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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>
This commit is contained in:
Michael Ellerman 2011-04-07 21:56:04 +00:00 committed by Benjamin Herrenschmidt
parent 9f0b079320
commit b91e136cdf
1 changed files with 27 additions and 34 deletions
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61
arch/powerpc/lib/sstep.c
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@ -44,6 +44,18 @@ extern int do_lxvd2x(int rn, unsigned long ea);
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.
*/
@ -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: