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)

Reviewed-by: Balamuruhan S <bal...@linux.ibm.com>
Signed-off-by: Jordan Niethe <jniet...@gmail.com>
---
v2: - Combine all load/store patches
    - Fix the name of Type 01 instructions
    - Remove sign extension flag from pstd/pld
    - Rename sufx -> suffix
v3: - Move prefixed loads and stores into the switch statement
v6: - Compile on ppc32
    - Add back in + GETLENGTH(op->type)
v8: Use fallthrough; keyword
---
 arch/powerpc/include/asm/sstep.h |   4 +
 arch/powerpc/lib/sstep.c         | 163 ++++++++++++++++++++++++++++++-
 2 files changed, 165 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/sstep.h b/arch/powerpc/include/asm/sstep.h
index c3ce903ac488..9b200a5f8794 100644
--- a/arch/powerpc/include/asm/sstep.h
+++ b/arch/powerpc/include/asm/sstep.h
@@ -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))
 
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index ecd756c346fd..6794a7672ad5 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -187,6 +187,44 @@ 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.
@@ -1166,6 +1204,9 @@ int analyse_instr(struct instruction_op *op, const struct 
pt_regs *regs,
                  struct ppc_inst instr)
 {
        unsigned int opcode, ra, rb, rc, rd, spr, u;
+#ifdef __powerpc64__
+       unsigned int suffixopcode, prefixtype, prefix_r;
+#endif
        unsigned long int imm;
        unsigned long int val, val2;
        unsigned int mb, me, sh;
@@ -2652,6 +2693,124 @@ 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 = suffix >> 26;
+               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 +2919,7 @@ 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 +3364,7 @@ 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);
-- 
2.17.1

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