Hi,
On 05/25/2017 12:56 AM, Jan Kiszka wrote:
> On 2017-03-21 13:19, tip-bot for Lu Baolu wrote:
>> Commit-ID: dd759d93f4dd4fd2f345a78ad1223bb3edf3ee7b
>> Gitweb: http://git.kernel.org/tip/dd759d93f4dd4fd2f345a78ad1223bb3edf3ee7b
>> Author: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>> AuthorDate: Tue, 21 Mar 2017 16:01:29 +0800
>> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
>> CommitDate: Tue, 21 Mar 2017 12:28:45 +0100
>>
>> x86/timers: Add simple udelay calibration
>>
>> Add a simple udelay calibration in x86 architecture-specific
>> boot-time initializations. This will get a workable estimate
>> for loops_per_jiffy. Hence, udelay() could be used after this
>> initialization.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
>> Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>> Cc: Andy Lutomirski <luto@xxxxxxxxxx>
>> Cc: Borislav Petkov <bp@xxxxxxxxx>
>> Cc: Brian Gerst <brgerst@xxxxxxxxx>
>> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
>> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
>> Cc: H. Peter Anvin <hpa@xxxxxxxxx>
>> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
>> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>> Cc: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
>> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>> Cc: linux-usb@xxxxxxxxxxxxxxx
>> Link: http://lkml.kernel.org/r/1490083293-3792-2-git-send-email-baolu.lu@xxxxxxxxxxxxxxx
>> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
>> ---
>> arch/x86/kernel/setup.c | 22 ++++++++++++++++++++++
>> 1 file changed, 22 insertions(+)
>>
>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>> index 4bf0c89..e70204e 100644
>> --- a/arch/x86/kernel/setup.c
>> +++ b/arch/x86/kernel/setup.c
>> @@ -837,6 +837,26 @@ dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
>> return 0;
>> }
>>
>> +static void __init simple_udelay_calibration(void)
>> +{
>> + unsigned int tsc_khz, cpu_khz;
>> + unsigned long lpj;
>> +
>> + if (!boot_cpu_has(X86_FEATURE_TSC))
>> + return;
>> +
>> + cpu_khz = x86_platform.calibrate_cpu();
>> + tsc_khz = x86_platform.calibrate_tsc();
>> +
>> + tsc_khz = tsc_khz ? : cpu_khz;
>> + if (!tsc_khz)
>> + return;
>> +
>> + lpj = tsc_khz * 1000;
>> + do_div(lpj, HZ);
>> + loops_per_jiffy = lpj;
>> +}
>> +
>> /*
>> * Determine if we were loaded by an EFI loader. If so, then we have also been
>> * passed the efi memmap, systab, etc., so we should use these data structures
>> @@ -985,6 +1005,8 @@ void __init setup_arch(char **cmdline_p)
>> */
>> x86_configure_nx();
>>
>> + simple_udelay_calibration();
>> +
>> parse_early_param();
>>
>> #ifdef CONFIG_MEMORY_HOTPLUG
>>
> Can we move this past init_hypervisor_platform()?
Yes, we can as far as I can see.
Best regards,
Lu Baolu
> Otherwise, the
> x86_platform hooks aren't fully initialized yet, and we may use the
> wrong functions.
>
> Jan
>
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|