diff options
Diffstat (limited to 'drivers/s390/sysinfo.c')
| -rw-r--r-- | drivers/s390/sysinfo.c | 63 |
1 files changed, 62 insertions, 1 deletions
diff --git a/drivers/s390/sysinfo.c b/drivers/s390/sysinfo.c index 1e788e815ce..090743d2f91 100644 --- a/drivers/s390/sysinfo.c +++ b/drivers/s390/sysinfo.c @@ -9,8 +9,14 @@ #include <linux/mm.h> #include <linux/proc_fs.h> #include <linux/init.h> +#include <linux/delay.h> #include <asm/ebcdic.h> +/* Sigh, math-emu. Don't ask. */ +#include <asm/sfp-util.h> +#include <math-emu/soft-fp.h> +#include <math-emu/single.h> + struct sysinfo_1_1_1 { char reserved_0[32]; char manufacturer[16]; @@ -198,7 +204,7 @@ static int stsi_1_2_2(struct sysinfo_1_2_2 *info, char *page, int len) * if the higher order 8 bits are not zero. Printing * a floating point number in the kernel is a no-no, * always print the number as 32 bit unsigned integer. - * The user-space needs to know about the stange + * The user-space needs to know about the strange * encoding of the alternate cpu capability. */ len += sprintf(page + len, "Capability: %u %u\n", @@ -351,3 +357,58 @@ static __init int create_proc_sysinfo(void) __initcall(create_proc_sysinfo); +/* + * CPU capability might have changed. Therefore recalculate loops_per_jiffy. + */ +void s390_adjust_jiffies(void) +{ + struct sysinfo_1_2_2 *info; + const unsigned int fmil = 0x4b189680; /* 1e7 as 32-bit float. */ + FP_DECL_S(SA); FP_DECL_S(SB); FP_DECL_S(SR); + FP_DECL_EX; + unsigned int capability; + + info = (void *) get_zeroed_page(GFP_KERNEL); + if (!info) + return; + + if (stsi(info, 1, 2, 2) != -ENOSYS) { + /* + * Major sigh. The cpu capability encoding is "special". + * If the first 9 bits of info->capability are 0 then it + * is a 32 bit unsigned integer in the range 0 .. 2^23. + * If the first 9 bits are != 0 then it is a 32 bit float. + * In addition a lower value indicates a proportionally + * higher cpu capacity. Bogomips are the other way round. + * To get to a halfway suitable number we divide 1e7 + * by the cpu capability number. Yes, that means a floating + * point division .. math-emu here we come :-) + */ + FP_UNPACK_SP(SA, &fmil); + if ((info->capability >> 23) == 0) + FP_FROM_INT_S(SB, info->capability, 32, int); + else + FP_UNPACK_SP(SB, &info->capability); + FP_DIV_S(SR, SA, SB); + FP_TO_INT_S(capability, SR, 32, 0); + } else + /* + * Really old machine without stsi block for basic + * cpu information. Report 42.0 bogomips. + */ + capability = 42; + loops_per_jiffy = capability * (500000/HZ); + free_page((unsigned long) info); +} + +/* + * calibrate the delay loop + */ +void __init calibrate_delay(void) +{ + s390_adjust_jiffies(); + /* Print the good old Bogomips line .. */ + printk(KERN_DEBUG "Calibrating delay loop (skipped)... " + "%lu.%02lu BogoMIPS preset\n", loops_per_jiffy/(500000/HZ), + (loops_per_jiffy/(5000/HZ)) % 100); +} |