From 826e7b827c5f83e88d5aa84c0bf0b3459f28ec35 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Herv=C3=A9=20Poussineau?= Date: Tue, 14 Jun 2011 23:27:56 +0200 Subject: [PATCH] target-ppc: Handle memory-forced I/O controller access MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On at least the PowerPC 601, a direct-store (T=1) with bus unit ID 0x07F is special-cased as memory-forced I/O controller access. It is supposed to be checked immediately if T=1, bypassing all protection mechanisms and acting cache-inhibited and global. Signed-off-by: Hervé Poussineau Simplified by avoiding reindentation. Added explanatory comments. Cc: Alexander Graf Signed-off-by: Andreas Färber Signed-off-by: Alexander Graf --- target-ppc/helper.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) 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 */