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 queries PALO table to get max number of outstanding
ptc.g instructions. PALO specification can be found at:
http://www.dig64.org/home/DIG64_PALO_R1_0.pdf
Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
---
arch/ia64/kernel/efi.c | 61 +++++++++++++++++++++++++++++++++++++++++++++
arch/ia64/kernel/palinfo.c | 21 +++++++++++----
arch/ia64/mm/tlb.c | 44 +++++++++++++++++++++-----------
include/asm-ia64/sal.h | 21 +++++++++++++++
4 files changed, 126 insertions(+), 21 deletions(-)
diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index 242d793..bdb079a 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -388,6 +388,58 @@ efi_get_pal_addr (void)
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 int __init handle_palo(unsigned long palo_phys)
+{
+ struct palo_table *tmp;
+ u8 checksum;
+
+ if (palo_phys == EFI_INVALID_TABLE_ADDR) {
+ printk(KERN_INFO "PALO not found.\n");
+ nptcg = 1;
+ goto exit_nptcg;
+ }
+
+ tmp = (struct palo_table *)__va(palo_phys);
+ if (strncmp(tmp->signature, PALO_SIG, sizeof(PALO_SIG) - 1)) {
+ printk(KERN_INFO "PALO signature incorrect.\n");
+ nptcg = 1;
+ goto exit_nptcg;
+ }
+
+ checksum = palo_checksum((u8 *)tmp, tmp->length);
+ if (checksum) {
+ printk(KERN_INFO "PALO checksum incorrect.\n");
+ nptcg = 1;
+ goto exit_nptcg;
+ }
+
+ /* When getting to here, palo points to a valid PALO table. */
+ palo = tmp;
+ nptcg = palo->max_tlb_purges;
+ if (nptcg == 0)
+ panic("Woah! Don't support global TLB purges.\n");
+
+exit_nptcg:
+ sema_init(&ptcg_sem, nptcg);
+ return nptcg;
+}
+
void
efi_map_pal_code (void)
{
@@ -417,6 +469,7 @@ efi_init (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 support... */
for (cp = boot_command_line; *cp; ) {
@@ -475,6 +528,8 @@ efi_init (void)
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;
@@ -494,10 +549,16 @@ efi_init (void)
} 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");
+ handle_palo(palo_phys);
+
runtime = __va(efi.systab->runtime);
efi.get_time = phys_get_time;
efi.set_time = phys_set_time;
diff --git a/arch/ia64/kernel/palinfo.c b/arch/ia64/kernel/palinfo.c
index 396004e..6fe8570 100644
--- a/arch/ia64/kernel/palinfo.c
+++ b/arch/ia64/kernel/palinfo.c
@@ -323,12 +323,21 @@ vm_info(char *page)
vm_info_1.pal_vm_info_1_s.key_size,
vm_info_1.pal_vm_info_1_s.hash_tag_id,
vm_info_2.pal_vm_info_2_s.rid_size);
- if (vm_info_2.pal_vm_info_2_s.max_purges == PAL_MAX_PURGES)
- p += sprintf(p, "unlimited\n");
- else
- p += sprintf(p, "%d\n",
- vm_info_2.pal_vm_info_2_s.max_purges ?
- vm_info_2.pal_vm_info_2_s.max_purges : 1);
+ if (!palo) {
+ if (vm_info_2.pal_vm_info_2_s.max_purges
+ == PAL_MAX_PURGES)
+ p += sprintf(p, "unlimited\n");
+ else
+ p += sprintf(p, "%d\n",
+ vm_info_2.pal_vm_info_2_s.max_purges ?
+ vm_info_2.pal_vm_info_2_s.max_purges:1);
+ } else {
+ if (palo->max_tlb_purges == PALO_MAX_TLB_PURGES)
+ p += sprintf(p, "unlimited\n");
+ else
+ p += sprintf(p, "%d\n",
+ palo->max_tlb_purges);
+ }
}
if (ia64_pal_mem_attrib(&attrib) == 0) {
diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index 655da24..e3935d3 100644
--- a/arch/ia64/mm/tlb.c
+++ b/arch/ia64/mm/tlb.c
@@ -11,6 +11,9 @@
* Rohit Seth <rohit.seth@xxxxxxxxx>
* Ken Chen <kenneth.w.chen@xxxxxxxxx>
* Christophe de Dinechin <ddd@xxxxxx>: Avoid ptc.e on memory allocation
+ * Copyright (C) 2007 Intel Corp
+ * Fenghua Yu <fenghua.yu@xxxxxxxxx>
+ * Add multiple ptc.g/ptc.ga instruction support in global tlb purge.
*/
#include <linux/module.h>
#include <linux/init.h>
@@ -26,6 +29,7 @@
#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 */
@@ -84,12 +88,15 @@ wrap_mmu_context (struct mm_struct *mm)
local_flush_tlb_all();
}
+struct palo_table *palo;
+struct semaphore ptcg_sem;
+u16 nptcg = 1;
+
void
ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
unsigned long end, unsigned long nbits)
{
- static DEFINE_SPINLOCK(ptcg_lock);
-
+ int do_ptcg_sem;
struct mm_struct *active_mm = current->active_mm;
if (mm != active_mm) {
@@ -102,19 +109,26 @@ ia64_global_tlb_purge (struct mm_struct *mm, unsigned long start,
}
}
- /* 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 unlimited outstanding ptc.g (nptcg==0xffff), it's unnecessary to
+ * serialize ptc.g instructions.
+ */
+ do_ptcg_sem = nptcg == PALO_MAX_TLB_PURGES ? 0 : 1;
+ if (do_ptcg_sem)
+ /* This might put the process into sleep. */
+ down(&ptcg_sem);
+
+ do {
+ /*
+ * Flush ALAT entries also.
+ */
+ ia64_ptcga(start, (nbits << 2));
+ ia64_srlz_i();
+ start += (1UL << nbits);
+ } while (start < end);
+
+ if (do_ptcg_sem)
+ up(&ptcg_sem);
if (mm != active_mm) {
activate_context(active_mm);
diff --git a/include/asm-ia64/sal.h b/include/asm-ia64/sal.h
index 1f5412d..ad63ac7 100644
--- a/include/asm-ia64/sal.h
+++ b/include/asm-ia64/sal.h
@@ -296,6 +296,9 @@ enum {
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
@@ -883,6 +886,24 @@ extern void ia64_jump_to_sal(struct sal_to_os_boot *);
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];
+};
+
+extern struct palo_table *palo;
+extern struct semaphore ptcg_sem;
+extern u16 nptcg;
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_IA64_SAL_H */
-
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