On Tue, May 10, 2005 at 03:51:25AM +0200, Andi Kleen wrote:
> >
> > Andrew, please don't drop this patch. There are Intel systems which are
> > broken with out this patch.
>
> Ok. Fine for now. Please submit it then Andrew.
>
> BTW I think there is more code that assume BP == id 0, e.g. apic.c seems
> to have several instances too.
>
> -Andi
Hi Andi
here is a slighly revised patch that Suresh submitted earlier. I did create one
that is similar to ia64 smp_build_cpu_map(), but it ended with about 50+ lines of code.
I think this is much simpler. Even in ia64 we assume that the sapic id list is ordered, and
essentially smp_build_cpus() creates it this way.
In addition the earlier code doesnt boot when bsp is not ordered and we use
maxcpus=1 option.
If this appears to be ok for you (a prettier hack :-)).
--
Cheers,
Ashok Raj
- Open Source Technology Center
This patch removes the assumption that LAPIC entries contain the BSP as its
first entry. This is a slight improvement to the temporary fix submitted by
Suresh Siddha.
- Removes assumption that LAPIC entries contain BSP first.
- Builds x86_acpiid_to_apicid[] and bios_cpu_apicid[] properly with
BSP as first entry.
- Made maxcpus=1 boot on these systems. Since the parsing earlier in
arch/x86_64/kernel/mpparse.c stopped after maxcpus entries, other entries
were not processed, this causes kernel not to boot on these systems.
TBD: x86_acpiid_to_apicid and bios_cpu_apicid[] seem to be exactly the same.
This could be removed, but might need more work to cleanup.
Signed-off-by: Ashok Raj <[email protected]>
-------
Index: linux-2.6.12-rc3-mm3/arch/x86_64/kernel/mpparse.c
===================================================================
--- linux-2.6.12-rc3-mm3.orig/arch/x86_64/kernel/mpparse.c 2005-05-10 14:40:45.000000000 -0700
+++ linux-2.6.12-rc3-mm3/arch/x86_64/kernel/mpparse.c 2005-05-10 16:08:59.000000000 -0700
@@ -107,6 +107,7 @@
static void __init MP_processor_info (struct mpc_config_processor *m)
{
int ver;
+ static int found_bsp=0;
if (!(m->mpc_cpuflag & CPU_ENABLED))
return;
@@ -126,11 +127,6 @@
" Processor ignored.\n", NR_CPUS);
return;
}
- if (num_processors >= maxcpus) {
- printk(KERN_WARNING "WARNING: maxcpus limit of %i reached."
- " Processor ignored.\n", maxcpus);
- return;
- }
num_processors++;
@@ -151,18 +147,19 @@
}
apic_version[m->mpc_apicid] = ver;
- if ((m->mpc_cpuflag & CPU_BOOTPROCESSOR) && num_processors > 1) {
- /* for now smp boot code assumes that the first element
- * in bios_cpu_apicid array is of boot processor's.
- * And we will bring up the AP's in the order listed
- * by the bios tables.
+ if (m->mpc_cpuflag & CPU_BOOTPROCESSOR) {
+ /*
+ * bios_cpu_apicid is required to have processors listed
+ * in same order as logical cpu numbers. Hence the first
+ * entry is BSP, and so on.
*/
- int j;
- for (j = num_processors - 1; j >= 1; j--)
- bios_cpu_apicid[j] = bios_cpu_apicid[j-1];
bios_cpu_apicid[0] = m->mpc_apicid;
- } else
- bios_cpu_apicid[num_processors - 1] = m->mpc_apicid;
+ x86_cpu_to_apicid[0] = m->mpc_apicid;
+ found_bsp = 1;
+ } else {
+ bios_cpu_apicid[num_processors - found_bsp] = m->mpc_apicid;
+ x86_cpu_to_apicid[num_processors - found_bsp] = m->mpc_apicid;
+ }
}
static void __init MP_bus_info (struct mpc_config_bus *m)
Index: linux-2.6.12-rc3-mm3/arch/x86_64/kernel/smpboot.c
===================================================================
--- linux-2.6.12-rc3-mm3.orig/arch/x86_64/kernel/smpboot.c 2005-05-10 14:40:46.000000000 -0700
+++ linux-2.6.12-rc3-mm3/arch/x86_64/kernel/smpboot.c 2005-05-10 16:09:00.000000000 -0700
@@ -531,7 +531,6 @@
printk("failed fork for CPU %d\n", cpu);
return PTR_ERR(idle);
}
- x86_cpu_to_apicid[cpu] = apicid;
cpu_pda[cpu].pcurrent = idle;
@@ -842,7 +841,6 @@
GET_APIC_ID(apic_read(APIC_ID)), boot_cpu_id);
/* Or can we switch back to PIC here? */
}
- x86_cpu_to_apicid[0] = boot_cpu_id;
/*
* Now start the IO-APICs
-
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