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authorMichael Ellerman <michael@ellerman.id.au>2011-04-07 21:56:04 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2011-04-27 14:18:46 +1000
commitb91e136cdf88e19e998dbf4631ead266de4b80b5 (patch)
tree6f53decf9d389438a740f77f7e907f5abdf5581a /arch
parent9f0b079320ad1cc71ad7ea4e0ed0b64cd72bbd6d (diff)
downloadlinaro-lsk-b91e136cdf88e19e998dbf4631ead266de4b80b5.tar.gz
powerpc: Use MSR_64BIT in sstep.c, fix kprobes on BOOK3E
We check MSR_SF a lot in sstep.c, to decide if we need to emulate the truncation of values when running in 32-bit mode. Factor out that code into a helper, and convert it and the other uses to use MSR_64BIT. This fixes a bug on BOOK3E where kprobes would end up returning to a 32-bit address, because regs->nip was truncated, because (msr & MSR_SF) was false. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/lib/sstep.c61
1 files changed, 27 insertions, 34 deletions
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index ae5189ab004..0e5e540c777 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -45,6 +45,18 @@ extern int do_stxvd2x(int rn, unsigned long ea);
#endif
/*
+ * Emulate the truncation of 64 bit values in 32-bit mode.
+ */
+static unsigned long truncate_if_32bit(unsigned long msr, unsigned long val)
+{
+#ifdef __powerpc64__
+ if ((msr & MSR_64BIT) == 0)
+ val &= 0xffffffffUL;
+#endif
+ return val;
+}
+
+/*
* Determine whether a conditional branch instruction would branch.
*/
static int __kprobes branch_taken(unsigned int instr, struct pt_regs *regs)
@@ -90,11 +102,8 @@ static unsigned long __kprobes dform_ea(unsigned int instr, struct pt_regs *regs
if (instr & 0x04000000) /* update forms */
regs->gpr[ra] = ea;
}
-#ifdef __powerpc64__
- if (!(regs->msr & MSR_SF))
- ea &= 0xffffffffUL;
-#endif
- return ea;
+
+ return truncate_if_32bit(regs->msr, ea);
}
#ifdef __powerpc64__
@@ -113,9 +122,8 @@ static unsigned long __kprobes dsform_ea(unsigned int instr, struct pt_regs *reg
if ((instr & 3) == 1) /* update forms */
regs->gpr[ra] = ea;
}
- if (!(regs->msr & MSR_SF))
- ea &= 0xffffffffUL;
- return ea;
+
+ return truncate_if_32bit(regs->msr, ea);
}
#endif /* __powerpc64 */
@@ -136,11 +144,8 @@ static unsigned long __kprobes xform_ea(unsigned int instr, struct pt_regs *regs
if (do_update) /* update forms */
regs->gpr[ra] = ea;
}
-#ifdef __powerpc64__
- if (!(regs->msr & MSR_SF))
- ea &= 0xffffffffUL;
-#endif
- return ea;
+
+ return truncate_if_32bit(regs->msr, ea);
}
/*
@@ -466,7 +471,7 @@ static void __kprobes set_cr0(struct pt_regs *regs, int rd)
regs->ccr = (regs->ccr & 0x0fffffff) | ((regs->xer >> 3) & 0x10000000);
#ifdef __powerpc64__
- if (!(regs->msr & MSR_SF))
+ if (!(regs->msr & MSR_64BIT))
val = (int) val;
#endif
if (val < 0)
@@ -487,7 +492,7 @@ static void __kprobes add_with_carry(struct pt_regs *regs, int rd,
++val;
regs->gpr[rd] = val;
#ifdef __powerpc64__
- if (!(regs->msr & MSR_SF)) {
+ if (!(regs->msr & MSR_64BIT)) {
val = (unsigned int) val;
val1 = (unsigned int) val1;
}
@@ -570,8 +575,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
if ((instr & 2) == 0)
imm += regs->nip;
regs->nip += 4;
- if ((regs->msr & MSR_SF) == 0)
- regs->nip &= 0xffffffffUL;
+ regs->nip = truncate_if_32bit(regs->msr, regs->nip);
if (instr & 1)
regs->link = regs->nip;
if (branch_taken(instr, regs))
@@ -604,13 +608,9 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
imm -= 0x04000000;
if ((instr & 2) == 0)
imm += regs->nip;
- if (instr & 1) {
- regs->link = regs->nip + 4;
- if ((regs->msr & MSR_SF) == 0)
- regs->link &= 0xffffffffUL;
- }
- if ((regs->msr & MSR_SF) == 0)
- imm &= 0xffffffffUL;
+ if (instr & 1)
+ regs->link = truncate_if_32bit(regs->msr, regs->nip + 4);
+ imm = truncate_if_32bit(regs->msr, imm);
regs->nip = imm;
return 1;
case 19:
@@ -618,11 +618,8 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
case 16: /* bclr */
case 528: /* bcctr */
imm = (instr & 0x400)? regs->ctr: regs->link;
- regs->nip += 4;
- if ((regs->msr & MSR_SF) == 0) {
- regs->nip &= 0xffffffffUL;
- imm &= 0xffffffffUL;
- }
+ regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
+ imm = truncate_if_32bit(regs->msr, imm);
if (instr & 1)
regs->link = regs->nip;
if (branch_taken(instr, regs))
@@ -1616,11 +1613,7 @@ int __kprobes emulate_step(struct pt_regs *regs, unsigned int instr)
return 0; /* invoke DSI if -EFAULT? */
}
instr_done:
- regs->nip += 4;
-#ifdef __powerpc64__
- if ((regs->msr & MSR_SF) == 0)
- regs->nip &= 0xffffffffUL;
-#endif
+ regs->nip = truncate_if_32bit(regs->msr, regs->nip + 4);
return 1;
logical_done: