On 10/23/25 16:46, Sourabh Jain wrote:
On 23/10/25 16:41, Aditya Gupta wrote:
On 25/10/23 02:35PM, Sourabh Jain wrote:
<...snip...>
+ /*
+ * CPUSTRT and CPUEND register entries follow this format:
+ *
+ * 8 Bytes Reg ID (BE) | 4 Bytes (0x0) | 4 Bytes Logical CPU ID
(BE)
+ */
+ curr_reg_entry->reg_id =
+ cpu_to_be64(fadump_str_to_u64("CPUSTRT"));
+ curr_reg_entry->reg_value = cpu_to_be64(
+ ppc_cpu->vcpu_id & FADUMP_CPU_ID_MASK);
Seems like converting full 64 bit CPU ID to 64 bit BE value will not
bring
reg
entry in below format. Isn't it?
8 Bytes Identifier (BE) | 4 Bytes Reserved (0x0) | 4 Bytes Logical
CPU ID
(BE)
<...snip...>
+ /* End the registers for this CPU with "CPUEND" reg entry */
+ curr_reg_entry->reg_id =
+ cpu_to_be64(fadump_str_to_u64("CPUEND"));
+ curr_reg_entry->reg_value = cpu_to_be64(
+ ppc_cpu->vcpu_id & FADUMP_CPU_ID_MASK);
Same here.
It will be in the same format, since even with storing 8 bytes at once,
we do a 8 byte swap on the CPU ID, thus bringing the cpu id in the
higher 4 bytes only (considering CPU ID fits in 4 bytes as ensured by
the FADUMP_CPU_ID_MASK).
So, it still follows the above format, just that it does not explicitly
use 4 byte blocks.
This is also consistent with how the Linux kernel reads this field:
/* Lower 4 bytes of reg_value contains logical cpu id */
cpu = (be64_to_cpu(reg_entry->reg_value) &
RTAS_FADUMP_CPU_ID_MASK);
Yeah looks good to me now. Thanks.
Reviewed-by: Sourabh Jain <[email protected]>
Thanks Sourabh and Shivang for your diligent reviews and validation efforts.
Queued.
regards,
Harsh
