target/ppc: 603: fix restore of GPRs 0-3 on rfi

After a TLB miss exception, GPRs 0-3 must be restored on rfi.

This is managed by hreg_store_msr() which is called by do_rfi()

However, hreg_store_msr() does it if MSR[TGPR] is unset in the
passed MSR value.

The problem is that do_rfi() is given the content of SRR1 as
the value to be set in MSR, but TGPR bit is not part of SRR1
and that bit is used for something else and is sometimes set
to 1, leading to hreg_store_msr() not restoring GPRs.

So, do the same way as for POW bit, force clearing it.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Cedric Le Goater <clg@kaod.org>
Cc: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20220120103824.239573-1-christophe.leroy@csgroup.eu>
Signed-off-by: Cédric Le Goater <clg@kaod.org>

diff --git a/target/ppc/excp_helper.c b/target/ppc/excp_helper.c
index bc646c67a0f5470159215020a408c2c2dd0408ad..980f62fd7964c16dac3501d72397854b8ca45842 100644 (file)
--- a/target/ppc/excp_helper.c
+++ b/target/ppc/excp_helper.c
@@ -1164,6 +1164,10 @@ static void do_rfi(CPUPPCState *env, target_ulong nip, target_ulong msr)
     /* MSR:POW cannot be set by any form of rfi */
     msr &= ~(1ULL << MSR_POW);
 
+    /* MSR:TGPR cannot be set by any form of rfi */
+    if (env->flags & POWERPC_FLAG_TGPR)
+        msr &= ~(1ULL << MSR_TGPR);
+
 #if defined(TARGET_PPC64)
     /* Switching to 32-bit ? Crop the nip */
     if (!msr_is_64bit(env, msr)) {