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x86/vsmp: Fix number of CPUs when vsmp is disabled

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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>
This commit is contained in:
Shai Fultheim 2012-04-16 10:39:35 +03:00 committed by Ingo Molnar
parent b2d0b7a061
commit ead91d4b8c
2 changed files with 41 additions and 0 deletions
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1
arch/x86/Kconfig
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@ -376,6 +376,7 @@ config X86_VSMP
select PARAVIRT
depends on X86_64 && PCI
depends on X86_EXTENDED_PLATFORM
depends on SMP
---help---
Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
supposed to run on these EM64T-based machines. Only choose this option

40
arch/x86/kernel/vsmp_64.c
View file

@ -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;
}