Commit 036b5560 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/inst: Avoid pointer dereferencing in ppc_inst_equal() 



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: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d8b155e930b7a9708ca110e8ff0ace6713a7af75.1621516826.git.christophe.leroy@csgroup.eu
parent 042e0860

arch/powerpc/include/asm/inst.h

+9 −10
Original line number Diff line number Diff line
@@ -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;