Revert "convert SLB miss handlers to C" and subsequent commits

This reverts commits:
  5e46e29e6a97 ("powerpc/64s/hash: convert SLB miss handlers to C")
  8fed04d0f6ae ("powerpc/64s/hash: remove user SLB data from the paca")
  655deecf67b2 ("powerpc/64s/hash: SLB allocation status bitmaps")
  2e1626744e8d ("powerpc/64s/hash: provide arch_setup_exec hooks for hash slice setup")
  89ca4e126a3f ("powerpc/64s/hash: Add a SLB preload cache")

This series had a few bugs, and the fixes are not all trivial. So
revert most of it for now.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 160 insertions, 42 deletions

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 786f4fa5100a..301a6a86a20f 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -596,36 +596,28 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
 
 
 EXC_REAL_BEGIN(data_access_slb, 0x380, 0x80)
-EXCEPTION_PROLOG(PACA_EXSLB, data_access_slb_common, EXC_STD, KVMTEST_PR, 0x380);
+	SET_SCRATCH0(r13)
+	EXCEPTION_PROLOG_0(PACA_EXSLB)
+	EXCEPTION_PROLOG_1(PACA_EXSLB, KVMTEST_PR, 0x380)
+	mr	r12,r3	/* save r3 */
+	mfspr	r3,SPRN_DAR
+	mfspr	r11,SPRN_SRR1
+	crset	4*cr6+eq
+	BRANCH_TO_COMMON(r10, slb_miss_common)
 EXC_REAL_END(data_access_slb, 0x380, 0x80)
 
 EXC_VIRT_BEGIN(data_access_slb, 0x4380, 0x80)
-EXCEPTION_RELON_PROLOG(PACA_EXSLB, data_access_slb_common, EXC_STD, NOTEST, 0x380);
+	SET_SCRATCH0(r13)
+	EXCEPTION_PROLOG_0(PACA_EXSLB)
+	EXCEPTION_PROLOG_1(PACA_EXSLB, NOTEST, 0x380)
+	mr	r12,r3	/* save r3 */
+	mfspr	r3,SPRN_DAR
+	mfspr	r11,SPRN_SRR1
+	crset	4*cr6+eq
+	BRANCH_TO_COMMON(r10, slb_miss_common)
 EXC_VIRT_END(data_access_slb, 0x4380, 0x80)
-
 TRAMP_KVM_SKIP(PACA_EXSLB, 0x380)
 
-EXC_COMMON_BEGIN(data_access_slb_common)
-	mfspr	r10,SPRN_DAR
-	std	r10,PACA_EXSLB+EX_DAR(r13)
-	EXCEPTION_PROLOG_COMMON(0x380, PACA_EXSLB)
-	ld	r4,PACA_EXSLB+EX_DAR(r13)
-	std	r4,_DAR(r1)
-	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	do_slb_fault
-	cmpdi	r3,0
-	bne-	1f
-	b	fast_exception_return
-1:	/* Error case */
-	std	r3,RESULT(r1)
-	bl	save_nvgprs
-	RECONCILE_IRQ_STATE(r10, r11)
-	ld	r4,_DAR(r1)
-	ld	r5,RESULT(r1)
-	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	do_bad_slb_fault
-	b	ret_from_except
-
 
 EXC_REAL(instruction_access, 0x400, 0x80)
 EXC_VIRT(instruction_access, 0x4400, 0x80, 0x400)
@@ -648,34 +640,160 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
 
 
 EXC_REAL_BEGIN(instruction_access_slb, 0x480, 0x80)
-EXCEPTION_PROLOG(PACA_EXSLB, instruction_access_slb_common, EXC_STD, KVMTEST_PR, 0x480);
+	SET_SCRATCH0(r13)
+	EXCEPTION_PROLOG_0(PACA_EXSLB)
+	EXCEPTION_PROLOG_1(PACA_EXSLB, KVMTEST_PR, 0x480)
+	mr	r12,r3	/* save r3 */
+	mfspr	r3,SPRN_SRR0		/* SRR0 is faulting address */
+	mfspr	r11,SPRN_SRR1
+	crclr	4*cr6+eq
+	BRANCH_TO_COMMON(r10, slb_miss_common)
 EXC_REAL_END(instruction_access_slb, 0x480, 0x80)
 
 EXC_VIRT_BEGIN(instruction_access_slb, 0x4480, 0x80)
-EXCEPTION_RELON_PROLOG(PACA_EXSLB, instruction_access_slb_common, EXC_STD, NOTEST, 0x480);
+	SET_SCRATCH0(r13)
+	EXCEPTION_PROLOG_0(PACA_EXSLB)
+	EXCEPTION_PROLOG_1(PACA_EXSLB, NOTEST, 0x480)
+	mr	r12,r3	/* save r3 */
+	mfspr	r3,SPRN_SRR0		/* SRR0 is faulting address */
+	mfspr	r11,SPRN_SRR1
+	crclr	4*cr6+eq
+	BRANCH_TO_COMMON(r10, slb_miss_common)
 EXC_VIRT_END(instruction_access_slb, 0x4480, 0x80)
-
 TRAMP_KVM(PACA_EXSLB, 0x480)
 
-EXC_COMMON_BEGIN(instruction_access_slb_common)
-	EXCEPTION_PROLOG_COMMON(0x480, PACA_EXSLB)
-	ld	r4,_NIP(r1)
-	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	do_slb_fault
-	cmpdi	r3,0
-	bne-	1f
-	b	fast_exception_return
-1:	/* Error case */
-	std	r3,RESULT(r1)
+
+/*
+ * This handler is used by the 0x380 and 0x480 SLB miss interrupts, as well as
+ * the virtual mode 0x4380 and 0x4480 interrupts if AIL is enabled.
+ */
+EXC_COMMON_BEGIN(slb_miss_common)
+	/*
+	 * r13 points to the PACA, r9 contains the saved CR,
+	 * r12 contains the saved r3,
+	 * r11 contain the saved SRR1, SRR0 is still ready for return
+	 * r3 has the faulting address
+	 * r9 - r13 are saved in paca->exslb.
+ 	 * cr6.eq is set for a D-SLB miss, clear for a I-SLB miss
+	 * We assume we aren't going to take any exceptions during this
+	 * procedure.
+	 */
+	mflr	r10
+	stw	r9,PACA_EXSLB+EX_CCR(r13)	/* save CR in exc. frame */
+	std	r10,PACA_EXSLB+EX_LR(r13)	/* save LR */
+
+	andi.	r9,r11,MSR_PR	// Check for exception from userspace
+	cmpdi	cr4,r9,MSR_PR	// And save the result in CR4 for later
+
+	/*
+	 * Test MSR_RI before calling slb_allocate_realmode, because the
+	 * MSR in r11 gets clobbered. However we still want to allocate
+	 * SLB in case MSR_RI=0, to minimise the risk of getting stuck in
+	 * recursive SLB faults. So use cr5 for this, which is preserved.
+	 */
+	andi.	r11,r11,MSR_RI	/* check for unrecoverable exception */
+	cmpdi	cr5,r11,MSR_RI
+
+	crset	4*cr0+eq
+#ifdef CONFIG_PPC_BOOK3S_64
+BEGIN_MMU_FTR_SECTION
+	bl	slb_allocate
+END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
+#endif
+
+	ld	r10,PACA_EXSLB+EX_LR(r13)
+	lwz	r9,PACA_EXSLB+EX_CCR(r13)	/* get saved CR */
+	mtlr	r10
+
+	/*
+	 * Large address, check whether we have to allocate new contexts.
+	 */
+	beq-	8f
+
+	bne-	cr5,2f		/* if unrecoverable exception, oops */
+
+	/* All done -- return from exception. */
+
+	bne	cr4,1f		/* returning to kernel */
+
+	mtcrf	0x80,r9
+	mtcrf	0x08,r9		/* MSR[PR] indication is in cr4 */
+	mtcrf	0x04,r9		/* MSR[RI] indication is in cr5 */
+	mtcrf	0x02,r9		/* I/D indication is in cr6 */
+	mtcrf	0x01,r9		/* slb_allocate uses cr0 and cr7 */
+
+	RESTORE_CTR(r9, PACA_EXSLB)
+	RESTORE_PPR_PACA(PACA_EXSLB, r9)
+	mr	r3,r12
+	ld	r9,PACA_EXSLB+EX_R9(r13)
+	ld	r10,PACA_EXSLB+EX_R10(r13)
+	ld	r11,PACA_EXSLB+EX_R11(r13)
+	ld	r12,PACA_EXSLB+EX_R12(r13)
+	ld	r13,PACA_EXSLB+EX_R13(r13)
+	RFI_TO_USER
+	b	.	/* prevent speculative execution */
+1:
+	mtcrf	0x80,r9
+	mtcrf	0x08,r9		/* MSR[PR] indication is in cr4 */
+	mtcrf	0x04,r9		/* MSR[RI] indication is in cr5 */
+	mtcrf	0x02,r9		/* I/D indication is in cr6 */
+	mtcrf	0x01,r9		/* slb_allocate uses cr0 and cr7 */
+
+	RESTORE_CTR(r9, PACA_EXSLB)
+	RESTORE_PPR_PACA(PACA_EXSLB, r9)
+	mr	r3,r12
+	ld	r9,PACA_EXSLB+EX_R9(r13)
+	ld	r10,PACA_EXSLB+EX_R10(r13)
+	ld	r11,PACA_EXSLB+EX_R11(r13)
+	ld	r12,PACA_EXSLB+EX_R12(r13)
+	ld	r13,PACA_EXSLB+EX_R13(r13)
+	RFI_TO_KERNEL
+	b	.	/* prevent speculative execution */
+
+
+2:	std     r3,PACA_EXSLB+EX_DAR(r13)
+	mr	r3,r12
+	mfspr	r11,SPRN_SRR0
+	mfspr	r12,SPRN_SRR1
+	LOAD_HANDLER(r10,unrecov_slb)
+	mtspr	SPRN_SRR0,r10
+	ld	r10,PACAKMSR(r13)
+	mtspr	SPRN_SRR1,r10
+	RFI_TO_KERNEL
+	b	.
+
+8:	std     r3,PACA_EXSLB+EX_DAR(r13)
+	mr	r3,r12
+	mfspr	r11,SPRN_SRR0
+	mfspr	r12,SPRN_SRR1
+	LOAD_HANDLER(r10, large_addr_slb)
+	mtspr	SPRN_SRR0,r10
+	ld	r10,PACAKMSR(r13)
+	mtspr	SPRN_SRR1,r10
+	RFI_TO_KERNEL
+	b	.
+
+EXC_COMMON_BEGIN(unrecov_slb)
+	EXCEPTION_PROLOG_COMMON(0x4100, PACA_EXSLB)
+	RECONCILE_IRQ_STATE(r10, r11)
 	bl	save_nvgprs
+1:	addi	r3,r1,STACK_FRAME_OVERHEAD
+	bl	unrecoverable_exception
+	b	1b
+
+EXC_COMMON_BEGIN(large_addr_slb)
+	EXCEPTION_PROLOG_COMMON(0x380, PACA_EXSLB)
 	RECONCILE_IRQ_STATE(r10, r11)
-	ld	r4,_NIP(r1)
-	ld	r5,RESULT(r1)
-	addi	r3,r1,STACK_FRAME_OVERHEAD
-	bl	do_bad_slb_fault
+	ld	r3, PACA_EXSLB+EX_DAR(r13)
+	std	r3, _DAR(r1)
+	beq	cr6, 2f
+	li	r10, 0x481		/* fix trap number for I-SLB miss */
+	std	r10, _TRAP(r1)
+2:	bl	save_nvgprs
+	addi	r3, r1, STACK_FRAME_OVERHEAD
+	bl	slb_miss_large_addr
 	b	ret_from_except
 
-
 EXC_REAL_BEGIN(hardware_interrupt, 0x500, 0x100)
 	.globl hardware_interrupt_hv;
 hardware_interrupt_hv: