* [PATCH v7 1/7] powerpc/mm: Implement set_memory() routines
2020-03-31 4:48 [PATCH v7 0/7] set_memory() routines and STRICT_MODULE_RWX Russell Currey
@ 2020-03-31 4:48 ` Russell Currey
2020-03-31 4:48 ` [PATCH v7 2/7] powerpc/kprobes: Mark newly allocated probes as RO Russell Currey
` (5 subsequent siblings)
6 siblings, 0 replies; 11+ messages in thread
From: Russell Currey @ 2020-03-31 4:48 UTC (permalink / raw)
To: linuxppc-dev
Cc: Russell Currey, christophe.leroy, mpe, ajd, dja, npiggin,
kernel-hardening
The set_memory_{ro/rw/nx/x}() functions are required for STRICT_MODULE_RWX,
and are generally useful primitives to have. This implementation is
designed to be completely generic across powerpc's many MMUs.
It's possible that this could be optimised to be faster for specific
MMUs, but the focus is on having a generic and safe implementation for
now.
This implementation does not handle cases where the caller is attempting
to change the mapping of the page it is executing from, or if another
CPU is concurrently using the page being altered. These cases likely
shouldn't happen, but a more complex implementation with MMU-specific code
could safely handle them, so that is left as a TODO for now.
These functions do nothing if STRICT_KERNEL_RWX is not enabled.
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
v7: Use apply_to_existing_page_range() and check for negative numpages
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/set_memory.h | 32 +++++++++++
arch/powerpc/mm/Makefile | 2 +-
arch/powerpc/mm/pageattr.c | 81 +++++++++++++++++++++++++++
4 files changed, 115 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/include/asm/set_memory.h
create mode 100644 arch/powerpc/mm/pageattr.c
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 497b7d0b2d7e..bd074246e34e 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -129,6 +129,7 @@ config PPC
select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_MEMBARRIER_CALLBACKS
select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64
+ select ARCH_HAS_SET_MEMORY
select ARCH_HAS_STRICT_KERNEL_RWX if ((PPC_BOOK3S_64 || PPC32) && !HIBERNATION)
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UACCESS_FLUSHCACHE
diff --git a/arch/powerpc/include/asm/set_memory.h b/arch/powerpc/include/asm/set_memory.h
new file mode 100644
index 000000000000..64011ea444b4
--- /dev/null
+++ b/arch/powerpc/include/asm/set_memory.h
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_SET_MEMORY_H
+#define _ASM_POWERPC_SET_MEMORY_H
+
+#define SET_MEMORY_RO 0
+#define SET_MEMORY_RW 1
+#define SET_MEMORY_NX 2
+#define SET_MEMORY_X 3
+
+int change_memory_attr(unsigned long addr, int numpages, long action);
+
+static inline int set_memory_ro(unsigned long addr, int numpages)
+{
+ return change_memory_attr(addr, numpages, SET_MEMORY_RO);
+}
+
+static inline int set_memory_rw(unsigned long addr, int numpages)
+{
+ return change_memory_attr(addr, numpages, SET_MEMORY_RW);
+}
+
+static inline int set_memory_nx(unsigned long addr, int numpages)
+{
+ return change_memory_attr(addr, numpages, SET_MEMORY_NX);
+}
+
+static inline int set_memory_x(unsigned long addr, int numpages)
+{
+ return change_memory_attr(addr, numpages, SET_MEMORY_X);
+}
+
+#endif
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index 5e147986400d..a998fdac52f9 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -5,7 +5,7 @@
ccflags-$(CONFIG_PPC64) := $(NO_MINIMAL_TOC)
-obj-y := fault.o mem.o pgtable.o mmap.o \
+obj-y := fault.o mem.o pgtable.o mmap.o pageattr.o \
init_$(BITS).o pgtable_$(BITS).o \
pgtable-frag.o ioremap.o ioremap_$(BITS).o \
init-common.o mmu_context.o drmem.o
diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c
new file mode 100644
index 000000000000..2da3fbab6ff7
--- /dev/null
+++ b/arch/powerpc/mm/pageattr.c
@@ -0,0 +1,81 @@
+// SPDX-License-Identifier: GPL-2.0
+
+/*
+ * MMU-generic set_memory implementation for powerpc
+ *
+ * Copyright 2019, IBM Corporation.
+ */
+
+#include <linux/mm.h>
+#include <linux/set_memory.h>
+
+#include <asm/mmu.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+
+/*
+ * Updates the attributes of a page in three steps:
+ *
+ * 1. invalidate the page table entry
+ * 2. flush the TLB
+ * 3. install the new entry with the updated attributes
+ *
+ * This is unsafe if the caller is attempting to change the mapping of the
+ * page it is executing from, or if another CPU is concurrently using the
+ * page being altered.
+ *
+ * TODO make the implementation resistant to this.
+ *
+ * NOTE: can be dangerous to call without STRICT_KERNEL_RWX
+ */
+static int change_page_attr(pte_t *ptep, unsigned long addr, void *data)
+{
+ long action = (long)data;
+ pte_t pte;
+
+ spin_lock(&init_mm.page_table_lock);
+
+ /* invalidate the PTE so it's safe to modify */
+ pte = ptep_get_and_clear(&init_mm, addr, ptep);
+ flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+
+ /* modify the PTE bits as desired, then apply */
+ switch (action) {
+ case SET_MEMORY_RO:
+ pte = pte_wrprotect(pte);
+ break;
+ case SET_MEMORY_RW:
+ pte = pte_mkwrite(pte);
+ break;
+ case SET_MEMORY_NX:
+ pte = pte_exprotect(pte);
+ break;
+ case SET_MEMORY_X:
+ pte = pte_mkexec(pte);
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ set_pte_at(&init_mm, addr, ptep, pte);
+ spin_unlock(&init_mm.page_table_lock);
+
+ return 0;
+}
+
+int change_memory_attr(unsigned long addr, int numpages, long action)
+{
+ unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE);
+ unsigned long sz = numpages * PAGE_SIZE;
+
+ if (!IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
+ return 0;
+
+ if (numpages <= 0)
+ return 0;
+
+ return apply_to_existing_page_range(&init_mm, start, sz,
+ change_page_attr, (void *)action);
+}
--
2.26.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 2/7] powerpc/kprobes: Mark newly allocated probes as RO
2020-03-31 4:48 [PATCH v7 0/7] set_memory() routines and STRICT_MODULE_RWX Russell Currey
2020-03-31 4:48 ` [PATCH v7 1/7] powerpc/mm: Implement set_memory() routines Russell Currey
@ 2020-03-31 4:48 ` Russell Currey
2020-03-31 4:48 ` [PATCH v7 3/7] powerpc/mm/ptdump: debugfs handler for W+X checks at runtime Russell Currey
` (4 subsequent siblings)
6 siblings, 0 replies; 11+ messages in thread
From: Russell Currey @ 2020-03-31 4:48 UTC (permalink / raw)
To: linuxppc-dev
Cc: Russell Currey, christophe.leroy, mpe, ajd, dja, npiggin,
kernel-hardening
With CONFIG_STRICT_KERNEL_RWX=y and CONFIG_KPROBES=y, there will be one
W+X page at boot by default. This can be tested with
CONFIG_PPC_PTDUMP=y and CONFIG_PPC_DEBUG_WX=y set, and checking the
kernel log during boot.
