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Date: Thu, 20 Mar 2008 23:28:39 -0700
From: "Yinghai Lu" <yhlu.kernel@...il.com>
To: "Jeremy Fitzhardinge" <jeremy@...p.org>
Cc: "Ravikiran G Thirumalai" <kiran@...lex86.org>,
"Andrew Morton" <akpm@...ux-foundation.org>,
"Ingo Molnar" <mingo@...e.hu>, linux-kernel@...r.kernel.org,
"Glauber de Oliveira Costa" <gcosta@...hat.com>,
"Andi Kleen" <ak@...e.de>, shai@...lex86.org
Subject: Re: [patch 2/4] x86: Fix build breakage when PCI is define and PARAVIRT is not
On Thu, Mar 20, 2008 at 9:30 PM, Jeremy Fitzhardinge <jeremy@...p.org> wrote:
> Ravikiran G Thirumalai wrote:
> > - Fix the the build breakage when PARAVIRT is defined
> > but PCI is not
> > This fixes problem reported at:
> > http://marc.info/?l=linux-kernel&m=120525966600698&w=2
> > - Make is_vsmp_box() available even when PARAVIRT is not defined.
> > This is needed to determine if tsc's are reliable as a time source
> > even when PARAVIRT is not defined.
> > - split vsmp_init to use is_vsmp_box() and set_vsmp_pv_ops()
> > set_vsmp_pv_ops will do nothing if PCI is not enabled in the config.
> >
>
> I'm a bit confused by all the config dependencies. I had assumed that
> VSMP depended on both PCI and PARAVIRT. Is this not actually true? You
> can have a VSMP system without either or both of PCI/PARAVIRT?
>
> The structure of the code suggests that at the very least VSMP depends
> on PCI (it never makes sense to enable VSMP on a non-PCI system), and
> therefore a number of your config decisions can just be predicated on VSMP.
>
>
> > Signed-off-by: Ravikiran Thirumalai <kiran@...lex86.org>
> >
> > Index: linux.git.trees/arch/x86/kernel/Makefile
> > ===================================================================
> > --- linux.git.trees.orig/arch/x86/kernel/Makefile 2008-03-19 13:39:29.000000000 -0700
> > +++ linux.git.trees/arch/x86/kernel/Makefile 2008-03-19 13:46:14.400935607 -0700
> > @@ -60,7 +60,7 @@ obj-$(CONFIG_KEXEC) += relocate_kernel_
> > obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o
> > obj-$(CONFIG_X86_NUMAQ) += numaq_32.o
> > obj-$(CONFIG_X86_SUMMIT_NUMA) += summit_32.o
> > -obj-$(CONFIG_PARAVIRT) += vsmp_64.o
> > +obj-y += vsmp_64.o
> >
>
> Couldn't this be make obj-$(CONFIG_X86_VSMP)?
>
>
>
> > obj-$(CONFIG_KPROBES) += kprobes.o
> > obj-$(CONFIG_MODULES) += module_$(BITS).o
> > obj-$(CONFIG_ACPI_SRAT) += srat_32.o
> > Index: linux.git.trees/arch/x86/kernel/setup_64.c
> > ===================================================================
> > --- linux.git.trees.orig/arch/x86/kernel/setup_64.c 2008-03-19 13:39:29.000000000 -0700
> > +++ linux.git.trees/arch/x86/kernel/setup_64.c 2008-03-19 13:57:43.951337318 -0700
> > @@ -353,9 +353,7 @@ void __init setup_arch(char **cmdline_p)
> > if (efi_enabled)
> > efi_init();
> >
> > -#ifdef CONFIG_PARAVIRT
> > vsmp_init();
> > -#endif
> >
> > dmi_scan_machine();
> >
> > Index: linux.git.trees/arch/x86/kernel/vsmp_64.c
> > ===================================================================
> > --- linux.git.trees.orig/arch/x86/kernel/vsmp_64.c 2008-03-19 13:39:50.000000000 -0700
> > +++ linux.git.trees/arch/x86/kernel/vsmp_64.c 2008-03-19 20:53:34.267707163 -0700
> > @@ -19,6 +19,7 @@
> > #include <asm/io.h>
> > #include <asm/paravirt.h>
> >
> > +#if defined CONFIG_PCI && defined CONFIG_PARAVIRT
> > /*
