[coreboot] printing TSC in printk
Carl-Daniel Hailfinger
c-d.hailfinger.devel.2006 at gmx.net
Sun Feb 17 00:51:59 CET 2008
Any reviews/opinions?
Regards,
Carl-Daniel
On 10.02.2008 00:49, Carl-Daniel Hailfinger wrote:
> On 09.02.2008 21:50, ron minnich wrote:
>
>> Define a new format letter, T, such that %T as a format means "time".
>>
>> [...] allows us to completely tailor the printing of
>> time, but you have to explicitly add %T when you want time printed.
>>
>
> Preliminary patch[...] does not compile yet, but you get the idea.
>
Needs an additional declaration in some header to fix compilation, code
itself should be sound.
> Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
>
> Index: LinuxBIOSv3-printktimestamp/include/console.h
> ===================================================================
> --- LinuxBIOSv3-printktimestamp/include/console.h (Revision 582)
> +++ LinuxBIOSv3-printktimestamp/include/console.h (Arbeitskopie)
> @@ -37,6 +37,7 @@
> unsigned char console_rx_byte(void);
> int console_tst_byte(void);
> void die(const char *msg);
> +u32 get_timestamp(void);
>
> struct console_driver {
> void (*init)(void);
> Index: LinuxBIOSv3-printktimestamp/lib/vtxprintf.c
> ===================================================================
> --- LinuxBIOSv3-printktimestamp/lib/vtxprintf.c (Revision 582)
> +++ LinuxBIOSv3-printktimestamp/lib/vtxprintf.c (Arbeitskopie)
> @@ -12,6 +12,7 @@
> #include <stdarg.h>
> #include <string.h>
> #include <div64.h>
> +#include <console.h>
>
> #define isdigit(c) ((c) >= '0' && (c) <= '9')
> #define is_digit isdigit
> @@ -118,6 +119,7 @@
> int qualifier; /* 'h', 'l', or 'L' for integer fields */
>
> int count;
> + u32 tstamp;
>
> for (count=0; *fmt ; ++fmt) {
> if (*fmt != '%') {
> @@ -218,6 +220,16 @@
> field_width, precision, flags);
> continue;
>
> + /* Timestamp in 32bit hex */
> + case 'T':
> + if (field_width == -1) {
> + field_width = 2 * sizeof(unsigned long);
> + flags |= ZEROPAD;
> + }
> + tstamp = get_timestamp();
> + count += number(tx_byte, arg, tstamp, 16,
> + field_width, precision, flags);
> + continue;
>
> case 'n':
> if (qualifier == 'L') {
> Index: LinuxBIOSv3-printktimestamp/arch/x86/geodelx/cpu.c
> ===================================================================
> --- LinuxBIOSv3-printktimestamp/arch/x86/geodelx/cpu.c (Revision 582)
> +++ LinuxBIOSv3-printktimestamp/arch/x86/geodelx/cpu.c (Arbeitskopie)
> @@ -37,6 +37,25 @@
> /* TODO: Better comment on vsm_end_post_smi, and define 0x05a2 down below. */
>
> /**
> + * Retrieve a 32-bit time stamp. The generic get_timestamp() offers no guarantee
> + * whatsoever about monotony, granularity, absence of wraparounds or linear
> + * relationship between the time stamp and real time.
> + * This implementation has wraparounds after 2^32 cycles of the TSC register
> + * and will usually have a linear dependency on real time.
> + * Qemu and Geode LX support the rdtsc instruction.
> + * If v3 ever is used on x86 architectures which don't support rdtsc, we have
> + * to provide an alternative.
> + *
> + * @return 32-bit truncated number of TSC cycles since poweron.
> + */
> +u32 get_timestamp(void)
> +{
> + u32 tstamp;
> + __asm__ __volatile__ ("rdtsc" : "=a" (tstamp) : : "edx");
> + return tstamp;
> +}
> +
> +/**
> * This is a call to the VSM.
> *
> * TODO: We need to know what it does.
>
>
>
--
http://www.hailfinger.org/
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