Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b91e136c authored by Michael Ellerman's avatar Michael Ellerman Committed by Benjamin Herrenschmidt
Browse files

powerpc: Use MSR_64BIT in sstep.c, fix kprobes on BOOK3E 



We check MSR_SF a lot in sstep.c, to decide if we need to emulate the
truncation of values when running in 32-bit mode. Factor out that code
into a helper, and convert it and the other uses to use MSR_64BIT.

This fixes a bug on BOOK3E where kprobes would end up returning to a
32-bit address, because regs->nip was truncated, because (msr & MSR_SF)
was false.

Signed-off-by: default avatarMichael Ellerman <michael@ellerman.id.au>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 9f0b0793

arch/powerpc/lib/sstep.c

+27 −34
Original line number Original line Diff line number Diff line
@@ -44,6 +44,18 @@ extern int do_lxvd2x(int rn, unsigned long ea); 
extern int do_stxvd2x(int rn, unsigned long ea);

extern int do_stxvd2x(int rn, unsigned long ea);

#endif

#endif





/*

 * Emulate the truncation of 64 bit values in 32-bit mode.

 */

static unsigned long truncate_if_32bit(unsigned long msr, unsigned long val)

{

#ifdef __powerpc64__

	if ((msr & MSR_64BIT) == 0)

		val &= 0xffffffffUL;

#endif

	return val;

}



/*

/*

 * Determine whether a conditional branch instruction would branch.

 * Determine whether a conditional branch instruction would branch.

 */

 */
@@ -90,11 +102,8 @@ static unsigned long __kprobes dform_ea(unsigned int instr, struct pt_regs *regs 
		if (instr & 0x04000000)		/* update forms */

		if (instr & 0x04000000)		/* update forms */

			regs->gpr[ra] = ea;

			regs->gpr[ra] = ea;

	}

	}

#ifdef __powerpc64__



	if (!(regs->msr & MSR_SF))

	return truncate_if_32bit(regs->msr, ea);

		ea &= 0xffffffffUL;

#endif

	return ea;

}

}





#ifdef __powerpc64__

#ifdef __powerpc64__
@@ -113,9 +122,8 @@ static unsigned long __kprobes dsform_ea(unsigned int instr, struct pt_regs *reg 
		if ((instr & 3) == 1)		/* update forms */

		if ((instr & 3) == 1)		/* update forms */

			regs->gpr[ra] = ea;

			regs->gpr[ra] = ea;

	}

	}

	if (!(regs->msr & MSR_SF))



		ea &= 0xffffffffUL;

	return truncate_if_32bit(regs->msr, ea);

	return ea;

}

}

#endif /* __powerpc64 */

#endif /* __powerpc64 */
@@ -136,11 +144,8 @@ static unsigned long __kprobes xform_ea(unsigned int instr, struct pt_regs *regs 
		if (do_update)		/* update forms */

		if (do_update)		/* update forms */

			regs->gpr[ra] = ea;

			regs->gpr[ra] = ea;

	}

	}

#ifdef __powerpc64__



	if (!(regs->msr & MSR_SF))

	return truncate_if_32bit(regs->msr, ea);

		ea &= 0xffffffffUL;

#endif

	return ea;

}

}





/*

/*
@@ -466,7 +471,7 @@ static void __kprobes set_cr0(struct pt_regs *regs, int rd) 




	regs->ccr = (regs->ccr & 0x0fffffff) | ((regs->xer >> 3) & 0x10000000);

	regs->ccr = (regs->ccr & 0x0fffffff) | ((regs->xer >> 3) & 0x10000000);

#ifdef __powerpc64__

#ifdef __powerpc64__

	if (!(regs->msr & MSR_SF))

	if (!(regs->msr & MSR_64BIT))

		val = (int) val;

		val = (int) val;

#endif

#endif

	if (val < 0)

	if (val < 0)
@@ -487,7 +492,7 @@ static void __kprobes add_with_carry(struct pt_regs *regs, int rd, 
		++val;

		++val;

	regs->gpr[rd] = val;

	regs->gpr[rd] = val;

#ifdef __powerpc64__

#ifdef __powerpc64__

	if (!(regs->msr & MSR_SF)) {

	if (!(regs->msr & MSR_64BIT)) {

		val = (unsigned int) val;

		val = (unsigned int) val;

		val1 = (unsigned int) val1;

		val1 = (unsigned int) val1;

	}

	}
@@ -570,8 +575,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr) 
		if ((instr & 2) == 0)

		if ((instr & 2) == 0)

			imm += regs->nip;

			imm += regs->nip;

		regs->nip += 4;

		regs->nip += 4;

		if ((regs->msr & MSR_SF) == 0)

		regs->nip = truncate_if_32bit(regs->msr, regs->nip);

			regs->nip &= 0xffffffffUL;

		if (instr & 1)

		if (instr & 1)

			regs->link = regs->nip;

			regs->link = regs->nip;

		if (branch_taken(instr, regs))

		if (branch_taken(instr, regs))
@@ -604,13 +608,9 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr) 
			imm -= 0x04000000;

			imm -= 0x04000000;

		if ((instr & 2) == 0)

		if ((instr & 2) == 0)

			imm += regs->nip;

			imm += regs->nip;

		if (instr & 1) {

		if (instr & 1)

			regs->link = regs->nip + 4;

			regs->link = truncate_if_32bit(regs->msr, regs->nip + 4);

			if ((regs->msr & MSR_SF) == 0)

		imm = truncate_if_32bit(regs->msr, imm);

				regs->link &= 0xffffffffUL;

		}

		if ((regs->msr & MSR_SF) == 0)

			imm &= 0xffffffffUL;

		regs->nip = imm;

		regs->nip = imm;

		return 1;

		return 1;

	case 19:

	case 19:
@@ -618,11 +618,8 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr) 
		case 16:	/* bclr */

		case 16:	/* bclr */

		case 528:	/* bcctr */

		case 528:	/* bcctr */

			imm = (instr & 0x400)? regs->ctr: regs->link;

			imm = (instr & 0x400)? regs->ctr: regs->link;

			regs->nip += 4;

			regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);

			if ((regs->msr & MSR_SF) == 0) {

			imm = truncate_if_32bit(regs->msr, imm);

				regs->nip &= 0xffffffffUL;

				imm &= 0xffffffffUL;

			}

			if (instr & 1)

			if (instr & 1)

				regs->link = regs->nip;

				regs->link = regs->nip;

			if (branch_taken(instr, regs))

			if (branch_taken(instr, regs))
@@ -1616,11 +1613,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr) 
		return 0;	/* invoke DSI if -EFAULT? */

		return 0;	/* invoke DSI if -EFAULT? */

	}

	}

 instr_done:

 instr_done:

	regs->nip += 4;

	regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);

#ifdef __powerpc64__

	if ((regs->msr & MSR_SF) == 0)

		regs->nip &= 0xffffffffUL;

#endif

	return 1;

	return 1;





 logical_done:

 logical_done: