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Subject: Re: [PATCH 3/3] m68k: switch to MEMBLOCK + NO_BOOTMEM
To:     Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc:     Geert Uytterhoeven <geert@linux-m68k.org>,
        Sam Creasey <sammy@sammy.net>,
        Michal Hocko <mhocko@kernel.org>,
        linux-m68k@lists.linux-m68k.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
References: <1530613795-6956-1-git-send-email-rppt@linux.vnet.ibm.com>
 <1530613795-6956-4-git-send-email-rppt@linux.vnet.ibm.com>
 <5388c6eb-2159-b103-51f9-2a211c54b4bc@linux-m68k.org>
 <0614f397-d9c9-cc99-69bc-25b7d0361af4@linux-m68k.org>
 <20180704042221.GG4809@rapoport-lnx>
From:   Greg Ungerer <gerg@linux-m68k.org>
Message-ID: <6403bb73-2c86-cf44-180e-58019b776ca3@linux-m68k.org>
Date:   Wed, 4 Jul 2018 14:39:05 +1000
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Hi Mike,

On 04/07/18 14:22, Mike Rapoport wrote:
> On Wed, Jul 04, 2018 at 12:02:52PM +1000, Greg Ungerer wrote:
>> On 04/07/18 11:39, Greg Ungerer wrote:
>>> On 03/07/18 20:29, Mike Rapoport wrote:
>>>> In m68k the physical memory is described by [memory_start, memory_end] for
>>>> !MMU variant and by m68k_memory array of memory ranges for the MMU version.
>>>> This information is directly used to register the physical memory with
>>>> memblock.
>>>>
>>>> The reserve_bootmem() calls are replaced with memblock_reserve() and the
>>>> bootmap bitmap allocation is simply dropped.
>>>>
>>>> Since the MMU variant creates early mappings only for the small part of the
>>>> memory we force bottom-up allocations in memblock because otherwise we will
>>>> attempt to access memory that not yet mapped
>>>>
>>>> Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
>>>
>>> This builds cleanly for me with a m5475_defconfig, but it fails
>>> to boot on real hardware. No console, no nothing on startup.
>>> I haven't debugged any further yet.
>>>
>>> The M5475 is a ColdFire with MMU enabled target.
>>
>> With some early serial debug trace I see:
>>
>> Linux version 4.18.0-rc3-00003-g109f5e551b18-dirty (gerg@goober) (gcc version 5.4.0 (GCC)) #5 Wed Jul 4 12:00:03 AEST 2018
>> On node 0 totalpages: 4096
>>    DMA zone: 18 pages used for memmap
>>    DMA zone: 0 pages reserved
>>    DMA zone: 4096 pages, LIFO batch:0
>> pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
>> pcpu-alloc: [0] 0
>> Built 1 zonelists, mobility grouping off.  Total pages: 4078
>> Kernel command line: root=/dev/mtdblock0
>> Dentry cache hash table entries: 4096 (order: 1, 16384 bytes)
>> Inode-cache hash table entries: 2048 (order: 0, 8192 bytes)
>> Sorting __ex_table...
>> Memory: 3032K/32768K available (1489K kernel code, 96K rwdata, 240K rodata, 56K init, 77K bss, 29736K reserved, 0K cma-reserved)
>                                                                                                   ^^^^^^
> It seems I was over enthusiastic when I reserved the memory for the kernel.
> Can you please try with the below patch:
> 
> diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
> index e9e60e1..18c7bf6 100644
> --- a/arch/m68k/mm/mcfmmu.c
> +++ b/arch/m68k/mm/mcfmmu.c
> @@ -174,7 +174,7 @@ void __init cf_bootmem_alloc(void)
>   	high_memory = (void *)_ramend;
>   
>   	/* Reserve kernel text/data/bss */
> -	memblock_reserve(memstart, _ramend - memstart);
> +	memblock_reserve(memstart, memstart - _rambase);
>   
>   	m68k_virt_to_node_shift = fls(_ramend - 1) - 6;
>   	module_fixup(NULL, __start_fixup, __stop_fixup);
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 03d48d8..98661be 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -54,7 +54,7 @@ struct memblock memblock __initdata_memblock = {
>   	.current_limit		= MEMBLOCK_ALLOC_ANYWHERE,
>   };
>   
> -int memblock_debug __initdata_memblock;
> +int memblock_debug __initdata_memblock = 1;
>   static bool system_has_some_mirror __initdata_memblock = false;
>   static int memblock_can_resize __initdata_memblock;
>   static int memblock_memory_in_slab __initdata_memblock = 0;
> 
> 
> The memblock hunk is needed to see early memblock debug messages as all the
> setup happens before parsing of the command line.

Ok, that works, boots all the way up now.

