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 */ - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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