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 <redacted>
---
arch/powerpc/lib/sstep.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 412dd46..5c09f36 100644
--- 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;
--
2.0.1