[#3957] bootmem code shadows global max_pfn

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[#3957] bootmem code shadows global max_pfn

Submitted By: Mike Frysinger

Open Date

2008-03-05 14:25:23     Close Date

2008-03-17 18:47:35

Priority:

Medium     Assignee:

Yi Li

Status:

Closed     Fixed In Release:

N/A

Found In Release:

N/A     Release:

Category:

N/A     Board:

N/A

Processor:

N/A     Silicon Revision:

Is this bug repeatable?:

Yes     Resolution:

Fixed

Uboot version or rev.:

    Toolchain version or rev.:

App binary format:

N/A     

Summary: bootmem code shadows global max_pfn

Details:

 

we have a local variable "max_pfn":

arch/blackfin/kernel/setup.c:   unsigned long min_pfn, max_pfn;

 

but common linux code has:

include/linux/bootmem.h:extern unsigned long max_pfn;

 

something is out of sync ...

 

Follow-ups

 

--- Yi Li                                                    2008-03-06 02:51:21

Yes. We need to find a place to initialize these globals.

 

Searched linux-2.6.24.3 source tree, found that there a few places in common

code uses the global max_pfn:

 

drivers/base/platform.c

block/ll_rw_blk.c

drivers/lguest/lguest_devices.c

 

As the notes in arch/arm/mm/init.c: bootmem_init() mentions:

""This doesn't seem to be used by the Linux memory manager anymore,

but is used by ll_rw_block".

 

--- Yi Li                                                    2008-03-13 03:05:42

There are a number of MM related globals:

 

initialized in arch/blackfin/kernel/setup.c:

linux/bootmem.h: max_pfn, min_low_pfn, max_low_pfn

 

initialized in arch/blackfin/mm/init.c:

linux/mm.h: max_mapnr, num_physpages, high_memory

linux/swap.h: totalram_pages

 

It is rather confusing to understand what they exactly mean.

 

 

 

 

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