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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

arch/powerpc/lib/sstep.c

+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;