powerpc: Implement emulation of string loads and stores

The size field of the op.type word is now the total number of bytes
to be loaded or stored.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 49 insertions, 10 deletions

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 209a506f8517..54651fc2d412 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1433,11 +1433,24 @@ int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
                         break;
 
 #endif
+                case 533:       /* lswx */
+                        op->type = MKOP(LOAD_MULTI, 0, regs->xer & 0x7f);
+                        break;
 
                 case 534:       /* lwbrx */
                         op->type = MKOP(LOAD, BYTEREV, 4);
                         break;
 
+                case 597:       /* lswi */
+                        if (rb == 0)
+                                rb = 32;        /* # bytes to load */
+                        op->type = MKOP(LOAD_MULTI, 0, rb);
+                        op->ea = 0;
+                        if (ra)
+                                op->ea = truncate_if_32bit(regs->msr,
+                                                           regs->gpr[ra]);
+                        break;
+
 #ifdef CONFIG_PPC_FPU
                 case 535:       /* lfsx */
                 case 567:       /* lfsux */
@@ -1475,11 +1488,25 @@ int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
                         break;
 
 #endif
+                case 661:       /* stswx */
+                        op->type = MKOP(STORE_MULTI, 0, regs->xer & 0x7f);
+                        break;
+
                 case 662:       /* stwbrx */
                         op->type = MKOP(STORE, BYTEREV, 4);
                         op->val = byterev_4(regs->gpr[rd]);
                         break;
 
+                case 725:
+                        if (rb == 0)
+                                rb = 32;        /* # bytes to store */
+                        op->type = MKOP(STORE_MULTI, 0, rb);
+                        op->ea = 0;
+                        if (ra)
+                                op->ea = truncate_if_32bit(regs->msr,
+                                                           regs->gpr[ra]);
+                        break;
+
                 case 790:       /* lhbrx */
                         op->type = MKOP(LOAD, BYTEREV, 2);
                         break;
@@ -1553,15 +1580,14 @@ int __kprobes analyse_instr(struct instruction_op *op, struct pt_regs *regs,
                 break;
 
         case 46:        /* lmw */
-                ra = (instr >> 16) & 0x1f;
                 if (ra >= rd)
                         break;          /* invalid form, ra in range to load */
-                op->type = MKOP(LOAD_MULTI, 0, 4);
+                op->type = MKOP(LOAD_MULTI, 0, 4 * (32 - rd));
                 op->ea = dform_ea(instr, regs);
                 break;
 
         case 47:        /* stmw */
-                op->type = MKOP(STORE_MULTI, 0, 4);
+                op->type = MKOP(STORE_MULTI, 0, 4 * (32 - rd));
                 op->ea = dform_ea(instr, regs);
                 break;
 
@@ -1744,7 +1770,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
         int r, err, size;
         unsigned long val;
         unsigned int cr;
-        int rd;
+        int i, rd, nb;
 
         r = analyse_instr(&op, regs, instr);
         if (r != 0)
@@ -1866,12 +1892,18 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
                 if (regs->msr & MSR_LE)
                         return 0;
                 rd = op.reg;
-                do {
-                        err = read_mem(&regs->gpr[rd], op.ea, 4, regs);
+                for (i = 0; i < size; i += 4) {
+                        nb = size - i;
+                        if (nb > 4)
+                                nb = 4;
+                        err = read_mem(&regs->gpr[rd], op.ea, nb, regs);
                         if (err)
                                 return 0;
+                        if (nb < 4)     /* left-justify last bytes */
+                                regs->gpr[rd] <<= 32 - 8 * nb;
                         op.ea += 4;
-                } while (++rd < 32);
+                        ++rd;
+                }
                 goto instr_done;
 
         case STORE:
@@ -1914,12 +1946,19 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
                 if (regs->msr & MSR_LE)
                         return 0;
                 rd = op.reg;
-                do {
-                        err = write_mem(regs->gpr[rd], op.ea, 4, regs);
+                for (i = 0; i < size; i += 4) {
+                        val = regs->gpr[rd];
+                        nb = size - i;
+                        if (nb > 4)
+                                nb = 4;
+                        else
+                                val >>= 32 - 8 * nb;
+                        err = write_mem(val, op.ea, nb, regs);
                         if (err)
                                 return 0;
                         op.ea += 4;
-                } while (++rd < 32);
+                        ++rd;
+                }
                 goto instr_done;
 
         case MFMSR: