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| author | Len Brown <len.brown@intel.com> | 2015-10-16 04:14:28 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-10-19 07:14:41 (GMT) |
| commit | f1ccd249319efca4ee4faf1d904f5a362cac7c81 (patch) | |
| tree | c92f1785121f3c0973c4627c15435688be336d91 /arch | |
| parent | c0ff971ef9acacd4d2caa508e444edad958dead9 (diff) | |
| download | linux-f1ccd249319efca4ee4faf1d904f5a362cac7c81.tar.xz | |
x86/smpboot: Fix cpu_init_udelay=10000 corner case boot parameter misbehavior
For legacy machines cpu_init_udelay defaults to 10,000.
For modern machines it is set to 0.
The user should be able to set cpu_init_udelay to
any value on the cmdline, including 10,000.
Before this patch, that was seen as "unchanged from default"
and thus on a modern machine, the user request was ignored
and the delay was set to 0.
Signed-off-by: Len Brown <len.brown@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dparsons@brightdsl.net
Cc: shrybman@teksavvy.com
Link: http://lkml.kernel.org/r/de363cdbbcfcca1d22569683f7eb9873e0177251.1444968087.git.len.brown@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index e0c198e..32267cc 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -509,7 +509,7 @@ void __inquire_remote_apic(int apicid) */ #define UDELAY_10MS_DEFAULT 10000 -static unsigned int init_udelay = UDELAY_10MS_DEFAULT; +static unsigned int init_udelay = INT_MAX; static int __init cpu_init_udelay(char *str) { @@ -522,13 +522,16 @@ 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 != UDELAY_10MS_DEFAULT) + if (init_udelay != INT_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))) init_udelay = 0; + + /* else, use legacy delay */ + init_udelay = UDELAY_10MS_DEFAULT; } /* |