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authorBrian Uhrain says <buhrain@rosettastone.com>2006-04-10 22:53:16 -0700
committerGreg Kroah-Hartman <gregkh@suse.de>2006-04-17 13:16:06 -0700
commit3e1792fa40be9dd0f530e2b32f439bb97c40bcee (patch)
parentd90fd1f7c1e1003d899df415456f4f7164ff11e1 (diff)
[PATCH] alpha: SMP boot fixes
I've encountered two problems with 2.6.16 and newer kernels on my API CS20 (dual 833MHz Alpha 21264b processors). The first is the kernel OOPSing because of a NULL pointer dereference while trying to populate SysFS with the CPU information. The other is that only one processor was being brought up. I've included a small Alpha-specific patch that fixes both problems. The first problem was caused by the CPUs never being properly registered using register_cpu(), the way it's done on other architectures. The second problem has to do with the removal of hwrpb_cpu_present_mask in arch/alpha/kernel/smp.c. In setup_smp() in the 2.6.15 kernel sources, hwrpb_cpu_present_mask has a bit set for each processor that is probed, and afterwards cpu_present_mask is set to the cpumask for the boot CPU. In the same function of the same file in the 2.6.16 sources, instead of hwrpb_cpu_present_mask being set, cpu_possible_map is updated for each probed CPU. cpu_present_mask is still set to the cpumask of the boot CPU afterwards. The problem lies in include/asm-alpha/smp.h, where cpu_possible_map is #define'd to be cpu_present_mask. Cleanups from: Ivan Kokshaysky <ink@jurassic.park.msu.ru> - cpu_present_mask and cpu_possible_map are essentially the same thing on alpha, as it doesn't support CPU hotplug; - allocate "struct cpu" only for present CPUs, like sparc64 does. Static array of "struct cpu" is just a waste of memory. Signed-off-by: Brian Uhrain <buhrain@rosettastone.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2 files changed, 20 insertions, 5 deletions
diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c
index b4e5f8ff2b25..45308bd3b3a4 100644
--- a/arch/alpha/kernel/setup.c
+++ b/arch/alpha/kernel/setup.c
@@ -24,6 +24,7 @@
#include <linux/config.h> /* CONFIG_ALPHA_LCA etc */
#include <linux/mc146818rtc.h>
#include <linux/console.h>
+#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/string.h>
@@ -477,6 +478,22 @@ page_is_ram(unsigned long pfn)
#undef PFN_PHYS
#undef PFN_MAX
+static int __init
+ int i;
+ for_each_possible_cpu(i) {
+ struct cpu *p = kzalloc(sizeof(*p), GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ register_cpu(p, i, NULL);
+ }
+ return 0;
void __init
setup_arch(char **cmdline_p)
diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index 02c2db08114a..185255416e85 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -439,7 +439,7 @@ setup_smp(void)
if ((cpu->flags & 0x1cc) == 0x1cc) {
/* Assume here that "whami" == index */
- cpu_set(i, cpu_possible_map);
+ cpu_set(i, cpu_present_mask);
cpu->pal_revision = boot_cpu_palrev;
@@ -450,9 +450,8 @@ setup_smp(void)
} else {
smp_num_probed = 1;
- cpu_set(boot_cpuid, cpu_possible_map);
+ cpu_set(boot_cpuid, cpu_present_mask);
- cpu_present_mask = cpumask_of_cpu(boot_cpuid);
printk(KERN_INFO "SMP: %d CPUs probed -- cpu_present_mask = %lx\n",
smp_num_probed, cpu_possible_map.bits[0]);
@@ -488,9 +487,8 @@ void __devinit
- * Mark the boot cpu (current cpu) as both present and online
+ * Mark the boot cpu (current cpu) as online
- cpu_set(smp_processor_id(), cpu_present_mask);
cpu_set(smp_processor_id(), cpu_online_map);