powerpc: Emulate load/store floating point as integer word instructions

This adds emulation for the lfiwax, lfiwzx and stfiwx instructions.
This necessitated adding a new flag to indicate whether a floating
point or an integer conversion was needed for LOAD_FP and STORE_FP,
so this moves the size field in op->type up 4 bits.

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

diff --git a/arch/powerpc/include/asm/sstep.h b/arch/powerpc/include/asm/sstep.h
index 309d1c5..ab9d849 100644 (file)
--- a/arch/powerpc/include/asm/sstep.h
+++ b/arch/powerpc/include/asm/sstep.h
@@ -68,6 +68,7 @@ enum instruction_type {
 #define SIGNEXT                0x20
 #define UPDATE         0x40    /* matches bit in opcode 31 instructions */
 #define BYTEREV                0x80
+#define FPCONV         0x100
 
 /* Barrier type field, ORed in with type */
 #define BARRIER_MASK   0xe0
@@ -93,8 +94,8 @@ enum instruction_type {
 #define VSX_CHECK_VEC  8       /* check MSR_VEC not MSR_VSX for reg >= 32 */
 
 /* Size field in type word */
-#define SIZE(n)                ((n) << 8)
-#define GETSIZE(w)     ((w) >> 8)
+#define SIZE(n)                ((n) << 12)
+#define GETSIZE(w)     ((w) >> 12)
 
 #define MKOP(t, f, s)  ((t) | (f) | SIZE(s))
 

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 4238155..f168ea0 100644 (file)
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -457,19 +457,23 @@ NOKPROBE_SYMBOL(write_mem);
  * These access either the real FP register or the image in the
  * thread_struct, depending on regs->msr & MSR_FP.
  */
-static int do_fp_load(int rn, unsigned long ea, int nb, struct pt_regs *regs,
-                     bool cross_endian)
+static int do_fp_load(struct instruction_op *op, unsigned long ea,
+                     struct pt_regs *regs, bool cross_endian)
 {
-       int err;
+       int err, rn, nb;
        union {
+               int i;
+               unsigned int u;
                float f;
                double d[2];
                unsigned long l[2];
                u8 b[2 * sizeof(double)];
        } u;
 
+       nb = GETSIZE(op->type);
        if (!address_ok(regs, ea, nb))
                return -EFAULT;
+       rn = op->reg;
        err = copy_mem_in(u.b, ea, nb, regs);
        if (err)
                return err;
@@ -479,8 +483,14 @@ static int do_fp_load(int rn, unsigned long ea, int nb, struct pt_regs *regs,
                        do_byte_reverse(&u.b[8], 8);
        }
        preempt_disable();
-       if (nb == 4)
-               conv_sp_to_dp(&u.f, &u.d[0]);
+       if (nb == 4) {
+               if (op->type & FPCONV)
+                       conv_sp_to_dp(&u.f, &u.d[0]);
+               else if (op->type & SIGNEXT)
+                       u.l[0] = u.i;
+               else
+                       u.l[0] = u.u;
+       }
        if (regs->msr & MSR_FP)
                put_fpr(rn, &u.d[0]);
        else
@@ -498,25 +508,33 @@ static int do_fp_load(int rn, unsigned long ea, int nb, struct pt_regs *regs,
 }
 NOKPROBE_SYMBOL(do_fp_load);
 
-static int do_fp_store(int rn, unsigned long ea, int nb, struct pt_regs *regs,
-                      bool cross_endian)
+static int do_fp_store(struct instruction_op *op, unsigned long ea,
+                      struct pt_regs *regs, bool cross_endian)
 {
+       int rn, nb;
        union {
+               unsigned int u;
                float f;
                double d[2];
                unsigned long l[2];
                u8 b[2 * sizeof(double)];
        } u;
 
+       nb = GETSIZE(op->type);
        if (!address_ok(regs, ea, nb))
                return -EFAULT;
+       rn = op->reg;
        preempt_disable();
        if (regs->msr & MSR_FP)
                get_fpr(rn, &u.d[0]);
        else
                u.l[0] = current->thread.TS_FPR(rn);
-       if (nb == 4)
-               conv_dp_to_sp(&u.d[0], &u.f);
+       if (nb == 4) {
+               if (op->type & FPCONV)
+                       conv_dp_to_sp(&u.d[0], &u.f);
+               else
+                       u.u = u.l[0];
+       }
        if (nb == 16) {
                rn |= 1;
                if (regs->msr & MSR_FP)
@@ -2049,7 +2067,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 #ifdef CONFIG_PPC_FPU
                case 535:       /* lfsx */
                case 567:       /* lfsux */
-                       op->type = MKOP(LOAD_FP, u, 4);
+                       op->type = MKOP(LOAD_FP, u | FPCONV, 4);
                        break;
 
                case 599:       /* lfdx */
@@ -2059,7 +2077,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 
                case 663:       /* stfsx */
                case 695:       /* stfsux */
-                       op->type = MKOP(STORE_FP, u, 4);
+                       op->type = MKOP(STORE_FP, u | FPCONV, 4);
                        break;
 
                case 727:       /* stfdx */
@@ -2072,9 +2090,21 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
                        op->type = MKOP(LOAD_FP, 0, 16);
                        break;
 
+               case 855:       /* lfiwax */
+                       op->type = MKOP(LOAD_FP, SIGNEXT, 4);
+                       break;
+
+               case 887:       /* lfiwzx */
+                       op->type = MKOP(LOAD_FP, 0, 4);
+                       break;
+
                case 919:       /* stfdpx */
                        op->type = MKOP(STORE_FP, 0, 16);
                        break;
+
+               case 983:       /* stfiwx */
+                       op->type = MKOP(STORE_FP, 0, 4);
+                       break;
 #endif /* __powerpc64 */
 #endif /* CONFIG_PPC_FPU */
 
@@ -2352,7 +2382,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 #ifdef CONFIG_PPC_FPU
        case 48:        /* lfs */
        case 49:        /* lfsu */
-               op->type = MKOP(LOAD_FP, u, 4);
+               op->type = MKOP(LOAD_FP, u | FPCONV, 4);
                op->ea = dform_ea(instr, regs);
                break;
 
@@ -2364,7 +2394,7 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
 
        case 52:        /* stfs */
        case 53:        /* stfsu */
-               op->type = MKOP(STORE_FP, u, 4);
+               op->type = MKOP(STORE_FP, u | FPCONV, 4);
                op->ea = dform_ea(instr, regs);
                break;
 
@@ -2792,7 +2822,7 @@ int emulate_loadstore(struct pt_regs *regs, struct instruction_op *op)
                 */
                if (!(regs->msr & MSR_PR) && !(regs->msr & MSR_FP))
                        return 0;
-               err = do_fp_load(op->reg, ea, size, regs, cross_endian);
+               err = do_fp_load(op, ea, regs, cross_endian);
                break;
 #endif
 #ifdef CONFIG_ALTIVEC
@@ -2862,7 +2892,7 @@ int emulate_loadstore(struct pt_regs *regs, struct instruction_op *op)
        case STORE_FP:
                if (!(regs->msr & MSR_PR) && !(regs->msr & MSR_FP))
                        return 0;
-               err = do_fp_store(op->reg, ea, size, regs, cross_endian);
+               err = do_fp_store(op, ea, regs, cross_endian);
                break;
 #endif
 #ifdef CONFIG_ALTIVEC