All of lore.kernel.org
 help / color / mirror / Atom feed
From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	dja@axtens.net
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
	linux-mm@kvack.org
Subject: [PATCH v5 07/17] powerpc: align stack to 2 * THREAD_SIZE with VMAP_STACK
Date: Sat, 21 Dec 2019 08:32:28 +0000 (UTC)	[thread overview]
Message-ID: <60e9ae86b7d2cdcf21468787076d345663648f46.1576916812.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1576916812.git.christophe.leroy@c-s.fr>

In order to ease stack overflow detection, align
stack to 2 * THREAD_SIZE when using VMAP_STACK.
This allows overflow detection using a single bit check.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/include/asm/thread_info.h | 13 +++++++++++++
 arch/powerpc/kernel/setup_32.c         |  2 +-
 arch/powerpc/kernel/setup_64.c         |  2 +-
 arch/powerpc/kernel/vmlinux.lds.S      |  2 +-
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 488d5c4670ff..a2270749b282 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -22,6 +22,19 @@
 
 #define THREAD_SIZE		(1 << THREAD_SHIFT)
 
+/*
+ * By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by
+ * checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
+ * assembly.
+ */
+#ifdef CONFIG_VMAP_STACK
+#define THREAD_ALIGN_SHIFT	(THREAD_SHIFT + 1)
+#else
+#define THREAD_ALIGN_SHIFT	THREAD_SHIFT
+#endif
+
+#define THREAD_ALIGN		(1 << THREAD_ALIGN_SHIFT)
+
 #ifndef __ASSEMBLY__
 #include <linux/cache.h>
 #include <asm/processor.h>
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index dcffe927f5b9..f014c4f7a337 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -140,7 +140,7 @@ arch_initcall(ppc_init);
 
 static void *__init alloc_stack(void)
 {
-	void *ptr = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
+	void *ptr = memblock_alloc(THREAD_SIZE, THREAD_ALIGN);
 
 	if (!ptr)
 		panic("cannot allocate %d bytes for stack at %pS\n",
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 6104917a282d..e05e6dd67ae6 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -633,7 +633,7 @@ static void *__init alloc_stack(unsigned long limit, int cpu)
 
 	BUILD_BUG_ON(STACK_INT_FRAME_SIZE % 16);
 
-	ptr = memblock_alloc_try_nid(THREAD_SIZE, THREAD_SIZE,
+	ptr = memblock_alloc_try_nid(THREAD_SIZE, THREAD_ALIGN,
 				     MEMBLOCK_LOW_LIMIT, limit,
 				     early_cpu_to_node(cpu));
 	if (!ptr)
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 8834220036a5..b4c89a1acebb 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -323,7 +323,7 @@ SECTIONS
 #endif
 
 	/* The initial task and kernel stack */
-	INIT_TASK_DATA_SECTION(THREAD_SIZE)
+	INIT_TASK_DATA_SECTION(THREAD_ALIGN)
 
 	.data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) {
 		PAGE_ALIGNED_DATA(PAGE_SIZE)
-- 
2.13.3


WARNING: multiple messages have this Message-ID (diff)
From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	 dja@axtens.net
Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v5 07/17] powerpc: align stack to 2 * THREAD_SIZE with VMAP_STACK
Date: Sat, 21 Dec 2019 08:32:28 +0000 (UTC)	[thread overview]
Message-ID: <60e9ae86b7d2cdcf21468787076d345663648f46.1576916812.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1576916812.git.christophe.leroy@c-s.fr>

In order to ease stack overflow detection, align
stack to 2 * THREAD_SIZE when using VMAP_STACK.
This allows overflow detection using a single bit check.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
 arch/powerpc/include/asm/thread_info.h | 13 +++++++++++++
 arch/powerpc/kernel/setup_32.c         |  2 +-
 arch/powerpc/kernel/setup_64.c         |  2 +-
 arch/powerpc/kernel/vmlinux.lds.S      |  2 +-
 4 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 488d5c4670ff..a2270749b282 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -22,6 +22,19 @@
 
 #define THREAD_SIZE		(1 << THREAD_SHIFT)
 
