According to SDM2.2, Itanium supports multiple outstanding ptc.g instructions.
But current kernel function ia64_global_tlb_purge() uses a spinlock to serialize
ptc.g instructions issued by multiple processors. This serialization might have
scalability issue on a big SMP machine where many processors could purge TLB
in parallel.
The patch fixes this problem by issuing multiple ptc.g instructions in
ia64_global_tlb_purge(). It also adds support for the "PALO" table to get
a platform view of the max number of outstanding ptc.g instructions (which
may be different from the processor view found from PAL_VM_SUMMARY).
PALO specification can be found at: http://www.dig64.org/home/DIG64_PALO_R1_0.pdf
spinaphore implementation by Matthew Wilcox.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/mca.h>
+#include <asm/tlbflush.h>
#define EFI_DEBUG 0
return NULL;
}
+
+static u8 __init palo_checksum(u8 *buffer, u32 length)
+{
+ u8 sum = 0;
+ u8 *end = buffer + length;
+
+ while (buffer < end)
+ sum = (u8) (sum + *(buffer++));
+
+ return sum;
+}
+
+/*
+ * Parse and handle PALO table which is published at:
+ * http://www.dig64.org/home/DIG64_PALO_R1_0.pdf
+ */
+static void __init handle_palo(unsigned long palo_phys)
+{
+ struct palo_table *palo = __va(palo_phys);
+ u8 checksum;
+
+ if (strncmp(palo->signature, PALO_SIG, sizeof(PALO_SIG) - 1)) {
+ printk(KERN_INFO "PALO signature incorrect.\n");
+ return;
+ }
+
+ checksum = palo_checksum((u8 *)palo, palo->length);
+ if (checksum) {
+ printk(KERN_INFO "PALO checksum incorrect.\n");
+ return;
+ }
+
+ setup_ptcg_sem(palo->max_tlb_purges, 1);
+}
+
void
efi_map_pal_code (void)
{
u64 efi_desc_size;
char *cp, vendor[100] = "unknown";
int i;
+ unsigned long palo_phys;
/*
* It's too early to be able to use the standard kernel command line
efi.hcdp = EFI_INVALID_TABLE_ADDR;
efi.uga = EFI_INVALID_TABLE_ADDR;
+ palo_phys = EFI_INVALID_TABLE_ADDR;
+
for (i = 0; i < (int) efi.systab->nr_tables; i++) {
if (efi_guidcmp(config_tables[i].guid, MPS_TABLE_GUID) == 0) {
efi.mps = config_tables[i].table;
} else if (efi_guidcmp(config_tables[i].guid, HCDP_TABLE_GUID) == 0) {
efi.hcdp = config_tables[i].table;
printk(" HCDP=0x%lx", config_tables[i].table);
+ } else if (efi_guidcmp(config_tables[i].guid,
+ PROCESSOR_ABSTRACTION_LAYER_OVERWRITE_GUID) == 0) {
+ palo_phys = config_tables[i].table;
+ printk(" PALO=0x%lx", config_tables[i].table);
}
}
printk("\n");
+ if (palo_phys != EFI_INVALID_TABLE_ADDR)
+ handle_palo(palo_phys);
+
runtime = __va(efi.systab->runtime);
efi.get_time = phys_get_time;
efi.set_time = phys_set_time;
#include <asm/setup.h>
#include <asm/smp.h>
#include <asm/system.h>
+#include <asm/tlbflush.h>
#include <asm/unistd.h>
#include <asm/hpsim.h>
#endif
/* set ia64_ctx.max_rid to the maximum RID that is supported by all CPUs: */
- if (ia64_pal_vm_summary(NULL, &vmi) == 0)
+ if (ia64_pal_vm_summary(NULL, &vmi) == 0) {
max_ctx = (1U << (vmi.pal_vm_info_2_s.rid_size - 3)) - 1;
- else {
+ setup_ptcg_sem(vmi.pal_vm_info_2_s.max_purges, 0);
+ } else {
printk(KERN_WARNING "cpu_init: PAL VM summary failed, assuming 18 RID bits\n");
max_ctx = (1U << 15) - 1; /* use architected minimum */
}
* Rohit Seth <rohit.seth@intel.com>
* Ken Chen <kenneth.w.chen@intel.com>
* Christophe de Dinechin <ddd@hp.com>: Avoid ptc.e on memory allocation
+ * Copyright (C) 2007 Intel Corp
+ * Fenghua Yu <fenghua.yu@intel.com>
+ * Add multiple ptc.g/ptc.ga instruction support in global tlb purge.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <asm/pal.h>
#include <asm/tlbflush.h>
#include <asm/dma.h>
+#include <asm/sal.h>
static struct {
unsigned long mask; /* mask of supported purge page-sizes */
local_flush_tlb_all();
}
+/*
+ * Implement "spinaphores" ... like counting semaphores, but they
+ * spin instead of sleeping. If there are ever any other users for
+ * this primitive it can be moved up to a spinaphore.h header.
