59 -0500
committerKyösti Mälkki <kyosti.malkki@gmail.com>2014-04-01 14:31:36 +0200
commit905bfb05dc3f6063c396d4665cc95dcde91a8ced (patch)
treeb066c99da313df1393b20b7ef297c8723f6b01f6 /src/cpu/x86
parentdeb2cb27e9bade18c4d186899edfaeabfc1131bd (diff)
x86: use car_(get|set)_var accessors for apic timer
The timer_fsb variable was not correctly being accessed in the presence of cache-as-ram. The cache-as-ram backing store could be torn down but then udelay() could be called causing hangs from accessing variables that have unknown values. Instead change the timer_fsb variable to g_timer_fsb and obtain the value through a local access method that does the correct things to obtain the correct value. Change-Id: Ia3e30808498cbe4a7f6f116c17a8cf1240a807a3 Signed-off-by: Aaron Durbin <adurbin@chromium.org> Reviewed-on: http://review.coreboot.org/5411 Reviewed-by: Patrick Georgi <patrick@georgi-clan.de> Tested-by: build bot (Jenkins)
Diffstat (limited to 'src/cpu/x86')
-rw-r--r--src/cpu/x86/lapic/apic_timer.c30
1 files changed, 22 insertions, 8 deletions
diff --git a/src/cpu/x86/lapic/apic_timer.c b/src/cpu/x86/lapic/apic_timer.c
index 868fb92716..a113143783 100644
--- a/src/cpu/x86/lapic/apic_timer.c
+++ b/src/cpu/x86/lapic/apic_timer.c
@@ -34,14 +34,17 @@
*/
#if CONFIG_UDELAY_LAPIC_FIXED_FSB
-static const u32 timer_fsb = CONFIG_UDELAY_LAPIC_FIXED_FSB;
+static inline u32 get_timer_fsb(void)
+{
+ return CONFIG_UDELAY_LAPIC_FIXED_FSB;
+}
static int set_timer_fsb(void)
{
return 0;
}
#else
-static u32 timer_fsb CAR_GLOBAL = 0;
+static u32 g_timer_fsb CAR_GLOBAL;
static int set_timer_fsb(void)
{
@@ -56,25 +59,30 @@ static int set_timer_fsb(void)
switch (c.x86_model) {
case 0xe: /* Core Solo/Duo */
case 0x1c: /* Atom */
- timer_fsb = core_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
+ car_set_var(g_timer_fsb, core_fsb[rdmsr(MSR_FSB_FREQ).lo & 7]);
break;
case 0xf: /* Core 2 or Xeon */
case 0x17: /* Enhanced Core */
- timer_fsb = core2_fsb[rdmsr(MSR_FSB_FREQ).lo & 7];
+ car_set_var(g_timer_fsb, core2_fsb[rdmsr(MSR_FSB_FREQ).lo & 7]);
break;
case 0x2a: /* SandyBridge BCLK fixed at 100MHz*/
case 0x3a: /* IvyBridge BCLK fixed at 100MHz*/
case 0x3c: /* Haswell BCLK fixed at 100MHz */
case 0x45: /* Haswell-ULT BCLK fixed at 100MHz */
- timer_fsb = 100;
+ car_set_var(g_timer_fsb, 100);
break;
default:
- timer_fsb = 200;
+ car_set_var(g_timer_fsb, 200);
break;
}
return 0;
}
+
+static inline u32 get_timer_fsb(void)
+{
+ return car_get_var(g_timer_fsb);
+}
#endif
void init_timer(void)
@@ -94,15 +102,18 @@ void init_timer(void)
void udelay(u32 usecs)
{
- u32 start, value, ticks;
+ u32 start, value, ticks, timer_fsb;
if (!thread_yield_microseconds(usecs))
return;
+ timer_fsb = get_timer_fsb();
if (!timer_fsb || (lapic_read(LAPIC_LVTT) &
(LAPIC_LVT_TIMER_PERIODIC | LAPIC_LVT_MASKED)) !=
- (LAPIC_LVT_TIMER_PERIODIC | LAPIC_LVT_MASKED))
+ (LAPIC_LVT_TIMER_PERIODIC | LAPIC_LVT_MASKED)) {
init_timer();
+ timer_fsb = get_timer_fsb();
+ }
/* Calculate the number of ticks to run, our FSB runs at timer_fsb Mhz */
ticks = usecs * timer_fsb;
@@ -125,9 +136,11 @@ void timer_monotonic_get(struct mono_time *mt)
{
uint32_t current_tick;
uint32_t usecs_elapsed;
+ uint32_t timer_fsb;
if (!mono_counter.initialized) {
init_timer();
+ timer_fsb = get_timer_fsb();
/* An FSB frequency of 200Mhz provides a 20 second polling
* interval between timer_monotonic_get() calls before wrap
* around occurs. */
@@ -139,6 +152,7 @@ void timer_monotonic_get(struct mono_time *mt)
mono_counter.initialized = 1;
}
+ timer_fsb = get_timer_fsb();
current_tick = lapic_read(LAPIC_TMCCT);
/* Note that the APIC timer counts down. */
usecs_elapsed = (mono_counter.last_value - current_tick) / timer_fsb;