From: grygorii.strashko@ti•com (Grygorii Strashko)
To: linux-arm-kernel@lists•infradead.org
Subject: ARM: issue with memory reservation from DT
Date: Wed, 15 Oct 2014 20:18:18 +0300 [thread overview]
Message-ID: <543EAC5A.6050209@ti.com> (raw)
Hi All,
I did some experiments with memory reservation from DT and got boot failure.
Input data:
- Platform Keystone 2 K2HK
- LPAE enabled
- RAM 1G:
memory {
reg = <0x8 0x00000000 0x0 0x40000000>;
};
- memory reservation 512M:
reserved-memory {
#address-cells = <2>;
#size-cells = <2>;
ranges;
dspsmem: dspsmem at 20000000 {
reg = <0x8 0x20000000 0x0 0x20000000>;
no-map;
};
};
So, total memory available for Kernel should be 512M, below is memory state for the case
when memory is reserved from u-boot:
[ 0.000000] Memory: 486200K/524288K available (5085K kernel code, 265K rwdata, 1776K rodata, 296K init, 178K bss, 38088K reserved, 0K highmem)
[ 0.000000] Virtual kernel memory layout:
[ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
[ 0.000000] fixmap : 0xffc00000 - 0xffe00000 (2048 kB)
[ 0.000000] vmalloc : 0xe0800000 - 0xff000000 ( 488 MB)
[ 0.000000] lowmem : 0xc0000000 - 0xe0000000 ( 512 MB)
[ 0.000000] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
[ 0.000000] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
[ 0.000000] .text : 0xc0008000 - 0xc06bb8a4 (6863 kB)
[ 0.000000] .init : 0xc06bc000 - 0xc0706000 ( 296 kB)
[ 0.000000] .data : 0xc0706000 - 0xc07485fc ( 266 kB)
[ 0.000000] .bss : 0xc07485fc - 0xc07751e0 ( 179 kB)
Why:
- I'm trying to reserve memory from kernel instead of u-boot.
Fast ;( investigation results:
1) The issue happens only if no-map; is used. In this case FDT
code will call memblock_remove() instead of memblock_reserve().
2) ARM limits are set wrongly from sanity_check_meminfo():
[ 0.000000] ======= memblock_limit=0x000000082f800000 arm_lowmem_limit=0x000000082f800000 vmalloc_limit=ef800000 high_memory=0x000000082f800000
instead of
[ 0.000000] ======= memblock_limit=0x0000000820000000 arm_lowmem_limit=0x0000000820000000 vmalloc_limit=e0000000 high_memory=0x000000082f800000
3) If I apply below change - I can boot:
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index c031063..85ad92b 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -917,8 +917,8 @@ void __init setup_arch(char **cmdline_p)
early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));
setup_dma_zone(mdesc);
- sanity_check_meminfo();
arm_memblock_init(mdesc);
+ sanity_check_meminfo();
paging_init(mdesc);
request_standard_resources(mdesc);
^^ not sure if it totally safe, because dma_contiguous_reserve(arm_dma_limit);
is called from inside arm_memblock_init() and it does bootmem allocations.
Sort Summary:
It looks like all static memory reservation and memory stealing's (calling of memblock_remove())
have to be done before any other operations and before calculating ARM memory limits.
Thank you for any comments.
Regards,
-grygorii
next reply other threads:[~2014-10-15 17:18 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-15 17:18 Grygorii Strashko [this message]
2014-10-15 17:50 ` ARM: issue with memory reservation from DT Russell King - ARM Linux
2014-10-16 17:32 ` Grygorii Strashko
2014-10-17 9:10 ` Laura Abbott
2014-10-17 10:21 ` Grygorii Strashko
2014-10-17 16:54 ` Laura Abbott
2014-10-20 20:48 ` Laura Abbott
2014-10-21 17:01 ` Grygorii Strashko
2014-10-21 18:32 ` Laura Abbott
2014-10-17 11:36 ` Santosh Shilimkar
2014-10-21 17:02 ` Grygorii Strashko
2014-10-21 17:16 ` Russell King - ARM Linux
2014-10-24 18:16 ` Laura Abbott
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