[PATCH] MIPS: Use common way to parse elfcorehdr

[PATCH] MIPS: Use common way to parse elfcorehdr

[Jinyang He]

"elfcorehdr" can be parsed at kernel/crash_dump.c

Signed-off-by: Jinyang He <hejinyang@loongson.cn>
---
 arch/mips/kernel/setup.c | 49 +++++++++++++++++++++---------------------------
 1 file changed, 21 insertions(+), 28 deletions(-)

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 7e1f8e2..4d2f915 100644
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -29,6 +29,7 @@
 #include <linux/of_fdt.h>
 #include <linux/of_reserved_mem.h>
 #include <linux/dmi.h>
+#include <linux/crash_dump.h>
 
 #include <asm/addrspace.h>
 #include <asm/bootinfo.h>
@@ -404,34 +405,32 @@ static int __init early_parse_memmap(char *p)
 }
 early_param("memmap", early_parse_memmap);
 
-#ifdef CONFIG_PROC_VMCORE
-static unsigned long setup_elfcorehdr, setup_elfcorehdr_size;
-static int __init early_parse_elfcorehdr(char *p)
+static void __init mips_reserve_vmcore(void)
 {
+#ifdef CONFIG_PROC_VMCORE
 	phys_addr_t start, end;
 	u64 i;
 
-	setup_elfcorehdr = memparse(p, &p);
-
-	for_each_mem_range(i, &start, &end) {
-		if (setup_elfcorehdr >= start && setup_elfcorehdr < end) {
-			/*
-			 * Reserve from the elf core header to the end of
-			 * the memory segment, that should all be kdump
-			 * reserved memory.
-			 */
-			setup_elfcorehdr_size = end - setup_elfcorehdr;
-			break;
+	if (!elfcorehdr_size) {
+		for_each_mem_range(i, &start, &end) {
+			if (elfcorehdr_addr >= start && elfcorehdr_addr < end) {
+				/*
+				 * Reserve from the elf core header to the end of
+				 * the memory segment, that should all be kdump
+				 * reserved memory.
+				 */
+				elfcorehdr_size = end - elfcorehdr_addr;
+				break;
+			}
 		}
 	}
-	/*
-	 * If we don't find it in the memory map, then we shouldn't
-	 * have to worry about it, as the new kernel won't use it.
-	 */
-	return 0;
-}
-early_param("elfcorehdr", early_parse_elfcorehdr);
+
+	pr_info("Reserving %ldKB of memory at %ldKB for kdump\n",
+		(unsigned long)elfcorehdr_size >> 10, (unsigned long)elfcorehdr_addr >> 10);
+
+	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
 #endif
+}
 
 #ifdef CONFIG_KEXEC
 
@@ -653,13 +652,7 @@ static void __init arch_mem_init(char **cmdline_p)
 	 */
 	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
 
-#ifdef CONFIG_PROC_VMCORE
-	if (setup_elfcorehdr && setup_elfcorehdr_size) {
-		printk(KERN_INFO "kdump reserved memory at %lx-%lx\n",
-		       setup_elfcorehdr, setup_elfcorehdr_size);
-		memblock_reserve(setup_elfcorehdr, setup_elfcorehdr_size);
-	}
-#endif
+	mips_reserve_vmcore();
 
 	mips_parse_crashkernel();
 #ifdef CONFIG_KEXEC
-- 
2.1.0

Re: [PATCH] MIPS: Use common way to parse elfcorehdr

[Randy Dunlap]

On 2/3/21 7:07 PM, Jinyang He wrote:
> "elfcorehdr" can be parsed at kernel/crash_dump.c
> 
> Signed-off-by: Jinyang He <hejinyang@loongson.cn>

Hm, looks like that would require CONFIG_CRASH_DUMP?