+ */
+struct spinaphore {
+ atomic_t cur;
+};
+
+static inline void spinaphore_init(struct spinaphore *ss, int val)
+{
+ atomic_set(&ss->cur, val);
+}
+
+static inline void down_spin(struct spinaphore *ss)
+{
+ while (unlikely(!atomic_add_unless(&ss->cur, -1, 0)))
+ while (atomic_read(&ss->cur) == 0)
+ cpu_relax();
+}
+
+static inline void up_spin(struct spinaphore *ss)
+{
+ atomic_add(1, &ss->cur);
+}
+
+static struct spinaphore ptcg_sem;
+static u16 nptcg = 1;
+static int need_ptcg_sem = 1;
+static int toolatetochangeptcgsem = 0;
+
+/*
+ * Maximum number of simultaneous ptc.g purges in the system can
+ * be defined by PAL_VM_SUMMARY (in which case we should take
+ * the smallest value for any cpu in the system) or by the PAL
+ * override table (in which case we should ignore the value from
+ * PAL_VM_SUMMARY).
+ *
+ * Complicating the logic here is the fact that num_possible_cpus()
+ * isn't fully setup until we start bringing cpus online.
+ */
+void
+setup_ptcg_sem(int max_purges, int from_palo)
+{
+ static int have_palo;
+ static int firstcpu = 1;
+
+ if (toolatetochangeptcgsem) {
+ BUG_ON(max_purges < nptcg);
+ return;
+ }
+
+ if (from_palo) {
+ have_palo = 1;
+
+ /* In PALO max_purges == 0 really means it! */
+ if (max_purges == 0)
+ panic("Whoa! Platform does not support global TLB purges.\n");
+ nptcg = max_purges;
+ if (nptcg == PALO_MAX_TLB_PURGES) {
+ need_ptcg_sem = 0;
+ return;
+ }
+ goto resetsema;
+ }
+ if (have_palo) {
+ if (nptcg != PALO_MAX_TLB_PURGES)
+ need_ptcg_sem = (num_possible_cpus() > nptcg);
+ return;
+ }
+
+ /* In PAL_VM_SUMMARY max_purges == 0 actually means 1 */
+ if (max_purges == 0) max_purges = 1;
+
+ if (firstcpu) {
+ nptcg = max_purges;
+ firstcpu = 0;
+ }
+ if (max_purges < nptcg)
+ nptcg = max_purges;
+ if (nptcg == PAL_MAX_PURGES) {
+ need_ptcg_sem = 0;
+ return;
+ } else
+ need_ptcg_sem = (num_possible_cpus() > nptcg);
+
+resetsema:
+ spinaphore_init(&ptcg_sem, max_purges);
+}
+
void
ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
unsigned long end, unsigned long nbits)
{
- static DEFINE_SPINLOCK(ptcg_lock);
-
struct mm_struct *active_mm = current->active_mm;
+ toolatetochangeptcgsem = 1;
+
if (mm != active_mm) {
/* Restore region IDs for mm */
if (mm && active_mm) {
}
}
- /* HW requires global serialization of ptc.ga. */
- spin_lock(&ptcg_lock);
- {
- do {
- /*
- * Flush ALAT entries also.
- */
- ia64_ptcga(start, (nbits<<2));
- ia64_srlz_i();
- start += (1UL << nbits);
- } while (start < end);
- }
- spin_unlock(&ptcg_lock);
+ if (need_ptcg_sem)
+ down_spin(&ptcg_sem);
+
+ do {
+ /*
+ * Flush ALAT entries also.
+ */
+ ia64_ptcga(start, (nbits << 2));
+ ia64_srlz_i();
+ start += (1UL << nbits);
+ } while (start < end);
+
+ if (need_ptcg_sem)
+ up_spin(&ptcg_sem);
if (mm != active_mm) {
activate_context(active_mm);
EFI_GUID(0xe429faf8, 0x3cb7, 0x11d4, 0xbc, 0xa7, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81)
#define SAL_PLAT_BUS_ERR_SECT_GUID \
EFI_GUID(0xe429faf9, 0x3cb7, 0x11d4, 0xbc, 0xa7, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81)
+#define PROCESSOR_ABSTRACTION_LAYER_OVERWRITE_GUID \
+ EFI_GUID(0x6cb0a200, 0x893a, 0x11da, 0x96, 0xd2, 0x0, 0x10, 0x83, 0xff, \
+ 0xca, 0x4d)
#define MAX_CACHE_ERRORS 6
#define MAX_TLB_ERRORS 6
extern void ia64_sal_handler_init(void *entry_point, void *gpval);
+#define PALO_MAX_TLB_PURGES 0xFFFF
+#define PALO_SIG "PALO"
+
+struct palo_table {
+ u8 signature[4]; /* Should be "PALO" */
+ u32 length;
+ u8 minor_revision;
+ u8 major_revision;
+ u8 checksum;
+ u8 reserved1[5];
+ u16 max_tlb_purges;
+ u8 reserved2[6];
+};
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_IA64_SAL_H */
* Now for some TLB flushing routines. This is the kind of stuff that
* can be very expensive, so try to avoid them whenever possible.
*/
+extern void setup_ptcg_sem(int max_purges, int from_palo);
/*
* Flush everything (kernel mapping may also have changed due to
projects / linux-2.6 / commitdiff