Kernel expects CPU states/register states in the format mentioned in
"Register Save Area" in PAPR.
The platform (in our case, QEMU) saves each CPU register in the form of
an array of "register entries", the start and end of this array is
signified by "CPUSTRT" and "CPUEND" register entries respectively.
The CPUSTRT and CPUEND register entry also has 4-byte logical CPU ID,
thus storing the CPU ID corresponding to the array of register entries.
Each register, and CPUSTRT, CPUEND has a predefined identifier.
Implement calculating identifier for a given register in
'fadump_str_to_u64', which has been taken from the linux kernel
Similarly GPRs also have predefined identifiers, and a corresponding
64-bit resiter value (split into two 32-bit cells). Implement
calculation of GPR identifiers with 'fadump_gpr_id_to_u64'
PAPR has restrictions on particular order of few registers, and is
free to be in any order for other registers.
Some registers mentioned in PAPR have not been exported as they are not
implemented in QEMU / don't make sense in QEMU.
Implement saving of CPU state according to the PAPR document
Signed-off-by: Aditya Gupta <adityag@linux.ibm.com>
Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Tested-by: Shivang Upadhyay <shivangu@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20251021134823.1861675-5-adityag@linux.ibm.com
Signed-off-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
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