2005-04-16 18:20:36 -04:00
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/bitops.h>
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#include <linux/smp.h>
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#include <linux/thread_info.h>
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2005-11-13 19:07:23 -05:00
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#include <linux/module.h>
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2005-04-16 18:20:36 -04:00
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#include <asm/processor.h>
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2007-10-17 12:04:33 -04:00
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#include <asm/pgtable.h>
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2005-04-16 18:20:36 -04:00
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#include <asm/msr.h>
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#include <asm/uaccess.h>
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2008-01-30 07:31:09 -05:00
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#include <asm/ptrace.h>
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#include <asm/ds.h>
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2008-02-04 10:48:04 -05:00
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#include <asm/bugs.h>
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2005-04-16 18:20:36 -04:00
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#include "cpu.h"
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#ifdef CONFIG_X86_LOCAL_APIC
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#include <asm/mpspec.h>
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#include <asm/apic.h>
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#include <mach_apic.h>
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#endif
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#ifdef CONFIG_X86_INTEL_USERCOPY
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/*
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* Alignment at which movsl is preferred for bulk memory copies.
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*/
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2005-07-07 20:56:59 -04:00
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struct movsl_mask movsl_mask __read_mostly;
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2005-04-16 18:20:36 -04:00
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#endif
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x86: use ELF section to list CPU vendor specific code
Replace the hardcoded list of initialization functions for each CPU
vendor by a list in an ELF section, which is read at initialization in
arch/x86/kernel/cpu/cpu.c to fill the cpu_devs[] array. The ELF
section, named .x86cpuvendor.init, is reclaimed after boot, and
contains entries of type "struct cpu_vendor_dev" which associates a
vendor number with a pointer to a "struct cpu_dev" structure.
This first modification allows to remove all the VENDOR_init_cpu()
functions.
This patch also removes the hardcoded calls to early_init_amd() and
early_init_intel(). Instead, we add a "c_early_init" member to the
cpu_dev structure, which is then called if not NULL by the generic CPU
initialization code. Unfortunately, in early_cpu_detect(), this_cpu is
not yet set, so we have to use the cpu_devs[] array directly.
This patch is part of the Linux Tiny project, and is needed for
further patch that will allow to disable compilation of unused CPU
support code.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-15 06:00:23 -05:00
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static void __cpuinit early_init_intel(struct cpuinfo_x86 *c)
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2005-04-16 18:20:36 -04:00
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{
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/* Netburst reports 64 bytes clflush size, but does IO in 128 bytes */
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if (c->x86 == 15 && c->x86_cache_alignment == 64)
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c->x86_cache_alignment = 128;
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2008-01-30 07:32:40 -05:00
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if ((c->x86 == 0xf && c->x86_model >= 0x03) ||
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(c->x86 == 0x6 && c->x86_model >= 0x0e))
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set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
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2005-04-16 18:20:36 -04:00
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}
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/*
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* Early probe support logic for ppro memory erratum #50
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*
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* This is called before we do cpu ident work
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*/
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2008-02-22 17:09:42 -05:00
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2006-03-23 05:59:33 -05:00
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int __cpuinit ppro_with_ram_bug(void)
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2005-04-16 18:20:36 -04:00
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{
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/* Uses data from early_cpu_detect now */
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if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
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boot_cpu_data.x86 == 6 &&
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boot_cpu_data.x86_model == 1 &&
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boot_cpu_data.x86_mask < 8) {
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printk(KERN_INFO "Pentium Pro with Errata#50 detected. Taking evasive action.\n");
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return 1;
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}
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return 0;
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}
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2008-02-22 17:09:42 -05:00
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2005-04-16 18:20:36 -04:00
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/*
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* P4 Xeon errata 037 workaround.
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* Hardware prefetcher may cause stale data to be loaded into the cache.
