On 11/09/23 4:01 pm, Baoquan He wrote:
> On 09/11/23 at 05:13pm, Michael Ellerman wrote:
>> Hari Bathini <[email protected]> writes:
>>> Currently, is_kdump_kernel() returns true when elfcorehdr_addr is set.
>>> While elfcorehdr_addr is set for kexec based kernel dump mechanism,
>>> alternate dump capturing methods like fadump [1] also set it to export
>>> the vmcore. Since, is_kdump_kernel() is used to restrict resources in
>>> crash dump capture kernel and such restrictions are not desirable for
>>> fadump, allow is_kdump_kernel() to be defined differently for fadump
>>> case. With that change, include is_fadump_active() check in functions
>>> is_vmcore_usable() & vmcore_unusable() to be able to export vmcore for
>>> fadump case too.
>> ...
>>> diff --git a/include/linux/crash_dump.h b/include/linux/crash_dump.h
>>> index 0f3a656293b0..de8a9fabfb6f 100644
>>> --- a/include/linux/crash_dump.h
>>> +++ b/include/linux/crash_dump.h
>>> @@ -50,6 +50,7 @@ void vmcore_cleanup(void);
>>> #define vmcore_elf64_check_arch(x) (elf_check_arch(x) || vmcore_elf_check_arch_cross(x))
>>> #endif
>>>
>>> +#ifndef is_kdump_kernel
>>> /*
>>> * is_kdump_kernel() checks whether this kernel is booting after a panic of
>>> * previous kernel or not. This is determined by checking if previous kernel
>>> @@ -64,6 +65,19 @@ static inline bool is_kdump_kernel(void)
>>> {
>>> return elfcorehdr_addr != ELFCORE_ADDR_MAX;
>>> }
>>> +#endif
>>> +
>>> +#ifndef is_fadump_active
>>> +/*
>>> + * If f/w assisted dump capturing mechanism (fadump), instead of kexec based
>>> + * dump capturing mechanism (kdump) is exporting the vmcore, then this function
>>> + * will be defined in arch specific code to return true, when appropriate.
>>> + */
>>> +static inline bool is_fadump_active(void)
>>> +{
>>> + return false;
>>> +}
>>> +#endif
>>>
>>> /* is_vmcore_usable() checks if the kernel is booting after a panic and
>>> * the vmcore region is usable.
>>> @@ -75,7 +89,8 @@ static inline bool is_kdump_kernel(void)
>>>
>>> static inline int is_vmcore_usable(void)
>>> {
>>> - return is_kdump_kernel() && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
>>> + return (is_kdump_kernel() || is_fadump_active())
>>> + && elfcorehdr_addr != ELFCORE_ADDR_ERR ? 1 : 0;
>>> }
>>>
>>> /* vmcore_unusable() marks the vmcore as unusable,
>>> @@ -84,7 +99,7 @@ static inline int is_vmcore_usable(void)
>>>
>>> static inline void vmcore_unusable(void)
>>> {
>>> - if (is_kdump_kernel())
>>> + if (is_kdump_kernel() || is_fadump_active())
>>> elfcorehdr_addr = ELFCORE_ADDR_ERR;
>>> }
>>
>> I think it would be cleaner to decouple is_vmcore_usable() and
>> vmcore_usable() from is_kdump_kernel().
>>
>> ie, make them operate solely based on the value of elforehdr_addr:
>>
>> static inline int is_vmcore_usable(void)
>> {
>> elfcorehdr_addr != ELFCORE_ADDR_ERR && \
>> elfcorehdr_addr != ELFCORE_ADDR_MAX;
>
> Agree. I fell into the blind corner of thinking earlier. Above change
> is better.
Thanks for the reviews.
Posted v3.
- Hari