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Commit c1469f13 authored by Kumar Gala's avatar Kumar Gala
Browse files

[POWERPC] Emulate isel (Integer Select) instruction 



isel (Integer Select) is a new user space instruction in the
PowerISA 2.04 spec.  Not all processors implement it so lets emulate
to ensure code built with isel will run everywhere.

Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
parent fd351b89

arch/powerpc/kernel/traps.c

+25 −0
Original line number Diff line number Diff line
@@ -622,6 +622,9 @@ static void parse_fpe(struct pt_regs *regs) 
#define INST_POPCNTB		0x7c0000f4

#define INST_POPCNTB_MASK	0xfc0007fe



#define INST_ISEL		0x7c00001e

#define INST_ISEL_MASK		0xfc00003e



static int emulate_string_inst(struct pt_regs *regs, u32 instword)

{

	u8 rT = (instword >> 21) & 0x1f;
@@ -707,6 +710,23 @@ static int emulate_popcntb_inst(struct pt_regs *regs, u32 instword) 
	return 0;

}



static int emulate_isel(struct pt_regs *regs, u32 instword)

{

	u8 rT = (instword >> 21) & 0x1f;

	u8 rA = (instword >> 16) & 0x1f;

	u8 rB = (instword >> 11) & 0x1f;

	u8 BC = (instword >> 6) & 0x1f;

	u8 bit;

	unsigned long tmp;



	tmp = (rA == 0) ? 0 : regs->gpr[rA];

	bit = (regs->ccr >> (31 - BC)) & 0x1;



	regs->gpr[rT] = bit ? tmp : regs->gpr[rB];



	return 0;

}



static int emulate_instruction(struct pt_regs *regs)

{

	u32 instword;
@@ -749,6 +769,11 @@ static int emulate_instruction(struct pt_regs *regs) 
		return emulate_popcntb_inst(regs, instword);

	}



	/* Emulate isel (Integer Select) instruction */

	if ((instword & INST_ISEL_MASK) == INST_ISEL) {

		return emulate_isel(regs, instword);

	}



	return -EINVAL;

}