Re: [PATCH 1/4] powerpc/rtas: Handle special return format for RTAS_FN_IBM_OPEN_ERRINJCT
From: Sourabh Jain <hidden>
Date: 2025-12-12 09:09:55
Also in:
lkml
On 05/12/25 15:15, Narayana Murty N wrote:
quoted hunk ↗ jump to hunk
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 <redacted> --- 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