From: Tom Musta <tommu...@gmail.com>
This patch modifies the unaligned access routines of the sstep.c
module so that it properly reverses the bytes of storage operands
in the little endian kernel kernel.
Signed-off-by: Tom Musta <tommu...@gmail.com>
---
arch/powerpc/lib/sstep.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 45 insertions(+), 0 deletions(-)
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 7bfaa9d..c8743e1 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -212,11 +212,19 @@ static int __kprobes read_mem_unaligned(unsigned long
*dest, unsigned long ea,
{
int err;
unsigned long x, b, c;
+#ifdef __LITTLE_ENDIAN__
+ int len = nb; /* save a copy of the length for byte reversal */
+#endif
/* unaligned, do this in pieces */
x = 0;
for (; nb > 0; nb -= c) {
+#ifdef __LITTLE_ENDIAN__
+ c = 1;
+#endif
+#ifdef __BIG_ENDIAN__
c = max_align(ea);
+#endif
if (c > nb)
c = max_align(nb);
err = read_mem_aligned(&b, ea, c);
@@ -225,7 +233,24 @@ static int __kprobes read_mem_unaligned(unsigned long
*dest, unsigned long ea,
x = (x << (8 * c)) + b;
ea += c;
}
+#ifdef __LITTLE_ENDIAN__
+ switch (len) {
+ case 2:
+ *dest = byterev_2(x);
+ break;
+ case 4:
+ *dest = byterev_4(x);
+ break;
+#ifdef __powerpc64__
+ case 8:
+ *dest = byterev_8(x);
+ break;
+#endif
+ }
+#endif
+#ifdef __BIG_ENDIAN__
*dest = x;
+#endif
return 0;
}
@@ -273,9 +298,29 @@ static int __kprobes write_mem_unaligned(unsigned long
val, unsigned long ea,
int err;
unsigned long c;
+#ifdef __LITTLE_ENDIAN__
+ switch (nb) {
+ case 2:
+ val = byterev_2(val);
+ break;
+ case 4:
+ val = byterev_4(val);
+ break;
+#ifdef __powerpc64__
+ case 8:
+ val = byterev_8(val);
+ break;
+#endif
+ }
+#endif
/* unaligned or little-endian, do this in pieces */
for (; nb > 0; nb -= c) {
+#ifdef __LITTLE_ENDIAN__
+ c = 1;
+#endif
+#ifdef __BIG_ENDIAN__
c = max_align(ea);
+#endif
if (c > nb)
c = max_align(nb);
err = write_mem_aligned(val >> (nb - c) * 8, ea, c);
--
1.7.1
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