[Qemu-devel] 4xx wrtee instructions

[Qemu-devel] 4xx wrtee instructions

[Andrew May]

When I try to boot a PPC 4xx linux kernel it fails somewhere after
expanding the ramdisk with:
"qemu: fatal: Trying to execute code outside RAM or ROM at 0xc007c70c"

It seems that the "wrteei" instruction is unsetting the address
translate bits in the MSR. This patch seems to fix it, and I think it
is correct, to and with the "not" of the bit instead of the bit itself
to disable interrupts.

The qemu log file doesn't display the correct instructions, but that
doesn't seem to be a problem.
====================
IN: 
0xc000d0cc:  mfmsr      r5
0xc000d0d0:  mfspr      r6,945
0xc000d0d4:  .long 0x7c000146
0xc000d0d8:  mtspr      945,r4
0xc000d0dc:  .long 0x7c601f25
0xc000d0e0:  mtspr      945,r6
0xc000d0e4:  .long 0x7ca00106
=======================

Please CC me since I am not on the list.

Here is the patch.
==========
diff --git a/trunk/target-ppc/translate.c b/trunk/target-ppc/translate.c
--- a/trunk/target-ppc/translate.c
+++ b/trunk/target-ppc/translate.c
@@ -6050,7 +6050,7 @@ GEN_HANDLER(wrteei, 0x1F, 0x03, 0x05, 0x000EFC01, PPC_WRTEE)
         /* Stop translation to have a chance to raise an exception */
         gen_stop_exception(ctx);
     } else {
-        tcg_gen_andi_tl(cpu_msr, cpu_msr, (1 << MSR_EE));
+        tcg_gen_andi_tl(cpu_msr, cpu_msr, ~(1 << MSR_EE));
     }
 #endif
 }

Re: [Qemu-devel] 4xx wrtee instructions

[Aurelien Jarno]

On Tue, Jan 13, 2009 at 04:04:18PM -0800, Andrew May wrote:
> When I try to boot a PPC 4xx linux kernel it fails somewhere after
> expanding the ramdisk with:
> "qemu: fatal: Trying to execute code outside RAM or ROM at 0xc007c70c"
> 
> It seems that the "wrteei" instruction is unsetting the address
> translate bits in the MSR. This patch seems to fix it, and I think it
> is correct, to and with the "not" of the bit instead of the bit itself
> to disable interrupts.
> 
> The qemu log file doesn't display the correct instructions, but that
> doesn't seem to be a problem.
> ====================
> IN: 
> 0xc000d0cc:  mfmsr      r5
> 0xc000d0d0:  mfspr      r6,945
> 0xc000d0d4:  .long 0x7c000146
> 0xc000d0d8:  mtspr      945,r4
> 0xc000d0dc:  .long 0x7c601f25
> 0xc000d0e0:  mtspr      945,r6
> 0xc000d0e4:  .long 0x7ca00106
> =======================
> 
> Please CC me since I am not on the list.
> 
> Here is the patch.
> ==========
> diff --git a/trunk/target-ppc/translate.c b/trunk/target-ppc/translate.c
> --- a/trunk/target-ppc/translate.c
> +++ b/trunk/target-ppc/translate.c
> @@ -6050,7 +6050,7 @@ GEN_HANDLER(wrteei, 0x1F, 0x03, 0x05, 0x000EFC01, PPC_WRTEE)
>          /* Stop translation to have a chance to raise an exception */
>          gen_stop_exception(ctx);
>      } else {
> -        tcg_gen_andi_tl(cpu_msr, cpu_msr, (1 << MSR_EE));
> +        tcg_gen_andi_tl(cpu_msr, cpu_msr, ~(1 << MSR_EE));
>      }
>  #endif
>  }
> 

Thanks, applied.

-- 
  .''`.  Aurelien Jarno	            | GPG: 1024D/F1BCDB73
 : :' :  Debian developer           | Electrical Engineer
 `. `'   aurel32@debian.org         | aurelien@aurel32.net
   `-    people.debian.org/~aurel32 | www.aurel32.net

Re: [Qemu-devel] 4xx wrtee instructions

[Hollis Blanchard]

On Tue, 2009-01-13 at 16:04 -0800, Andrew May wrote:
> When I try to boot a PPC 4xx linux kernel it fails somewhere after
> expanding the ramdisk with:
> "qemu: fatal: Trying to execute code outside RAM or ROM at 0xc007c70c"

By the way, how did you load the kernel? The last time I tried to use
the 405 emulation, I was told I needed a u-boot binary as the ROM, but
couldn't find any that worked.

-- 
Hollis Blanchard
IBM Linux Technology Center