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authorShai Fultheim <shai@scalemp.com>2012-04-16 10:39:35 +0300
committerIngo Molnar <mingo@kernel.org>2012-05-14 14:42:33 +0200
commitead91d4b8c3b1fb08a73aaa4a191230ecf717ee0 (patch)
treedb906a57cfa3824b8d3f6dcf39a10113076853e7 /arch/x86/kernel/vsmp_64.c
parentb2d0b7a061bfddd27155c7dcd53f365d9dc0c7c3 (diff)
downloadlinux-ead91d4b8c3b1fb08a73aaa4a191230ecf717ee0.tar.gz
x86/vsmp: Fix number of CPUs when vsmp is disabled
In case CONFIG_X86_VSMP is not set, limit the number of CPUs to the number of CPUs of the first board. Also make CONFIG_X86_VSMP depend on CONFIG_SMP, as there's little point in having a vsmp machine with a single CPU. Signed-off-by: Shai Fultheim <shai@scalemp.com> [ido@wizery.com: rebased, fixed minor coding-style issues] Signed-off-by: Ido Yariv <ido@wizery.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/vsmp_64.c')
-rw-r--r--arch/x86/kernel/vsmp_64.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/arch/x86/kernel/vsmp_64.c b/arch/x86/kernel/vsmp_64.c
index a1d804bcd48..8eeb55a551b 100644
--- a/arch/x86/kernel/vsmp_64.c
+++ b/arch/x86/kernel/vsmp_64.c
@@ -15,6 +15,7 @@
#include <linux/init.h>
#include <linux/pci_ids.h>
#include <linux/pci_regs.h>
+#include <linux/smp.h>
#include <asm/apic.h>
#include <asm/pci-direct.h>
@@ -22,6 +23,8 @@
#include <asm/paravirt.h>
#include <asm/setup.h>
+#define TOPOLOGY_REGISTER_OFFSET 0x10
+
#if defined CONFIG_PCI && defined CONFIG_PARAVIRT
/*
* Interrupt control on vSMPowered systems:
@@ -149,12 +152,49 @@ int is_vsmp_box(void)
return 0;
}
#endif
+
+static void __init vsmp_cap_cpus(void)
+{
+#if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP)
+ void __iomem *address;
+ unsigned int cfg, topology, node_shift, maxcpus;
+
+ /*
+ * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
+ * ones present in the first board, unless explicitly overridden by
+ * setup_max_cpus
+ */
+ if (setup_max_cpus != NR_CPUS)
+ return;
+
+ /* Read the vSMP Foundation topology register */
+ cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
+ address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
+ if (WARN_ON(!address))
+ return;
+
+ topology = readl(address);
+ node_shift = (topology >> 16) & 0x7;
+ if (!node_shift)
+ /* The value 0 should be decoded as 8 */
+ node_shift = 8;
+ maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
+
+ pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
+ maxcpus);
+ setup_max_cpus = maxcpus;
+ early_iounmap(address, 4);
+#endif
+}
+
void __init vsmp_init(void)
{
detect_vsmp_box();
if (!is_vsmp_box())
return;
+ vsmp_cap_cpus();
+
set_vsmp_pv_ops();
return;
}