+/*
+ * By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by
+ * checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
+ * assembly.
+ */
+#ifdef CONFIG_VMAP_STACK
+#define THREAD_ALIGN_SHIFT	(THREAD_SHIFT + 1)
+#else
+#define THREAD_ALIGN_SHIFT	THREAD_SHIFT
+#endif
+
+#define THREAD_ALIGN		(1 << THREAD_ALIGN_SHIFT)
+
 #ifndef __ASSEMBLY__
 #include <linux/cache.h>
 #include <asm/processor.h>
diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index dcffe927f5b9..f014c4f7a337 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -140,7 +140,7 @@ arch_initcall(ppc_init);
 
 static void *__init alloc_stack(void)
 {
-	void *ptr = memblock_alloc(THREAD_SIZE, THREAD_SIZE);
+	void *ptr = memblock_alloc(THREAD_SIZE, THREAD_ALIGN);
 
 	if (!ptr)
 		panic("cannot allocate %d bytes for stack at %pS\n",
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 6104917a282d..e05e6dd67ae6 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -633,7 +633,7 @@ static void *__init alloc_stack(unsigned long limit, int cpu)
 
 	BUILD_BUG_ON(STACK_INT_FRAME_SIZE % 16);
 
-	ptr = memblock_alloc_try_nid(THREAD_SIZE, THREAD_SIZE,
+	ptr = memblock_alloc_try_nid(THREAD_SIZE, THREAD_ALIGN,
 				     MEMBLOCK_LOW_LIMIT, limit,
 				     early_cpu_to_node(cpu));
 	if (!ptr)
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index 8834220036a5..b4c89a1acebb 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -323,7 +323,7 @@ SECTIONS
 #endif
 
 	/* The initial task and kernel stack */
-	INIT_TASK_DATA_SECTION(THREAD_SIZE)
+	INIT_TASK_DATA_SECTION(THREAD_ALIGN)
 
 	.data..page_aligned : AT(ADDR(.data..page_aligned) - LOAD_OFFSET) {
 		PAGE_ALIGNED_DATA(PAGE_SIZE)
-- 
2.13.3


  parent reply	other threads:[~2019-12-21  8:32 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-21  8:32 [PATCH v5 00/17] Enable CONFIG_VMAP_STACK on PPC32 Christophe Leroy
2019-12-21  8:32 ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 01/17] powerpc/32: replace MTMSRD() by mtmsr Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2020-01-29  5:17   ` Michael Ellerman
2019-12-21  8:32 ` [PATCH v5 02/17] powerpc/32: Add EXCEPTION_PROLOG_0 in head_32.h Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 03/17] powerpc/32: save DEAR/DAR before calling handle_page_fault Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 04/17] powerpc/32: move MSR_PR test into EXCEPTION_PROLOG_0 Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 05/17] powerpc/32: add a macro to get and/or save DAR and DSISR on stack Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 06/17] powerpc/32: prepare for CONFIG_VMAP_STACK Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` Christophe Leroy [this message]
2019-12-21  8:32   ` [PATCH v5 07/17] powerpc: align stack to 2 * THREAD_SIZE with VMAP_STACK Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 08/17] powerpc/32: Add early stack overflow detection with VMAP stack Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 09/17] powerpc/32: Use vmapped stacks for interrupts Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 10/17] powerpc/8xx: Use alternative scratch registers in DTLB miss handler Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 11/17] powerpc/8xx: drop exception entries for non-existing exceptions Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 12/17] powerpc/8xx: move DataStoreTLBMiss perf handler Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 13/17] powerpc/8xx: split breakpoint exception Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 14/17] powerpc/8xx: Enable CONFIG_VMAP_STACK Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 15/17] powerpc/32s: reorganise DSI handler Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 16/17] powerpc/32s: avoid crossing page boundary while changing SRR0/1 Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2019-12-21  8:32 ` [PATCH v5 17/17] powerpc/32s: Enable CONFIG_VMAP_STACK Christophe Leroy
2019-12-21  8:32   ` Christophe Leroy
2020-01-18 12:46   ` Michael Ellerman
2020-01-18 12:46     ` Michael Ellerman
2020-02-06 20:31   ` Guenter Roeck
2020-02-06 20:31     ` Guenter Roeck
2020-02-07  6:13     ` Christophe Leroy
2020-02-07  6:13       ` Christophe Leroy
2020-02-07  8:28       ` Christophe Leroy
2020-02-07  8:28         ` Christophe Leroy
2020-02-07 13:08         ` Guenter Roeck
2020-02-07 13:08           ` Guenter Roeck
2020-02-07 13:29           ` Christophe Leroy
2020-02-07 13:29             ` Christophe Leroy
2020-02-07 13:44             ` Guenter Roeck
2020-02-07 13:44               ` Guenter Roeck
2020-02-07 17:16               ` Christophe Leroy
2020-02-07 17:16                 ` Christophe Leroy

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=60e9ae86b7d2cdcf21468787076d345663648f46.1576916812.git.christophe.leroy@c-s.fr \
    --to=christophe.leroy@c-s.fr \
    --cc=benh@kernel.crashing.org \
    --cc=dja@axtens.net \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mpe@ellerman.id.au \
    --cc=paulus@samba.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.