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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>,
	Andrew Morton <akpm@linux-foundation.org>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>, Arnd Bergmann <arnd@arndb.de>,
	Kees Cook <keescook@chromium.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH v4 10/13] lkdtm: Force do_nothing() out of line
Date: Tue, 15 Feb 2022 13:41:05 +0100	[thread overview]
Message-ID: <a5dcf4d2088e6aca47ab3b4c6d5c0f7fa064e25a.1644928018.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1644928018.git.christophe.leroy@csgroup.eu>

LKDTM tests display that the run do_nothing() at a given
address, but in reality do_nothing() is inlined into the
caller.

Force it out of line so that it really runs text at the
displayed address.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 drivers/misc/lkdtm/perms.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 2dede2ef658f..60b3b2fe929d 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -21,7 +21,7 @@
 /* This is non-const, so it will end up in the .data section. */
 static u8 data_area[EXEC_SIZE];
 
-/* This is cost, so it will end up in the .rodata section. */
+/* This is const, so it will end up in the .rodata section. */
 static const unsigned long rodata = 0xAA55AA55;
 
 /* This is marked __ro_after_init, so it should ultimately be .rodata. */
@@ -31,7 +31,7 @@ static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
  * This just returns to the caller. It is designed to be copied into
  * non-executable memory regions.
  */
-static void do_nothing(void)
+static noinline void do_nothing(void)
 {
 	return;
 }
-- 
2.34.1


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>,
	Andrew Morton <akpm@linux-foundation.org>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>, Arnd Bergmann <arnd@arndb.de>,
	Kees Cook <keescook@chromium.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-arch@vger.kernel.org, linux-ia64@vger.kernel.org,
	linux-parisc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v4 10/13] lkdtm: Force do_nothing() out of line
Date: Tue, 15 Feb 2022 13:41:05 +0100	[thread overview]
Message-ID: <a5dcf4d2088e6aca47ab3b4c6d5c0f7fa064e25a.1644928018.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1644928018.git.christophe.leroy@csgroup.eu>

LKDTM tests display that the run do_nothing() at a given
address, but in reality do_nothing() is inlined into the
caller.

Force it out of line so that it really runs text at the
displayed address.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 drivers/misc/lkdtm/perms.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 2dede2ef658f..60b3b2fe929d 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -21,7 +21,7 @@
 /* This is non-const, so it will end up in the .data section. */
 static u8 data_area[EXEC_SIZE];
 
-/* This is cost, so it will end up in the .rodata section. */
+/* This is const, so it will end up in the .rodata section. */
 static const unsigned long rodata = 0xAA55AA55;
 
 /* This is marked __ro_after_init, so it should ultimately be .rodata. */
@@ -31,7 +31,7 @@ static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
  * This just returns to the caller. It is designed to be copied into
  * non-executable memory regions.
  */
-static void do_nothing(void)
+static noinline void do_nothing(void)
 {
 	return;
 }
-- 
2.34.1


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>,
	Andrew Morton <akpm@linux-foundation.org>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>, Arnd Bergmann <arnd@arndb.de>,
	Kees Cook <keescook@chromium.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>,
	linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH v4 10/13] lkdtm: Force do_nothing() out of line
Date: Tue, 15 Feb 2022 12:41:05 +0000	[thread overview]
Message-ID: <a5dcf4d2088e6aca47ab3b4c6d5c0f7fa064e25a.1644928018.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1644928018.git.christophe.leroy@csgroup.eu>

LKDTM tests display that the run do_nothing() at a given
address, but in reality do_nothing() is inlined into the
caller.

Force it out of line so that it really runs text at the
displayed address.

Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 drivers/misc/lkdtm/perms.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 2dede2ef658f..60b3b2fe929d 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -21,7 +21,7 @@
 /* This is non-const, so it will end up in the .data section. */
 static u8 data_area[EXEC_SIZE];
 
-/* This is cost, so it will end up in the .rodata section. */
+/* This is const, so it will end up in the .rodata section. */
 static const unsigned long rodata = 0xAA55AA55;
 