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*/
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2006-03-23 05:59:33 -05:00
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static void __cpuinit Intel_errata_workarounds(struct cpuinfo_x86 *c)
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2005-04-16 18:20:36 -04:00
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{
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unsigned long lo, hi;
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if ((c->x86 == 15) && (c->x86_model == 1) && (c->x86_mask == 1)) {
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2008-02-22 17:09:42 -05:00
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rdmsr(MSR_IA32_MISC_ENABLE, lo, hi);
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2005-04-16 18:20:36 -04:00
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if ((lo & (1<<9)) == 0) {
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printk (KERN_INFO "CPU: C0 stepping P4 Xeon detected.\n");
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printk (KERN_INFO "CPU: Disabling hardware prefetching (Errata 037)\n");
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lo |= (1<<9); /* Disable hw prefetching */
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wrmsr (MSR_IA32_MISC_ENABLE, lo, hi);
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}
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}
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}
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2005-04-16 18:25:15 -04:00
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/*
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* find out the number of processor cores on the die
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*/
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2006-03-23 05:59:33 -05:00
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static int __cpuinit num_cpu_cores(struct cpuinfo_x86 *c)
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2005-04-16 18:25:15 -04:00
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{
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2005-09-03 18:56:42 -04:00
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unsigned int eax, ebx, ecx, edx;
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2005-04-16 18:25:15 -04:00
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if (c->cpuid_level < 4)
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return 1;
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2005-09-03 18:56:42 -04:00
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/* Intel has a non-standard dependency on %ecx for this CPUID level. */
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cpuid_count(4, 0, &eax, &ebx, &ecx, &edx);
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2005-04-16 18:25:15 -04:00
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if (eax & 0x1f)
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return ((eax >> 26) + 1);
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else
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return 1;
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}
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2007-10-17 12:04:33 -04:00
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#ifdef CONFIG_X86_F00F_BUG
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static void __cpuinit trap_init_f00f_bug(void)
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{
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__set_fixmap(FIX_F00F_IDT, __pa(&idt_table), PAGE_KERNEL_RO);
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/*
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* Update the IDT descriptor and reload the IDT so that
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* it uses the read-only mapped virtual address.
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*/
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idt_descr.address = fix_to_virt(FIX_F00F_IDT);
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load_idt(&idt_descr);
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}
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#endif
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2006-03-23 05:59:33 -05:00
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static void __cpuinit init_intel(struct cpuinfo_x86 *c)
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2005-04-16 18:20:36 -04:00
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{
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unsigned int l2 = 0;
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char *p = NULL;
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2008-01-30 07:32:40 -05:00
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early_init_intel(c);
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2005-04-16 18:20:36 -04:00
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#ifdef CONFIG_X86_F00F_BUG
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/*
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* All current models of Pentium and Pentium with MMX technology CPUs
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* have the F0 0F bug, which lets nonprivileged users lock up the system.
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* Note that the workaround only should be initialized once...
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*/
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c->f00f_bug = 0;
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2006-12-06 20:14:08 -05:00
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if (!paravirt_enabled() && c->x86 == 5) {
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2008-02-22 17:09:42 -05:00
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static int f00f_workaround_enabled;
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2005-04-16 18:20:36 -04:00
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c->f00f_bug = 1;
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2008-02-22 17:09:42 -05:00
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if (!f00f_workaround_enabled) {
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2005-04-16 18:20:36 -04:00
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trap_init_f00f_bug();
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printk(KERN_NOTICE "Intel Pentium with F0 0F bug - workaround enabled.\n");
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f00f_workaround_enabled = 1;
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}
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}
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#endif
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l2 = init_intel_cacheinfo(c);
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2008-02-22 17:09:42 -05:00
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if (c->cpuid_level > 9) {
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2006-06-26 07:59:59 -04:00
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unsigned eax = cpuid_eax(10);
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/* Check for version and the number of counters */
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if ((eax & 0xff) && (((eax>>8) & 0xff) > 1))
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2008-02-26 02:52:33 -05:00
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set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
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2006-06-26 07:59:59 -04:00
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}
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2005-04-16 18:20:36 -04:00
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/* SEP CPUID bug: Pentium Pro reports SEP but doesn't have it until model 3 mask 3 */
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if ((c->x86<<8 | c->x86_model<<4 | c->x86_mask) < 0x633)
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2008-02-26 02:52:33 -05:00
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clear_cpu_cap(c, X86_FEATURE_SEP);
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2005-04-16 18:20:36 -04:00
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2008-02-22 17:09:42 -05:00
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/*
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* Names for the Pentium II/Celeron processors
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* detectable only by also checking the cache size.
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* Dixon is NOT a Celeron.
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*/
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2005-04-16 18:20:36 -04:00
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if (c->x86 == 6) {
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switch (c->x86_model) {
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case 5:
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if (c->x86_mask == 0) {
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if (l2 == 0)
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p = "Celeron (Covington)";
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else if (l2 == 256)
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p = "Mobile Pentium II (Dixon)";
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}
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break;
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2008-02-22 17:09:42 -05:00
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2005-04-16 18:20:36 -04:00
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case 6:
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if (l2 == 128)
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p = "Celeron (Mendocino)";
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else if (c->x86_mask == 0 || c->x86_mask == 5)
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p = "Celeron-A";
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break;
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2008-02-22 17:09:42 -05:00
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2005-04-16 18:20:36 -04:00
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case 8:
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if (l2 == 128)
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p = "Celeron (Coppermine)";
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break;
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}
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}
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2008-02-22 17:09:42 -05:00
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if (p)
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2005-04-16 18:20:36 -04:00
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strcpy(c->x86_model_id, p);
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2008-02-22 17:09:42 -05:00
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2005-11-05 11:25:54 -05:00
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c->x86_max_cores = num_cpu_cores(c);
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2005-04-16 18:25:15 -04:00
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2005-04-16 18:20:36 -04:00
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detect_ht(c);
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/* Work around errata */
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Intel_errata_workarounds(c);
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#ifdef CONFIG_X86_INTEL_USERCOPY
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/*
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* Set up the preferred alignment for movsl bulk memory moves
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*/
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switch (c->x86) {
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case 4: /* 486: untested */
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break;
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case 5: /* Old Pentia: untested */
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break;
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case 6: /* PII/PIII only like movsl with 8-byte alignment */
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movsl_mask.mask = 7;
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break;
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case 15: /* P4 is OK down to 8-byte alignment */
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movsl_mask.mask = 7;
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break;
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}
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#endif
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2008-01-30 07:32:38 -05:00
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if (cpu_has_xmm2)
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2008-02-26 02:52:33 -05:00
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set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
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2007-05-02 13:27:20 -04:00
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if (c->x86 == 15) {
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2008-02-26 02:52:33 -05:00
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set_cpu_cap(c, X86_FEATURE_P4);
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2007-05-02 13:27:20 -04:00
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}
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2008-02-22 17:09:42 -05:00
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if (c->x86 == 6)
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2008-02-26 02:52:33 -05:00
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set_cpu_cap(c, X86_FEATURE_P3);
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2006-12-06 20:14:01 -05:00
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if (cpu_has_ds) {
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unsigned int l1;
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rdmsr(MSR_IA32_MISC_ENABLE, l1, l2);
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2006-12-06 20:14:11 -05:00
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if (!(l1 & (1<<11)))
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2008-02-26 02:52:33 -05:00
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set_cpu_cap(c, X86_FEATURE_BTS);
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2006-12-06 20:14:01 -05:00
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if (!(l1 & (1<<12)))
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2008-02-26 02:52:33 -05:00
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set_cpu_cap(c, X86_FEATURE_PEBS);
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2006-12-06 20:14:01 -05:00
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}
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2008-01-30 07:31:09 -05:00
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if (cpu_has_bts)
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ds_init_intel(c);
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2008-07-13 01:52:55 -04:00
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x86: APIC: remove apic_write_around(); use alternatives
Use alternatives to select the workaround for the 11AP Pentium erratum
for the affected steppings on the fly rather than build time. Remove the
X86_GOOD_APIC configuration option and replace all the calls to
apic_write_around() with plain apic_write(), protecting accesses to the
ESR as appropriate due to the 3AP Pentium erratum. Remove
apic_read_around() and all its invocations altogether as not needed.
Remove apic_write_atomic() and all its implementing backends. The use of
ASM_OUTPUT2() is not strictly needed for input constraints, but I have
used it for readability's sake.
I had the feeling no one else was brave enough to do it, so I went ahead
and here it is. Verified by checking the generated assembly and tested
with both a 32-bit and a 64-bit configuration, also with the 11AP
"feature" forced on and verified with gdb on /proc/kcore to work as
expected (as an 11AP machines are quite hard to get hands on these days).
Some script complained about the use of "volatile", but apic_write() needs
it for the same reason and is effectively a replacement for writel(), so I
have disregarded it.
I am not sure what the policy wrt defconfig files is, they are generated
and there is risk of a conflict resulting from an unrelated change, so I
have left changes to them out. The option will get removed from them at
the next run.
