[SeaBIOS] [PATCH 1/3] Halt if number of started cpus are more then expected
Kevin O'Connor
kevin at koconnor.net
Tue Mar 13 00:51:42 CET 2012
On Sat, Mar 10, 2012 at 12:47:26PM +0100, Igor Mammedov wrote:
> 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.
>
> Signed-off-by: Igor Mammedov <imammedo at redhat.com>
> ---
> 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();
> + }
I suggest just changing the "while !=" to a "while <". The chance of
detecting the error is pretty slim anyway. (Under normal
circumstances, the processor is spinning on the count - the chance of
two other processors getting in to increment before the first
processor sees a change is pretty small.)
-Kevin
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