[RFC 2/5] powerpc: kvm: drop 32-bit booke

[Arnd Bergmann]

On Fri, Dec 13, 2024, at 07:25, Christophe Leroy wrote:
> Le 12/12/2024 à 22:08, Arnd Bergmann a écrit :
>
> So yes it is used on e5500/e6500 but only when they run a 32 bits kernel 
> built with CONFIG_PPC_85xx. Isn't it what you want to get rid of with 
> this patch ?
>
> Am I missing something ?

I think I mixed up CONFIG_PPC_E500 and CONFIG_PPC_85xx and hadn't
realized that we use CONFIG_PPC_BOOK3E_64 instead of PPC_85xx for
the 64-bit mode. I found a few more things that can be removed
now and folded in the patch below, which includes your suggestions.

     Arnd

diff --git a/arch/powerpc/kernel/head_85xx.S b/arch/powerpc/kernel/head_85xx.S
index f9a73fae6464..661903d31b54 100644
--- a/arch/powerpc/kernel/head_85xx.S
+++ b/arch/powerpc/kernel/head_85xx.S
@@ -425,16 +425,10 @@ interrupt_base:
 	mtspr	SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
 	mfspr	r10, SPRN_SPRG_THREAD
 	stw	r11, THREAD_NORMSAVE(0)(r10)
-#ifdef CONFIG_KVM_BOOKE_HV
-BEGIN_FTR_SECTION
-	mfspr	r11, SPRN_SRR1
-END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
-#endif
 	stw	r12, THREAD_NORMSAVE(1)(r10)
 	stw	r13, THREAD_NORMSAVE(2)(r10)
 	mfcr	r13
 	stw	r13, THREAD_NORMSAVE(3)(r10)
-	DO_KVM	BOOKE_INTERRUPT_DTLB_MISS SPRN_SRR1
 START_BTB_FLUSH_SECTION
 	mfspr r11, SPRN_SRR1
 	andi. r10,r11,MSR_PR
@@ -517,16 +511,10 @@ END_BTB_FLUSH_SECTION
 	mtspr	SPRN_SPRG_WSCRATCH0, r10 /* Save some working registers */
 	mfspr	r10, SPRN_SPRG_THREAD
 	stw	r11, THREAD_NORMSAVE(0)(r10)
-#ifdef CONFIG_KVM_BOOKE_HV
-BEGIN_FTR_SECTION
-	mfspr	r11, SPRN_SRR1
-END_FTR_SECTION_IFSET(CPU_FTR_EMB_HV)
-#endif
 	stw	r12, THREAD_NORMSAVE(1)(r10)
 	stw	r13, THREAD_NORMSAVE(2)(r10)
 	mfcr	r13
 	stw	r13, THREAD_NORMSAVE(3)(r10)
-	DO_KVM	BOOKE_INTERRUPT_ITLB_MISS SPRN_SRR1
 START_BTB_FLUSH_SECTION
 	mfspr r11, SPRN_SRR1
 	andi. r10,r11,MSR_PR
@@ -660,8 +648,6 @@ END_BTB_FLUSH_SECTION
 	DEBUG_DEBUG_EXCEPTION
 	DEBUG_CRIT_EXCEPTION
 
-	GUEST_DOORBELL_EXCEPTION
-
 	CRITICAL_EXCEPTION(0, GUEST_DBELL_CRIT, CriticalGuestDoorbell, \
 			   unknown_exception)
 
diff --git a/arch/powerpc/kernel/head_booke.h b/arch/powerpc/kernel/head_booke.h
index 0b5c1993809e..d1ffef4d05b5 100644
--- a/arch/powerpc/kernel/head_booke.h
+++ b/arch/powerpc/kernel/head_booke.h
@@ -3,8 +3,6 @@
 #define __HEAD_BOOKE_H__
 
