xref: /linux/arch/powerpc/include/asm/sstep.h (revision 2874c5fd284268364ece81a7bd936f3c8168e567)

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C) 2004 Paul Mackerras <paulus@au.ibm.com>, IBM
 */

struct pt_regs;

/*
 * We don't allow single-stepping an mtmsrd that would clear
 * MSR_RI, since that would make the exception unrecoverable.
 * Since we need to single-step to proceed from a breakpoint,
 * we don't allow putting a breakpoint on an mtmsrd instruction.
 * Similarly we don't allow breakpoints on rfid instructions.
 * These macros tell us if an instruction is a mtmsrd or rfid.
 * Note that IS_MTMSRD returns true for both an mtmsr (32-bit)
 * and an mtmsrd (64-bit).
 */
#define IS_MTMSRD(instr)	(((instr) & 0xfc0007be) == 0x7c000124)
#define IS_RFID(instr)		(((instr) & 0xfc0007fe) == 0x4c000024)
#define IS_RFI(instr)		(((instr) & 0xfc0007fe) == 0x4c000064)

enum instruction_type {
	COMPUTE,		/* arith/logical/CR op, etc. */
	LOAD,			/* load and store types need to be contiguous */
	LOAD_MULTI,
	LOAD_FP,
	LOAD_VMX,
	LOAD_VSX,
	STORE,
	STORE_MULTI,
	STORE_FP,
	STORE_VMX,
	STORE_VSX,
	LARX,
	STCX,
	BRANCH,
	MFSPR,
	MTSPR,
	CACHEOP,
	BARRIER,
	SYSCALL,
	MFMSR,
	MTMSR,
	RFI,
	INTERRUPT,
	UNKNOWN
};

#define INSTR_TYPE_MASK	0x1f

#define OP_IS_LOAD_STORE(type)	(LOAD <= (type) && (type) <= STCX)

/* Compute flags, ORed in with type */
#define SETREG		0x20
#define SETCC		0x40
#define SETXER		0x80

/* Branch flags, ORed in with type */
#define SETLK		0x20
#define BRTAKEN		0x40
#define DECCTR		0x80

/* Load/store flags, ORed in with type */
#define SIGNEXT		0x20
#define UPDATE		0x40	/* matches bit in opcode 31 instructions */
#define BYTEREV		0x80
#define FPCONV		0x100

/* Barrier type field, ORed in with type */
#define BARRIER_MASK	0xe0
#define BARRIER_SYNC	0x00
#define BARRIER_ISYNC	0x20
#define BARRIER_EIEIO	0x40
#define BARRIER_LWSYNC	0x60
#define BARRIER_PTESYNC	0x80

/* Cacheop values, ORed in with type */
#define CACHEOP_MASK	0x700
#define DCBST		0
#define DCBF		0x100
#define DCBTST		0x200
#define DCBT		0x300
#define ICBI		0x400
#define DCBZ		0x500

/* VSX flags values */
#define VSX_FPCONV	1	/* do floating point SP/DP conversion */
#define VSX_SPLAT	2	/* store loaded value into all elements */
#define VSX_LDLEFT	4	/* load VSX register from left */
#define VSX_CHECK_VEC	8	/* check MSR_VEC not MSR_VSX for reg >= 32 */

/* Size field in type word */
#define SIZE(n)		((n) << 12)
#define GETSIZE(w)	((w) >> 12)

#define GETTYPE(t)	((t) & INSTR_TYPE_MASK)

#define MKOP(t, f, s)	((t) | (f) | SIZE(s))

struct instruction_op {
	int type;
	int reg;
	unsigned long val;
	/* For LOAD/STORE/LARX/STCX */
	unsigned long ea;
	int update_reg;
	/* For MFSPR */
	int spr;
	u32 ccval;
	u32 xerval;
	u8 element_size;	/* for VSX/VMX loads/stores */
	u8 vsx_flags;
};

union vsx_reg {
	u8	b[16];
	u16	h[8];
	u32	w[4];
	unsigned long d[2];
	float	fp[4];
	double	dp[2];
	__vector128 v;
};

/*
 * Decode an instruction, and return information about it in *op
 * without changing *regs.
 *
 * Return value is 1 if the instruction can be emulated just by
 * updating *regs with the information in *op, -1 if we need the
 * GPRs but *regs doesn't contain the full register set, or 0
 * otherwise.
 */
extern int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
			 unsigned int instr);

/*
 * Emulate an instruction that can be executed just by updating
 * fields in *regs.
 */
void emulate_update_regs(struct pt_regs *reg, struct instruction_op *op);

/*
 * Emulate instructions that cause a transfer of control,
 * arithmetic/logical instructions, loads and stores,
 * cache operations and barriers.
 *
 * Returns 1 if the instruction was emulated successfully,
 * 0 if it could not be emulated, or -1 for an instruction that
 * should not be emulated (rfid, mtmsrd clearing MSR_RI, etc.).
 */
extern int emulate_step(struct pt_regs *regs, unsigned int instr);

/*
 * Emulate a load or store instruction by reading/writing the
 * memory of the current process.  FP/VMX/VSX registers are assumed
 * to hold live values if the appropriate enable bit in regs->msr is
 * set; otherwise this will use the saved values in the thread struct
 * for user-mode accesses.
 */
extern int emulate_loadstore(struct pt_regs *regs, struct instruction_op *op);

extern void emulate_vsx_load(struct instruction_op *op, union vsx_reg *reg,
			     const void *mem, bool cross_endian);
extern void emulate_vsx_store(struct instruction_op *op,
			      const union vsx_reg *reg, void *mem,
			      bool cross_endian);
extern int emulate_dcbz(unsigned long ea, struct pt_regs *regs);