[PATCH 06/18] powerpc sstep: Add support for prefixed integer load/stores
Jordan Niethe
jniethe5 at gmail.com
Fri Feb 7 11:20:57 AEDT 2020
On Sat, Jan 11, 2020 at 2:13 AM Balamuruhan S <bala24 at linux.ibm.com> wrote:
>
> On Tue, Nov 26, 2019 at 04:21:29PM +1100, Jordan Niethe wrote:
> > 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)
> >
> > Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>
> > ---
> > arch/powerpc/lib/sstep.c | 110 +++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 110 insertions(+)
> >
> > diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
> > index ade3f5eba2e5..4f5ad1f602d8 100644
> > --- a/arch/powerpc/lib/sstep.c
> > +++ b/arch/powerpc/lib/sstep.c
> > @@ -187,6 +187,43 @@ 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 sufx,
> > + const struct pt_regs *regs)
> > +{
> > + int ra, prefix_r;
> > + unsigned int dd;
> > + unsigned long ea, d0, d1, d;
> > +
> > + prefix_r = instr & (1ul << 20);
> > + ra = (sufx >> 16) & 0x1f;
> > +
> > + d0 = instr & 0x3ffff;
> > + d1 = sufx & 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.
> > @@ -1166,6 +1203,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
> > unsigned int instr, unsigned int sufx)
> > {
> > unsigned int opcode, ra, rb, rc, rd, spr, u;
> > + unsigned int sufxopcode, prefixtype, prefix_r;
> > unsigned long int imm;
> > unsigned long int val, val2;
> > unsigned int mb, me, sh;
> > @@ -2652,6 +2690,78 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
> >
> > }
> >
> > +/*
> > + * Prefixed instructions
> > + */
> > + switch (opcode) {
> > + case 1:
> > + prefix_r = instr & (1ul << 20);
> > + ra = (sufx >> 16) & 0x1f;
> > + op->update_reg = ra;
> > + rd = (sufx >> 21) & 0x1f;
> > + op->reg = rd;
> > + op->val = regs->gpr[rd];
> > +
> > + sufxopcode = sufx >> 26;
> > + prefixtype = (instr >> 24) & 0x3;
> > + switch (prefixtype) {
> > + case 0: /* Type 00 Eight-Byte Load/Store */
> > + if (prefix_r && ra)
> > + break;
> > + op->ea = mlsd_8lsd_ea(instr, sufx, regs);
> > + switch (sufxopcode) {
> > + case 41: /* plwa */
> > + op->type = MKOP(LOAD, PREFIXED | SIGNEXT, 4);
> > + break;
> > + case 56: /* plq */
> > + op->type = MKOP(LOAD, PREFIXED, 16);
> > + break;
> > + case 57: /* pld */
> > + op->type = MKOP(LOAD, PREFIXED | SIGNEXT, 8);
> > + break;
> > + case 60: /* stq */
> > + op->type = MKOP(STORE, PREFIXED, 16);
> > + break;
> > + case 61: /* pstd */
> > + op->type = MKOP(STORE, PREFIXED | SIGNEXT, 8);
>
> sorry, we don't do SIGNEXT for 1 byte below in Type 10, so does 8 byte is used
> conscious without definition in `do_signext()` as we don't really need to do
> anything ?
No, it was mistake. Those instructions should not have been marked as SIGNEXT.
>
> -- Bala
>
> > + break;
> > + }
> > + break;
> > + case 1: /* Type 01 Modified Register-to-Register */
> > + break;
> > + case 2: /* Type 10 Modified Load/Store */
> > + if (prefix_r && ra)
> > + break;
> > + op->ea = mlsd_8lsd_ea(instr, sufx, regs);
> > + switch (sufxopcode) {
> > + 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;
> > + }
> > + break;
> > + case 3: /* Type 11 Modified Register-to-Register */
> > + break;
> > + }
> > + }
> > +
> > #ifdef CONFIG_VSX
> > if ((GETTYPE(op->type) == LOAD_VSX ||
> > GETTYPE(op->type) == STORE_VSX) &&
> > --
> > 2.20.1
> >
>
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