[PATCH] x86: sutomatically enable bigsmp when we have more than 8 CPUs

i386 generic subarchitecture requires explicit dmi strings or command line
to enable bigsmp mode.  The patch below removes that restriction, and uses
bigsmp as soon as it finds more than 8 logical CPUs, Intel processors and
xAPIC support.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index b7808a89d94507fd41abf6c24bd471d5d9099209..34ee500c26e59a4a992dd6c89dbb5cd68ae3bd92 100644 (file)
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -833,6 +833,9 @@ acpi_process_madt(void)
                if (!error) {
                        acpi_lapic = 1;
 
+#ifdef CONFIG_X86_GENERICARCH
+                       generic_bigsmp_probe();
+#endif
                        /*
                         * Parse MADT IO-APIC entries
                         */

diff --git a/arch/i386/kernel/mpparse.c b/arch/i386/kernel/mpparse.c
index ce838abb27d8b48ab23d06a191766b0e2f9c7272..788efffa993091afc57ef22398b115ca749af4b1 100644 (file)
--- a/arch/i386/kernel/mpparse.c
+++ b/arch/i386/kernel/mpparse.c
@@ -65,6 +65,8 @@ int nr_ioapics;
 int pic_mode;
 unsigned long mp_lapic_addr;
 
+unsigned int def_to_bigsmp = 0;
+
 /* Processor that is doing the boot up */
 unsigned int boot_cpu_physical_apicid = -1U;
 /* Internal processor count */
@@ -213,6 +215,13 @@ static void __init MP_processor_info (struct mpc_config_processor *m)
                ver = 0x10;
        }
        apic_version[m->mpc_apicid] = ver;
+       if ((num_processors > 8) &&
+           APIC_XAPIC(ver) &&
+           (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL))
+               def_to_bigsmp = 1;
+       else
+               def_to_bigsmp = 0;
+
        bios_cpu_apicid[num_processors - 1] = m->mpc_apicid;
 }
 

diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index 9adbf710ec8deb648ee72314c514296e25fc6566..294bcca985ab7ec2de873dff4716f0681500c0be 100644 (file)
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -1585,8 +1585,14 @@ void __init setup_arch(char **cmdline_p)
         */
        acpi_boot_table_init();
        acpi_boot_init();
-#endif
 
+#if defined(CONFIG_SMP) && defined(CONFIG_X86_PC)
+       if (def_to_bigsmp)
+               printk(KERN_WARNING "More than 8 CPUs detected and "
+                       "CONFIG_X86_PC cannot handle it.\nUse "
+                       "CONFIG_X86_GENERICARCH or CONFIG_X86_BIGSMP.\n");
+#endif
+#endif
 #ifdef CONFIG_X86_LOCAL_APIC
        if (smp_found_config)
                get_smp_config();

diff --git a/arch/i386/mach-generic/bigsmp.c b/arch/i386/mach-generic/bigsmp.c
index 25883b44f6253f092b4eab9a67cc61c822e0401e..037b2af1a1f4972a0940f723d1fa39310b4e1dfd 100644 (file)
--- a/arch/i386/mach-generic/bigsmp.c
+++ b/arch/i386/mach-generic/bigsmp.c
@@ -47,7 +47,10 @@ static struct dmi_system_id __initdata bigsmp_dmi_table[] = {
 
 static __init int probe_bigsmp(void)
 { 
-       dmi_check_system(bigsmp_dmi_table);
+       if (def_to_bigsmp)
+               dmi_bigsmp = 1;
+       else
+               dmi_check_system(bigsmp_dmi_table);
        return dmi_bigsmp; 
 } 
 

diff --git a/arch/i386/mach-generic/probe.c b/arch/i386/mach-generic/probe.c
index 5497c65a8790bfd0175564aed83b7129f5f5ceb2..cea5b3ce4b5766c9747294090542e4eb063b75eb 100644 (file)
--- a/arch/i386/mach-generic/probe.c
+++ b/arch/i386/mach-generic/probe.c
@@ -30,6 +30,25 @@ struct genapic *apic_probe[] __initdata = {
        NULL,
 };
 
+static int cmdline_apic;
+
+void __init generic_bigsmp_probe(void)
+{
+       /*
+        * This routine is used to switch to bigsmp mode when
+        * - There is no apic= option specified by the user
+        * - generic_apic_probe() has choosen apic_default as the sub_arch
+        * - we find more than 8 CPUs in acpi LAPIC listing with xAPIC support
+        */
+
+       if (!cmdline_apic && genapic == &apic_default)
+               if (apic_bigsmp.probe()) {
+                       genapic = &apic_bigsmp;
+                       printk(KERN_INFO "Overriding APIC driver with %s\n",
+                              genapic->name);
+               }
+}
+
 void __init generic_apic_probe(char *command_line) 
 { 
        char *s;
@@ -52,6 +71,7 @@ void __init generic_apic_probe(char *command_line)
                if (!changed)
                        printk(KERN_ERR "Unknown genapic `%s' specified.\n", s);
                *p = old;
+               cmdline_apic = changed;
        } 
        for (i = 0; !changed && apic_probe[i]; i++) { 
                if (apic_probe[i]->probe()) {

diff --git a/include/asm-i386/apicdef.h b/include/asm-i386/apicdef.h
index a96a8f48fbfcea171f9a65a22cc0f1b2a022649d..03185cef8e0a3977de51cb2467943d59f31dabd6 100644 (file)
--- a/include/asm-i386/apicdef.h
+++ b/include/asm-i386/apicdef.h
@@ -16,6 +16,7 @@
 #define                        GET_APIC_VERSION(x)     ((x)&0xFF)
 #define                        GET_APIC_MAXLVT(x)      (((x)>>16)&0xFF)
 #define                        APIC_INTEGRATED(x)      ((x)&0xF0)
+#define                        APIC_XAPIC(x)           ((x) >= 0x14)
 #define                APIC_TASKPRI    0x80
 #define                        APIC_TPRI_MASK          0xFF
 #define                APIC_ARBPRI     0x90

diff --git a/include/asm-i386/mach-generic/mach_apic.h b/include/asm-i386/mach-generic/mach_apic.h
index b13767a4e9345211eaa68a5c1439ee59f82e6cdc..d9dc039da94a3a12b4902d477bb48c0e6d8f205e 100644 (file)
--- a/include/asm-i386/mach-generic/mach_apic.h
+++ b/include/asm-i386/mach-generic/mach_apic.h
@@ -28,4 +28,6 @@
 #define enable_apic_mode (genapic->enable_apic_mode)
 #define phys_pkg_id (genapic->phys_pkg_id)
 
+extern void generic_bigsmp_probe(void);
+
 #endif /* __ASM_MACH_APIC_H */

diff --git a/include/asm-i386/mpspec.h b/include/asm-i386/mpspec.h
index d9fafba075bc41852dfeccb90d32a24182da41a5..d84a9c326c2238e70cdc3159d18dd864a481fd01 100644 (file)
--- a/include/asm-i386/mpspec.h
+++ b/include/asm-i386/mpspec.h
@@ -11,6 +11,7 @@ extern int mp_bus_id_to_local [MAX_MP_BUSSES];
 extern int quad_local_to_mp_bus_id [NR_CPUS/4][4];
 extern int mp_bus_id_to_pci_bus [MAX_MP_BUSSES];
 
+extern unsigned int def_to_bigsmp;
 extern unsigned int boot_cpu_physical_apicid;
 extern int smp_found_config;
 extern void find_smp_config (void);