[SeaBIOS] [PATCH v2] Halt if number of started cpus are more then expected

[Igor Mammedov]

Reduce amount of consumed cpu time (i.e. don't spin forever) if
number of started cpus are more then expected. And print a bug
message into debug port.

And it is not safe to continue to boot if CountCPUs is more than
cmos_smp_count and might be still racing, due to mp/acpi could be
build with still changing CountCPUs. It is safer to stop and allow
user to notice and restart system rather than debug possible
inxplicable bugs later.

v2:
extendend commit message with explanation why not continue to boot

Signed-off-by: Igor Mammedov 
---
 src/smp.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/src/smp.c b/src/smp.c
index 8c077a1..9933ac6 100644
--- a/src/smp.c
+++ b/src/smp.c
@@ -115,8 +115,14 @@ smp_probe(void)
         msleep(10);
     } else {
         u8 cmos_smp_count = inb_cmos(CMOS_BIOS_SMP_COUNT);
-        while (cmos_smp_count + 1 != readl(&CountCPUs))
+        while (cmos_smp_count + 1 != readl(&CountCPUs)) {
+            if (cmos_smp_count + 1 < readl(&CountCPUs)) {
+                dprintf(1, "BUG: Expected %d cpu(s) but %d cpus started\n",
+                        cmos_smp_count + 1, readl(&CountCPUs));
+                hlt();
+            }
             yield();
+        }
     }

// Restore memory.