 /* This is marked __ro_after_init, so it should ultimately be .rodata. */
@@ -31,7 +31,7 @@ static unsigned long ro_after_init __ro_after_init = 0x55AA5500;
  * This just returns to the caller. It is designed to be copied into
  * non-executable memory regions.
  */
-static void do_nothing(void)
+static noinline void do_nothing(void)
 {
 	return;
 }
-- 
2.34.1

  parent reply	other threads:[~2022-02-15 12:50 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-15 12:40 [PATCH v4 00/13] Fix LKDTM for PPC64/IA64/PARISC v4 Christophe Leroy
2022-02-15 12:40 ` Christophe Leroy
2022-02-15 12:40 ` Christophe Leroy
2022-02-15 12:40 ` [PATCH v4 01/13] powerpc: Fix 'sparse' checking on PPC64le Christophe Leroy
2022-02-15 12:40   ` Christophe Leroy
2022-02-15 12:40   ` Christophe Leroy
2022-02-15 16:06   ` Kees Cook
2022-02-15 16:06     ` Kees Cook
2022-02-15 16:06     ` Kees Cook
2022-02-15 12:40 ` [PATCH v4 02/13] powerpc: Move and rename func_descr_t Christophe Leroy
2022-02-15 12:40   ` Christophe Leroy
2022-02-15 12:40   ` Christophe Leroy
2022-02-15 12:40 ` [PATCH v4 03/13] powerpc: Use 'struct func_desc' instead of 'struct ppc64_opd_entry' Christophe Leroy
2022-02-15 12:40   ` Christophe Leroy
2022-02-15 12:40   ` Christophe Leroy
2022-02-15 12:40 ` [PATCH v4 04/13] powerpc: Remove " Christophe Leroy
2022-02-15 12:40   ` Christophe Leroy
2022-02-15 12:40   ` Christophe Leroy
2022-02-15 12:41 ` [PATCH v4 05/13] powerpc: Prepare func_desc_t for refactorisation Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41 ` [PATCH v4 06/13] ia64: Rename 'ip' to 'addr' in 'struct fdesc' Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41 ` [PATCH v4 07/13] asm-generic: Define CONFIG_HAVE_FUNCTION_DESCRIPTORS Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41 ` [PATCH v4 08/13] asm-generic: Define 'func_desc_t' to commonly describe function descriptors Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41 ` [PATCH v4 09/13] asm-generic: Refactor dereference_[kernel]_function_descriptor() Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41 ` Christophe Leroy [this message]
2022-02-15 12:41   ` [PATCH v4 10/13] lkdtm: Force do_nothing() out of line Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41 ` [PATCH v4 11/13] lkdtm: Really write into kernel text in WRITE_KERN Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41 ` [PATCH v4 12/13] lkdtm: Fix execute_[user]_location() Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41 ` [PATCH v4 13/13] lkdtm: Add a test for function descriptors protection Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 12:41   ` Christophe Leroy
2022-02-15 16:07 ` [PATCH v4 00/13] Fix LKDTM for PPC64/IA64/PARISC v4 Kees Cook
2022-02-15 16:07   ` Kees Cook
2022-02-15 16:07   ` Kees Cook
2022-02-16 12:22   ` Michael Ellerman
2022-02-16 12:22     ` Michael Ellerman
2022-02-16 12:22     ` Michael Ellerman
2022-02-16 16:20     ` Kees Cook
2022-02-16 16:20       ` Kees Cook
2022-02-16 16:20       ` Kees Cook
2022-02-16 13:26   ` Helge Deller
2022-02-16 13:26     ` Helge Deller
2022-02-16 13:26     ` Helge Deller
2022-02-16 12:25 ` John Paul Adrian Glaubitz
2022-02-16 12:25   ` John Paul Adrian Glaubitz
2022-02-16 12:25   ` John Paul Adrian Glaubitz
2022-02-21 20:06   ` John Paul Adrian Glaubitz
2022-02-21 20:06     ` John Paul Adrian Glaubitz
2022-02-21 20:06     ` John Paul Adrian Glaubitz
2022-03-08 12:07 ` Michael Ellerman
2022-03-08 12:07   ` Michael Ellerman
2022-03-08 12:07   ` Michael Ellerman
2022-03-09  1:37   ` Michael Ellerman
2022-03-09  1:37     ` Michael Ellerman
2022-03-09  1:37     ` Michael Ellerman
2022-03-09 16:30     ` Kees Cook
2022-03-09 16:30       ` Kees Cook
2022-03-09 16:30       ` Kees Cook

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