[V2 PATCH 2/3] powerpc: Fix Unaligned Fixed Point Loads and Stores
From: Tom <hidden>
Date: 2013-10-31 18:39:53
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
From: Tom Musta <redacted> 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 <redacted> --- 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