From:   Christophe Leroy <christophe.leroy@csgroup.eu>
To:     Josh Poimboeuf <jpoimboe@redhat.com>,
        Jiri Kosina <jikos@kernel.org>,
        Miroslav Benes <mbenes@suse.cz>,
        Petr Mladek <pmladek@suse.com>,
        Joe Lawrence <joe.lawrence@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        "Naveen N . Rao" <naveen.n.rao@linux.vnet.ibm.com>
CC:     Christophe Leroy <christophe.leroy@csgroup.eu>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
        "live-patching@vger.kernel.org" <live-patching@vger.kernel.org>
Subject: [PATCH v2 04/13] powerpc/ftrace: Add support for livepatch to PPC32
Thread-Topic: [PATCH v2 04/13] powerpc/ftrace: Add support for livepatch to
 PPC32
Thread-Index: AQHX9b/6eBLNZiqJgUWhrC7ryztVNA==
Date:   Mon, 20 Dec 2021 16:38:12 +0000
Message-ID: <63cb094125b6a6038c65eeac2abaabbabe63addd.1640017960.git.christophe.leroy@csgroup.eu>
References: <cover.1640017960.git.christophe.leroy@csgroup.eu>
In-Reply-To: <cover.1640017960.git.christophe.leroy@csgroup.eu>
Accept-Language: fr-FR, en-US
Content-Language: en-US
x-ms-exchange-antispam-messagedata-chunkcount: 1
x-ms-exchange-antispam-messagedata-0: =?iso-8859-1?Q?ka2bGgJtLnZN2CA2CQumpwoG36Uz6X4rVGWGH/o7wbunC3Cdrg6DKHjW62?=
 =?iso-8859-1?Q?ty0UJFEOMdRZ3jnGUTVre22qcivXEOxSi9xLeBg8ULCxXiB3ixOYVoRx2q?=
 =?iso-8859-1?Q?RsjRvIdzf+r7gv5wdcxC3nYKT8+H6gCsB88inejWCPWkehBZjE9Jc+YWLh?=
 =?iso-8859-1?Q?ilm8FiOzwVzsyL41E+xAeTj0jrdlbZImg3EWdQTaLA8kkGVr7mHNHw76kz?=
 =?iso-8859-1?Q?OkH3JWxQGsYYglsurE3caOF0BN9VfTncjB8xl0fUBDYAF3IxI1yw/U5Cy6?=
 =?iso-8859-1?Q?AyqgTNXosy8PX+g5lnGlK18LaD6kZ3o0Eqbsh7/OSsBaLQUUHN4/q+SM4U?=
 =?iso-8859-1?Q?t03NKlIT95QwVzZlTgK2iojOQcqiV+dsP7ellXBwcLJmdE0Rz5BIwjTtAy?=
 =?iso-8859-1?Q?mbiSK3+GlOS80bCjndm2i+94JRRRInCsZZyHt9Zf/KYf7Vcm0tnUCHy5wz?=
 =?iso-8859-1?Q?dKn7RsdVnX3LbAZCP/1T5OinfrCtuzL2rBe2gsxJrHWld1yHLmMb5N8vmE?=
 =?iso-8859-1?Q?joppzb7cJ2a4yY+yGcPZriYYeLeGVI4HSyos0HrRMGFpiNizVLK7njiEdz?=
 =?iso-8859-1?Q?Ik7vhlz1PBjPzCgQnGBk+1/SOHQfcqc/mhMXHco0QinkX7ZgvTLDCisRkC?=
 =?iso-8859-1?Q?KV+ePrxOq1TisePMx810UiiR01nZE+pz9YYfcJunqqg7NJ1NvgLqD0a1qp?=
 =?iso-8859-1?Q?pyLWd5VJEQWBlk8YICaAHxeDWINp/UamSdKcQvkl2aZTxDdSkPWXgo1qZO?=
