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From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	naveen.n.rao@linux.vnet.ibm.com, jniethe5@gmail.com
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 04/12] powerpc/inst: Avoid pointer dereferencing in ppc_inst_equal()
Date: Thu, 20 May 2021 13:50:41 +0000 (UTC)	[thread overview]
Message-ID: <d8b155e930b7a9708ca110e8ff0ace6713a7af75.1621516826.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1621516826.git.christophe.leroy@csgroup.eu>

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


  parent reply	other threads:[~2021-05-20 13:51 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-20 13:50 [PATCH v2 00/12] powerpc: Cleanup use of 'struct ppc_inst' Christophe Leroy
2021-05-20 13:50 ` [PATCH v2 01/12] powerpc/inst: Fix sparse detection on get_user_instr() Christophe Leroy
2021-05-20 13:50 ` [PATCH v2 02/12] powerpc/inst: Reduce casts in get_user_instr() Christophe Leroy
2021-05-20 13:50 ` [PATCH v2 03/12] powerpc/inst: Improve readability of get_user_instr() and friends Christophe Leroy
2021-05-20 13:50 ` Christophe Leroy [this message]
2021-06-15  3:38   ` [PATCH v2 04/12] powerpc/inst: Avoid pointer dereferencing in ppc_inst_equal() Jordan Niethe
2021-05-20 13:50 ` [PATCH v2 05/12] powerpc: Do not dereference code as 'struct ppc_inst' (uprobe, code-patching, feature-fixups) Christophe Leroy
2021-06-15  3:41   ` Jordan Niethe
2021-05-20 13:50 ` [PATCH v2 06/12] powerpc/lib/code-patching: Make instr_is_branch_to_addr() static Christophe Leroy
2021-06-15  3:42   ` Jordan Niethe
2021-05-20 13:50 ` [PATCH v2 07/12] powerpc/lib/code-patching: Don't use struct 'ppc_inst' for runnable code in tests Christophe Leroy
2021-06-15  3:42   ` Jordan Niethe
2021-05-20 13:50 ` [PATCH v2 08/12] powerpc: Don't use 'struct ppc_inst' to reference instruction location Christophe Leroy
2021-06-15  2:01   ` Michael Ellerman
2021-06-15  3:47     ` Jordan Niethe
2021-05-20 13:50 ` [PATCH v2 09/12] powerpc/inst: Refactor PPC32 and PPC64 versions Christophe Leroy
2021-06-15  3:48   ` Jordan Niethe
2021-05-20 13:50 ` [PATCH v2 10/12] powerpc/optprobes: Minimise casts Christophe Leroy
2021-05-20 13:50 ` [PATCH v2 11/12] powerpc/optprobes: Compact code source a bit Christophe Leroy
2021-05-20 13:50 ` [PATCH v2 12/12] powerpc/optprobes: use PPC_RAW_ macros Christophe Leroy
2021-06-08 12:46 ` [PATCH v2 00/12] powerpc: Cleanup use of 'struct ppc_inst' Christophe Leroy
2021-06-15  7:18 ` Michael Ellerman
2021-06-15  7:24   ` Christophe Leroy
2021-06-16 13:05     ` Michael Ellerman
2021-06-18  3:51 ` Michael Ellerman

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