Some testing with machines other than mine will be needed to avoid some
stupid mistake, but despite its volume, the change is not really that
intrusive, so I am fairly confident that because it works for me, it will
everywhere.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-16 14:15:30 -04:00
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/*
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* See if we have a good local APIC by checking for buggy Pentia,
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* i.e. all B steppings and the C2 stepping of P54C when using their
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* integrated APIC (see 11AP erratum in "Pentium Processor
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* Specification Update").
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*/
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if (cpu_has_apic && (c->x86<<8 | c->x86_model<<4) == 0x520 &&
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(c->x86_mask < 0x6 || c->x86_mask == 0xb))
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set_cpu_cap(c, X86_FEATURE_11AP);
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2008-07-13 01:52:55 -04:00
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#ifdef CONFIG_X86_NUMAQ
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numaq_tsc_disable();
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#endif
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2006-12-06 20:14:01 -05:00
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}
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2005-04-16 18:20:36 -04:00
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2008-02-22 17:09:42 -05:00
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static unsigned int __cpuinit intel_size_cache(struct cpuinfo_x86 *c, unsigned int size)
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2005-04-16 18:20:36 -04:00
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{
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2008-02-22 17:09:42 -05:00
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/*
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* Intel PIII Tualatin. This comes in two flavours.
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2005-04-16 18:20:36 -04:00
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* One has 256kb of cache, the other 512. We have no way
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* to determine which, so we use a boottime override
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* for the 512kb model, and assume 256 otherwise.
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*/
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if ((c->x86 == 6) && (c->x86_model == 11) && (size == 0))
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size = 256;
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return size;
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}
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2006-03-23 05:59:33 -05:00
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static struct cpu_dev intel_cpu_dev __cpuinitdata = {
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2005-04-16 18:20:36 -04:00
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.c_vendor = "Intel",
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2008-02-22 17:09:42 -05:00
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.c_ident = { "GenuineIntel" },
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2005-04-16 18:20:36 -04:00
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.c_models = {
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2008-02-22 17:09:42 -05:00
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{ .vendor = X86_VENDOR_INTEL, .family = 4, .model_names =
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{
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[0] = "486 DX-25/33",
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[1] = "486 DX-50",
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[2] = "486 SX",
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[3] = "486 DX/2",
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[4] = "486 SL",
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|
|
|
[5] = "486 SX/2",
|
|
|
|
[7] = "486 DX/2-WB",
|
|
|
|
[8] = "486 DX/4",
|
2005-04-16 18:20:36 -04:00
|
|
|
[9] = "486 DX/4-WB"
|
|
|
|
}
|
|
|
|
},
|
|
|
|
{ .vendor = X86_VENDOR_INTEL, .family = 5, .model_names =
|
2008-02-22 17:09:42 -05:00
|
|
|
{
|
|
|
|
[0] = "Pentium 60/66 A-step",
|
|
|
|
[1] = "Pentium 60/66",
|
2005-04-16 18:20:36 -04:00
|
|
|
[2] = "Pentium 75 - 200",
|
2008-02-22 17:09:42 -05:00
|
|
|
[3] = "OverDrive PODP5V83",
|
2005-04-16 18:20:36 -04:00
|
|
|
[4] = "Pentium MMX",
|
2008-02-22 17:09:42 -05:00
|
|
|
[7] = "Mobile Pentium 75 - 200",
|
2005-04-16 18:20:36 -04:00
|
|
|
[8] = "Mobile Pentium MMX"
|
|
|
|
}
|
|
|
|
},
|
|
|
|
{ .vendor = X86_VENDOR_INTEL, .family = 6, .model_names =
|
2008-02-22 17:09:42 -05:00
|
|
|
{
|
2005-04-16 18:20:36 -04:00
|
|
|
[0] = "Pentium Pro A-step",
|
2008-02-22 17:09:42 -05:00
|
|
|
[1] = "Pentium Pro",
|
|
|
|
[3] = "Pentium II (Klamath)",
|
|
|
|
[4] = "Pentium II (Deschutes)",
|
|
|
|
[5] = "Pentium II (Deschutes)",
|
2005-04-16 18:20:36 -04:00
|
|
|
[6] = "Mobile Pentium II",
|
2008-02-22 17:09:42 -05:00
|
|
|
[7] = "Pentium III (Katmai)",
|
|
|
|
[8] = "Pentium III (Coppermine)",
|
2005-04-16 18:20:36 -04:00
|
|
|
[10] = "Pentium III (Cascades)",
|
|
|
|
[11] = "Pentium III (Tualatin)",
|
|
|
|
}
|
|
|
|
},
|
|
|
|
{ .vendor = X86_VENDOR_INTEL, .family = 15, .model_names =
|
|
|
|
{
|
|
|
|
[0] = "Pentium 4 (Unknown)",
|
|
|
|
[1] = "Pentium 4 (Willamette)",
|
|
|
|
[2] = "Pentium 4 (Northwood)",
|
|
|
|
[4] = "Pentium 4 (Foster)",
|
|
|
|
[5] = "Pentium 4 (Foster)",
|
|
|
|
}
|
|
|
|
},
|
|
|
|
},
|
x86: use ELF section to list CPU vendor specific code
Replace the hardcoded list of initialization functions for each CPU
vendor by a list in an ELF section, which is read at initialization in
arch/x86/kernel/cpu/cpu.c to fill the cpu_devs[] array. The ELF
section, named .x86cpuvendor.init, is reclaimed after boot, and
contains entries of type "struct cpu_vendor_dev" which associates a
vendor number with a pointer to a "struct cpu_dev" structure.
