diff options
| -rw-r--r-- | target-ppc/helper.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/target-ppc/helper.c b/target-ppc/helper.c index cf2a368b57..2944b062a5 100644 --- a/target-ppc/helper.c +++ b/target-ppc/helper.c @@ -949,8 +949,24 @@ static inline int get_segment(CPUState *env, mmu_ctx_t *ctx, ret = -3; } } else { + target_ulong sr; LOG_MMU("direct store...\n"); /* Direct-store segment : absolutely *BUGGY* for now */ + + /* Direct-store implies a 32-bit MMU. + * Check the Segment Register's bus unit ID (BUID). + */ + sr = env->sr[eaddr >> 28]; + if ((sr & 0x1FF00000) >> 20 == 0x07f) { + /* Memory-forced I/O controller interface access */ + /* If T=1 and BUID=x'07F', the 601 performs a memory access + * to SR[28-31] LA[4-31], bypassing all protection mechanisms. + */ + ctx->raddr = ((sr & 0xF) << 28) | (eaddr & 0x0FFFFFFF); + ctx->prot = PAGE_READ | PAGE_WRITE | PAGE_EXEC; + return 0; + } + switch (type) { case ACCESS_INT: /* Integer load/store : only access allowed */ |