> > * Interrupt control on vSMPowered systems:
> > * ~AC is a shadow of IF. If IF is 'on' AC should be 'off'
> > @@ -72,39 +73,11 @@ static unsigned __init vsmp_patch(u8 typ
> >
> > }
> >
> > -static int vsmp = -1;
> > -
> > -int is_vsmp_box(void)
> > -{
> > - if (vsmp != -1)
> > - return vsmp;
> > -
> > - vsmp = 0;
> > - if (!early_pci_allowed())
> > - return vsmp;
> > -
> > - /* Check if we are running on a ScaleMP vSMP box */
> > - if ((read_pci_config_16(0, 0x1f, 0, PCI_VENDOR_ID) ==
> > - PCI_VENDOR_ID_SCALEMP) &&
> > - (read_pci_config_16(0, 0x1f, 0, PCI_DEVICE_ID) ==
> > - PCI_DEVICE_ID_SCALEMP_VSMP_CTL))
> > - vsmp = 1;
> > -
> > - return vsmp;
> > -}
> > -
> > -void __init vsmp_init(void)
> > +static void __init set_vsmp_pv_ops(void)
> > {
> > void *address;
> > unsigned int cap, ctl, cfg;
> >
> > - if (!is_vsmp_box())
> > - return;
> > -
> > - if (!early_pci_allowed())
> > - return;
> > -
> > - /* If we are, use the distinguished irq functions */
> > pv_irq_ops.irq_disable = vsmp_irq_disable;
> > pv_irq_ops.irq_enable = vsmp_irq_enable;
> > pv_irq_ops.save_fl = vsmp_save_fl;
> > @@ -127,5 +100,46 @@ void __init vsmp_init(void)
> > }
> >
> > early_iounmap(address, 8);
> > +}
> > +#else
> > +static void __init set_vsmp_pv_ops(void)
> > +{
> > +}
> > +#endif
> > +
> > +#ifdef CONFIG_PCI
> > +static int vsmp = -1;
> > +
> > +int is_vsmp_box(void)
> > +{
> > + if (vsmp != -1)
> > + return vsmp;
> > +
> > + vsmp = 0;
> > + if (!early_pci_allowed())
> > + return vsmp;
> > +
> > + /* Check if we are running on a ScaleMP vSMP box */
> > + if ((read_pci_config_16(0, 0x1f, 0, PCI_VENDOR_ID) ==
> > + PCI_VENDOR_ID_SCALEMP) &&
> > + (read_pci_config_16(0, 0x1f, 0, PCI_DEVICE_ID) ==
> > + PCI_DEVICE_ID_SCALEMP_VSMP_CTL))
> > + vsmp = 1;
> > +
> > + return vsmp;
> > +}
> > +#else
> > +int is_vsmp_box(void)
> > +{
> > + return 0;
> > +}
> > +#endif
> >
>
> Rather than doing this, I'd propose putting
>
> #ifndef CONFIG_X86_VSMP
> static inline int is_vsmp_box(void)
> {
> return 0;
> }
> #endif
>
> in a header, and then making the definition in vsmp_64.c unconditional
> (or rather, the whole of vsmp_64.o conditional on CONFIG_X86_VSMP).
>
>
> > +
> > +void __init vsmp_init(void)
> > +{
> > + if (!is_vsmp_box())
> > + return;
> > +
> > + set_vsmp_pv_ops();
> > return;
> > }
> >
>
> Similarly with this.
>
>
> > Index: linux.git.trees/include/asm-x86/apic.h
> > ===================================================================
> > --- linux.git.trees.orig/include/asm-x86/apic.h 2008-03-19 13:39:29.000000000 -0700
> > +++ linux.git.trees/include/asm-x86/apic.h 2008-03-19 13:57:14.550893819 -0700
> > @@ -51,19 +51,16 @@ extern unsigned boot_cpu_id;
> > */
> > #ifdef CONFIG_PARAVIRT
> > #include <asm/paravirt.h>
> > -extern int is_vsmp_box(void);
> > #else
> > #define apic_write native_apic_write
> > #define apic_write_atomic native_apic_write_atomic
> > #define apic_read native_apic_read
> > #define setup_boot_clock setup_boot_APIC_clock
> > #define setup_secondary_clock setup_secondary_APIC_clock
> > -static int inline is_vsmp_box(void)
> > -{
> > - return 0;
> > -}
> > #endif
> >
> > +extern int is_vsmp_box(void);
> > +
> >
>
> This was almost right, except it should have been in a #ifdef
> CONFIG_X86_VSMP block.
>
>
agreed
http://lkml.org/lkml/2008/3/18/76
YH
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