powerpc doesn't implement its own alloc() for kprobes like other
architectures do, but we couldn't immediately mark RO anyway since we do
a memcpy to the page we allocate later. After that, nothing should be
allowed to modify the page, and write permissions are removed well
before the kprobe is armed.
The memcpy() would fail if >1 probes were allocated, so use
patch_instruction() instead which is safe for RO.
Reviewed-by: Daniel Axtens <dja@axtens.net>
Signed-off-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/kprobes.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 2d27ec4feee4..bfab91ded234 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -24,6 +24,8 @@
#include <asm/sstep.h>
#include <asm/sections.h>
#include <linux/uaccess.h>
+#include <linux/set_memory.h>
+#include <linux/vmalloc.h>
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
@@ -102,6 +104,16 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
return addr;
}
+void *alloc_insn_page(void)
+{
+ void *page = vmalloc_exec(PAGE_SIZE);
+
+ if (page)
+ set_memory_ro((unsigned long)page, 1);
+
+ return page;
+}
+
int arch_prepare_kprobe(struct kprobe *p)
{
int ret = 0;
@@ -124,11 +136,8 @@ int arch_prepare_kprobe(struct kprobe *p)
}
if (!ret) {
- memcpy(p->ainsn.insn, p->addr,
- MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
+ patch_instruction(p->ainsn.insn, *p->addr);
p->opcode = *p->addr;
- flush_icache_range((unsigned long)p->ainsn.insn,
- (unsigned long)p->ainsn.insn + sizeof(kprobe_opcode_t));
}
p->ainsn.boostable = 0;
--
2.26.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 3/7] powerpc/mm/ptdump: debugfs handler for W+X checks at runtime
2020-03-31 4:48 [PATCH v7 0/7] set_memory() routines and STRICT_MODULE_RWX Russell Currey
2020-03-31 4:48 ` [PATCH v7 1/7] powerpc/mm: Implement set_memory() routines Russell Currey
2020-03-31 4:48 ` [PATCH v7 2/7] powerpc/kprobes: Mark newly allocated probes as RO Russell Currey
@ 2020-03-31 4:48 ` Russell Currey
2020-03-31 4:48 ` [PATCH v7 4/7] powerpc: Set ARCH_HAS_STRICT_MODULE_RWX Russell Currey
` (3 subsequent siblings)
6 siblings, 0 replies; 11+ messages in thread
From: Russell Currey @ 2020-03-31 4:48 UTC (permalink / raw)
To: linuxppc-dev
Cc: Russell Currey, christophe.leroy, mpe, ajd, dja, npiggin,
kernel-hardening, Kees Cook
Very rudimentary, just
echo 1 > [debugfs]/check_wx_pages
and check the kernel log. Useful for testing strict module RWX.
Updated the Kconfig entry to reflect this.
Also fixed a typo.
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Russell Currey <ruscur@russell.cc>
---
arch/powerpc/Kconfig.debug | 6 ++++--
arch/powerpc/mm/ptdump/ptdump.c | 21 ++++++++++++++++++++-
2 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 0b063830eea8..e37960ef68c6 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -370,7 +370,7 @@ config PPC_PTDUMP
If you are unsure, say N.
config PPC_DEBUG_WX
- bool "Warn on W+X mappings at boot"
+ bool "Warn on W+X mappings at boot & enable manual checks at runtime"
depends on PPC_PTDUMP && STRICT_KERNEL_RWX
help
Generate a warning if any W+X mappings are found at boot.
@@ -384,7 +384,9 @@ config PPC_DEBUG_WX
of other unfixed kernel bugs easier.
There is no runtime or memory usage effect of this option
- once the kernel has booted up - it's a one time check.
+ once the kernel has booted up, it only automatically checks once.
+
+ Enables the "check_wx_pages" debugfs entry for checking at runtime.
If in doubt, say "Y".
diff --git a/arch/powerpc/mm/ptdump/ptdump.c b/arch/powerpc/mm/ptdump/ptdump.c
index 206156255247..a15e19a3b14e 100644
--- a/arch/powerpc/mm/ptdump/ptdump.c
+++ b/arch/powerpc/mm/ptdump/ptdump.c
@@ -4,7 +4,7 @@
*
* This traverses the kernel pagetables and dumps the
* information about the used sections of memory to
- * /sys/kernel/debug/kernel_pagetables.
+ * /sys/kernel/debug/kernel_page_tables.
*
* Derived from the arm64 implementation:
* Copyright (c) 2014, The Linux Foundation, Laura Abbott.