This first modification allows to remove all the VENDOR_init_cpu()
functions.
This patch also removes the hardcoded calls to early_init_amd() and
early_init_intel(). Instead, we add a "c_early_init" member to the
cpu_dev structure, which is then called if not NULL by the generic CPU
initialization code. Unfortunately, in early_cpu_detect(), this_cpu is
not yet set, so we have to use the cpu_devs[] array directly.
This patch is part of the Linux Tiny project, and is needed for
further patch that will allow to disable compilation of unused CPU
support code.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-15 06:00:23 -05:00
|
|
|
.c_early_init = early_init_intel,
|
2005-04-16 18:20:36 -04:00
|
|
|
.c_init = init_intel,
|
|
|
|
.c_size_cache = intel_size_cache,
|
|
|
|
};
|
|
|
|
|
x86: use ELF section to list CPU vendor specific code
Replace the hardcoded list of initialization functions for each CPU
vendor by a list in an ELF section, which is read at initialization in
arch/x86/kernel/cpu/cpu.c to fill the cpu_devs[] array. The ELF
section, named .x86cpuvendor.init, is reclaimed after boot, and
contains entries of type "struct cpu_vendor_dev" which associates a
vendor number with a pointer to a "struct cpu_dev" structure.
This first modification allows to remove all the VENDOR_init_cpu()
functions.
This patch also removes the hardcoded calls to early_init_amd() and
early_init_intel(). Instead, we add a "c_early_init" member to the
cpu_dev structure, which is then called if not NULL by the generic CPU
initialization code. Unfortunately, in early_cpu_detect(), this_cpu is
not yet set, so we have to use the cpu_devs[] array directly.
This patch is part of the Linux Tiny project, and is needed for
further patch that will allow to disable compilation of unused CPU
support code.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-02-15 06:00:23 -05:00
|
|
|
cpu_vendor_dev_register(X86_VENDOR_INTEL, &intel_cpu_dev);
|
2005-04-16 18:20:36 -04:00
|
|
|
|
2005-11-13 19:07:23 -05:00
|
|
|
#ifndef CONFIG_X86_CMPXCHG
|
|
|
|
unsigned long cmpxchg_386_u8(volatile void *ptr, u8 old, u8 new)
|
|
|
|
{
|
|
|
|
u8 prev;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
/* Poor man's cmpxchg for 386. Unsuitable for SMP */
|
|
|
|
local_irq_save(flags);
|
|
|
|
prev = *(u8 *)ptr;
|
|
|
|
if (prev == old)
|
|
|
|
*(u8 *)ptr = new;
|
|
|
|
local_irq_restore(flags);
|
|
|
|
return prev;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cmpxchg_386_u8);
|
|
|
|
|
|
|
|
unsigned long cmpxchg_386_u16(volatile void *ptr, u16 old, u16 new)
|
|
|
|
{
|
|
|
|
u16 prev;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
/* Poor man's cmpxchg for 386. Unsuitable for SMP */
|
|
|
|
local_irq_save(flags);
|
|
|
|
prev = *(u16 *)ptr;
|
|
|
|
if (prev == old)
|
|
|
|
*(u16 *)ptr = new;
|
|
|
|
local_irq_restore(flags);
|
|
|
|
return prev;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cmpxchg_386_u16);
|
|
|
|
|
|
|
|
unsigned long cmpxchg_386_u32(volatile void *ptr, u32 old, u32 new)
|
|
|
|
{
|
|
|
|
u32 prev;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
/* Poor man's cmpxchg for 386. Unsuitable for SMP */
|
|
|
|
local_irq_save(flags);
|
|
|
|
prev = *(u32 *)ptr;
|
|
|
|
if (prev == old)
|
|
|
|
*(u32 *)ptr = new;
|
|
|
|
local_irq_restore(flags);
|
|
|
|
return prev;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cmpxchg_386_u32);
|
|
|
|
#endif
|
|
|
|
|
x86: fall back on interrupt disable in cmpxchg8b on 80386 and 80486
Actually, on 386, cmpxchg and cmpxchg_local fall back on
cmpxchg_386_u8/16/32: it disables interruptions around non atomic
updates to mimic the cmpxchg behavior.
