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[IA64] Fix CONFIG_PRINTK_TIME 

There were two problems with enabling the PRINTK_TIME config
option:
1) The first calls to printk() occur before per-cpu data virtual
address is pinned into the TLB, so sched_clock() can fault.
2) sched_clock() is based on ar.itc, which may not be synchronized
across cpus.

Ken Chen started this patch, Tony Luck tinkered with it, and Jes
Sorensen perfected it.

Signed-off-by: Tony Luck <tony.luck@intel.com>
hifive-unleashed-5.1
Tony Luck 2006-02-07 15:25:57 -08:00
parent 9d78f43d1f
commit d6e56a2a08
4 changed files with 59 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/ia64/kernel/head.S
View File

@ -352,6 +352,7 @@ start_ap:
mov ar.rsc=0 // place RSE in enforced lazy mode
;;
loadrs // clear the dirty partition
mov IA64_KR(PER_CPU_DATA)=r0 // clear physical per-CPU base
;;
mov ar.bspstore=r2 // establish the new RSE stack
;;

4
arch/ia64/kernel/setup.c
View File

@ -71,6 +71,8 @@ unsigned long __per_cpu_offset[NR_CPUS];
EXPORT_SYMBOL(__per_cpu_offset);
#endif
extern void ia64_setup_printk_clock(void);
DEFINE_PER_CPU(struct cpuinfo_ia64, cpu_info);
DEFINE_PER_CPU(unsigned long, local_per_cpu_offset);
DEFINE_PER_CPU(unsigned long, ia64_phys_stacked_size_p8);
@ -445,6 +447,8 @@ setup_arch (char **cmdline_p)
/* process SAL system table: */
ia64_sal_init(efi.sal_systab);
ia64_setup_printk_clock();
#ifdef CONFIG_SMP
cpu_physical_id(0) = hard_smp_processor_id();

27
arch/ia64/kernel/time.c
View File

@ -278,3 +278,30 @@ udelay (unsigned long usecs)
}
}
EXPORT_SYMBOL(udelay);
static unsigned long long ia64_itc_printk_clock(void)
{
if (ia64_get_kr(IA64_KR_PER_CPU_DATA))
return sched_clock();
return 0;
}
static unsigned long long ia64_default_printk_clock(void)
{
return (unsigned long long)(jiffies_64 - INITIAL_JIFFIES) *
(1000000000/HZ);
}
unsigned long long (*ia64_printk_clock)(void) = &ia64_default_printk_clock;
unsigned long long printk_clock(void)
{
return ia64_printk_clock();
}
void __init
ia64_setup_printk_clock(void)
{
if (!(sal_platform_features & IA64_SAL_PLATFORM_FEATURE_ITC_DRIFT))
ia64_printk_clock = ia64_itc_printk_clock;
}

40
arch/ia64/sn/kernel/setup.c
View File

@ -67,6 +67,7 @@ extern unsigned long last_time_offset;
extern void (*ia64_mark_idle) (int);
extern void snidle(int);
extern unsigned char acpi_kbd_controller_present;
extern unsigned long long (*ia64_printk_clock)(void);
unsigned long sn_rtc_cycles_per_second;
EXPORT_SYMBOL(sn_rtc_cycles_per_second);
@ -372,6 +373,16 @@ sn_scan_pcdp(void)
}
}
static unsigned long sn2_rtc_initial;
static unsigned long long ia64_sn2_printk_clock(void)
{
unsigned long rtc_now = rtc_time();
return (rtc_now - sn2_rtc_initial) *
(1000000000 / sn_rtc_cycles_per_second);
}
/**
* sn_setup - SN platform setup routine
* @cmdline_p: kernel command line
@ -386,6 +397,7 @@ void __init sn_setup(char **cmdline_p)
u32 version = sn_sal_rev();
extern void sn_cpu_init(void);
sn2_rtc_initial = rtc_time();
ia64_sn_plat_set_error_handling_features(); // obsolete
ia64_sn_set_os_feature(OSF_MCA_SLV_TO_OS_INIT_SLV);
ia64_sn_set_os_feature(OSF_FEAT_LOG_SBES);
@ -437,19 +449,6 @@ void __init sn_setup(char **cmdline_p)
*/
build_cnode_tables();
/*
* Old PROMs do not provide an ACPI FADT. Disable legacy keyboard
* support here so we don't have to listen to failed keyboard probe
* messages.
*/
if (version <= 0x0209 && acpi_kbd_controller_present) {
printk(KERN_INFO "Disabling legacy keyboard support as prom "
"is too old and doesn't provide FADT\n");
acpi_kbd_controller_present = 0;
}
printk("SGI SAL version %x.%02x\n", version >> 8, version & 0x00FF);
status =
ia64_sal_freq_base(SAL_FREQ_BASE_REALTIME_CLOCK, &ticks_per_sec,
&drift);
@ -463,6 +462,21 @@ void __init sn_setup(char **cmdline_p)
platform_intr_list[ACPI_INTERRUPT_CPEI] = IA64_CPE_VECTOR;
ia64_printk_clock = ia64_sn2_printk_clock;
/*
* Old PROMs do not provide an ACPI FADT. Disable legacy keyboard
* support here so we don't have to listen to failed keyboard probe
* messages.
*/
if (version <= 0x0209 && acpi_kbd_controller_present) {
printk(KERN_INFO "Disabling legacy keyboard support as prom "
"is too old and doesn't provide FADT\n");
acpi_kbd_controller_present = 0;
}
printk("SGI SAL version %x.%02x\n", version >> 8, version & 0x00FF);
/*
* we set the default root device to /dev/hda
* to make simulation easy