Selecting Processor Type in Kernel Configuration

dwhitney67 · 08-28-2007, 12:49 PM

Hi,

I am curious about something. I have a kernel image and related Linux OS which I have built that works like a charm under an M586MXX system. I also need this kernel to support other Intel CPUs (e.g. PentiumII, PentiumM, etc).

Would there be any harm if I select multiple processors within my kernel configuration? Or do I need to create a separate kernel for each processor I intend to support?

Sorry if these sound like silly questions.

jailbait · 08-28-2007, 01:40 PM

Quote:

Originally Posted by dwhitney67

Hi,

I am curious about something. I have a kernel image and related Linux OS which I have built that works like a charm under an M586MXX system. I also need this kernel to support other Intel CPUs (e.g. PentiumII, PentiumM, etc).

Would there be any harm if I select multiple processors within my kernel configuration? Or do I need to create a separate kernel for each processor I intend to support?

Sorry if these sound like silly questions.

I don't think that you can select more than one processor. When you select a processor you are telling the kernel that it is OK to use hardware features which are unique to that processor. Since Intel processors are upward compatible, when you select a processor then it should also work on newer processors.

What I think that you should do is to select the oldest Intel CPU.

If any of your machines are multiple processors then you should compile a seperate kernel for that machine. Otherwise your generic kernel will run the multi-processor as a uni-processor.

----------------
Steve Stites

dwhitney67 · 08-29-2007, 12:16 PM

Thanks Jailbait for the reply. Unfortunately it is not wanted to see, but if that is the case, then I may be required to create distinct kernels.

I have consulted with the EE at my company, and he states that we need to support the following Intel CPUs:

PENTIUM-MMX
PENTIUM T3
PENTIUM-M (CELERON-M?)

Will I have to create 3 separate kernels (I am using version 2.6.11.1 but would consider upgrading)? I currently chose to configure with the option CONFIG_M586MMX, and my kernel appears functional for the Pentium-MMX, but on the others not so.

Perhaps I am missing something within my configuration? Here it is:

PHP Code:



# Processor type and features 
# 
CONFIG_X86_PC=y 
# CONFIG_X86_ELAN is not set 
# CONFIG_X86_VOYAGER is not set 
# CONFIG_X86_NUMAQ is not set 
# CONFIG_X86_SUMMIT is not set 
# CONFIG_X86_BIGSMP is not set 
# CONFIG_X86_VISWS is not set 
# CONFIG_X86_GENERICARCH is not set 
# CONFIG_X86_ES7000 is not set 
# CONFIG_M386 is not set 
# CONFIG_M486 is not set 
# CONFIG_M586 is not set 
# CONFIG_M586TSC is not set 
CONFIG_M586MMX=y 
# CONFIG_M686 is not set 
# CONFIG_MPENTIUMII is not set 
# CONFIG_MPENTIUMIII is not set 
# CONFIG_MPENTIUMM is not set 
# CONFIG_MPENTIUM4 is not set 
# CONFIG_MK6 is not set 
# CONFIG_MK7 is not set 
# CONFIG_MK8 is not set 
# CONFIG_MCRUSOE is not set 
# CONFIG_MEFFICEON is not set 
# CONFIG_MWINCHIPC6 is not set 
# CONFIG_MWINCHIP2 is not set 
# CONFIG_MWINCHIP3D is not set 
# CONFIG_MCYRIXIII is not set 
# CONFIG_MVIAC3_2 is not set 
CONFIG_X86_GENERIC=y 
CONFIG_X86_CMPXCHG=y 
CONFIG_X86_XADD=y 
CONFIG_X86_L1_CACHE_SHIFT=7 
CONFIG_RWSEM_XCHGADD_ALGORITHM=y 
CONFIG_GENERIC_CALIBRATE_DELAY=y 
CONFIG_X86_PPRO_FENCE=y 
CONFIG_X86_F00F_BUG=y 
CONFIG_X86_WP_WORKS_OK=y 
CONFIG_X86_INVLPG=y 
CONFIG_X86_BSWAP=y 
CONFIG_X86_POPAD_OK=y 
CONFIG_X86_ALIGNMENT_16=y 
CONFIG_X86_GOOD_APIC=y 
CONFIG_X86_INTEL_USERCOPY=y 
CONFIG_HPET_TIMER=y 
# CONFIG_SMP is not set 
# CONFIG_PREEMPT is not set 
# CONFIG_X86_UP_APIC is not set 
CONFIG_X86_TSC=y 
CONFIG_X86_MCE=y 
# CONFIG_X86_MCE_NONFATAL is not set 
# CONFIG_TOSHIBA is not set 
# CONFIG_I8K is not set 
CONFIG_MICROCODE=m 
CONFIG_X86_MSR=m 
CONFIG_X86_CPUID=m

jailbait · 08-29-2007, 01:31 PM

Quote:

Originally Posted by dwhitney67

I have consulted with the EE at my company, and he states that we need to support the following Intel CPUs:

PENTIUM-MMX
PENTIUM T3
PENTIUM-M (CELERON-M?)

The PENTIUM-MMX is a single core CPU. The PENTIUM-M is a dual core CPU. Therefore I think that you will have to configure two different kernels for the PENTIUM-MMX and the PENTIUM-M.

I don't know what the PENTIUM T3 is so I can't answer that question.

---------------------
Steve Stites

merer · 08-30-2007, 01:15 AM

No, pentium m is not dual core. They are based on pentium 3 and were replaced by core solo (single core) and core duo (dual core).

dwhitney67 · 08-30-2007, 04:58 AM

Quote:

Originally Posted by merer

No, pentium m is not dual core. They are based on pentium 3 and were replaced by core solo (single core) and core duo (dual core).

Do you have any suggestions on how I should configure my kernel to support the Pentium-MMX and Pentium-M processors? Do I require separate kernels for these?

In the past my company relied on the 2.4.27 version of the kernel to support the Pentium-MMX and Pentium-T3 (or whatever the proper name is). That kernel was configured with CONFIG_M586MMX. Should I continue with this for the Pentium-M?