> ---
>  arch/mips/kernel/setup.c | 49 +++++++++++++++++++++---------------------------
>  1 file changed, 21 insertions(+), 28 deletions(-)
> 
> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
> index 7e1f8e2..4d2f915 100644
> --- a/arch/mips/kernel/setup.c
> +++ b/arch/mips/kernel/setup.c
> @@ -29,6 +29,7 @@
>  #include <linux/of_fdt.h>
>  #include <linux/of_reserved_mem.h>
>  #include <linux/dmi.h>
> +#include <linux/crash_dump.h>
>  
>  #include <asm/addrspace.h>
>  #include <asm/bootinfo.h>
> @@ -404,34 +405,32 @@ static int __init early_parse_memmap(char *p)
>  }
>  early_param("memmap", early_parse_memmap);
>  
> -#ifdef CONFIG_PROC_VMCORE
> -static unsigned long setup_elfcorehdr, setup_elfcorehdr_size;
> -static int __init early_parse_elfcorehdr(char *p)
> +static void __init mips_reserve_vmcore(void)
>  {
> +#ifdef CONFIG_PROC_VMCORE
>  	phys_addr_t start, end;
>  	u64 i;
>  
> -	setup_elfcorehdr = memparse(p, &p);
> -
> -	for_each_mem_range(i, &start, &end) {
> -		if (setup_elfcorehdr >= start && setup_elfcorehdr < end) {
> -			/*
> -			 * Reserve from the elf core header to the end of
> -			 * the memory segment, that should all be kdump
> -			 * reserved memory.
> -			 */
> -			setup_elfcorehdr_size = end - setup_elfcorehdr;
> -			break;
> +	if (!elfcorehdr_size) {
> +		for_each_mem_range(i, &start, &end) {
> +			if (elfcorehdr_addr >= start && elfcorehdr_addr < end) {
> +				/*
> +				 * Reserve from the elf core header to the end of
> +				 * the memory segment, that should all be kdump
> +				 * reserved memory.
> +				 */
> +				elfcorehdr_size = end - elfcorehdr_addr;
> +				break;
> +			}
>  		}
>  	}
> -	/*
> -	 * If we don't find it in the memory map, then we shouldn't
> -	 * have to worry about it, as the new kernel won't use it.
> -	 */
> -	return 0;
> -}
> -early_param("elfcorehdr", early_parse_elfcorehdr);
> +
> +	pr_info("Reserving %ldKB of memory at %ldKB for kdump\n",
> +		(unsigned long)elfcorehdr_size >> 10, (unsigned long)elfcorehdr_addr >> 10);
> +
> +	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
>  #endif
> +}
>  
>  #ifdef CONFIG_KEXEC
>  
> @@ -653,13 +652,7 @@ static void __init arch_mem_init(char **cmdline_p)
>  	 */
>  	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
>  
> -#ifdef CONFIG_PROC_VMCORE
> -	if (setup_elfcorehdr && setup_elfcorehdr_size) {
> -		printk(KERN_INFO "kdump reserved memory at %lx-%lx\n",
> -		       setup_elfcorehdr, setup_elfcorehdr_size);
> -		memblock_reserve(setup_elfcorehdr, setup_elfcorehdr_size);
> -	}
> -#endif
> +	mips_reserve_vmcore();
>  
>  	mips_parse_crashkernel();
>  #ifdef CONFIG_KEXEC
> 


-- 
~Randy

Re: [PATCH] MIPS: Use common way to parse elfcorehdr

[Jinyang He]

On 02/04/2021 11:28 AM, Randy Dunlap wrote:

> On 2/3/21 7:07 PM, Jinyang He wrote:
>> "elfcorehdr" can be parsed at kernel/crash_dump.c
>>
>> Signed-off-by: Jinyang He <hejinyang@loongson.cn>
> Hm, looks like that would require CONFIG_CRASH_DUMP?
Hi,

I don't think so. We expect to generate a /proc/vmcore when we reserved
memory for elfcorehdr. So put it under CONFIG_PROC_VMCORE. If only rely
on CONFIG_CRASH_DUMP and CONFIG_PROC_VMCORE is not enabled, we will
reserve these memory while cannot use these later. And the reason why
kernel/crash_dump.c being under CONFIG_CRASH_DUMP is that it provide
is_kdump_kernel() for others.

