Commit 50b80a12 authored by Jordan Niethe's avatar Jordan Niethe Committed by Michael Ellerman
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powerpc sstep: Add support for prefixed load/stores 



This adds emulation support for the following prefixed integer
load/stores:
  * Prefixed Load Byte and Zero (plbz)
  * Prefixed Load Halfword and Zero (plhz)
  * Prefixed Load Halfword Algebraic (plha)
  * Prefixed Load Word and Zero (plwz)
  * Prefixed Load Word Algebraic (plwa)
  * Prefixed Load Doubleword (pld)
  * Prefixed Store Byte (pstb)
  * Prefixed Store Halfword (psth)
  * Prefixed Store Word (pstw)
  * Prefixed Store Doubleword (pstd)
  * Prefixed Load Quadword (plq)
  * Prefixed Store Quadword (pstq)

the follow prefixed floating-point load/stores:
  * Prefixed Load Floating-Point Single (plfs)
  * Prefixed Load Floating-Point Double (plfd)
  * Prefixed Store Floating-Point Single (pstfs)
  * Prefixed Store Floating-Point Double (pstfd)

and for the following prefixed VSX load/stores:
  * Prefixed Load VSX Scalar Doubleword (plxsd)
  * Prefixed Load VSX Scalar Single-Precision (plxssp)
  * Prefixed Load VSX Vector [0|1]  (plxv, plxv0, plxv1)
  * Prefixed Store VSX Scalar Doubleword (pstxsd)
  * Prefixed Store VSX Scalar Single-Precision (pstxssp)
  * Prefixed Store VSX Vector [0|1] (pstxv, pstxv0, pstxv1)

Signed-off-by: default avatarJordan Niethe <jniethe5@gmail.com>
Reviewed-by: default avatarBalamuruhan S <bala24@linux.ibm.com>
[mpe: Use CONFIG_PPC64 not __powerpc64__, use get_op()]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200506034050.24806-30-jniethe5@gmail.com
parent 9409d2f9

arch/powerpc/include/asm/sstep.h

+4 −0
Original line number Diff line number Diff line
@@ -90,11 +90,15 @@ enum instruction_type { 
#define VSX_LDLEFT	4	/* load VSX register from left */

#define VSX_CHECK_VEC	8	/* check MSR_VEC not MSR_VSX for reg >= 32 */



/* Prefixed flag, ORed in with type */

#define PREFIXED       0x800



/* Size field in type word */

#define SIZE(n)		((n) << 12)

#define GETSIZE(w)	((w) >> 12)



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

#define GETLENGTH(t)   (((t) & PREFIXED) ? 8 : 4)



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

arch/powerpc/lib/sstep.c

+162 −2
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/uaccess.h>

#include <asm/cpu_has_feature.h>

#include <asm/cputable.h>

#include <asm/disassemble.h>



extern char system_call_common[];
@@ -187,6 +188,44 @@ static nokprobe_inline unsigned long xform_ea(unsigned int instr, 
	return ea;

}



/*

 * Calculate effective address for a MLS:D-form / 8LS:D-form

 * prefixed instruction

 */

static nokprobe_inline unsigned long mlsd_8lsd_ea(unsigned int instr,

						  unsigned int suffix,

						  const struct pt_regs *regs)

{

	int ra, prefix_r;

	unsigned int  dd;

	unsigned long ea, d0, d1, d;



	prefix_r = instr & (1ul << 20);

	ra = (suffix >> 16) & 0x1f;



	d0 = instr & 0x3ffff;

	d1 = suffix & 0xffff;

	d = (d0 << 16) | d1;



	/*

	 * sign extend a 34 bit number

	 */

	dd = (unsigned int)(d >> 2);

	ea = (signed int)dd;

	ea = (ea << 2) | (d & 0x3);



	if (!prefix_r && ra)

		ea += regs->gpr[ra];

	else if (!prefix_r && !ra)

		; /* Leave ea as is */

	else if (prefix_r && !ra)

		ea += regs->nip;

	else if (prefix_r && ra)

		; /* Invalid form. Should already be checked for by caller! */



	return ea;

}



/*

 * Return the largest power of 2, not greater than sizeof(unsigned long),

 * such that x is a multiple of it.
@@ -1165,6 +1204,9 @@ static nokprobe_inline int trap_compare(long v1, long v2) 
int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,

		  struct ppc_inst instr)

{

#ifdef CONFIG_PPC64

	unsigned int suffixopcode, prefixtype, prefix_r;

#endif

	unsigned int opcode, ra, rb, rc, rd, spr, u;

	unsigned long int imm;

	unsigned long int val, val2;
@@ -2652,6 +2694,124 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs, 
			break;

