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authorBrian Uhrain says <buhrain@rosettastone.com>2006-04-10 22:53:16 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-04-11 06:18:34 -0700
commit917b1f78a9871a1985004df09ed1eb2e0dc3bf4f (patch)
treefad71a349195be55c35d026c24422678c1b73e6e /arch/alpha/kernel/setup.c
parent1c08ca89b07eeca241fcf1ec297d3ef173a999a9 (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> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/alpha/kernel/setup.c')
-rw-r--r--arch/alpha/kernel/setup.c17
1 files changed, 17 insertions, 0 deletions
diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c
index a15e18a0025..558b8336855 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>
@@ -471,6 +472,22 @@ page_is_ram(unsigned long pfn)
return 0;
}
+static int __init
+register_cpus(void)
+{
+ 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;
+}
+
+arch_initcall(register_cpus);
+
void __init
setup_arch(char **cmdline_p)
{