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Commit 6888199f authored by Ananth N Mavinakayanahalli's avatar Ananth N Mavinakayanahalli Committed by Paul Mackerras
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[POWERPC] Emulate more instructions in software



Emulate a few more instructions in software - especially useful during
singlestepping (xmon/kprobes).

Instructions emulated with this patch are mfcr/mtcr rX, mfxer/mtxer rX,
mflr/mtlr rX, mfctr/mtctr rX and mr rA,rB.

Signed-off-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 5cc5133a
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+44 −1
Original line number Original line Diff line number Diff line
@@ -54,7 +54,7 @@ static int __kprobes branch_taken(unsigned int instr, struct pt_regs *regs)
 */
 */
int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
{
{
	unsigned int opcode, rd;
	unsigned int opcode, rs, rb, rd, spr;
	unsigned long int imm;
	unsigned long int imm;


	opcode = instr >> 26;
	opcode = instr >> 26;
@@ -152,6 +152,49 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
				regs->nip &= 0xffffffffUL;
				regs->nip &= 0xffffffffUL;
			return 1;
			return 1;
#endif
#endif
		case 0x26:	/* mfcr */
			regs->gpr[rd] = regs->ccr;
			regs->gpr[rd] &= 0xffffffffUL;
			goto mtspr_out;
		case 0x2a6:	/* mfspr */
			spr = (instr >> 11) & 0x3ff;
			switch (spr) {
			case 0x20:	/* mfxer */
				regs->gpr[rd] = regs->xer;
				regs->gpr[rd] &= 0xffffffffUL;
				goto mtspr_out;
			case 0x100:	/* mflr */
				regs->gpr[rd] = regs->link;
				goto mtspr_out;
			case 0x120:	/* mfctr */
				regs->gpr[rd] = regs->ctr;
				goto mtspr_out;
			}
			break;
		case 0x378:	/* orx */
			rs = (instr >> 21) & 0x1f;
			rb = (instr >> 11) & 0x1f;
			if (rs == rb) {		/* mr */
				rd = (instr >> 16) & 0x1f;
				regs->gpr[rd] = regs->gpr[rs];
				goto mtspr_out;
			}
			break;
		case 0x3a6:	/* mtspr */
			spr = (instr >> 11) & 0x3ff;
			switch (spr) {
			case 0x20:	/* mtxer */
				regs->xer = (regs->gpr[rd] & 0xffffffffUL);
				goto mtspr_out;
			case 0x100:	/* mtlr */
				regs->link = regs->gpr[rd];
				goto mtspr_out;
			case 0x120:	/* mtctr */
				regs->ctr = regs->gpr[rd];
mtspr_out:
				regs->nip += 4;
				return 1;
			}
		}
		}
	}
	}
	return 0;
	return 0;