@@ -413,6 +413,25 @@ void ptdump_check_wx(void)
else
pr_info("Checked W+X mappings: passed, no W+X pages found\n");
}
+
+static int check_wx_debugfs_set(void *data, u64 val)
+{
+ if (val != 1ULL)
+ return -EINVAL;
+
+ ptdump_check_wx();
+
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(check_wx_fops, NULL, check_wx_debugfs_set, "%llu\n");
+
+static int ptdump_check_wx_init(void)
+{
+ return debugfs_create_file("check_wx_pages", 0200, NULL,
+ NULL, &check_wx_fops) ? 0 : -ENOMEM;
+}
+device_initcall(ptdump_check_wx_init);
#endif
static int ptdump_init(void)
--
2.26.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 4/7] powerpc: Set ARCH_HAS_STRICT_MODULE_RWX
2020-03-31 4:48 [PATCH v7 0/7] set_memory() routines and STRICT_MODULE_RWX Russell Currey
` (2 preceding siblings ...)
2020-03-31 4:48 ` [PATCH v7 3/7] powerpc/mm/ptdump: debugfs handler for W+X checks at runtime Russell Currey
@ 2020-03-31 4:48 ` Russell Currey
2020-03-31 4:48 ` [PATCH v7 5/7] powerpc/configs: Enable STRICT_MODULE_RWX in skiroot_defconfig Russell Currey
` (2 subsequent siblings)
6 siblings, 0 replies; 11+ messages in thread
From: Russell Currey @ 2020-03-31 4:48 UTC (permalink / raw)
To: linuxppc-dev
Cc: Russell Currey, christophe.leroy, mpe, ajd, dja, npiggin,
kernel-hardening
To enable strict module RWX on powerpc, set:
CONFIG_STRICT_MODULE_RWX=y
You should also have CONFIG_STRICT_KERNEL_RWX=y set to have any real
security benefit.
ARCH_HAS_STRICT_MODULE_RWX is set to require ARCH_HAS_STRICT_KERNEL_RWX.
This is due to a quirk in arch/Kconfig and arch/powerpc/Kconfig that
makes STRICT_MODULE_RWX *on by default* in configurations where
STRICT_KERNEL_RWX is *unavailable*.
Since this doesn't make much sense, and module RWX without kernel RWX
doesn't make much sense, having the same dependencies as kernel RWX
works around this problem.
Signed-off-by: Russell Currey <ruscur@russell.cc>
---
arch/powerpc/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index bd074246e34e..e1fc7fba10bf 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -131,6 +131,7 @@ config PPC
select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64
select ARCH_HAS_SET_MEMORY
select ARCH_HAS_STRICT_KERNEL_RWX if ((PPC_BOOK3S_64 || PPC32) && !HIBERNATION)
+ select ARCH_HAS_STRICT_MODULE_RWX if ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UACCESS_FLUSHCACHE
select ARCH_HAS_UACCESS_MCSAFE if PPC64
--
2.26.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 5/7] powerpc/configs: Enable STRICT_MODULE_RWX in skiroot_defconfig
2020-03-31 4:48 [PATCH v7 0/7] set_memory() routines and STRICT_MODULE_RWX Russell Currey
` (3 preceding siblings ...)
2020-03-31 4:48 ` [PATCH v7 4/7] powerpc: Set ARCH_HAS_STRICT_MODULE_RWX Russell Currey
@ 2020-03-31 4:48 ` Russell Currey
2020-03-31 4:48 ` [PATCH v7 6/7] powerpc/mm: implement set_memory_attr() Russell Currey
2020-03-31 4:48 ` [PATCH v7 7/7] powerpc/32: use set_memory_attr() Russell Currey
6 siblings, 0 replies; 11+ messages in thread
From: Russell Currey @ 2020-03-31 4:48 UTC (permalink / raw)
To: linuxppc-dev
Cc: Russell Currey, christophe.leroy, mpe, ajd, dja, npiggin,
kernel-hardening, Joel Stanley
skiroot_defconfig is the only powerpc defconfig with STRICT_KERNEL_RWX
enabled, and if you want memory protection for kernel text you'd want it
for modules too, so enable STRICT_MODULE_RWX there.
Acked-by: Joel Stanley <joel@joel.id.au>
Signed-off-by: Russell Currey <ruscur@russell.cc>
---
arch/powerpc/configs/skiroot_defconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/configs/skiroot_defconfig b/arch/powerpc/configs/skiroot_defconfig
index 1b6bdad36b13..66d20dbe67b7 100644
--- a/arch/powerpc/configs/skiroot_defconfig
+++ b/arch/powerpc/configs/skiroot_defconfig
@@ -51,6 +51,7 @@ CONFIG_CMDLINE="console=tty0 console=hvc0 ipr.fast_reboot=1 quiet"
# CONFIG_PPC_MEM_KEYS is not set
CONFIG_JUMP_LABEL=y
CONFIG_STRICT_KERNEL_RWX=y
+CONFIG_STRICT_MODULE_RWX=y
CONFIG_MODULES=y
CONFIG_MODULE_UNLOAD=y
CONFIG_MODULE_SIG_FORCE=y
--
2.26.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 6/7] powerpc/mm: implement set_memory_attr()
2020-03-31 4:48 [PATCH v7 0/7] set_memory() routines and STRICT_MODULE_RWX Russell Currey
` (4 preceding siblings ...)
2020-03-31 4:48 ` [PATCH v7 5/7] powerpc/configs: Enable STRICT_MODULE_RWX in skiroot_defconfig Russell Currey
@ 2020-03-31 4:48 ` Russell Currey
2020-03-31 4:48 ` [PATCH v7 7/7] powerpc/32: use set_memory_attr() Russell Currey
6 siblings, 0 replies; 11+ messages in thread
From: Russell Currey @ 2020-03-31 4:48 UTC (permalink / raw)
To: linuxppc-dev
Cc: Christophe Leroy, mpe, ajd, dja, npiggin, kernel-hardening,
kbuild test robot, Russell Currey
From: Christophe Leroy <christophe.leroy@c-s.fr>
In addition to the set_memory_xx() functions which allows to change
the memory attributes of not (yet) used memory regions, implement a
set_memory_attr() function to:
- set the final memory protection after init on currently used
kernel regions.
- enable/disable kernel memory regions in the scope of DEBUG_PAGEALLOC.
Unlike the set_memory_xx() which can act in three step as the regions
are unused, this function must modify 'on the fly' as the kernel is
executing from them. At the moment only PPC32 will use it and changing
page attributes on the fly is not an issue.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reported-by: kbuild test robot <lkp@intel.com>
[ruscur: cast "data" to unsigned long instead of int]
Signed-off-by: Russell Currey <ruscur@russell.cc>
---
v7: Use apply_to_existing_page_range() and check for negative numpages
arch/powerpc/include/asm/set_memory.h | 2 ++
arch/powerpc/mm/pageattr.c | 33 +++++++++++++++++++++++++++
2 files changed, 35 insertions(+)
diff --git a/arch/powerpc/include/asm/set_memory.h b/arch/powerpc/include/asm/set_memory.h
index 64011ea444b4..b040094f7920 100644
--- a/arch/powerpc/include/asm/set_memory.h
+++ b/arch/powerpc/include/asm/set_memory.h
@@ -29,4 +29,6 @@ static inline int set_memory_x(unsigned long addr, int numpages)
return change_memory_attr(addr, numpages, SET_MEMORY_X);
}
+int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot);
+
#endif
diff --git a/arch/powerpc/mm/pageattr.c b/arch/powerpc/mm/pageattr.c
index 2da3fbab6ff7..2fde1b195c85 100644
--- a/arch/powerpc/mm/pageattr.c
+++ b/arch/powerpc/mm/pageattr.c
@@ -79,3 +79,36 @@ int change_memory_attr(unsigned long addr, int numpages, long action)
return apply_to_existing_page_range(&init_mm, start, sz,
change_page_attr, (void *)action);
}
+
+/*
+ * Set the attributes of a page:
+ *
+ * This function is used by PPC32 at the end of init to set final kernel memory
+ * protection. It includes changing the maping of the page it is executing from
+ * and data pages it is using.
+ */
+static int set_page_attr(pte_t *ptep, unsigned long addr, void *data)
+{
+ pgprot_t prot = __pgprot((unsigned long)data);
+
+ spin_lock(&init_mm.page_table_lock);
+
+ set_pte_at(&init_mm, addr, ptep, pte_modify(*ptep, prot));
+ flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
+
+ spin_unlock(&init_mm.page_table_lock);
+
+ return 0;
+}
+
+int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot)
+{
+ unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE);
+ unsigned long sz = numpages * PAGE_SIZE;
+
+ if (numpages <= 0)
+ return 0;
+
+ return apply_to_existing_page_range(&init_mm, start, sz, set_page_attr,
+ (void *)pgprot_val(prot));
+}
--
2.26.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* [PATCH v7 7/7] powerpc/32: use set_memory_attr()
2020-03-31 4:48 [PATCH v7 0/7] set_memory() routines and STRICT_MODULE_RWX Russell Currey
` (5 preceding siblings ...)
2020-03-31 4:48 ` [PATCH v7 6/7] powerpc/mm: implement set_memory_attr() Russell Currey
@ 2020-03-31 4:48 ` Russell Currey
2020-03-31 9:56 ` Christophe Leroy
6 siblings, 1 reply; 11+ messages in thread
From: Russell Currey @ 2020-03-31 4:48 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Christophe Leroy, mpe, ajd, dja, npiggin, kernel-hardening
From: Christophe Leroy <christophe.leroy@c-s.fr>
Use set_memory_attr() instead of the PPC32 specific change_page_attr()
change_page_attr() was checking that the address was not mapped by
blocks and was handling highmem, but that's unneeded because the
affected pages can't be in highmem and block mapping verification
is already done by the callers.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/mm/pgtable_32.c | 95 ++++--------------------------------
1 file changed, 10 insertions(+), 85 deletions(-)
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index 5fb90edd865e..3d92eaf3ee2f 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -23,6 +23,7 @@
#include <linux/highmem.h>
#include <linux/memblock.h>
#include <linux/slab.h>
+#include <linux/set_memory.h>
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
@@ -121,99 +122,20 @@ void __init mapin_ram(void)
}
}
-/* Scan the real Linux page tables and return a PTE pointer for
- * a virtual address in a context.
- * Returns true (1) if PTE was found, zero otherwise. The pointer to
- * the PTE pointer is unmodified if PTE is not found.
- */
-static int
-get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
-{
- pgd_t *pgd;
- pud_t *pud;
- pmd_t *pmd;
- pte_t *pte;
- int retval = 0;
-
- pgd = pgd_offset(mm, addr & PAGE_MASK);
- if (pgd) {
- pud = pud_offset(pgd, addr & PAGE_MASK);
- if (pud && pud_present(*pud)) {
- pmd = pmd_offset(pud, addr & PAGE_MASK);
- if (pmd_present(*pmd)) {
- pte = pte_offset_map(pmd, addr & PAGE_MASK);
- if (pte) {
- retval = 1;
- *ptep = pte;
- if (pmdp)
- *pmdp = pmd;
- /* XXX caller needs to do pte_unmap, yuck */
- }
- }
- }
- }
- return(retval);
-}
-
-static int __change_page_attr_noflush(struct page *page, pgprot_t prot)
-{
- pte_t *kpte;
- pmd_t *kpmd;
- unsigned long address;
-
- BUG_ON(PageHighMem(page));
- address = (unsigned long)page_address(page);
-
- if (v_block_mapped(address))
- return 0;
- if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
- return -EINVAL;
- __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
- pte_unmap(kpte);
-
- return 0;
-}
-
-/*
- * Change the page attributes of an page in the linear mapping.
- *
- * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
- */
-static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
-{
- int i, err = 0;
- unsigned long flags;
- struct page *start = page;
-
- local_irq_save(flags);
- for (i = 0; i < numpages; i++, page++) {
- err = __change_page_attr_noflush(page, prot);
- if (err)
- break;
- }
- wmb();
- local_irq_restore(flags);
- flush_tlb_kernel_range((unsigned long)page_address(start),
- (unsigned long)page_address(page));
- return err;
-}
-
void mark_initmem_nx(void)
{
- struct page *page = virt_to_page(_sinittext);
unsigned long numpages = PFN_UP((unsigned long)_einittext) -
PFN_DOWN((unsigned long)_sinittext);
if (v_block_mapped((unsigned long)_stext + 1))
mmu_mark_initmem_nx();
else
- change_page_attr(page, numpages, PAGE_KERNEL);
+ set_memory_attr((unsigned long)_sinittext, numpages, PAGE_KERNEL);
}
#ifdef CONFIG_STRICT_KERNEL_RWX
void mark_rodata_ro(void)
{
- struct page *page;
unsigned long numpages;
if (v_block_mapped((unsigned long)_sinittext)) {
@@ -222,20 +144,18 @@ void mark_rodata_ro(void)
return;
}
- page = virt_to_page(_stext);
numpages = PFN_UP((unsigned long)_etext) -
PFN_DOWN((unsigned long)_stext);
- change_page_attr(page, numpages, PAGE_KERNEL_ROX);
+ set_memory_attr((unsigned long)_stext, numpages, PAGE_KERNEL_ROX);
/*
* mark .rodata as read only. Use __init_begin rather than __end_rodata
* to cover NOTES and EXCEPTION_TABLE.
*/
- page = virt_to_page(__start_rodata);
numpages = PFN_UP((unsigned long)__init_begin) -
PFN_DOWN((unsigned long)__start_rodata);
- change_page_attr(page, numpages, PAGE_KERNEL_RO);
+ set_memory_attr((unsigned long)__start_rodata, numpages, PAGE_KERNEL_RO);
// mark_initmem_nx() should have already run by now
ptdump_check_wx();
@@ -245,9 +165,14 @@ void mark_rodata_ro(void)
#ifdef CONFIG_DEBUG_PAGEALLOC
void __kernel_map_pages(struct page *page, int numpages, int enable)
{
+ unsigned long addr = (unsigned long)page_address(page);
+
if (PageHighMem(page))
return;
- change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
+ if (enable)
+ set_memory_attr(addr, numpages, PAGE_KERNEL);
+ else
+ set_memory_attr(addr, numpages, __pgprot(0));
}
#endif /* CONFIG_DEBUG_PAGEALLOC */
--
2.26.0
^ permalink raw reply related [flat|nested] 11+ messages in thread* Re: [PATCH v7 7/7] powerpc/32: use set_memory_attr()
2020-03-31 4:48 ` [PATCH v7 7/7] powerpc/32: use set_memory_attr() Russell Currey
@ 2020-03-31 9:56 ` Christophe Leroy
2020-04-01 2:27 ` Russell Currey
0 siblings, 1 reply; 11+ messages in thread
From: Christophe Leroy @ 2020-03-31 9:56 UTC (permalink / raw)
To: Russell Currey, linuxppc-dev; +Cc: mpe, ajd, dja, npiggin, kernel-hardening
Le 31/03/2020 à 06:48, Russell Currey a écrit :
> From: Christophe Leroy <christophe.leroy@c-s.fr>
>
> Use set_memory_attr() instead of the PPC32 specific change_page_attr()
>
> change_page_attr() was checking that the address was not mapped by
> blocks and was handling highmem, but that's unneeded because the
> affected pages can't be in highmem and block mapping verification
> is already done by the callers.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/mm/pgtable_32.c | 95 ++++--------------------------------
> 1 file changed, 10 insertions(+), 85 deletions(-)
>
> diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
> index 5fb90edd865e..3d92eaf3ee2f 100644
> --- a/arch/powerpc/mm/pgtable_32.c
> +++ b/arch/powerpc/mm/pgtable_32.c
> @@ -23,6 +23,7 @@
> #include <linux/highmem.h>
> #include <linux/memblock.h>
> #include <linux/slab.h>
> +#include <linux/set_memory.h>
>
> #include <asm/pgtable.h>
> #include <asm/pgalloc.h>
> @@ -121,99 +122,20 @@ void __init mapin_ram(void)
> }
> }
>
> -/* Scan the real Linux page tables and return a PTE pointer for
> - * a virtual address in a context.
> - * Returns true (1) if PTE was found, zero otherwise. The pointer to
> - * the PTE pointer is unmodified if PTE is not found.
> - */
> -static int
> -get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep, pmd_t **pmdp)
This will conflict, get_pteptr() is gone now, see
https://github.com/linuxppc/linux/commit/2efc7c085f05870eda6f29ac71eeb83f3bd54415
Christophe
> -{
> - pgd_t *pgd;
> - pud_t *pud;
> - pmd_t *pmd;
> - pte_t *pte;
> - int retval = 0;
> -
> - pgd = pgd_offset(mm, addr & PAGE_MASK);
> - if (pgd) {
> - pud = pud_offset(pgd, addr & PAGE_MASK);
> - if (pud && pud_present(*pud)) {
> - pmd = pmd_offset(pud, addr & PAGE_MASK);
> - if (pmd_present(*pmd)) {
> - pte = pte_offset_map(pmd, addr & PAGE_MASK);
> - if (pte) {
> - retval = 1;
> - *ptep = pte;
> - if (pmdp)
> - *pmdp = pmd;
> - /* XXX caller needs to do pte_unmap, yuck */
> - }
> - }
> - }
> - }
> - return(retval);
> -}
> -
> -static int __change_page_attr_noflush(struct page *page, pgprot_t prot)
> -{
> - pte_t *kpte;
> - pmd_t *kpmd;
> - unsigned long address;
> -
> - BUG_ON(PageHighMem(page));
> - address = (unsigned long)page_address(page);
> -
> - if (v_block_mapped(address))
> - return 0;
> - if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
> - return -EINVAL;
> - __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
> - pte_unmap(kpte);
> -
> - return 0;
> -}
> -
> -/*
> - * Change the page attributes of an page in the linear mapping.
> - *
> - * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
> - */
> -static int change_page_attr(struct page *page, int numpages, pgprot_t prot)
> -{
> - int i, err = 0;
> - unsigned long flags;
> - struct page *start = page;
> -
> - local_irq_save(flags);
> - for (i = 0; i < numpages; i++, page++) {
> - err = __change_page_attr_noflush(page, prot);
> - if (err)
> - break;
> - }
> - wmb();
> - local_irq_restore(flags);
> - flush_tlb_kernel_range((unsigned long)page_address(start),
> - (unsigned long)page_address(page));
> - return err;
> -}
> -
> void mark_initmem_nx(void)
> {
> - struct page *page = virt_to_page(_sinittext);
> unsigned long numpages = PFN_UP((unsigned long)_einittext) -
> PFN_DOWN((unsigned long)_sinittext);
>
> if (v_block_mapped((unsigned long)_stext + 1))
> mmu_mark_initmem_nx();
> else
> - change_page_attr(page, numpages, PAGE_KERNEL);
> + set_memory_attr((unsigned long)_sinittext, numpages, PAGE_KERNEL);
> }
>
> #ifdef CONFIG_STRICT_KERNEL_RWX
> void mark_rodata_ro(void)
> {
> - struct page *page;
> unsigned long numpages;
>
> if (v_block_mapped((unsigned long)_sinittext)) {
> @@ -222,20 +144,18 @@ void mark_rodata_ro(void)
> return;
> }
>
> - page = virt_to_page(_stext);
> numpages = PFN_UP((unsigned long)_etext) -
> PFN_DOWN((unsigned long)_stext);
>
> - change_page_attr(page, numpages, PAGE_KERNEL_ROX);
> + set_memory_attr((unsigned long)_stext, numpages, PAGE_KERNEL_ROX);
> /*
> * mark .rodata as read only. Use __init_begin rather than __end_rodata
> * to cover NOTES and EXCEPTION_TABLE.
> */
> - page = virt_to_page(__start_rodata);
> numpages = PFN_UP((unsigned long)__init_begin) -
> PFN_DOWN((unsigned long)__start_rodata);
>
> - change_page_attr(page, numpages, PAGE_KERNEL_RO);
> + set_memory_attr((unsigned long)__start_rodata, numpages, PAGE_KERNEL_RO);
>
> // mark_initmem_nx() should have already run by now
> ptdump_check_wx();
> @@ -245,9 +165,14 @@ void mark_rodata_ro(void)
> #ifdef CONFIG_DEBUG_PAGEALLOC
> void __kernel_map_pages(struct page *page, int numpages, int enable)
> {
> + unsigned long addr = (unsigned long)page_address(page);
> +
> if (PageHighMem(page))
> return;
>
> - change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0));
> + if (enable)
> + set_memory_attr(addr, numpages, PAGE_KERNEL);
> + else
> + set_memory_attr(addr, numpages, __pgprot(0));
> }
> #endif /* CONFIG_DEBUG_PAGEALLOC */
>
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH v7 7/7] powerpc/32: use set_memory_attr()
2020-03-31 9:56 ` Christophe Leroy
@ 2020-04-01 2:27 ` Russell Currey
2020-04-01 5:50 ` Christophe Leroy
0 siblings, 1 reply; 11+ messages in thread
From: Russell Currey @ 2020-04-01 2:27 UTC (permalink / raw)
To: Christophe Leroy, linuxppc-dev; +Cc: mpe, ajd, dja, npiggin, kernel-hardening
On Tue, 2020-03-31 at 11:56 +0200, Christophe Leroy wrote:
>
> Le 31/03/2020 à 06:48, Russell Currey a écrit :
> > From: Christophe Leroy <christophe.leroy@c-s.fr>
> >
> > Use set_memory_attr() instead of the PPC32 specific
> > change_page_attr()
> >
> > change_page_attr() was checking that the address was not mapped by
> > blocks and was handling highmem, but that's unneeded because the
> > affected pages can't be in highmem and block mapping verification
> > is already done by the callers.
> >
> > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> > ---
> > arch/powerpc/mm/pgtable_32.c | 95 ++++---------------------------
> > -----
> > 1 file changed, 10 insertions(+), 85 deletions(-)
> >
> > diff --git a/arch/powerpc/mm/pgtable_32.c
> > b/arch/powerpc/mm/pgtable_32.c
> > index 5fb90edd865e..3d92eaf3ee2f 100644
> > --- a/arch/powerpc/mm/pgtable_32.c
> > +++ b/arch/powerpc/mm/pgtable_32.c
> > @@ -23,6 +23,7 @@
> > #include <linux/highmem.h>
> > #include <linux/memblock.h>
> > #include <linux/slab.h>
> > +#include <linux/set_memory.h>
> >
> > #include <asm/pgtable.h>
> > #include <asm/pgalloc.h>
> > @@ -121,99 +122,20 @@ void __init mapin_ram(void)
> > }
> > }
> >
> > -/* Scan the real Linux page tables and return a PTE pointer for
> > - * a virtual address in a context.
> > - * Returns true (1) if PTE was found, zero otherwise. The pointer
> > to
> > - * the PTE pointer is unmodified if PTE is not found.
> > - */
> > -static int
> > -get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep,
> > pmd_t **pmdp)
>
> This will conflict, get_pteptr() is gone now, see
> https://github.com/linuxppc/linux/commit/2efc7c085f05870eda6f29ac71eeb83f3bd54415
>
> Christophe
OK cool, so I can just drop that hunk? Will try that and make sure it
rebases on powerpc/next
- Russell
>
>
> > -{
> > - pgd_t *pgd;
> > - pud_t *pud;
> > - pmd_t *pmd;
> > - pte_t *pte;
> > - int retval = 0;
> > -
> > - pgd = pgd_offset(mm, addr & PAGE_MASK);
> > - if (pgd) {
> > - pud = pud_offset(pgd, addr & PAGE_MASK);
> > - if (pud && pud_present(*pud)) {
> > - pmd = pmd_offset(pud, addr & PAGE_MASK);
> > - if (pmd_present(*pmd)) {
> > - pte = pte_offset_map(pmd, addr &
> > PAGE_MASK);
> > - if (pte) {
> > - retval = 1;
> > - *ptep = pte;
> > - if (pmdp)
> > - *pmdp = pmd;
> > - /* XXX caller needs to do
> > pte_unmap, yuck */
> > - }
> > - }
> > - }
> > - }
> > - return(retval);
> > -}
> > -
> > -static int __change_page_attr_noflush(struct page *page, pgprot_t
> > prot)
> > -{
> > - pte_t *kpte;
> > - pmd_t *kpmd;
> > - unsigned long address;
> > -
> > - BUG_ON(PageHighMem(page));
> > - address = (unsigned long)page_address(page);
> > -
> > - if (v_block_mapped(address))
> > - return 0;
> > - if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
> > - return -EINVAL;
> > - __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
> > - pte_unmap(kpte);
> > -
> > - return 0;
> > -}
> > -
> > -/*
> > - * Change the page attributes of an page in the linear mapping.
> > - *
> > - * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
> > - */
> > -static int change_page_attr(struct page *page, int numpages,
> > pgprot_t prot)
> > -{
> > - int i, err = 0;
> > - unsigned long flags;
> > - struct page *start = page;
> > -
> > - local_irq_save(flags);
> > - for (i = 0; i < numpages; i++, page++) {
> > - err = __change_page_attr_noflush(page, prot);
> > - if (err)
> > - break;
> > - }
> > - wmb();
> > - local_irq_restore(flags);
> > - flush_tlb_kernel_range((unsigned long)page_address(start),
> > - (unsigned long)page_address(page));
> > - return err;
> > -}
> > -
> > void mark_initmem_nx(void)
> > {
> > - struct page *page = virt_to_page(_sinittext);
> > unsigned long numpages = PFN_UP((unsigned long)_einittext) -
> > PFN_DOWN((unsigned long)_sinittext);
> >
> > if (v_block_mapped((unsigned long)_stext + 1))
> > mmu_mark_initmem_nx();
> > else
> > - change_page_attr(page, numpages, PAGE_KERNEL);
> > + set_memory_attr((unsigned long)_sinittext, numpages,
> > PAGE_KERNEL);
> > }
> >
> > #ifdef CONFIG_STRICT_KERNEL_RWX
> > void mark_rodata_ro(void)
> > {
> > - struct page *page;
> > unsigned long numpages;
> >
> > if (v_block_mapped((unsigned long)_sinittext)) {
> > @@ -222,20 +144,18 @@ void mark_rodata_ro(void)
> > return;
> > }
> >
> > - page = virt_to_page(_stext);
> > numpages = PFN_UP((unsigned long)_etext) -
> > PFN_DOWN((unsigned long)_stext);
> >
> > - change_page_attr(page, numpages, PAGE_KERNEL_ROX);
> > + set_memory_attr((unsigned long)_stext, numpages,
> > PAGE_KERNEL_ROX);
> > /*
> > * mark .rodata as read only. Use __init_begin rather than
> > __end_rodata
> > * to cover NOTES and EXCEPTION_TABLE.
> > */
> > - page = virt_to_page(__start_rodata);
> > numpages = PFN_UP((unsigned long)__init_begin) -
> > PFN_DOWN((unsigned long)__start_rodata);
> >
> > - change_page_attr(page, numpages, PAGE_KERNEL_RO);
> > + set_memory_attr((unsigned long)__start_rodata, numpages,
> > PAGE_KERNEL_RO);
> >
> > // mark_initmem_nx() should have already run by now
> > ptdump_check_wx();
> > @@ -245,9 +165,14 @@ void mark_rodata_ro(void)
> > #ifdef CONFIG_DEBUG_PAGEALLOC
> > void __kernel_map_pages(struct page *page, int numpages, int
> > enable)
> > {
> > + unsigned long addr = (unsigned long)page_address(page);
> > +
> > if (PageHighMem(page))
> > return;
> >
> > - change_page_attr(page, numpages, enable ? PAGE_KERNEL :
> > __pgprot(0));
> > + if (enable)
> > + set_memory_attr(addr, numpages, PAGE_KERNEL);
> > + else
> > + set_memory_attr(addr, numpages, __pgprot(0));
> > }
> > #endif /* CONFIG_DEBUG_PAGEALLOC */
> >
^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [PATCH v7 7/7] powerpc/32: use set_memory_attr()
2020-04-01 2:27 ` Russell Currey
@ 2020-04-01 5:50 ` Christophe Leroy
0 siblings, 0 replies; 11+ messages in thread
From: Christophe Leroy @ 2020-04-01 5:50 UTC (permalink / raw)
To: Russell Currey, linuxppc-dev; +Cc: mpe, ajd, dja, npiggin, kernel-hardening
Le 01/04/2020 à 04:27, Russell Currey a écrit :
> On Tue, 2020-03-31 at 11:56 +0200, Christophe Leroy wrote:
>>
>> Le 31/03/2020 à 06:48, Russell Currey a écrit :
>>> From: Christophe Leroy <christophe.leroy@c-s.fr>
>>>
>>> Use set_memory_attr() instead of the PPC32 specific
>>> change_page_attr()
>>>
>>> change_page_attr() was checking that the address was not mapped by
>>> blocks and was handling highmem, but that's unneeded because the
>>> affected pages can't be in highmem and block mapping verification
>>> is already done by the callers.
>>>
>>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>>> ---
>>> arch/powerpc/mm/pgtable_32.c | 95 ++++---------------------------
>>> -----
>>> 1 file changed, 10 insertions(+), 85 deletions(-)
>>>
>>> diff --git a/arch/powerpc/mm/pgtable_32.c
>>> b/arch/powerpc/mm/pgtable_32.c
>>> index 5fb90edd865e..3d92eaf3ee2f 100644
>>> --- a/arch/powerpc/mm/pgtable_32.c
>>> +++ b/arch/powerpc/mm/pgtable_32.c
>>> @@ -23,6 +23,7 @@
>>> #include <linux/highmem.h>
>>> #include <linux/memblock.h>
>>> #include <linux/slab.h>
>>> +#include <linux/set_memory.h>
>>>
>>> #include <asm/pgtable.h>
>>> #include <asm/pgalloc.h>
>>> @@ -121,99 +122,20 @@ void __init mapin_ram(void)
>>> }
>>> }
>>>
>>> -/* Scan the real Linux page tables and return a PTE pointer for
>>> - * a virtual address in a context.
>>> - * Returns true (1) if PTE was found, zero otherwise. The pointer
>>> to
>>> - * the PTE pointer is unmodified if PTE is not found.
>>> - */
>>> -static int
>>> -get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep,
>>> pmd_t **pmdp)
>>
>> This will conflict, get_pteptr() is gone now, see
>> https://github.com/linuxppc/linux/commit/2efc7c085f05870eda6f29ac71eeb83f3bd54415
>>
>> Christophe
>
> OK cool, so I can just drop that hunk? Will try that and make sure it
> rebases on powerpc/next
Well, you still have to remove __change_page_attr_noflush() and
change_page_attr(), everything else in this patch should still be the same.
Christophe
>
> - Russell
>
>>
>>
>>> -{
>>> - pgd_t *pgd;
>>> - pud_t *pud;
>>> - pmd_t *pmd;
>>> - pte_t *pte;
>>> - int retval = 0;
>>> -
>>> - pgd = pgd_offset(mm, addr & PAGE_MASK);
>>> - if (pgd) {
>>> - pud = pud_offset(pgd, addr & PAGE_MASK);
>>> - if (pud && pud_present(*pud)) {
>>> - pmd = pmd_offset(pud, addr & PAGE_MASK);
>>> - if (pmd_present(*pmd)) {
>>> - pte = pte_offset_map(pmd, addr &
>>> PAGE_MASK);
>>> - if (pte) {
>>> - retval = 1;
>>> - *ptep = pte;
>>> - if (pmdp)
>>> - *pmdp = pmd;
>>> - /* XXX caller needs to do
>>> pte_unmap, yuck */
>>> - }
>>> - }
>>> - }
>>> - }
>>> - return(retval);
>>> -}
>>> -
>>> -static int __change_page_attr_noflush(struct page *page, pgprot_t
>>> prot)
>>> -{
>>> - pte_t *kpte;
>>> - pmd_t *kpmd;
>>> - unsigned long address;
>>> -
>>> - BUG_ON(PageHighMem(page));
>>> - address = (unsigned long)page_address(page);
>>> -
>>> - if (v_block_mapped(address))
>>> - return 0;
>>> - if (!get_pteptr(&init_mm, address, &kpte, &kpmd))
>>> - return -EINVAL;
>>> - __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0);
>>> - pte_unmap(kpte);
>>> -
>>> - return 0;
>>> -}
>>> -
>>> -/*
>>> - * Change the page attributes of an page in the linear mapping.
>>> - *
>>> - * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY
>>> - */
>>> -static int change_page_attr(struct page *page, int numpages,
>>> pgprot_t prot)
>>> -{
>>> - int i, err = 0;
>>> - unsigned long flags;
>>> - struct page *start = page;
>>> -
>>> - local_irq_save(flags);
>>> - for (i = 0; i < numpages; i++, page++) {
>>> - err = __change_page_attr_noflush(page, prot);
>>> - if (err)
>>> - break;
>>> - }
>>> - wmb();
>>> - local_irq_restore(flags);
>>> - flush_tlb_kernel_range((unsigned long)page_address(start),
>>> - (unsigned long)page_address(page));
>>> - return err;
>>> -}
>>> -
>>> void mark_initmem_nx(void)
>>> {
>>> - struct page *page = virt_to_page(_sinittext);
>>> unsigned long numpages = PFN_UP((unsigned long)_einittext) -
>>> PFN_DOWN((unsigned long)_sinittext);
>>>
>>> if (v_block_mapped((unsigned long)_stext + 1))
>>> mmu_mark_initmem_nx();
>>> else
>>> - change_page_attr(page, numpages, PAGE_KERNEL);
>>> + set_memory_attr((unsigned long)_sinittext, numpages,
>>> PAGE_KERNEL);
>>> }
>>>
>>> #ifdef CONFIG_STRICT_KERNEL_RWX
>>> void mark_rodata_ro(void)
>>> {
>>> - struct page *page;
>>> unsigned long numpages;
>>>
>>> if (v_block_mapped((unsigned long)_sinittext)) {
>>> @@ -222,20 +144,18 @@ void mark_rodata_ro(void)
>>> return;
>>> }
>>>
>>> - page = virt_to_page(_stext);
>>> numpages = PFN_UP((unsigned long)_etext) -
>>> PFN_DOWN((unsigned long)_stext);
>>>
>>> - change_page_attr(page, numpages, PAGE_KERNEL_ROX);
>>> + set_memory_attr((unsigned long)_stext, numpages,
>>> PAGE_KERNEL_ROX);
>>> /*
>>> * mark .rodata as read only. Use __init_begin rather than
>>> __end_rodata
>>> * to cover NOTES and EXCEPTION_TABLE.
>>> */
>>> - page = virt_to_page(__start_rodata);
>>> numpages = PFN_UP((unsigned long)__init_begin) -
>>> PFN_DOWN((unsigned long)__start_rodata);
>>>
>>> - change_page_attr(page, numpages, PAGE_KERNEL_RO);
>>> + set_memory_attr((unsigned long)__start_rodata, numpages,
>>> PAGE_KERNEL_RO);
>>>
>>> // mark_initmem_nx() should have already run by now
>>> ptdump_check_wx();
>>> @@ -245,9 +165,14 @@ void mark_rodata_ro(void)
>>> #ifdef CONFIG_DEBUG_PAGEALLOC
>>> void __kernel_map_pages(struct page *page, int numpages, int
>>> enable)
>>> {
>>> + unsigned long addr = (unsigned long)page_address(page);
>>> +
>>> if (PageHighMem(page))
>>> return;
>>>
>>> - change_page_attr(page, numpages, enable ? PAGE_KERNEL :
>>> __pgprot(0));
>>> + if (enable)
>>> + set_memory_attr(addr, numpages, PAGE_KERNEL);
>>> + else
>>> + set_memory_attr(addr, numpages, __pgprot(0));
>>> }
>>> #endif /* CONFIG_DEBUG_PAGEALLOC */
>>>
^ permalink raw reply [flat|nested] 11+ messages in thread