[Qemu-devel] Re: 4xx booting into Linux userspace

[Andrew May <acmay@acmay.homeip.net>]

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On Sat, 17 Jan 2009 00:25:13 -0800
Andrew May <acmay@acmay.homeip.net> wrote:

> I finally got a 405 linux kernel booted into userspace.
> The op_helper change is pretty straight forward, where the "tlb->attr"
> values should have been set from the tlbwe_lo function instead of the
> high function.
> I am not sure that the tlb->attr bits completely line up with the
> tlbwe_lo bits, since I don't know how else they are used besides the
> zone bits.
> 
> For the helper.c I am not sure on the best way to deal with things.
> The first change should be ok, where the zone mapping was just off.
> But the other part where the 405 SPR doesn't seem to match up with
> SPR's used in the core TLB lookup code.

Just after I sent this I realized I didn't include the older patches I
had posted to the list on getting the 4xx stuff going. And then when I
tried to sync to the lastest I hit a snag with the display changes.

I feel pretty good about all the op_helper.c fixes.
1. Don't abort on Little endian pages, if they aren't valid.
2. Fix tlb->attr to get setting from lo reg instead of the high one.
3. Allow 4xx_tlbwe_lo, writes to leave the "tlb->prot valid" bit set,
and invalid pages to get the updates.

I don't know the best way to handle the spr SPR_DAR vs SPR_40x_DEAR
difference in helper.c

So if anyone knows the best way to address this, please let me know.

And I am not on the list so, please CC me.

Thanks.

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diff --git a/trunk/target-ppc/helper.c b/trunk/target-ppc/helper.c
index 2bf7650..df37152 100644
--- a/trunk/target-ppc/helper.c
+++ b/trunk/target-ppc/helper.c
@@ -1141,7 +1141,7 @@ static int mmu40x_get_physical_address (CPUState *env, mmu_ctx_t *ctx,
                              env->spr[SPR_40x_PID], 0, i) < 0)
             continue;
         zsel = (tlb->attr >> 4) & 0xF;
-        zpr = (env->spr[SPR_40x_ZPR] >> (28 - (2 * zsel))) & 0x3;
+        zpr = (env->spr[SPR_40x_ZPR] >> (30 - (2 * zsel))) & 0x3;
         LOG_SWTLB("%s: TLB %d zsel %d zpr %d rw %d attr %08x\n",
                     __func__, i, zsel, zpr, rw, tlb->attr);
         /* Check execute enable bit */
@@ -2089,6 +2089,9 @@ static always_inline void powerpc_excp (CPUState *env,
         new_msr &= ~((target_ulong)1 << MSR_RI);
         if (lpes1 == 0)
             new_msr |= (target_ulong)MSR_HVB;
+        /*Not sure why this isn't the same */
+        env->spr[SPR_40x_DEAR] = env->spr[SPR_DAR];
+        env->spr[SPR_40x_ESR] = 0x00800000;
         goto store_next;
     case POWERPC_EXCP_ISI:       /* Instruction storage exception            */
         LOG_EXCP("ISI exception: msr=" ADDRX ", nip=" ADDRX "\n",
diff --git a/trunk/target-ppc/op_helper.c b/trunk/target-ppc/op_helper.c
index d531dd8..e165424 100644
--- a/trunk/target-ppc/op_helper.c
+++ b/trunk/target-ppc/op_helper.c
@@ -3737,12 +3737,11 @@ void helper_4xx_tlbwe_hi (target_ulong entry, target_ulong val)
         tlb->prot |= PAGE_VALID;
     else
         tlb->prot &= ~PAGE_VALID;
-    if (val & 0x20) {
+    if (val & 0x40 && val & 0x20) {
         /* XXX: TO BE FIXED */
         cpu_abort(env, "Little-endian TLB entries are not supported by now\n");
     }
     tlb->PID = env->spr[SPR_40x_PID]; /* PID */
-    tlb->attr = val & 0xFF;
     LOG_SWTLB("%s: set up TLB %d RPN " PADDRX " EPN " ADDRX
                 " size " ADDRX " prot %c%c%c%c PID %d\n", __func__,
                 (int)entry, tlb->RPN, tlb->EPN, tlb->size,
@@ -3768,11 +3767,21 @@ void helper_4xx_tlbwe_lo (target_ulong entry, target_ulong val)
     entry &= 0x3F;
     tlb = &env->tlb[entry].tlbe;
     tlb->RPN = val & 0xFFFFFC00;
-    tlb->prot = PAGE_READ;
+    tlb->attr = val & 0xFF;
+    tlb->prot &= ~(PAGE_EXEC | PAGE_WRITE);
+    tlb->prot |= PAGE_READ;
     if (val & 0x200)
         tlb->prot |= PAGE_EXEC;
     if (val & 0x100)
         tlb->prot |= PAGE_WRITE;
+
+    /* If the page is valid flush it for the prot change */
+    if (tlb->prot & PAGE_VALID) {
+            target_ulong page, end;
+        end = tlb->EPN + tlb->size;
+        for (page = tlb->EPN; page < end; page += TARGET_PAGE_SIZE)
+            tlb_flush_page(env, page);
+    }
     LOG_SWTLB("%s: set up TLB %d RPN " PADDRX " EPN " ADDRX
                 " size " ADDRX " prot %c%c%c%c PID %d\n", __func__,
                 (int)entry, tlb->RPN, tlb->EPN, tlb->size,