powerpc: Fix bugs in emulate_step()

This fixes some bugs in emulate_step().  First, the setting of the carry
bit for the arithmetic right-shift instructions was not correct on 64-bit
machines because we were masking with a mask of type int rather than
unsigned long.  Secondly, the sld (shift left doubleword) instruction was
using the wrong instruction field for the register containing the shift
count.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 412dd46..5c09f36 100644 (file)
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1198,7 +1198,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
                        sh = regs->gpr[rb] & 0x3f;
                        ival = (signed int) regs->gpr[rd];
                        regs->gpr[ra] = ival >> (sh < 32 ? sh : 31);
-                       if (ival < 0 && (sh >= 32 || (ival & ((1 << sh) - 1)) != 0))
+                       if (ival < 0 && (sh >= 32 || (ival & ((1ul << sh) - 1)) != 0))
                                regs->xer |= XER_CA;
                        else
                                regs->xer &= ~XER_CA;
@@ -1208,7 +1208,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
                        sh = rb;
                        ival = (signed int) regs->gpr[rd];
                        regs->gpr[ra] = ival >> sh;
-                       if (ival < 0 && (ival & ((1 << sh) - 1)) != 0)
+                       if (ival < 0 && (ival & ((1ul << sh) - 1)) != 0)
                                regs->xer |= XER_CA;
                        else
                                regs->xer &= ~XER_CA;
@@ -1216,7 +1216,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
 
 #ifdef __powerpc64__
                case 27:        /* sld */
-                       sh = regs->gpr[rd] & 0x7f;
+                       sh = regs->gpr[rb] & 0x7f;
                        if (sh < 64)
                                regs->gpr[ra] = regs->gpr[rd] << sh;
                        else
@@ -1235,7 +1235,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
                        sh = regs->gpr[rb] & 0x7f;
                        ival = (signed long int) regs->gpr[rd];
                        regs->gpr[ra] = ival >> (sh < 64 ? sh : 63);
-                       if (ival < 0 && (sh >= 64 || (ival & ((1 << sh) - 1)) != 0))
+                       if (ival < 0 && (sh >= 64 || (ival & ((1ul << sh) - 1)) != 0))
                                regs->xer |= XER_CA;
                        else
                                regs->xer &= ~XER_CA;
@@ -1246,7 +1246,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
                        sh = rb | ((instr & 2) << 4);
                        ival = (signed long int) regs->gpr[rd];
                        regs->gpr[ra] = ival >> sh;
-                       if (ival < 0 && (ival & ((1 << sh) - 1)) != 0)
+                       if (ival < 0 && (ival & ((1ul << sh) - 1)) != 0)
                                regs->xer |= XER_CA;
                        else
                                regs->xer &= ~XER_CA;