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List:       qemu-ppc
Subject:    [RFC PATCH v2 2/4] target/ppc: Disable unused facilities in the e600 CPU
From:       Fabiano Rosas <farosas () linux ! ibm ! com>
Date:       2021-11-30 23:01:21
Message-ID: 20211130230123.781844-3-farosas () linux ! ibm ! com
[Download RAW message or body]

The e600 CPU is a successor of the 7448 and like all the 7450s CPUs,
it has an optional software TLB feature.

We have determined that there is no OS software support for the 7450
software TLB available these days. See the previous commit for more
information.

This patch disables the SPRs and instructions related to software TLB
from the e600 CPU.

No functional change intended. These facilities should be used by the
OS in interrupt handlers for interrupts that QEMU never generates.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
---
 target/ppc/cpu_init.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/target/ppc/cpu_init.c b/target/ppc/cpu_init.c
index 509df35d09..962acf295f 100644
--- a/target/ppc/cpu_init.c
+++ b/target/ppc/cpu_init.c
@@ -2537,9 +2537,6 @@ static void init_excp_7450(CPUPPCState *env)
     env->excp_vectors[POWERPC_EXCP_TRACE]    = 0x00000D00;
     env->excp_vectors[POWERPC_EXCP_PERFM]    = 0x00000F00;
     env->excp_vectors[POWERPC_EXCP_VPU]      = 0x00000F20;
-    env->excp_vectors[POWERPC_EXCP_IFTLB]    = 0x00001000;
-    env->excp_vectors[POWERPC_EXCP_DLTLB]    = 0x00001100;
-    env->excp_vectors[POWERPC_EXCP_DSTLB]    = 0x00001200;
     env->excp_vectors[POWERPC_EXCP_IABR]     = 0x00001300;
     env->excp_vectors[POWERPC_EXCP_SMI]      = 0x00001400;
     env->excp_vectors[POWERPC_EXCP_VPUA]     = 0x00001600;
@@ -6643,7 +6640,6 @@ static void init_proc_e600(CPUPPCState *env)
     /* Memory management */
     register_low_BATs(env);
     register_high_BATs(env);
-    register_74xx_soft_tlb(env, 128, 2);
     init_excp_7450(env);
     env->dcache_line_size = 32;
     env->icache_line_size = 32;
@@ -6667,7 +6663,7 @@ POWERPC_FAMILY(e600)(ObjectClass *oc, void *data)
                        PPC_CACHE_DCBA | PPC_CACHE_DCBZ |
                        PPC_MEM_SYNC | PPC_MEM_EIEIO |
                        PPC_MEM_TLBIE | PPC_MEM_TLBSYNC |
-                       PPC_MEM_TLBIA | PPC_74xx_TLB |
+                       PPC_MEM_TLBIA |
                        PPC_SEGMENT | PPC_EXTERN |
                        PPC_ALTIVEC;
     pcc->insns_flags2 = PPC_NONE;
-- 
2.33.1


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