[PATCH 1/1] riscv: select CONFIG_ARCH_KEEP_MEMBLOCK

[Heinrich Schuchardt]

On 8/16/21 5:30 PM, Kefeng Wang wrote:
> 
> On 2021/8/16 22:47, Heinrich Schuchardt wrote:
>> For analyzing memory blocks we can either use the memblock=debug command
>> line argument which creates massive output or a debug file system.
>>
>> Select CONFIG_ARCH_KEEP_MEMBLOCK to provide a debugfs at
>> /sys/kernel/debug/memblock to analyze memory blocks. The
>> same is already done for arm, arm64, mips, powerpc.
>>
>> The actual provisioning of the file system depends on CONFIG_DEBUG_FS.
> 
> Hi，for riscv, it don't use memblock(eg, no provide pfn_valid to use 
> memblock),
> 
> we could call memblock_discard() to discard memblock private memory to save
> 
> some memory, right?  So I think we don't need this config for now.

What do you mean by "it don't use memblock?

If you boot the HiFive Unmatched with memblock=debug you will see output 
like the one below. This is the information that you can see in the 
debug file system if CONFIG_DEBUG_FS and CONFIG_ARCH_KEEP_MEMBLOCK will 
be enabled.

[    0.000000] MEMBLOCK configuration:
[    0.000000]  memory size = 0x00000003ffe00000 reserved size = 
0x000000001290fb70
[    0.000000]  memory.cnt  = 0x25
[    0.000000]  memory[0x0]     [0x0000000080200000-0x00000000fe6e2fff], 
0x000000007e4e3000 bytes flags: 0x0
[    0.000000]  memory[0x1]     [0x00000000fe6e3000-0x00000000fe6e5fff], 
0x0000000000003000 bytes flags: 0x4
[    0.000000]  memory[0x2]     [0x00000000fe6e6000-0x00000000fe709fff], 
0x0000000000024000 bytes flags: 0x0
[    0.000000]  memory[0x3]     [0x00000000fe70a000-0x00000000fe70bfff], 
0x0000000000002000 bytes flags: 0x4
[    0.000000]  memory[0x4]     [0x00000000fe70c000-0x00000000fe70ffff], 
0x0000000000004000 bytes flags: 0x0
[    0.000000]  memory[0x5]     [0x00000000fe710000-0x00000000fe710fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x6]     [0x00000000fe711000-0x00000000fe712fff], 
0x0000000000002000 bytes flags: 0x0
[    0.000000]  memory[0x7]     [0x00000000fe713000-0x00000000fe716fff], 
0x0000000000004000 bytes flags: 0x4
[    0.000000]  memory[0x8]     [0x00000000fe717000-0x00000000fe717fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x9]     [0x00000000fe718000-0x00000000fe71cfff], 
0x0000000000005000 bytes flags: 0x4
[    0.000000]  memory[0xa]     [0x00000000fe71d000-0x00000000fe71dfff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0xb]     [0x00000000fe71e000-0x00000000fe71efff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0xc]     [0x00000000fe71f000-0x00000000fe71ffff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0xd]     [0x00000000fe720000-0x00000000fe720fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0xe]     [0x00000000fe721000-0x00000000fe721fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0xf]     [0x00000000fe722000-0x00000000fe722fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x10]    [0x00000000fe723000-0x00000000fe723fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x11]    [0x00000000fe724000-0x00000000fe724fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x12]    [0x00000000fe725000-0x00000000fe725fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x13]    [0x00000000fe726000-0x00000000fe726fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x14]    [0x00000000fe727000-0x00000000fe728fff], 
0x0000000000002000 bytes flags: 0x0
[    0.000000]  memory[0x15]    [0x00000000fe729000-0x00000000fe729fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x16]    [0x00000000fe72a000-0x00000000fe72afff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x17]    [0x00000000fe72b000-0x00000000fe72cfff], 
0x0000000000002000 bytes flags: 0x4
[    0.000000]  memory[0x18]    [0x00000000fe72d000-0x00000000fe72dfff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x19]    [0x00000000fe72e000-0x00000000fe72efff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x1a]    [0x00000000fe72f000-0x00000000fe72ffff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x1b]    [0x00000000fe730000-0x00000000fe730fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x1c]    [0x00000000fe731000-0x00000000fe731fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x1d]    [0x00000000fe732000-0x00000000fe732fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x1e]    [0x00000000fe733000-0x00000000fe733fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  memory[0x1f]    [0x00000000fe734000-0x00000000fe734fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x20]    [0x00000000fe735000-0x00000000fe736fff], 
0x0000000000002000 bytes flags: 0x0
[    0.000000]  memory[0x21]    [0x00000000fe737000-0x00000000fe737fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x22]    [0x00000000fe738000-0x00000000fff60fff], 
0x0000000001829000 bytes flags: 0x0
[    0.000000]  memory[0x23]    [0x00000000fff61000-0x00000000fff61fff], 
0x0000000000001000 bytes flags: 0x4
[    0.000000]  memory[0x24]    [0x00000000fff62000-0x000000047fffffff], 
0x000000038009e000 bytes flags: 0x0
[    0.000000]  reserved.cnt  = 0xd
[    0.000000]  reserved[0x0]   [0x0000000080000000-0x000000008007ffff], 
0x0000000000080000 bytes flags: 0x0
[    0.000000]  reserved[0x1]   [0x0000000080200000-0x00000000815fffff], 
0x0000000001400000 bytes flags: 0x0
[    0.000000]  reserved[0x2]   [0x0000000087f00000-0x0000000087f05fff], 
0x0000000000006000 bytes flags: 0x0
[    0.000000]  reserved[0x3]   [0x00000000db0a2000-0x00000000db0a48b4], 
0x00000000000028b5 bytes flags: 0x0
[    0.000000]  reserved[0x4]   [0x00000000db2a2000-0x00000000dc709fff], 
0x0000000001468000 bytes flags: 0x0
[    0.000000]  reserved[0x5]   [0x00000000fe701000-0x00000000fe701fff], 
0x0000000000001000 bytes flags: 0x0
[    0.000000]  reserved[0x6]   [0x00000000fe704040-0x00000000fe70404f], 
0x0000000000000010 bytes flags: 0x0
[    0.000000]  reserved[0x7]   [0x000000046ffe1d40-0x000000047dfe253f], 
0x000000000e000800 bytes flags: 0x0
[    0.000000]  reserved[0x8]   [0x000000047dfe2548-0x000000047dfe2578], 
0x0000000000000031 bytes flags: 0x0
[    0.000000]  reserved[0x9]   [0x000000047dfe2580-0x000000047dfe25ae], 
0x000000000000002f bytes flags: 0x0
[    0.000000]  reserved[0xa]   [0x000000047dfe25b0-0x000000047dfe25de], 
0x000000000000002f bytes flags: 0x0
[    0.000000]  reserved[0xb]   [0x000000047dfe25e0-0x000000047dfefffb], 
0x000000000000da1c bytes flags: 0x0
[    0.000000]  reserved[0xc]   [0x000000047dff0000-0x000000047fffffff], 
0x0000000002010000 bytes flags: 0x0

Best regards

Heinrich

> 
>>
>> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt at canonical.com>
>> ---
>>   arch/riscv/Kconfig | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>> index 4f7b70ae7c31..a6e57614c3fd 100644
>> --- a/arch/riscv/Kconfig
>> +++ b/arch/riscv/Kconfig
>> @@ -31,6 +31,7 @@ config RISCV
>>       select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
>>       select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL
>>       select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
>> +    select ARCH_KEEP_MEMBLOCK
>>       select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
>>       select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT
>>       select ARCH_SUPPORTS_HUGETLBFS if MMU