Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 172 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/exception-64e.h b/arch/powerpc/include/asm/exception-64e.h
new file mode 100644
index 000000000..b1ef1e92c
--- /dev/null
+++ b/arch/powerpc/include/asm/exception-64e.h
@@ -0,0 +1,172 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ *  Definitions for use by exception code on Book3-E
+ *
+ *  Copyright (C) 2008 Ben. Herrenschmidt (benh@kernel.crashing.org), IBM Corp.
+ */
+#ifndef _ASM_POWERPC_EXCEPTION_64E_H
+#define _ASM_POWERPC_EXCEPTION_64E_H
+
+/*
+ * SPRGs usage an other considerations...
+ *
+ * Since TLB miss and other standard exceptions can be interrupted by
+ * critical exceptions which can themselves be interrupted by machine
+ * checks, and since the two later can themselves cause a TLB miss when
+ * hitting the linear mapping for the kernel stacks, we need to be a bit
+ * creative on how we use SPRGs.
+ *
+ * The base idea is that we have one SRPG reserved for critical and one
+ * for machine check interrupts. Those are used to save a GPR that can
+ * then be used to get the PACA, and store as much context as we need
+ * to save in there. That includes saving the SPRGs used by the TLB miss
+ * handler for linear mapping misses and the associated SRR0/1 due to
+ * the above re-entrancy issue.
+ *
+ * So here's the current usage pattern. It's done regardless of which
+ * SPRGs are user-readable though, thus we might have to change some of
+ * this later. In order to do that more easily, we use special constants
+ * for naming them
+ *
+ * WARNING: Some of these SPRGs are user readable. We need to do something
+ * about it as some point by making sure they can't be used to leak kernel
+ * critical data
+ */
+
+#define PACA_EXGDBELL PACA_EXGEN
+
+/* We are out of SPRGs so we save some things in the PACA. The normal
+ * exception frame is smaller than the CRIT or MC one though
+ */
+#define EX_R1		(0 * 8)
+#define EX_CR		(1 * 8)
+#define EX_R10		(2 * 8)
+#define EX_R11		(3 * 8)
+#define EX_R14		(4 * 8)
+#define EX_R15		(5 * 8)
+
+/*
+ * The TLB miss exception uses different slots.
+ *
+ * The bolted variant uses only the first six fields,
+ * which in combination with pgd and kernel_pgd fits in
+ * one 64-byte cache line.
+ */
+
+#define EX_TLB_R10	( 0 * 8)
+#define EX_TLB_R11	( 1 * 8)
+#define EX_TLB_R14	( 2 * 8)
+#define EX_TLB_R15	( 3 * 8)
+#define EX_TLB_R16	( 4 * 8)
+#define EX_TLB_CR	( 5 * 8)
+#define EX_TLB_R12	( 6 * 8)
+#define EX_TLB_R13	( 7 * 8)
+#define EX_TLB_DEAR	( 8 * 8) /* Level 0 and 2 only */
+#define EX_TLB_ESR	( 9 * 8) /* Level 0 and 2 only */
+#define EX_TLB_SRR0	(10 * 8)
+#define EX_TLB_SRR1	(11 * 8)
+#define EX_TLB_R7	(12 * 8)
+#define EX_TLB_SIZE	(13 * 8)
+
+#define	START_EXCEPTION(label)						\
+	.globl exc_##label##_book3e;					\
+exc_##label##_book3e:
+
+/* TLB miss exception prolog
+ *
+ * This prolog handles re-entrancy (up to 3 levels supported in the PACA
+ * though we currently don't test for overflow). It provides you with a
+ * re-entrancy safe working space of r10...r16 and CR with r12 being used
+ * as the exception area pointer in the PACA for that level of re-entrancy
+ * and r13 containing the PACA pointer.
+ *
+ * SRR0 and SRR1 are saved, but DEAR and ESR are not, since they don't apply
+ * as-is for instruction exceptions. It's up to the actual exception code
+ * to save them as well if required.
+ */
+#define TLB_MISS_PROLOG							    \
+	mtspr	SPRN_SPRG_TLB_SCRATCH,r12;				    \
+	mfspr	r12,SPRN_SPRG_TLB_EXFRAME;				    \
+	std	r10,EX_TLB_R10(r12);					    \
+	mfcr	r10;							    \
+	std	r11,EX_TLB_R11(r12);					    \
+	mfspr	r11,SPRN_SPRG_TLB_SCRATCH;				    \
+	std	r13,EX_TLB_R13(r12);					    \
+	mfspr	r13,SPRN_SPRG_PACA;					    \
+	std	r14,EX_TLB_R14(r12);					    \
+	addi	r14,r12,EX_TLB_SIZE;					    \
+	std	r15,EX_TLB_R15(r12);					    \
+	mfspr	r15,SPRN_SRR1;						    \
+	std	r16,EX_TLB_R16(r12);					    \
+	mfspr	r16,SPRN_SRR0;						    \
+	std	r10,EX_TLB_CR(r12);					    \
+	std	r11,EX_TLB_R12(r12);					    \
+	mtspr	SPRN_SPRG_TLB_EXFRAME,r14;				    \
+	std	r15,EX_TLB_SRR1(r12);					    \
+	std	r16,EX_TLB_SRR0(r12);
+
+/* And these are the matching epilogs that restores things
+ *
+ * There are 3 epilogs:
+ *
+ * - SUCCESS       : Unwinds one level
+ * - ERROR         : restore from level 0 and reset
+ * - ERROR_SPECIAL : restore from current level and reset
+ *
+ * Normal errors use ERROR, that is, they restore the initial fault context
+ * and trigger a fault. However, there is a special case for linear mapping
+ * errors. Those should basically never happen, but if they do happen, we
+ * want the error to point out the context that did that linear mapping
+ * fault, not the initial level 0 (basically, we got a bogus PGF or something
+ * like that). For userland errors on the linear mapping, there is no
+ * difference since those are always level 0 anyway
+ */
+
+#define TLB_MISS_RESTORE(freg)						    \
+	ld	r14,EX_TLB_CR(r12);					    \
+	ld	r10,EX_TLB_R10(r12);					    \
+	ld	r15,EX_TLB_SRR0(r12);					    \
+	ld	r16,EX_TLB_SRR1(r12);					    \
+	mtspr	SPRN_SPRG_TLB_EXFRAME,freg;				    \
+	ld	r11,EX_TLB_R11(r12);					    \
+	mtcr	r14;							    \
+	ld	r13,EX_TLB_R13(r12);					    \
+	ld	r14,EX_TLB_R14(r12);					    \
+	mtspr	SPRN_SRR0,r15;						    \
+	ld	r15,EX_TLB_R15(r12);					    \
+	mtspr	SPRN_SRR1,r16;						    \
+	ld	r16,EX_TLB_R16(r12);					    \
+	ld	r12,EX_TLB_R12(r12);					    \
+
+#define TLB_MISS_EPILOG_SUCCESS						    \
+	TLB_MISS_RESTORE(r12)
+
+#define TLB_MISS_EPILOG_ERROR						    \
+	addi	r12,r13,PACA_EXTLB;					    \
+	TLB_MISS_RESTORE(r12)
+
+#define TLB_MISS_EPILOG_ERROR_SPECIAL					    \
+	addi	r11,r13,PACA_EXTLB;					    \
+	TLB_MISS_RESTORE(r11)
+
+#ifndef __ASSEMBLY__
+extern unsigned int interrupt_base_book3e;
+#endif
+
+#define SET_IVOR(vector_number, vector_offset)	\
+	LOAD_REG_ADDR(r3,interrupt_base_book3e);\
+	ori	r3,r3,vector_offset@l;		\
+	mtspr	SPRN_IVOR##vector_number,r3;
+/*
+ * powerpc relies on return from interrupt/syscall being context synchronising
+ * (which rfi is) to support ARCH_HAS_MEMBARRIER_SYNC_CORE without additional
+ * synchronisation instructions.
+ */
+#define RFI_TO_KERNEL							\
+	rfi
+
+#define RFI_TO_USER							\
+	rfi
+
+#endif /* _ASM_POWERPC_EXCEPTION_64E_H */
+