Messages in this thread Patch in this message | | | Date | Mon, 24 Mar 2008 14:48:36 -0700 | From | Ravikiran G Thirumalai <> | Subject | Re: [patch 4/4] x86: apic_is_clustered_box to indicate unsynched TSC's on multiboard vSMP systems |
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On Sat, Mar 22, 2008 at 09:02:51PM +0100, Ingo Molnar wrote: > >* Ravikiran G Thirumalai <kiran@scalex86.org> wrote: > >> OK. Something like this? > >yeah. > >small nit: > >> +int is_vsmp_box(void) >> +{ >> + if (is_vsmp != -1) >> + return is_vsmp; >> + else { >> + printk("ScaleMP vSMPowered system detection called too early!\n"); >> + return 0; >> + } >> } > >since this is an "impossible" scenario, just stick in a WARN_ON_ONCE(). >
Sure. Here's the modified patch.
vSMP detection: Access pci config space early in boot to detect if the system is a vSMPowered box, and cache the result in a flag, so that is_vsmp_box() retrieves the value of the flag always.
Signed-off-by; Ravikiran Thirumalai <kiran@scalex86.org>
Index: linux.git.trees/arch/x86/kernel/vsmp_64.c =================================================================== --- linux.git.trees.orig/arch/x86/kernel/vsmp_64.c 2008-03-21 13:15:17.000000000 -0700 +++ linux.git.trees/arch/x86/kernel/vsmp_64.c 2008-03-24 13:57:09.387437626 -0700 @@ -108,25 +108,34 @@ static void __init set_vsmp_pv_ops(void) #endif #ifdef CONFIG_PCI -static int vsmp = -1; +static int is_vsmp = -1; -int is_vsmp_box(void) +static void __init detect_vsmp_box(void) { - if (vsmp != -1) - return vsmp; + is_vsmp = 0; - vsmp = 0; if (!early_pci_allowed()) - return vsmp; + return; - /* Check if we are running on a ScaleMP vSMP box */ + /* Check if we are running on a ScaleMP vSMPowered box */ if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) == (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16))) - vsmp = 1; + is_vsmp = 1; +} - return vsmp; +int is_vsmp_box(void) +{ + if (is_vsmp != -1) + return is_vsmp; + else { + WARN_ON_ONCE(1); + return 0; + } } #else +static int __init detect_vsmp_box(void) +{ +} int is_vsmp_box(void) { return 0; @@ -135,6 +144,7 @@ int is_vsmp_box(void) void __init vsmp_init(void) { + detect_vsmp_box(); if (!is_vsmp_box()) return;
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