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authorTom Musta <tommusta@gmail.com>2013-10-18 14:44:17 -0500
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2013-10-30 16:01:36 +1100
commitdbc2fbd7c29a78724e761711d516930246c0e1c2 (patch)
treeda410fc25920bad6355d2cc121ef31f9faa5a1d8 /arch/powerpc/lib
parent6506b4718bb59c5d4e59235b81b5e13ea5d3c49a (diff)
downloadop-kernel-dev-dbc2fbd7c29a78724e761711d516930246c0e1c2.zip
op-kernel-dev-dbc2fbd7c29a78724e761711d516930246c0e1c2.tar.gz
powerpc: Fix Unaligned LE Floating Point Loads and Stores
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>
Diffstat (limited to 'arch/powerpc/lib')
-rw-r--r--arch/powerpc/lib/sstep.c52
1 files changed, 40 insertions, 12 deletions
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 0121d21..c0511c2 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -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;
}
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