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Date: Tue, 26 Dec 2023 20:31:20 +0800
From: Youling Tang <youling.tang@...look.com>
To: Huacai Chen <chenhuacai@...nel.org>
Cc: WANG Xuerui <kernel@...0n.name>, Baoquan He <bhe@...hat.com>,
loongarch@...ts.linux.dev, linux-kernel@...r.kernel.org,
Youling Tang <tangyouling@...inos.cn>
Subject: Re: [PATCH] LoongArch: use generic interface to support
crashkernel=X,[high,low]
Hi, Huacai
On 2023/12/26 18:56, Huacai Chen wrote:
> Hi, Youling,
>
> On Mon, Dec 25, 2023 at 10:18 PM Youling Tang <youling.tang@...look.com> wrote:
>> From: Youling Tang <tangyouling@...inos.cn>
>>
>> LoongArch already supports two crashkernel regions in kexec-tools, so we
>> can directly use the common interface to support crashkernel=X,[hign,low].
>>
>> With the help of newly changed function parse_crashkernel() and generic
>> reserve_crashkernel_generic(), crashkernel reservation can be simplified
>> by steps:
> It is better to refer the commits introduce those changes.
ok
>
>> 1) Add a new header file <asm/crash_core.h>, and define CRASH_ALIGN,
>> CRASH_ADDR_LOW_MAX, CRASH_ADDR_HIGH_MAX and
>> DEFAULT_CRASH_KERNEL_LOW_SIZE in <asm/crash_core.h>;
>>
>> 2) Add arch_reserve_crashkernel() to call parse_crashkernel() and
>> reserve_crashkernel_generic();
>>
>> 3) Add ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION Kconfig in
>> arch/loongarch/Kconfig.
>>
>> One can reserve the crash kernel from high memory above DMA zone range
>> by explicitly passing "crashkernel=X,high"; or reserve a memory range
>> below 4G with "crashkernel=X,low". Besides, there are few rules need
>> to take notice:
>>
>> 1) "crashkernel=X,[high,low]" will be ignored if "crashkernel=size"
>> is specified.
>> 2) "crashkernel=X,low" is valid only when "crashkernel=X,high" is passed
>> and there is enough memory to be allocated under 4G.
>> 3) When allocating crashkernel above 4G and no "crashkernel=X,low" is
>> specified, a 128M low memory will be allocated automatically for
>> swiotlb bounce buffer.
>> See Documentation/admin-guide/kernel-parameters.txt for more information.
>>
>> Following test cases have been performed as expected:
> It is better to group them into "Recommended use cases", "Valid use
> cases (not recommended)" and "Invalid use cases".
ok
>> 1) crashkernel=256M //low=256M
>> 2) crashkernel=1G //low=1G
>> 3) crashkernel=4G //high=4G, low=128M(default)
>> 4) crashkernel=4G crashkernel=256M,high //high=4G, low=128M(default), high is ignored
>> 5) crashkernel=4G crashkernel=256M,low //high=4G, low=128M(default), low is ignored
>> 6) crashkernel=4G,high //high=4G, low=128M(default)
>> 7) crashkernel=256M,low //low=0M, invalid
>> 8) crashkernel=4G,high crashkernel=256M,low //high=4G, low=256M
>> 9) crashkernel=4G,high crashkernel=4G,low //high=0M, low=0M, invalid
>> 10) crashkernel=512M@...0M //low=512M
>> 11) crashkernel=1G,high crashkernel=0M,low //high=1G, low=0M
>>
>> Signed-off-by: Youling Tang <tangyouling@...inos.cn>
>> ---
>> arch/loongarch/Kconfig | 3 ++
>> arch/loongarch/include/asm/crash_core.h | 11 ++++++
>> arch/loongarch/kernel/setup.c | 48 +++++++------------------
>> 3 files changed, 27 insertions(+), 35 deletions(-)
>> create mode 100644 arch/loongarch/include/asm/crash_core.h
>>
>> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
>> index ee123820a476..02060b2ac3f2 100644
>> --- a/arch/loongarch/Kconfig
>> +++ b/arch/loongarch/Kconfig
>> @@ -575,6 +575,9 @@ config ARCH_SELECTS_CRASH_DUMP
>> depends on CRASH_DUMP
>> select RELOCATABLE
>>
>> +config ARCH_HAS_GENERIC_CRASHKERNEL_RESERVATION
>> + def_bool CRASH_CORE
>> +
>> config RELOCATABLE
>> bool "Relocatable kernel"
>> help
>> diff --git a/arch/loongarch/include/asm/crash_core.h b/arch/loongarch/include/asm/crash_core.h
>> new file mode 100644
>> index 000000000000..1f7040d8ed0f
>> --- /dev/null
>> +++ b/arch/loongarch/include/asm/crash_core.h
>> @@ -0,0 +1,11 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +#ifndef _LOONGARCH_CRASH_CORE_H
>> +#define _LOONGARCH_CRASH_CORE_H
>> +
>> +#define CRASH_ALIGN SZ_2M
>> +
>> +#define CRASH_ADDR_LOW_MAX SZ_4G
>> +#define CRASH_ADDR_HIGH_MAX memblock_end_of_DRAM()
>> +
>> +extern phys_addr_t memblock_end_of_DRAM(void);
>> +#endif
>> diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
>> index d183a745fb85..2a69a36419da 100644
>> --- a/arch/loongarch/kernel/setup.c
>> +++ b/arch/loongarch/kernel/setup.c
>> @@ -252,38 +252,25 @@ static void __init arch_reserve_vmcore(void)
>> #endif
>> }
>>
>> -/* 2MB alignment for crash kernel regions */
>> -#define CRASH_ALIGN SZ_2M
>> -#define CRASH_ADDR_MAX SZ_4G
>> -
>> -static void __init arch_parse_crashkernel(void)
>> +static void __init arch_reserve_crashkernel(void)
>> {
>> -#ifdef CONFIG_KEXEC
>> - int ret;
>> - unsigned long long total_mem;
>> + unsigned long long low_size = 0;
>> unsigned long long crash_base, crash_size;
>> + char *cmdline = boot_command_line;
>> + bool high = false;
>> + int ret;
>>
>> - total_mem = memblock_phys_mem_size();
>> - ret = parse_crashkernel(boot_command_line, total_mem,
>> - &crash_size, &crash_base,
>> - NULL, NULL);
>> - if (ret < 0 || crash_size <= 0)
>> + if (!IS_ENABLED(CONFIG_KEXEC_CORE))
>> return;
>>
>> - if (crash_base <= 0) {
>> - crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN, CRASH_ALIGN, CRASH_ADDR_MAX);
>> - if (!crash_base) {
>> - pr_warn("crashkernel reservation failed - No suitable area found.\n");
>> - return;
>> - }
>> - } else if (!memblock_phys_alloc_range(crash_size, CRASH_ALIGN, crash_base, crash_base + crash_size)) {
>> - pr_warn("Invalid memory region reserved for crash kernel\n");
>> + ret = parse_crashkernel(cmdline, memblock_phys_mem_size(),
>> + &crash_size, &crash_base,
>> + &low_size, &high);
> This line can be merged with its above line.
ok
>
>> + if (ret)
>> return;
>> - }
>>
>> - crashk_res.start = crash_base;
>> - crashk_res.end = crash_base + crash_size - 1;
>> -#endif
>> + reserve_crashkernel_generic(cmdline, crash_size, crash_base,
>> + low_size, high);
> They can be in one line.
ok.
I will synchronize the description of LoongArch in the crashkernel parameter
in Documentation/admin-guide/kernel-parameters.txt.
Thanks,
Youling.
>
> Huacai
>> }
>>
>> static void __init fdt_setup(void)
>> @@ -357,7 +344,7 @@ static void __init bootcmdline_init(char **cmdline_p)
>> void __init platform_init(void)
>> {
>> arch_reserve_vmcore();
>> - arch_parse_crashkernel();
>> + arch_reserve_crashkernel();
>>
>> #ifdef CONFIG_ACPI_TABLE_UPGRADE
>> acpi_table_upgrade();
>> @@ -467,15 +454,6 @@ static void __init resource_init(void)
>> request_resource(res, &data_resource);
>> request_resource(res, &bss_resource);
>> }
>> -
>> -#ifdef CONFIG_KEXEC
>> - if (crashk_res.start < crashk_res.end) {
>> - insert_resource(&iomem_resource, &crashk_res);
>> - pr_info("Reserving %ldMB of memory at %ldMB for crashkernel\n",
>> - (unsigned long)((crashk_res.end - crashk_res.start + 1) >> 20),
>> - (unsigned long)(crashk_res.start >> 20));
>> - }
>> -#endif
>> }
>>
>> static int __init add_legacy_isa_io(struct fwnode_handle *fwnode,
>> --
>> 2.40.0
>>
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