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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>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	Michael Neuling <mikey@neuling.org>
Subject: [PATCH v2 1/3] powerpc/code-patching: Improve verification of patchability
Date: Sat, 25 Sep 2021 10:31:42 +0200	[thread overview]
Message-ID: <a7a35416ddab4b42617e2c81fe5816c7f8d0c63f.1632558672.git.christophe.leroy@csgroup.eu> (raw)

Today, patch_instruction() assumes that is called exclusively on valid
addresses, and only checks that it is not called on an init address
after init section has been freed.

Improve verification by calling kernel_text_address() instead.

kernel_text_address() already includes a verification of
initmem release.

Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/lib/code-patching.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index f9a3019e37b4..20ec6648aacc 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -190,10 +190,9 @@ static int do_patch_instruction(u32 *addr, struct ppc_inst instr)
 int patch_instruction(u32 *addr, struct ppc_inst instr)
 {
 	/* Make sure we aren't patching a freed init section */
-	if (init_mem_is_free && init_section_contains(addr, 4)) {
-		pr_debug("Skipping init section patching addr: 0x%px\n", addr);
+	if (!kernel_text_address((unsigned long)addr))
 		return 0;
-	}
+
 	return do_patch_instruction(addr, instr);
 }
 NOKPROBE_SYMBOL(patch_instruction);
-- 
2.31.1


WARNING: multiple messages have this Message-ID (diff)
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>
Cc: Michael Neuling <mikey@neuling.org>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 1/3] powerpc/code-patching: Improve verification of patchability
Date: Sat, 25 Sep 2021 10:31:42 +0200	[thread overview]
Message-ID: <a7a35416ddab4b42617e2c81fe5816c7f8d0c63f.1632558672.git.christophe.leroy@csgroup.eu> (raw)

Today, patch_instruction() assumes that is called exclusively on valid
addresses, and only checks that it is not called on an init address
after init section has been freed.

Improve verification by calling kernel_text_address() instead.

kernel_text_address() already includes a verification of
initmem release.

Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/lib/code-patching.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index f9a3019e37b4..20ec6648aacc 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -190,10 +190,9 @@ static int do_patch_instruction(u32 *addr, struct ppc_inst instr)
 int patch_instruction(u32 *addr, struct ppc_inst instr)
 {
 	/* Make sure we aren't patching a freed init section */
-	if (init_mem_is_free && init_section_contains(addr, 4)) {
-		pr_debug("Skipping init section patching addr: 0x%px\n", addr);
+	if (!kernel_text_address((unsigned long)addr))
 		return 0;
-	}
+
 	return do_patch_instruction(addr, instr);
 }
 NOKPROBE_SYMBOL(patch_instruction);
-- 
2.31.1


             reply	other threads:[~2021-09-25 12:24 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-25  8:31 Christophe Leroy [this message]
2021-09-25  8:31 ` [PATCH v2 1/3] powerpc/code-patching: Improve verification of patchability Christophe Leroy
2021-09-25  8:31 ` [PATCH v2 2/3] powerpc: Stop using init_mem_is_free Christophe Leroy
2021-09-25  8:31   ` Christophe Leroy
2021-09-25  8:31 ` [PATCH v2 3/3] powerpc: Remove init_mem_is_free Christophe Leroy
2021-09-25  8:31   ` Christophe Leroy

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