The comment:
/* Poor man's cmpxchg for 386. Unsuitable for SMP */
already present in cmpxchg_386_u32 tells much about how this cmpxchg
implementation should not be used in a SMP context. However, the cmpxchg_local
can perfectly use this fallback, since it only needs to be atomic wrt the local
cpu.
This patch adds a cmpxchg_486_u64 and uses it as a fallback for cmpxchg64
and cmpxchg64_local on 80386 and 80486.
Q:
but why is it called cmpxchg_486 when the other functions are called
A:
Because the standard cmpxchg is missing only on 386, but cmpxchg8b is
missing both on 386 and 486.
Citing Intel's Instruction set reference:
cmpxchg:
This instruction is not supported on Intel processors earlier than the
Intel486 processors.
cmpxchg8b:
This instruction encoding is not supported on Intel processors earlier
than the Pentium processors.
Q:
What's the reason to have cmpxchg64_local on 32 bit architectures?
Without that need all this would just be a few simple defines.
A:
cmpxchg64_local on 32 bits architectures takes unsigned long long
parameters, but cmpxchg_local only takes longs. Since we have cmpxchg8b
to execute a 8 byte cmpxchg atomically on pentium and +, it makes sense
to provide a flavor of cmpxchg and cmpxchg_local using this instruction.
Also, for 32 bits architectures lacking the 64 bits atomic cmpxchg, it
makes sense _not_ to define cmpxchg64 while cmpxchg could still be
available.
Moreover, the fallback for cmpxchg8b on i386 for 386 and 486 is a
However, cmpxchg64_local will be emulated by disabling interrupts on all
architectures where it is not supported atomically.
Therefore, we *could* turn cmpxchg64_local into a cmpxchg_local, but it
would make the 386/486 fallbacks ugly, make its design different from
cmpxchg/cmpxchg64 (which really depends on atomic operations and cannot
be emulated) and require the __cmpxchg_local to be expressed as a macro
rather than an inline function so the parameters would not be fixed to
unsigned long long in every case.
So I think cmpxchg64_local makes sense there, but I am open to
suggestions.
Q:
Are there any callers?
A:
I am actually using it in LTTng in my timestamping code. I use it to
work around CPUs with asynchronous TSCs. I need to update 64 bits
values atomically on this 32 bits architecture.
Changelog:
- Ran though checkpatch.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-30 07:30:47 -05:00
|
|
|
#ifndef CONFIG_X86_CMPXCHG64
|
|
|
|
unsigned long long cmpxchg_486_u64(volatile void *ptr, u64 old, u64 new)
|
|
|
|
{
|
|
|
|
u64 prev;
|
|
|
|
unsigned long flags;
|
|
|
|
|
|
|
|
/* Poor man's cmpxchg8b for 386 and 486. Unsuitable for SMP */
|
|
|
|
local_irq_save(flags);
|
|
|
|
prev = *(u64 *)ptr;
|
|
|
|
if (prev == old)
|
|
|
|
*(u64 *)ptr = new;
|
|
|
|
local_irq_restore(flags);
|
|
|
|
return prev;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL(cmpxchg_486_u64);
|
|
|
|
#endif
|
|
|
|
|
2008-02-22 17:09:42 -05:00
|
|
|
/* arch_initcall(intel_cpu_init); */
|
2005-04-16 18:20:36 -04:00
|
|
|
|