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: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 6/6] powerpc/32s: Use dedicated segment for modules with STRICT_KERNEL_RWX
Date: Mon, 29 Jun 2020 11:15:26 +0000 (UTC) [thread overview]
Message-ID: <eb8faba9148b6cf17c696ba776b4e8ee2f6313bf.1593428200.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <cover.1593428200.git.christophe.leroy@csgroup.eu>
When STRICT_KERNEL_RWX is set, we want to set NX bit on vmalloc
segments. But modules require exec.
Use a dedicated segment for modules. There is not much space
above kernel, and we don't waste vmalloc space to do alignment.
Therefore, we take the segment before PAGE_OFFSET for modules.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/book3s/32/pgtable.h | 15 +++++----------
arch/powerpc/mm/ptdump/ptdump.c | 8 ++++++++
3 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 51abc59c3334..963b3bc7d969 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -1194,6 +1194,7 @@ config TASK_SIZE_BOOL
config TASK_SIZE
hex "Size of user task space" if TASK_SIZE_BOOL
default "0x80000000" if PPC_8xx
+ default "0xb0000000" if PPC_BOOK3S_32 && STRICT_KERNEL_RWX
default "0xc0000000"
endmenu
diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 224912432821..36443cda8dcf 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -184,17 +184,7 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
*/
#define VMALLOC_OFFSET (0x1000000) /* 16M */
-/*
- * With CONFIG_STRICT_KERNEL_RWX, kernel segments are set NX. But when modules
- * are used, NX cannot be set on VMALLOC space. So vmalloc VM space and linear
- * memory shall not share segments.
- */
-#if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_MODULES)
-#define VMALLOC_START ((ALIGN((long)high_memory, 256L << 20) + VMALLOC_OFFSET) & \
- ~(VMALLOC_OFFSET - 1))
-#else
#define VMALLOC_START ((((long)high_memory + VMALLOC_OFFSET) & ~(VMALLOC_OFFSET-1)))
-#endif
#ifdef CONFIG_KASAN_VMALLOC
#define VMALLOC_END ALIGN_DOWN(ioremap_bot, PAGE_SIZE << KASAN_SHADOW_SCALE_SHIFT)
@@ -202,6 +192,11 @@ int map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot);
#define VMALLOC_END ioremap_bot
#endif
+#ifdef CONFIG_STRICT_KERNEL_RWX
+#define MODULES_END ALIGN_DOWN(PAGE_OFFSET, SZ_256M)
+#define MODULES_VADDR (MODULES_END - SZ_256M)
+#endif
+
#ifndef __ASSEMBLY__
#include <linux/sched.h>
#include <linux/threads.h>
diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
index 9d942136c7be..b2ed1ca4f254 100644
--- a/arch/powerpc/mm/ptdump/ptdump.c
+++ b/arch/powerpc/mm/ptdump/ptdump.c
@@ -74,6 +74,10 @@ struct addr_marker {
static struct addr_marker address_markers[] = {
{ 0, "Start of kernel VM" },
+#ifdef MODULES_VADDR
+ { 0, "modules start" },
+ { 0, "modules end" },
+#endif
{ 0, "vmalloc() Area" },
{ 0, "vmalloc() End" },
#ifdef CONFIG_PPC64
@@ -352,6 +356,10 @@ static void populate_markers(void)
address_markers[i++].start_address = PAGE_OFFSET;
#else
address_markers[i++].start_address = TASK_SIZE;
+#endif
+#ifdef MODULES_VADDR
+ address_markers[i++].start_address = MODULES_VADDR;
+ address_markers[i++].start_address = MODULES_END;
#endif
address_markers[i++].start_address = VMALLOC_START;
address_markers[i++].start_address = VMALLOC_END;
--
2.25.0
next prev parent reply other threads:[~2020-06-29 18:51 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 11:15 [PATCH v2 0/6] powerpc/32s: Allocate modules outside of vmalloc space for STRICT_KERNEL_RWX Christophe Leroy
2020-06-29 11:15 ` [PATCH v2 1/6] powerpc/lib: Prepare code-patching for modules allocated outside vmalloc space Christophe Leroy
2020-06-29 11:15 ` [PATCH v2 2/6] powerpc: Use MODULES_VADDR if defined Christophe Leroy
2020-06-29 11:15 ` [PATCH v2 3/6] powerpc/32s: Only leave NX unset on segments used for modules Christophe Leroy
2020-08-20 22:00 ` Andreas Schwab
2020-08-21 5:11 ` Christophe Leroy
2020-08-21 6:43 ` Christophe Leroy
2020-06-29 11:15 ` [PATCH v2 4/6] powerpc/32: Set user/kernel boundary at TASK_SIZE instead of PAGE_OFFSET Christophe Leroy
2020-06-29 11:15 ` [PATCH v2 5/6] powerpc/32s: Kernel space starts at TASK_SIZE Christophe Leroy
2020-06-29 11:15 ` Christophe Leroy [this message]
2020-07-27 7:26 ` [PATCH v2 0/6] powerpc/32s: Allocate modules outside of vmalloc space for STRICT_KERNEL_RWX Michael Ellerman
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