 =?iso-8859-1?Q?74E1G7JMr7HhKv/Gfujg58RPWoQjU7pkOp7SUJfosGE/I2qCA+b5Q6mjps?=
 =?iso-8859-1?Q?B/W20NEE1Axy49l3eH/h6ug91jYsxb+ZnfCG9qESydD+/ZOTAfDu8R4UdO?=
 =?iso-8859-1?Q?j28OqvS30gSjAFKn0db0pyDjDxJbzL+0F2VtvHmbFFLvnWRhSP3RKzS8le?=
 =?iso-8859-1?Q?XvtphFMK5t9ZO0ZZ5K5ObKk/MZRjkA4Y03ZXR43UIh2KqBGOXzWcqXMv5+?=
 =?iso-8859-1?Q?TJ/IP259W/ETjDN0wIih2l9TQsQA1OIfiCFdjkKg4fsEyV5xGHApQnZUGx?=
 =?iso-8859-1?Q?hchz9+ssCu/nA27a9iZ+4pMH/kGqrna2+2W1ypzUnKzfnd9ElitXs8SSby?=
 =?iso-8859-1?Q?cb+L0RUQwi/C9clhMxJyFnWpLOM2M1OJbPucedYV+3Qivh8Dy47SYCkTlB?=
 =?iso-8859-1?Q?2TD9jXuOdq5gNzytbKmBokFa1RdFM1bfpXXgLfWba794GNQs+5HysmVMul?=
 =?iso-8859-1?Q?i/WhE5Hgx0snlUkwfFKUeirMOkknFJv2oCeTnTw8VI/CjnlcZ0azsDJrJo?=
 =?iso-8859-1?Q?l/trGjk7nnywCqabHnsuyJa/KPD11bs/Ay8gvlrR6ZQFZsFRt4+/tDY//O?=
 =?iso-8859-1?Q?1minA+nrAuaMFsyZGUOX92JmIHCJP8z8pZBMqc4D8CxgrPGRg+BzJxLFLQ?=
 =?iso-8859-1?Q?WteBesLAyWweJ5BTNRu5gxmU1gPFciGZMYpTf2c163Lbe/8v9DguBwHR03?=
 =?iso-8859-1?Q?eHnNp6RkbDUceshzwMtAkRKmhTeOeWWL7z2lGYW/2PPTVroPo+NmfWzTQb?=
 =?iso-8859-1?Q?QSRU1/thAT2Ej3DNSYCQOBrHflBkRKVqfliMW0E4MeArX6sf9UAfHoa3tr?=
 =?iso-8859-1?Q?XkTAQcCY+CHpaNX+94+GKA/LOXMz/4SfnC84eZAWutEueKHe52KTRZDUZF?=
 =?iso-8859-1?Q?99c4wB4MWK73HpWl1Gefy14UXG5iMHfWJhv4+6qKXcIpSHjh9YkzGUYQv6?=
 =?iso-8859-1?Q?YgzObRikG/gjQae7rJavYJghY=3D?=
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: 8BIT
MIME-Version: 1.0
X-OriginatorOrg: csgroup.eu
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-AuthSource: MRZP264MB2988.FRAP264.PROD.OUTLOOK.COM
X-MS-Exchange-CrossTenant-Network-Message-Id: e2addbaa-6311-4300-5c8d-08d9c3d71d84
X-MS-Exchange-CrossTenant-originalarrivaltime: 20 Dec 2021 16:38:12.9297
 (UTC)
X-MS-Exchange-CrossTenant-fromentityheader: Hosted
X-MS-Exchange-CrossTenant-id: 9914def7-b676-4fda-8815-5d49fb3b45c8
X-MS-Exchange-CrossTenant-mailboxtype: HOSTED
X-MS-Exchange-CrossTenant-userprincipalname: ChFmWvWOABelcK9FVA5CY/jemslILH9HrJKlFWvJrU/THHALjlfOvWr/epV4BVLBynysYBJSCHF0RiFzaHXAvF+74PCzGav04vtBbcHJyKY=
X-MS-Exchange-Transport-CrossTenantHeadersStamped: MRZP264MB2924
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