Thanks,
Jinyang

>
>> ---
>>   arch/mips/kernel/setup.c | 49 +++++++++++++++++++++---------------------------
>>   1 file changed, 21 insertions(+), 28 deletions(-)
>>
>> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
>> index 7e1f8e2..4d2f915 100644
>> --- a/arch/mips/kernel/setup.c
>> +++ b/arch/mips/kernel/setup.c
>> @@ -29,6 +29,7 @@
>>   #include <linux/of_fdt.h>
>>   #include <linux/of_reserved_mem.h>
>>   #include <linux/dmi.h>
>> +#include <linux/crash_dump.h>
>>   
>>   #include <asm/addrspace.h>
>>   #include <asm/bootinfo.h>
>> @@ -404,34 +405,32 @@ static int __init early_parse_memmap(char *p)
>>   }
>>   early_param("memmap", early_parse_memmap);
>>   
>> -#ifdef CONFIG_PROC_VMCORE
>> -static unsigned long setup_elfcorehdr, setup_elfcorehdr_size;
>> -static int __init early_parse_elfcorehdr(char *p)
>> +static void __init mips_reserve_vmcore(void)
>>   {
>> +#ifdef CONFIG_PROC_VMCORE
>>   	phys_addr_t start, end;
>>   	u64 i;
>>   
>> -	setup_elfcorehdr = memparse(p, &p);
>> -
>> -	for_each_mem_range(i, &start, &end) {
>> -		if (setup_elfcorehdr >= start && setup_elfcorehdr < end) {
>> -			/*
>> -			 * Reserve from the elf core header to the end of
>> -			 * the memory segment, that should all be kdump
>> -			 * reserved memory.
>> -			 */
>> -			setup_elfcorehdr_size = end - setup_elfcorehdr;
>> -			break;
>> +	if (!elfcorehdr_size) {
>> +		for_each_mem_range(i, &start, &end) {
>> +			if (elfcorehdr_addr >= start && elfcorehdr_addr < end) {
>> +				/*
>> +				 * Reserve from the elf core header to the end of
>> +				 * the memory segment, that should all be kdump
>> +				 * reserved memory.
>> +				 */
>> +				elfcorehdr_size = end - elfcorehdr_addr;
>> +				break;
>> +			}
>>   		}
>>   	}
>> -	/*
>> -	 * If we don't find it in the memory map, then we shouldn't
>> -	 * have to worry about it, as the new kernel won't use it.
>> -	 */
>> -	return 0;
>> -}
>> -early_param("elfcorehdr", early_parse_elfcorehdr);
>> +
>> +	pr_info("Reserving %ldKB of memory at %ldKB for kdump\n",
>> +		(unsigned long)elfcorehdr_size >> 10, (unsigned long)elfcorehdr_addr >> 10);
>> +
>> +	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
>>   #endif
>> +}
>>   
>>   #ifdef CONFIG_KEXEC
>>   
>> @@ -653,13 +652,7 @@ static void __init arch_mem_init(char **cmdline_p)
>>   	 */
>>   	memblock_set_current_limit(PFN_PHYS(max_low_pfn));
>>   
>> -#ifdef CONFIG_PROC_VMCORE
>> -	if (setup_elfcorehdr && setup_elfcorehdr_size) {
>> -		printk(KERN_INFO "kdump reserved memory at %lx-%lx\n",
>> -		       setup_elfcorehdr, setup_elfcorehdr_size);
>> -		memblock_reserve(setup_elfcorehdr, setup_elfcorehdr_size);
>> -	}
>> -#endif
>> +	mips_reserve_vmcore();
>>   
>>   	mips_parse_crashkernel();
>>   #ifdef CONFIG_KEXEC
>>
>

Re: [PATCH] MIPS: Use common way to parse elfcorehdr

[Randy Dunlap]

On 2/3/21 7:57 PM, Jinyang He wrote:
> On 02/04/2021 11:28 AM, Randy Dunlap wrote:
> 
>> On 2/3/21 7:07 PM, Jinyang He wrote:
>>> "elfcorehdr" can be parsed at kernel/crash_dump.c
>>>
>>> Signed-off-by: Jinyang He <hejinyang@loongson.cn>
>> Hm, looks like that would require CONFIG_CRASH_DUMP?
> Hi,
> 
> I don't think so. We expect to generate a /proc/vmcore when we reserved
> memory for elfcorehdr. So put it under CONFIG_PROC_VMCORE. If only rely
> on CONFIG_CRASH_DUMP and CONFIG_PROC_VMCORE is not enabled, we will
> reserve these memory while cannot use these later. And the reason why
> kernel/crash_dump.c being under CONFIG_CRASH_DUMP is that it provide
> is_kdump_kernel() for others.
> 
> Thanks,
> Jinyang

Hi,

I'm referring to kernel/Makefile:

obj-$(CONFIG_CRASH_DUMP) += crash_dump.o

so that's not an issue here?  Please explain.

