Messages in this thread Patch in this message | | | Date | Thu, 13 Apr 2006 16:08:53 -0700 | From | Greg KH <> | Subject | [patch 15/22] alpha: SMP boot fixes |
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-stable review patch. If anyone has any objections, please let us know.
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From: Brian Uhrain <buhrain@rosettastone.com> says:
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>
--- arch/alpha/kernel/setup.c | 17 +++++++++++++++++ arch/alpha/kernel/smp.c | 8 +++----- 2 files changed, 20 insertions(+), 5 deletions(-)
--- linux-2.6.16.5.orig/arch/alpha/kernel/setup.c +++ linux-2.6.16.5/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 +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) { --- linux-2.6.16.5.orig/arch/alpha/kernel/smp.c +++ linux-2.6.16.5/arch/alpha/kernel/smp.c @@ -439,7 +439,7 @@ setup_smp(void) if ((cpu->flags & 0x1cc) == 0x1cc) { smp_num_probed++; /* 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 smp_prepare_boot_cpu(void) { /* - * 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); } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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