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powerpc: Fix Unaligned LE Floating Point Loads and Stores

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This patch addresses unaligned single precision floating point loads
and stores in the single-step code.  The old implementation
improperly treated an 8 byte structure as an array of two 4 byte
words, which is a classic little endian bug.

Signed-off-by: Tom Musta <tmusta@gmail.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Tom Musta 2013-10-18 14:44:17 -05:00 committed by Benjamin Herrenschmidt
parent 6506b4718b
commit dbc2fbd7c2
1 changed files with 40 additions and 12 deletions
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52
arch/powerpc/lib/sstep.c
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@ -355,22 +355,36 @@ static int __kprobes do_fp_load(int rn, int (*func)(int, unsigned long),
struct pt_regs *regs)
{
int err;
unsigned long val[sizeof(double) / sizeof(long)];
union {
double dbl;
unsigned long ul[2];
struct {
#ifdef __BIG_ENDIAN__
unsigned _pad_;
unsigned word;
#endif
#ifdef __LITTLE_ENDIAN__
unsigned word;
unsigned _pad_;
#endif
} single;
} data;
unsigned long ptr;
if (!address_ok(regs, ea, nb))
return -EFAULT;
if ((ea & 3) == 0)
return (*func)(rn, ea);
ptr = (unsigned long) &val[0];
ptr = (unsigned long) &data.ul;
if (sizeof(unsigned long) == 8 || nb == 4) {
err = read_mem_unaligned(&val[0], ea, nb, regs);
ptr += sizeof(unsigned long) - nb;
err = read_mem_unaligned(&data.ul[0], ea, nb, regs);
if (nb == 4)
ptr = (unsigned long)&(data.single.word);
} else {
/* reading a double on 32-bit */
err = read_mem_unaligned(&val[0], ea, 4, regs);
err = read_mem_unaligned(&data.ul[0], ea, 4, regs);
if (!err)
err = read_mem_unaligned(&val[1], ea + 4, 4, regs);
err = read_mem_unaligned(&data.ul[1], ea + 4, 4, regs);
}
if (err)
return err;
@ -382,28 +396,42 @@ static int __kprobes do_fp_store(int rn, int (*func)(int, unsigned long),
struct pt_regs *regs)
{
int err;
unsigned long val[sizeof(double) / sizeof(long)];
union {
double dbl;
unsigned long ul[2];
struct {
#ifdef __BIG_ENDIAN__
unsigned _pad_;
unsigned word;
#endif
#ifdef __LITTLE_ENDIAN__
unsigned word;
unsigned _pad_;
#endif
} single;
} data;
unsigned long ptr;
if (!address_ok(regs, ea, nb))
return -EFAULT;
if ((ea & 3) == 0)
return (*func)(rn, ea);
ptr = (unsigned long) &val[0];
ptr = (unsigned long) &data.ul[0];
if (sizeof(unsigned long) == 8 || nb == 4) {
ptr += sizeof(unsigned long) - nb;
if (nb == 4)
ptr = (unsigned long)&(data.single.word);
err = (*func)(rn, ptr);
if (err)
return err;
err = write_mem_unaligned(val[0], ea, nb, regs);
err = write_mem_unaligned(data.ul[0], ea, nb, regs);
} else {
/* writing a double on 32-bit */
err = (*func)(rn, ptr);
if (err)
return err;
err = write_mem_unaligned(val[0], ea, 4, regs);
err = write_mem_unaligned(data.ul[0], ea, 4, regs);
if (!err)
err = write_mem_unaligned(val[1], ea + 4, 4, regs);
err = write_mem_unaligned(data.ul[1], ea + 4, 4, regs);
}
return err;
}