>>> ---
>>>   arch/mips/kernel/setup.c | 49 +++++++++++++++++++++---------------------------
>>>   1 file changed, 21 insertions(+), 28 deletions(-)
>>>
>>> diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
>>> index 7e1f8e2..4d2f915 100644
>>> --- a/arch/mips/kernel/setup.c
>>> +++ b/arch/mips/kernel/setup.c
>>> @@ -29,6 +29,7 @@
>>>   #include <linux/of_fdt.h>
>>>   #include <linux/of_reserved_mem.h>
>>>   #include <linux/dmi.h>
>>> +#include <linux/crash_dump.h>
>>>     #include <asm/addrspace.h>
>>>   #include <asm/bootinfo.h>
>>> @@ -404,34 +405,32 @@ static int __init early_parse_memmap(char *p)
>>>   }
>>>   early_param("memmap", early_parse_memmap);
>>>   -#ifdef CONFIG_PROC_VMCORE
>>> -static unsigned long setup_elfcorehdr, setup_elfcorehdr_size;
>>> -static int __init early_parse_elfcorehdr(char *p)
>>> +static void __init mips_reserve_vmcore(void)
>>>   {
>>> +#ifdef CONFIG_PROC_VMCORE
>>>       phys_addr_t start, end;
>>>       u64 i;
>>>   -    setup_elfcorehdr = memparse(p, &p);
>>> -
>>> -    for_each_mem_range(i, &start, &end) {
>>> -        if (setup_elfcorehdr >= start && setup_elfcorehdr < end) {
>>> -            /*
>>> -             * Reserve from the elf core header to the end of
>>> -             * the memory segment, that should all be kdump
>>> -             * reserved memory.
>>> -             */
>>> -            setup_elfcorehdr_size = end - setup_elfcorehdr;
>>> -            break;
>>> +    if (!elfcorehdr_size) {
>>> +        for_each_mem_range(i, &start, &end) {
>>> +            if (elfcorehdr_addr >= start && elfcorehdr_addr < end) {
>>> +                /*
>>> +                 * Reserve from the elf core header to the end of
>>> +                 * the memory segment, that should all be kdump
>>> +                 * reserved memory.
>>> +                 */
>>> +                elfcorehdr_size = end - elfcorehdr_addr;
>>> +                break;
>>> +            }
>>>           }
>>>       }
>>> -    /*
>>> -     * If we don't find it in the memory map, then we shouldn't
>>> -     * have to worry about it, as the new kernel won't use it.
>>> -     */
>>> -    return 0;
>>> -}
>>> -early_param("elfcorehdr", early_parse_elfcorehdr);
>>> +
>>> +    pr_info("Reserving %ldKB of memory at %ldKB for kdump\n",
>>> +        (unsigned long)elfcorehdr_size >> 10, (unsigned long)elfcorehdr_addr >> 10);
>>> +
>>> +    memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
>>>   #endif
>>> +}
>>>     #ifdef CONFIG_KEXEC
>>>   @@ -653,13 +652,7 @@ static void __init arch_mem_init(char **cmdline_p)
>>>        */
>>>       memblock_set_current_limit(PFN_PHYS(max_low_pfn));
>>>   -#ifdef CONFIG_PROC_VMCORE
>>> -    if (setup_elfcorehdr && setup_elfcorehdr_size) {
>>> -        printk(KERN_INFO "kdump reserved memory at %lx-%lx\n",
>>> -               setup_elfcorehdr, setup_elfcorehdr_size);
>>> -        memblock_reserve(setup_elfcorehdr, setup_elfcorehdr_size);
>>> -    }
>>> -#endif
>>> +    mips_reserve_vmcore();
>>>         mips_parse_crashkernel();
>>>   #ifdef CONFIG_KEXEC
>>>
>>
> 


-- 
~Randy

Re: [PATCH] MIPS: Use common way to parse elfcorehdr

[Randy Dunlap]

On 2/3/21 8:19 PM, Jinyang He wrote:
> On 02/04/2021 12:01 PM, Randy Dunlap wrote:
> 
>> On 2/3/21 7:57 PM, Jinyang He wrote:
>>> On 02/04/2021 11:28 AM, Randy Dunlap wrote:
>>>
>>>> On 2/3/21 7:07 PM, Jinyang He wrote:
>>>>> "elfcorehdr" can be parsed at kernel/crash_dump.c
>>>>>
>>>>> Signed-off-by: Jinyang He <hejinyang@loongson.cn>
>>>> Hm, looks like that would require CONFIG_CRASH_DUMP?
>>> Hi,
>>>
>>> I don't think so. We expect to generate a /proc/vmcore when we reserved
>>> memory for elfcorehdr. So put it under CONFIG_PROC_VMCORE. If only rely
>>> on CONFIG_CRASH_DUMP and CONFIG_PROC_VMCORE is not enabled, we will
>>> reserve these memory while cannot use these later. And the reason why
>>> kernel/crash_dump.c being under CONFIG_CRASH_DUMP is that it provide
>>> is_kdump_kernel() for others.
>>>
>>> Thanks,
>>> Jinyang
>> Hi,
>>
>> I'm referring to kernel/Makefile:
>>
>> obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
>>
>> so that's not an issue here?  Please explain.
> Hi,
> 
> CONFIG_PROC_VMCORE depends on CONFIG_PROC_FS && CONFIG_CRASH_DUMP.
> So...

Got it. Thank you.

-- 
~Randy