5.15-stable review patch. If anyone has any objections, please let me know.
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From: Nathan Lynch nathanl@linux.ibm.com
[ Upstream commit cc4b26eab1859fa1a70711872caaf6414809973f ]
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: Nathan Lynch nathanl@linux.ibm.com Fixes: 8ba214267382 ("powerpc/hv-24x7: Add rtas call in hv-24x7 driver to get processor details") Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20230125-b4-powerpc-rtas-queue-v3-2-26929c8cce78@l... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/perf/hv-24x7.c | 42 ++++++++++++++++--------------------- 1 file changed, 18 insertions(+), 24 deletions(-)
diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index 284ccc90fb11c..f68fa53f4b1a2 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -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); + 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]); + } + } + 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); - } 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; - - 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); }
/* Domains for which more than one result element are returned for each event. */