Re: [PATCH V3] x86, cpu: trivial printk formatting fixes

From: Joe Perches
Date: Wed Nov 05 2014 - 17:41:33 EST


On Wed, 2014-11-05 at 22:28 +0000, Steven Honeyman wrote:
> dmesg (from util-linux) currently has two methods for reading the
> kernel message ring buffer: /dev/kmsg and syslog(2). Since kernel
> 3.5.0 kmsg has been the default, which escapes control characters
> (e.g. new lines) before they are shown.
>
> This change means that when dmesg is using /dev/kmsg, a 2 line printk
> makes the output messy, because the second line does not get a
> timestamp.
> For example:
>
> [ 0.012863] CPU0: Thermal monitoring enabled (TM1)
> [ 0.012869] Last level iTLB entries: 4KB 1024, 2MB 1024, 4MB 1024
> Last level dTLB entries: 4KB 1024, 2MB 1024, 4MB 1024, 1GB 4
> [ 0.012958] Freeing SMP alternatives memory: 28K (ffffffff81d86000
> - ffffffff81d8d000)
> [ 0.014961] dmar: Host address width 39
>
> Because printk.c intentionally escapes control characters, they should
> not be there in the first place.
> This patch fixes two occurrences of this.
>
> V2: Revert change to log level, only fix the newline formatting issue
> V3: Expand patch description

The log level change is back...

> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
[]
> @@ -487,10 +487,8 @@ static void init_intel(struct cpuinfo_x86 *c)
>
> rdmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
> if ((epb & 0xF) == ENERGY_PERF_BIAS_PERFORMANCE) {
> - printk_once(KERN_WARNING "ENERGY_PERF_BIAS:"
> - " Set to 'normal', was 'performance'\n"
> - "ENERGY_PERF_BIAS: View and update with"
> - " x86_energy_perf_policy(8)\n");
> + pr_info_once("ENERGY_PERF_BIAS: Set to 'normal', was 'performance'\n");
> + pr_info_once("ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)\n");
> epb = (epb & ~0xF) | ENERGY_PERF_BIAS_NORMAL;
> wrmsrl(MSR_IA32_ENERGY_PERF_BIAS, epb);
> }



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