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Subject[PATCH v2 04/12] powerpc/inst: Avoid pointer dereferencing in ppc_inst_equal()
Date
Avoid casting/dereferencing ppc_inst() as u64* , check each member
of the struct when relevant.

And remove the 0xff initialisation of the suffix for non
prefixed instruction. An instruction with 0xff as a suffix
might be invalid, but still is a prefixed instruction and
has to be considered as this.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/inst.h | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
index fc6adef528a5..5a0740ebf132 100644
--- a/arch/powerpc/include/asm/inst.h
+++ b/arch/powerpc/include/asm/inst.h
@@ -61,7 +61,7 @@ static inline int ppc_inst_primary_opcode(struct ppc_inst x)
}

#ifdef CONFIG_PPC64
-#define ppc_inst(x) ((struct ppc_inst){ .val = (x), .suffix = 0xff })
+#define ppc_inst(x) ((struct ppc_inst){ .val = (x) })

#define ppc_inst_prefix(x, y) ((struct ppc_inst){ .val = (x), .suffix = (y) })

@@ -72,7 +72,7 @@ static inline u32 ppc_inst_suffix(struct ppc_inst x)

static inline bool ppc_inst_prefixed(struct ppc_inst x)
{
- return ppc_inst_primary_opcode(x) == OP_PREFIX && ppc_inst_suffix(x) != 0xff;
+ return ppc_inst_primary_opcode(x) == OP_PREFIX;
}

static inline struct ppc_inst ppc_inst_swab(struct ppc_inst x)
@@ -93,11 +93,6 @@ static inline struct ppc_inst ppc_inst_read(const struct ppc_inst *ptr)
}
}

-static inline bool ppc_inst_equal(struct ppc_inst x, struct ppc_inst y)
-{
- return *(u64 *)&x == *(u64 *)&y;
-}
-
#else

#define ppc_inst(x) ((struct ppc_inst){ .val = x })
@@ -124,13 +119,17 @@ static inline struct ppc_inst ppc_inst_read(const struct ppc_inst *ptr)
return *ptr;
}

+#endif /* CONFIG_PPC64 */
+
static inline bool ppc_inst_equal(struct ppc_inst x, struct ppc_inst y)
{
- return ppc_inst_val(x) == ppc_inst_val(y);
+ if (ppc_inst_val(x) != ppc_inst_val(y))
+ return false;
+ if (!ppc_inst_prefixed(x))
+ return true;
+ return ppc_inst_suffix(x) == ppc_inst_suffix(y);
}

-#endif /* CONFIG_PPC64 */
-
static inline int ppc_inst_len(struct ppc_inst x)
{
return ppc_inst_prefixed(x) ? 8 : 4;
--
2.25.0
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