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Fri, 12 Dec 2025 09:09:29 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1F52F2004D; Fri, 12 Dec 2025 09:09:29 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9CA4E20040; Fri, 12 Dec 2025 09:09:25 +0000 (GMT) Received: from [9.124.208.61] (unknown [9.124.208.61]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 12 Dec 2025 09:09:25 +0000 (GMT) Message-ID: Date: Fri, 12 Dec 2025 14:39:22 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] powerpc/rtas: Handle special return format for RTAS_FN_IBM_OPEN_ERRINJCT To: Narayana Murty N , mahesh@linux.ibm.com, maddy@linux.ibm.com, mpe@ellerman.id.au, christophe.leroy@csgroup.eu, gregkh@linuxfoundation.org, oohall@gmail.com, npiggin@gmail.com Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, tyreld@linux.ibm.com, vaibhav@linux.ibm.com, sbhat@linux.ibm.com, ganeshgr@linux.ibm.com References: <20251205094510.4671-1-nnmlinux@linux.ibm.com> <20251205094510.4671-2-nnmlinux@linux.ibm.com> Content-Language: en-US From: Sourabh Jain In-Reply-To: <20251205094510.4671-2-nnmlinux@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMjA2MDAyMCBTYWx0ZWRfX8lEFbAi2wU+F eryK2WYEdRWtjU/S+f26YVFcmfj7ZhlnZrQpJJ03LiurYzLJA8WsdB4Sdr2NU/SoBSw6UqMfvAk KQY3UyzXIB51+AvU02jQsF1k1wGnkHIYjnbCnsHYjY/+qPlrE5nTUYL68LvxvQjN33gO7/5pt7k GjM/1p2TjWkvocnKOcxWkOLTwNz/A/+NXusPfruU7b20STWujMCYpOZlUlhTiFwYeWkTivfxa6M jng0F7hyoeNlCITdtBW83j8tRtsVGZrmH/DSJ9HGYHyCEoilbZQE7bxORCE73t5MvvA7f1XJWYZ sqQmHrqisyNBNegvWnrQZPWtyWhnNGCAV6hAtmOlDvI1O3vHLOyCaqvyXvKleQYeo3ChS1PA4wN UQWup3694iPSTlCWyHEmtNjp0t5JWg== X-Authority-Analysis: v=2.4 cv=S/DUAYsP c=1 sm=1 tr=0 ts=693bdbce cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=wP3pNCr1ah4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=1mVJ_uiqAAAA:8 a=VnNF1IyMAAAA:8 a=wuzzdS_Pp81vOozeCfcA:9 a=QEXdDO2ut3YA:10 a=h67g7WpEjx8dfGT80pje:22 X-Proofpoint-ORIG-GUID: uNwl2orSMHX32CqJd60F3qms68BuM2yR X-Proofpoint-GUID: mBIcHnJxZiC0ysyunJILagbug3kBFLB9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-12-12_02,2025-12-11_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 phishscore=0 clxscore=1015 impostorscore=0 suspectscore=0 lowpriorityscore=0 adultscore=0 spamscore=0 bulkscore=0 priorityscore=1501 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2512060020 On 05/12/25 15:15, Narayana Murty N wrote: > RTAS_FN_IBM_OPEN_ERRINJCT returns results in special format: > rets[0] = session token (output) > rets[1] = status code > rets[2..] = additional outputs (if any) > > Unlike standard RTAS calls where: > rets[0] = status code > rets[1..] = outputs > > This patch adds special handling for OPEN_ERRINJCT to: > 1. Check correct status position (rets[1]) for __fetch_rtas_last_error() > 2. Copy all rets[0..nret-1] to outputs[] (including token at rets[0]) > 3. Return status from rets[1] instead of rets[0] > > Reference: OpenPOWER PAPR documentation > https://files.openpower.foundation/s/XFgfMaqLMD5Bcm8 > Signed-off-by: Narayana Murty N > --- > arch/powerpc/kernel/rtas.c | 30 ++++++++++++++++++++++++------ > 1 file changed, 24 insertions(+), 6 deletions(-) > > diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c > index 8d81c1e7a8db..04c8438aadda 100644 > --- a/arch/powerpc/kernel/rtas.c > +++ b/arch/powerpc/kernel/rtas.c > @@ -1183,7 +1183,7 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...) > unsigned long flags; > struct rtas_args *args; > char *buff_copy = NULL; > - int ret; > + int ret = 0; > > if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE) > return -1; > @@ -1213,15 +1213,33 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...) > va_rtas_call_unlocked(args, token, nargs, nret, list); > va_end(list); > > + /* Special handling for RTAS_FN_IBM_OPEN_ERRINJCT for error fetching */ It would be more helpful if we explain why special handling is needed. > /* A -1 return code indicates that the last command couldn't > be completed due to a hardware error. */ > - if (be32_to_cpu(args->rets[0]) == -1) > + The above empty line can be avoided. > + if (token == rtas_function_token(RTAS_FN_IBM_OPEN_ERRINJCT) && nret > 1) > + ret = be32_to_cpu(args->rets[1]); > + else if (nret > 0) > + ret = be32_to_cpu(args->rets[0]); > + > + if (ret == -1)It would be more helpful if we explain why special handling is needed. > > buff_copy = __fetch_rtas_last_error(NULL); > > - if (nret > 1 && outputs != NULL) > - for (i = 0; i < nret-1; ++i) > - outputs[i] = be32_to_cpu(args->rets[i + 1]); > - ret = (nret > 0) ? be32_to_cpu(args->rets[0]) : 0; > + /* Handle outputs and return status */ Return status is already handled above, isn't it? > + if (nret > 1 && outputs != NULL) { > + if (token == rtas_function_token(RTAS_FN_IBM_OPEN_ERRINJCT)) { > + /* Special case: rets[0]=token, rets[1]=status, rets[2..]=outputs */ > + for (i = 0; i < nret; ++i) > + outputs[i] = be32_to_cpu(args->rets[i]); > + } else { > + /* Normal case: rets[0]=status, rets[1..]=outputs */ > + for (i = 0; i < nret - 1; ++i) > + outputs[i] = be32_to_cpu(args->rets[i + 1]); > + } > + } else { > + /* No outputs: just ret is status */ > + ret = (nret > 0) ? be32_to_cpu(args->rets[0]) : 0; > + } Do we really need to calculated the ret again here? > > lockdep_unpin_lock(&rtas_lock, cookie); > raw_spin_unlock_irqrestore(&rtas_lock, flags); - Sourabh Jain