 #include <asm/ptrace.h>	/* for STACK_FRAME_REGS_MARKER */
-#include <asm/kvm_asm.h>
-#include <asm/kvm_booke_hv_asm.h>
 #include <asm/thread_info.h>	/* for THREAD_SHIFT */
 
 #ifdef __ASSEMBLY__
@@ -52,7 +50,6 @@ END_BTB_FLUSH_SECTION
 	stw	r13, THREAD_NORMSAVE(2)(r10);				     \
 	mfcr	r13;			/* save CR in r13 for now	   */\
 	mfspr	r11, SPRN_SRR1;		                                     \
-	DO_KVM	BOOKE_INTERRUPT_##intno SPRN_SRR1;			     \
 	andi.	r11, r11, MSR_PR;	/* check whether user or kernel    */\
 	LOAD_REG_IMMEDIATE(r11, MSR_KERNEL);				\
 	mtmsr	r11;							\
@@ -114,25 +111,7 @@ END_BTB_FLUSH_SECTION
 
 .macro SYSCALL_ENTRY trapno intno srr1
 	mfspr	r10, SPRN_SPRG_THREAD
-#ifdef CONFIG_KVM_BOOKE_HV
-BEGIN_FTR_SECTION
-	mtspr	SPRN_SPRG_WSCRATCH0, r10
-	stw	r11, THREAD_NORMSAVE(0)(r10)
-	stw	r13, THREAD_NORMSAVE(2)(r10)
-	mfcr	r13			/* save CR in r13 for now	   */
-	mfspr	r11, SPRN_SRR1
-	mtocrf	0x80, r11	/* check MSR[GS] without clobbering reg */
-	bf	3, 1975f
-	b	kvmppc_handler_\intno\()_\srr1
-1975:
-	mr	r12, r13
-	lwz	r13, THREAD_NORMSAVE(2)(r10)
-FTR_SECTION_ELSE
 	mfcr	r12
-ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
-#else
-	mfcr	r12
-#endif
 	mfspr	r9, SPRN_SRR1
 	BOOKE_CLEAR_BTB(r11)
 	mr	r11, r1
@@ -198,7 +177,6 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 	stw	r11,GPR11(r8);						     \
 	stw	r9,_CCR(r8);		/* save CR on stack		   */\
 	mfspr	r11,exc_level_srr1;	/* check whether user or kernel    */\
-	DO_KVM	BOOKE_INTERRUPT_##intno exc_level_srr1;		             \
 	BOOKE_CLEAR_BTB(r10)						\
 	andi.	r11,r11,MSR_PR;						     \
 	LOAD_REG_IMMEDIATE(r11, MSR_KERNEL & ~(MSR_ME|MSR_DE|MSR_CE));	\
@@ -272,23 +250,6 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_EMB_HV)
 		EXC_LEVEL_EXCEPTION_PROLOG(MC, trapno+4, MACHINE_CHECK, \
 			SPRN_MCSRR0, SPRN_MCSRR1)
 
-/*
- * Guest Doorbell -- this is a bit odd in that uses GSRR0/1 despite
- * being delivered to the host.  This exception can only happen
- * inside a KVM guest -- so we just handle up to the DO_KVM rather
- * than try to fit this into one of the existing prolog macros.
- */
-#define GUEST_DOORBELL_EXCEPTION \
-	START_EXCEPTION(GuestDoorbell);					     \
-	mtspr	SPRN_SPRG_WSCRATCH0, r10;	/* save one register */	     \
-	mfspr	r10, SPRN_SPRG_THREAD;					     \
-	stw	r11, THREAD_NORMSAVE(0)(r10);				     \
-	mfspr	r11, SPRN_SRR1;		                                     \
-	stw	r13, THREAD_NORMSAVE(2)(r10);				     \
-	mfcr	r13;			/* save CR in r13 for now	   */\
-	DO_KVM	BOOKE_INTERRUPT_GUEST_DBELL SPRN_GSRR1;			     \
-	trap
-
 /*
  * Exception vectors.
  */