PPC64 needs some special logic to properly set up the TOC.
See commit 85baa095497f ("powerpc/livepatch: Add live patching support
on ppc64le") for details.

PPC32 doesn't have TOC so it doesn't need that logic, so adding
LIVEPATCH support is straight forward.

Add CONFIG_LIVEPATCH_64 and move livepatch stack logic into that item.

Livepatch sample modules all work.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/Kconfig                   | 6 +++++-
 arch/powerpc/include/asm/livepatch.h   | 8 +++++---
 arch/powerpc/include/asm/thread_info.h | 2 +-
 arch/powerpc/kernel/asm-offsets.c      | 2 +-
 4 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 0631c9241af3..cdac2115eb00 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -9,6 +9,10 @@ config 64BIT
 	bool
 	default y if PPC64
 
+config LIVEPATCH_64
+	def_bool PPC64
+	depends	on LIVEPATCH
+
 config MMU
 	bool
 	default y
@@ -230,7 +234,7 @@ config PPC
 	select HAVE_KPROBES_ON_FTRACE
 	select HAVE_KRETPROBES
 	select HAVE_LD_DEAD_CODE_DATA_ELIMINATION
-	select HAVE_LIVEPATCH			if HAVE_DYNAMIC_FTRACE_WITH_REGS && PPC64
+	select HAVE_LIVEPATCH			if HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_MOD_ARCH_SPECIFIC
 	select HAVE_NMI				if PERF_EVENTS || (PPC64 && PPC_BOOK3S)
 	select HAVE_OPTPROBES
diff --git a/arch/powerpc/include/asm/livepatch.h b/arch/powerpc/include/asm/livepatch.h
index 4fe018cc207b..37af961eb74c 100644
--- a/arch/powerpc/include/asm/livepatch.h
+++ b/arch/powerpc/include/asm/livepatch.h
@@ -23,12 +23,14 @@ static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
 static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
 {
 	/*
-	 * Live patch works only with -mprofile-kernel on PPC. In this case,
-	 * the ftrace location is always within the first 16 bytes.
+	 * Live patch works on PPC32 and only with -mprofile-kernel on PPC64. In
+	 * both cases, the ftrace location is always within the first 16 bytes.
 	 */
 	return ftrace_location_range(faddr, faddr + 16);
 }
+#endif /* CONFIG_LIVEPATCH */
 
+#ifdef CONFIG_LIVEPATCH_64
 static inline void klp_init_thread_info(struct task_struct *p)
 {
 	/* + 1 to account for STACK_END_MAGIC */
@@ -36,6 +38,6 @@ static inline void klp_init_thread_info(struct task_struct *p)
 }
 #else
 static inline void klp_init_thread_info(struct task_struct *p) { }
-#endif /* CONFIG_LIVEPATCH */
+#endif
 
 #endif /* _ASM_POWERPC_LIVEPATCH_H */
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 5725029aaa29..42f8a1f99036 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -51,7 +51,7 @@ struct thread_info {
 	unsigned int	cpu;
 #endif
 	unsigned long	local_flags;		/* private flags for thread */
-#ifdef CONFIG_LIVEPATCH
+#ifdef CONFIG_LIVEPATCH_64
 	unsigned long *livepatch_sp;
 #endif
 #if defined(CONFIG_VIRT_CPU_ACCOUNTING_NATIVE) && defined(CONFIG_PPC32)
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 7582f3e3a330..eec536aef83a 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -94,7 +94,7 @@ int main(void)
 	OFFSET(TASK_CPU, task_struct, thread_info.cpu);
 #endif
 
-#ifdef CONFIG_LIVEPATCH
+#ifdef CONFIG_LIVEPATCH_64
 	OFFSET(TI_livepatch_sp, thread_info, livepatch_sp);
 #endif
 
-- 
2.33.1