Linux version 4.18.0-rc3-00003-g109f5e551b18-dirty (gerg@goober) (gcc version 5.4.0 (GCC)) #7 Wed Jul 4 14:34:48 AEST 2018
memblock_add: [0x00000000-0x01ffffff] 0x001ebaa0
memblock_reserve: [0x00332000-0x00663fff] 0x001ebafa
memblock_reserve: [0x01ffe000-0x01ffffff] 0x001efd38
memblock_reserve: [0x01ff8000-0x01ffdfff] 0x001efd38
memblock_virt_alloc_try_nid_nopanic: 147456 bytes align=0x0 nid=0 from=0x0 max_addr=0x0 0x00190dea
memblock_reserve: [0x01fd4000-0x01ff7fff] 0x001f0466
memblock_virt_alloc_try_nid_nopanic: 4 bytes align=0x0 nid=0 from=0x0 max_addr=0x0 0x001ee234
memblock_reserve: [0x01fd3ff0-0x01fd3ff3] 0x001f0466
memblock_virt_alloc_try_nid: 20 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ea488
memblock_reserve: [0x01fd3fd0-0x01fd3fe3] 0x001f0466
memblock_virt_alloc_try_nid: 20 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ea4a8
memblock_reserve: [0x01fd3fb0-0x01fd3fc3] 0x001f0466
memblock_virt_alloc_try_nid: 20 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ea4c0
memblock_reserve: [0x01fd3f90-0x01fd3fa3] 0x001f0466
memblock_virt_alloc_try_nid_nopanic: 8192 bytes align=0x2000 nid=-1 from=0x0 max_addr=0x0 0x001eef30
memblock_reserve: [0x01fd0000-0x01fd1fff] 0x001f0466
memblock_virt_alloc_try_nid_nopanic: 32768 bytes align=0x2000 nid=-1 from=0x0 max_addr=0x0 0x001ef5d6
memblock_reserve: [0x01fc8000-0x01fcffff] 0x001f0466
memblock_virt_alloc_try_nid: 4 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ef2ac
memblock_reserve: [0x01fd3f80-0x01fd3f83] 0x001f0466
memblock_virt_alloc_try_nid: 4 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ef2c2
memblock_reserve: [0x01fd3f70-0x01fd3f73] 0x001f0466
memblock_virt_alloc_try_nid: 4 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ef2d6
memblock_reserve: [0x01fd3f60-0x01fd3f63] 0x001f0466
memblock_virt_alloc_try_nid: 4 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ef2e6
memblock_reserve: [0x01fd3f50-0x01fd3f53] 0x001f0466
memblock_virt_alloc_try_nid: 120 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ef506
memblock_reserve: [0x01fd3ed0-0x01fd3f47] 0x001f0466
memblock_virt_alloc_try_nid: 67 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001eece0
memblock_reserve: [0x01fd3e80-0x01fd3ec2] 0x001f0466
memblock_virt_alloc_try_nid: 1024 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001eed0e
memblock_reserve: [0x01fd3a80-0x01fd3e7f] 0x001f0466
memblock_virt_alloc_try_nid: 1028 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001eed2c
memblock_reserve: [0x01fd3670-0x01fd3a73] 0x001f0466
memblock_virt_alloc_try_nid: 80 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001eed4e
memblock_reserve: [0x01fd3620-0x01fd366f] 0x001f0466
__memblock_free_early: [0x00000001fd0000-0x00000001fd1fff] 0x001eef80
Built 1 zonelists, mobility grouping off.  Total pages: 4078
Kernel command line: root=/dev/mtdblock0
memblock_virt_alloc_try_nid_nopanic: 16384 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ee828
memblock_reserve: [0x01fc4000-0x01fc7fff] 0x001f0466
Dentry cache hash table entries: 4096 (order: 1, 16384 bytes)
memblock_virt_alloc_try_nid_nopanic: 8192 bytes align=0x0 nid=-1 from=0x0 max_addr=0x0 0x001ee828
memblock_reserve: [0x01fd1620-0x01fd361f] 0x001f0466
Inode-cache hash table entries: 2048 (order: 0, 8192 bytes)
Sorting __ex_table...
Memory: 29256K/32768K available (1489K kernel code, 96K rwdata, 240K rodata, 56K init, 77K bss, 3512K reserved, 0K cma-reserved)
SLUB: HWalign=16, Order=0-3, MinObjects=0, CPUs=1, Nodes=8
NR_IRQS: 256
clocksource: slt: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 14370379300 ns
Calibrating delay loop... 264.19 BogoMIPS (lpj=1320960)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 2048 (order: 0, 8192 bytes)
Mountpoint-cache hash table entries: 2048 (order: 0, 8192 bytes)
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
ColdFire: PCI bus initialization...
Coldfire: PCI IO/config window mapped to 0xe0000000
PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [io  0x0000-0xffff]
pci_bus 0000:00: root bus resource [mem 0x00000000-0xffffffff]
pci_bus 0000:00: root bus resource [bus 00-ff]
pci 0000:00:14.0: BAR 2: assigned [mem 0xf0000000-0xf00fffff]
pci 0000:00:14.0: BAR 6: assigned [mem 0xf0100000-0xf01fffff pref]
pci 0000:00:14.0: BAR 0: assigned [mem 0xf0200000-0xf0200fff]
pci 0000:00:14.0: BAR 1: assigned [io  0x0400-0x043f]
vgaarb: loaded
clocksource: Switched to clocksource slt
workingset: timestamp_bits=27 max_order=12 bucket_order=0
romfs: ROMFS MTD (C) 2007 Red Hat, Inc.
io scheduler noop registered (default)
io scheduler mq-deadline registered
io scheduler kyber registered
ColdFire internal UART serial driver
mcfuart.0: ttyS0 at MMIO 0xff008600 (irq = 99, base_baud = 8312500) is a ColdFire UART
console [ttyS0] enabled
mcfuart.0: ttyS1 at MMIO 0xff008700 (irq = 98, base_baud = 8312500) is a ColdFire UART
mcfuart.0: ttyS2 at MMIO 0xff008800 (irq = 97, base_baud = 8312500) is a ColdFire UART
mcfuart.0: ttyS3 at MMIO 0xff008900 (irq = 96, base_baud = 8312500) is a ColdFire UART
brd: module loaded
uclinux[mtd]: probe address=0x20bb84 size=0x126000
Creating 1 MTD partitions on "ram":
0x000000000000-0x000000126000 : "ROMfs"
random: get_random_bytes called from 0x000283b6 with crng_init=0
VFS: Mounted root (romfs filesystem) readonly on device 31:0.
Freeing unused kernel memory: 56K
This architecture does not have kernel memory protection.

Regards
Greg