Commit cc4b26ea authored by Nathan Lynch's avatar Nathan Lynch Committed by Michael Ellerman
Browse files

powerpc/perf/hv-24x7: add missing RTAS retry status handling 



The ibm,get-system-parameter RTAS function may return -2 or 990x,
which indicate that the caller should try again. read_24x7_sys_info()
ignores this, allowing transient failures in reporting processor
module information.

Move the RTAS call into a coventional rtas_busy_delay()-based loop,
along with the parsing of results on success.

Signed-off-by: default avatarNathan Lynch <nathanl@linux.ibm.com>
Fixes: 8ba21426 ("powerpc/hv-24x7: Add rtas call in hv-24x7 driver to get processor details")
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-2-26929c8cce78@linux.ibm.com
parent 09d1ea72

arch/powerpc/perf/hv-24x7.c

+18 −24
Original line number Diff line number Diff line
@@ -79,9 +79,8 @@ static u32 phys_coresperchip; /* Physical cores per chip */ 
 */

void read_24x7_sys_info(void)

{

	int call_status, len, ntypes;



	spin_lock(&rtas_data_buf_lock);

	const s32 token = rtas_token("ibm,get-system-parameter");

	int call_status;



	/*

	 * Making system parameter: chips and sockets and cores per chip
@@ -91,32 +90,27 @@ void read_24x7_sys_info(void) 
	phys_chipspersocket = 1;

	phys_coresperchip = 1;



	call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,

				NULL,

				PROCESSOR_MODULE_INFO,

				__pa(rtas_data_buf),

				RTAS_DATA_BUF_SIZE);



	if (call_status != 0) {

		pr_err("Error calling get-system-parameter %d\n",

		       call_status);

	} else {

		len = be16_to_cpup((__be16 *)&rtas_data_buf[0]);

		if (len < 8)

			goto out;



		ntypes = be16_to_cpup((__be16 *)&rtas_data_buf[2]);



		if (!ntypes)

			goto out;

	do {

		spin_lock(&rtas_data_buf_lock);

		call_status = rtas_call(token, 3, 1, NULL, PROCESSOR_MODULE_INFO,

					__pa(rtas_data_buf), RTAS_DATA_BUF_SIZE);

		if (call_status == 0) {

			int ntypes = be16_to_cpup((__be16 *)&rtas_data_buf[2]);

			int len = be16_to_cpup((__be16 *)&rtas_data_buf[0]);



			if (len >= 8 && ntypes != 0) {

				phys_sockets = be16_to_cpup((__be16 *)&rtas_data_buf[4]);

				phys_chipspersocket = be16_to_cpup((__be16 *)&rtas_data_buf[6]);

				phys_coresperchip = be16_to_cpup((__be16 *)&rtas_data_buf[8]);

			}



out:

		}

		spin_unlock(&rtas_data_buf_lock);

	} while (rtas_busy_delay(call_status));



	if (call_status != 0) {

		pr_err("Error calling get-system-parameter %d\n",

		       call_status);

	}

}



/* Domains for which more than one result element are returned for each event. */