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authorBrian Uhrain says <buhrain@rosettastone.com>2006-04-11 01:53:16 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-04-11 09:18:34 -0400
commit917b1f78a9871a1985004df09ed1eb2e0dc3bf4f (patch)
treefad71a349195be55c35d026c24422678c1b73e6e
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>
-rw-r--r--arch/alpha/kernel/setup.c17
-rw-r--r--arch/alpha/kernel/smp.c8
2 files changed, 20 insertions, 5 deletions
diff --git a/arch/alpha/kernel/setup.c b/arch/alpha/kernel/setup.c
index a15e18a00258..558b83368559 100644
--- a/arch/alpha/kernel/setup.c
+++ b/arch/alpha/kernel/setup.c
@@ -24,6 +24,7 @@
24#include <linux/config.h> /* CONFIG_ALPHA_LCA etc */ 24#include <linux/config.h> /* CONFIG_ALPHA_LCA etc */
25#include <linux/mc146818rtc.h> 25#include <linux/mc146818rtc.h>
26#include <linux/console.h> 26#include <linux/console.h>
27#include <linux/cpu.h>
27#include <linux/errno.h> 28#include <linux/errno.h>
28#include <linux/init.h> 29#include <linux/init.h>
29#include <linux/string.h> 30#include <linux/string.h>
@@ -471,6 +472,22 @@ page_is_ram(unsigned long pfn)
471 return 0; 472 return 0;
472} 473}
473 474
475static int __init
476register_cpus(void)
477{
478 int i;
479
480 for_each_possible_cpu(i) {
481 struct cpu *p = kzalloc(sizeof(*p), GFP_KERNEL);
482 if (!p)
483 return -ENOMEM;
484 register_cpu(p, i, NULL);
485 }
486 return 0;
487}
488
489arch_initcall(register_cpus);
490
474void __init 491void __init
475setup_arch(char **cmdline_p) 492setup_arch(char **cmdline_p)
476{ 493{
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)
439 if ((cpu->flags & 0x1cc) == 0x1cc) { 439 if ((cpu->flags & 0x1cc) == 0x1cc) {
440 smp_num_probed++; 440 smp_num_probed++;
441 /* Assume here that "whami" == index */ 441 /* Assume here that "whami" == index */
442 cpu_set(i, cpu_possible_map); 442 cpu_set(i, cpu_present_mask);
443 cpu->pal_revision = boot_cpu_palrev; 443 cpu->pal_revision = boot_cpu_palrev;
444 } 444 }
445 445
@@ -450,9 +450,8 @@ setup_smp(void)
450 } 450 }
451 } else { 451 } else {
452 smp_num_probed = 1; 452 smp_num_probed = 1;
453 cpu_set(boot_cpuid, cpu_possible_map); 453 cpu_set(boot_cpuid, cpu_present_mask);
454 } 454 }
455 cpu_present_mask = cpumask_of_cpu(boot_cpuid);
456 455
457 printk(KERN_INFO "SMP: %d CPUs probed -- cpu_present_mask = %lx\n", 456 printk(KERN_INFO "SMP: %d CPUs probed -- cpu_present_mask = %lx\n",
458 smp_num_probed, cpu_possible_map.bits[0]); 457 smp_num_probed, cpu_possible_map.bits[0]);
@@ -488,9 +487,8 @@ void __devinit
488smp_prepare_boot_cpu(void) 487smp_prepare_boot_cpu(void)
489{ 488{
490 /* 489 /*
491 * Mark the boot cpu (current cpu) as both present and online 490 * Mark the boot cpu (current cpu) as online
492 */ 491 */
493 cpu_set(smp_processor_id(), cpu_present_mask);
494 cpu_set(smp_processor_id(), cpu_online_map); 492 cpu_set(smp_processor_id(), cpu_online_map);
495} 493}
496 494