ACPI: boot correctly with "nosmp" or "maxcpus=0"
In MPS mode, "nosmp" and "maxcpus=0" boot a UP kernel with IOAPIC disabled.
However, in ACPI mode, these parameters didn't completely disable
the IO APIC initialization code and boot failed.
init/main.c:
Disable the IO_APIC if "nosmp" or "maxcpus=0"
undefine disable_ioapic_setup() when it doesn't apply.
i386:
delete ioapic_setup(), it was a duplicate of parse_noapic()
delete undefinition of disable_ioapic_setup()
x86_64:
rename disable_ioapic_setup() to parse_noapic() to match i386
define disable_ioapic_setup() in header to match i386
http://bugzilla.kernel.org/show_bug.cgi?id=1641
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/init/main.c b/init/main.c
index d3bcb3b..cc0653e 100644
--- a/init/main.c
+++ b/init/main.c
@@ -146,9 +146,14 @@
* greater than 0, limits the maximum number of CPUs activated in
* SMP mode to <NUM>.
*/
+#ifndef CONFIG_X86_IO_APIC
+static inline void disable_ioapic_setup(void) {};
+#endif
+
static int __init nosmp(char *str)
{
max_cpus = 0;
+ disable_ioapic_setup();
return 0;
}
@@ -157,10 +162,13 @@
static int __init maxcpus(char *str)
{
get_option(&str, &max_cpus);
- return 1;
+ if (max_cpus == 0)
+ disable_ioapic_setup();
+
+ return 0;
}
-__setup("maxcpus=", maxcpus);
+early_param("maxcpus=", maxcpus);
#else
#define max_cpus NR_CPUS
#endif