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Commit 656279a1 authored by Len Brown's avatar Len Brown Committed by Thomas Gleixner
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x86 smpboot: Re-enable init_udelay=0 by default on modern CPUs 



commit f1ccd249 allowed the cmdline "cpu_init_udelay=" to work
with all values, including the default of 10000.

But in setting the default of 10000, it over-rode the code that sets
the delay 0 on modern processors.

Also, tidy up use of INT/UINT.

Fixes: f1ccd249 "x86/smpboot: Fix cpu_init_udelay=10000 corner case boot parameter misbehavior"
Reported-by: default avatarShane <shrybman@teksavvy.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
Cc: dparsons@brightdsl.net
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/9082eb809ef40dad02db714759c7aaf618c518d4.1448232494.git.len.brown@intel.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent f1075053

arch/x86/kernel/smpboot.c

+5 −4
Original line number Diff line number Diff line
@@ -509,7 +509,7 @@ void __inquire_remote_apic(int apicid) 
 */

#define UDELAY_10MS_DEFAULT 10000



static unsigned int init_udelay = INT_MAX;

static unsigned int init_udelay = UINT_MAX;



static int __init cpu_init_udelay(char *str)

{
@@ -522,14 +522,15 @@ early_param("cpu_init_udelay", cpu_init_udelay); 
static void __init smp_quirk_init_udelay(void)

{

	/* if cmdline changed it from default, leave it alone */

	if (init_udelay != INT_MAX)

	if (init_udelay != UINT_MAX)

		return;



	/* if modern processor, use no delay */

	if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) ||

	    ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF)))

	    ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) {

		init_udelay = 0;



		return;

	}

	/* else, use legacy delay */

	init_udelay = UDELAY_10MS_DEFAULT;

}