RESEND: Re: Problem booting a PowerBook G4 Aluminum after commit cd08f109 with CONFIG_VMAP_STACK=y

[Christophe Leroy]

On 02/14/2020 06:24 PM, Larry Finger wrote:
> On 2/14/20 12:24 AM, Christophe Leroy wrote:
>>
>> Did you try with the patch at 
>> https://patchwork.ozlabs.org/patch/1237387/ ?
> 
> Christophe,
> 
> When I apply that patch, there is an error at
> 
> --- a/arch/powerpc/kernel/head_32.S
> +++ b/arch/powerpc/kernel/head_32.S
> @@ -301,6 +301,39 @@  MachineCheck:
>       . = 0x300
>       DO_KVM  0x300
>   DataAccess:
> 
> It complains about "an attempt to move .org backwards".
> 

Argh !

> When I change the 0x300 to 0x310 in two places, it builds OK. Is that OK?

No you can't do that.

The following should solve it for your case.

---
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index 32875afb3319..f9941b766f63 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -270,6 +270,9 @@ __secondary_hold_acknowledge:
   * pointer when we take an exception from supervisor mode.)
   *	-- paulus.
   */
+#ifdef CONFIG_PPC_CHRP
+1:	b	machine_check_in_rtas
+#endif
  	. = 0x200
  	DO_KVM  0x200
  MachineCheck:
@@ -290,12 +293,9 @@ MachineCheck:
  7:	EXCEPTION_PROLOG_2
  	addi	r3,r1,STACK_FRAME_OVERHEAD
  #ifdef CONFIG_PPC_CHRP
-	bne	cr1,1f
+	bne	cr1,1b
  #endif
  	EXC_XFER_STD(0x200, machine_check_exception)
-#ifdef CONFIG_PPC_CHRP
-1:	b	machine_check_in_rtas
-#endif

  /* Data access exception. */
  	. = 0x300
---

Christophe