		}

		break;

	case 1: /* Prefixed instructions */

		prefix_r = word & (1ul << 20);

		ra = (suffix >> 16) & 0x1f;

		op->update_reg = ra;

		rd = (suffix >> 21) & 0x1f;

		op->reg = rd;

		op->val = regs->gpr[rd];



		suffixopcode = get_op(suffix);

		prefixtype = (word >> 24) & 0x3;

		switch (prefixtype) {

		case 0: /* Type 00  Eight-Byte Load/Store */

			if (prefix_r && ra)

				break;

			op->ea = mlsd_8lsd_ea(word, suffix, regs);

			switch (suffixopcode) {

			case 41:	/* plwa */

				op->type = MKOP(LOAD, PREFIXED | SIGNEXT, 4);

				break;

			case 42:        /* plxsd */

				op->reg = rd + 32;

				op->type = MKOP(LOAD_VSX, PREFIXED, 8);

				op->element_size = 8;

				op->vsx_flags = VSX_CHECK_VEC;

				break;

			case 43:	/* plxssp */

				op->reg = rd + 32;

				op->type = MKOP(LOAD_VSX, PREFIXED, 4);

				op->element_size = 8;

				op->vsx_flags = VSX_FPCONV | VSX_CHECK_VEC;

				break;

			case 46:	/* pstxsd */

				op->reg = rd + 32;

				op->type = MKOP(STORE_VSX, PREFIXED, 8);

				op->element_size = 8;

				op->vsx_flags = VSX_CHECK_VEC;

				break;

			case 47:	/* pstxssp */

				op->reg = rd + 32;

				op->type = MKOP(STORE_VSX, PREFIXED, 4);

				op->element_size = 8;

				op->vsx_flags = VSX_FPCONV | VSX_CHECK_VEC;

				break;

			case 51:	/* plxv1 */

				op->reg += 32;

				fallthrough;

			case 50:	/* plxv0 */

				op->type = MKOP(LOAD_VSX, PREFIXED, 16);

				op->element_size = 16;

				op->vsx_flags = VSX_CHECK_VEC;

				break;

			case 55:	/* pstxv1 */

				op->reg = rd + 32;

				fallthrough;

			case 54:	/* pstxv0 */

				op->type = MKOP(STORE_VSX, PREFIXED, 16);

				op->element_size = 16;

				op->vsx_flags = VSX_CHECK_VEC;

				break;

			case 56:        /* plq */

				op->type = MKOP(LOAD, PREFIXED, 16);

				break;

			case 57:	/* pld */

				op->type = MKOP(LOAD, PREFIXED, 8);

				break;

			case 60:        /* stq */

				op->type = MKOP(STORE, PREFIXED, 16);

				break;

			case 61:	/* pstd */

				op->type = MKOP(STORE, PREFIXED, 8);

				break;

			}

			break;

		case 1: /* Type 01 Eight-Byte Register-to-Register */

			break;

		case 2: /* Type 10 Modified Load/Store */

			if (prefix_r && ra)

				break;

			op->ea = mlsd_8lsd_ea(word, suffix, regs);

			switch (suffixopcode) {

			case 32:	/* plwz */

				op->type = MKOP(LOAD, PREFIXED, 4);

				break;

			case 34:	/* plbz */

				op->type = MKOP(LOAD, PREFIXED, 1);

				break;

			case 36:	/* pstw */

				op->type = MKOP(STORE, PREFIXED, 4);

				break;

			case 38:	/* pstb */

				op->type = MKOP(STORE, PREFIXED, 1);

				break;

			case 40:	/* plhz */

				op->type = MKOP(LOAD, PREFIXED, 2);

				break;

			case 42:	/* plha */

				op->type = MKOP(LOAD, PREFIXED | SIGNEXT, 2);

				break;

			case 44:	/* psth */

				op->type = MKOP(STORE, PREFIXED, 2);

				break;

			case 48:        /* plfs */

				op->type = MKOP(LOAD_FP, PREFIXED | FPCONV, 4);

				break;

			case 50:        /* plfd */

				op->type = MKOP(LOAD_FP, PREFIXED, 8);

				break;

			case 52:        /* pstfs */

				op->type = MKOP(STORE_FP, PREFIXED | FPCONV, 4);

				break;

			case 54:        /* pstfd */

				op->type = MKOP(STORE_FP, PREFIXED, 8);

				break;

			}

			break;

		case 3: /* Type 11 Modified Register-to-Register */

			break;

		}

#endif /* __powerpc64__ */



	}
@@ -2760,7 +2920,7 @@ void emulate_update_regs(struct pt_regs *regs, struct instruction_op *op) 
{

	unsigned long next_pc;



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

	next_pc = truncate_if_32bit(regs->msr, regs->nip + GETLENGTH(op->type));

	switch (GETTYPE(op->type)) {

	case COMPUTE:

		if (op->type & SETREG)
@@ -3205,7 +3365,7 @@ int emulate_step(struct pt_regs *regs, struct ppc_inst instr) 
	return 0;



 instr_done:

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

	regs->nip = truncate_if_32bit(regs->msr, regs->nip + GETLENGTH(op.type));

	return 1;

}

NOKPROBE_SYMBOL(emulate_step);