[Skiboot] [PATCH 5/7] hmi: Don't cause an unrecoverable HMI if a CPU is asleep

[Russell Currey]

decode_core_fir looks at the FIR for every CPU.  If the XSCOM read
fails, which it will if the CPU is asleep, the code path results in
raising an unrecoverable HMI.  This is incorrect as if the CPU is
asleep, it's likely not the cause of any problems.

Resolve this by skipping the CPU if it's asleep.

If the sleeping CPU was actually the cause of the HMI and no other
components were found to have errors (i.e other CPUs, NX, CAPP), an
unknown, unrecoverable HMI is raised anyway.  This patch just prevents
unrecoverable errors being thrown when a recoverable component has a HMI
and a CPU happens to be sleeping.

Signed-off-by: Russell Currey <ruscur at russell.cc>
---
 core/hmi.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/core/hmi.c b/core/hmi.c
index 127686f..09bf610 100644
--- a/core/hmi.c
+++ b/core/hmi.c
@@ -299,6 +299,7 @@ static bool decode_core_fir(struct cpu_thread *cpu,
 	uint32_t core_id;
 	int i;
 	bool found = false;
+	int64_t ret;
 
 	/* Sanity check */
 	if (!cpu || !hmi_evt)
@@ -307,10 +308,18 @@ static bool decode_core_fir(struct cpu_thread *cpu,
 	core_id = pir_to_core_id(cpu->pir);
 
 	/* Get CORE FIR register value. */
-	if (xscom_read(cpu->chip_id, XSCOM_ADDR_P8_EX(core_id, CORE_FIR),
-							&core_fir) != 0) {
+	ret = xscom_read(cpu->chip_id, XSCOM_ADDR_P8_EX(core_id, CORE_FIR),
+			 &core_fir);
+
+	if (ret == OPAL_HARDWARE) {
 		prerror("HMI: XSCOM error reading CORE FIR\n");
 		return false;
+	} else if (ret == OPAL_WRONG_STATE) {
+		/* CPU is asleep, so it probably didn't cause the checkstop */
+		prlog(PR_DEBUG,
+		      "HMI: FIR read failed, chip %d core %d asleep\n",
+		      cpu->chip_id, core_id);
+		return true;
 	}
 
 	prlog(PR_INFO, "HMI: CHIP ID: %x, CORE ID: %x, FIR: %016llx\n",
-- 
2.7.3