lkml.org 
[lkml]   [2015]   [May]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH 4/5] livepatch: arm64: add support for livepatch on arm64
Date
This patch add support for livepatch on arm64 based on the gcc -mfentry
feature and the ftrace DYNAMIC_FTRACE_WITH_REGS feature.

Signed-off-by: Li Bin <huawei.libin@huawei.com>
---
arch/arm64/Kconfig | 3 ++
arch/arm64/include/asm/livepatch.h | 45 ++++++++++++++++++++++++++++++++++++
arch/arm64/kernel/Makefile | 1 +
arch/arm64/kernel/livepatch.c | 38 ++++++++++++++++++++++++++++++
kernel/livepatch/core.c | 17 +++++++++----
5 files changed, 99 insertions(+), 5 deletions(-)
create mode 100644 arch/arm64/include/asm/livepatch.h
create mode 100644 arch/arm64/kernel/livepatch.c

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 7bb2468..8a3845c 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -85,6 +85,7 @@ config ARM64
select SPARSE_IRQ
select SYSCTL_EXCEPTION_TRACE
select HAVE_CONTEXT_TRACKING
+ select HAVE_LIVEPATCH
help
ARM 64-bit (AArch64) Linux support.

@@ -159,6 +160,8 @@ source "init/Kconfig"

source "kernel/Kconfig.freezer"

+source "kernel/livepatch/Kconfig"
+
menu "Platform selection"

config ARCH_EXYNOS
diff --git a/arch/arm64/include/asm/livepatch.h b/arch/arm64/include/asm/livepatch.h
new file mode 100644
index 0000000..1890413
--- /dev/null
+++ b/arch/arm64/include/asm/livepatch.h
@@ -0,0 +1,45 @@
+/*
+ * livepatch.h - arm64-specific Kernel Live Patching Core
+ *
+ * Copyright (C) 2014 Li Bin <huawei.libin@huawei.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _ASM_ARM64_LIVEPATCH_H
+#define _ASM_ARM64_LIVEPATCH_H
+
+#include <linux/module.h>
+#include <linux/ftrace.h>
+
+#ifdef CONFIG_LIVEPATCH
+static inline int klp_check_compiler_support(void)
+{
+#ifndef CC_USING_FENTRY
+ return 1;
+#endif
+ return 0;
+}
+extern int klp_write_module_reloc(struct module *mod, unsigned long type,
+ unsigned long loc, unsigned long value);
+
+static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+ regs->pc = pc;
+}
+#else
+#error Live patching support is disabled; check CONFIG_LIVEPATCH
+#endif
+
+#endif /* _ASM_ARM64_LIVEPATCH_H */
diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 426d076..30d307b 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -23,6 +23,7 @@ arm64-obj-$(CONFIG_COMPAT) += sys32.o kuser32.o signal32.o \
sys_compat.o entry32.o \
../../arm/kernel/opcodes.o
arm64-obj-$(CONFIG_FUNCTION_TRACER) += ftrace.o entry-ftrace.o
+arm64-obj-$(CONFIG_LIVEPATCH) += livepatch.o
arm64-obj-$(CONFIG_MODULES) += arm64ksyms.o module.o
arm64-obj-$(CONFIG_SMP) += smp.o smp_spin_table.o topology.o
arm64-obj-$(CONFIG_PERF_EVENTS) += perf_regs.o
diff --git a/arch/arm64/kernel/livepatch.c b/arch/arm64/kernel/livepatch.c
new file mode 100644
index 0000000..2a55532
--- /dev/null
+++ b/arch/arm64/kernel/livepatch.c
@@ -0,0 +1,38 @@
+/*
+ * livepatch.c - arm64-specific Kernel Live Patching Core
+ *
+ * Copyright (C) 2014 Li Bin <huawei.libin@huawei.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <asm/livepatch.h>
+
+/**
+ * klp_write_module_reloc() - write a relocation in a module
+ * @mod: module in which the section to be modified is found
+ * @type: ELF relocation type (see asm/elf.h)
+ * @loc: address that the relocation should be written to
+ * @value: relocation value (sym address + addend)
+ *
+ * This function writes a relocation to the specified location for
+ * a particular module.
+ */
+int klp_write_module_reloc(struct module *mod, unsigned long type,
+ unsigned long loc, unsigned long value)
+{
+ pr_err("lpc_write_module_reloc has not supported now\n");
+ return -ENOSYS;
+}
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 284e269..945065f 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -321,6 +321,7 @@ static void notrace klp_ftrace_handler(unsigned long ip,
{
struct klp_ops *ops;
struct klp_func *func;
+ unsigned long new_ip;

ops = container_of(fops, struct klp_ops, fops);

@@ -330,7 +331,8 @@ static void notrace klp_ftrace_handler(unsigned long ip,
if (WARN_ON_ONCE(!func))
goto unlock;

- klp_arch_set_pc(regs, (unsigned long)func->new_func);
+ new_ip = ftrace_function_stub_ip((unsigned long)func->new_func);
+ klp_arch_set_pc(regs, new_ip);
unlock:
rcu_read_unlock();
}
@@ -338,6 +340,8 @@ unlock:
static void klp_disable_func(struct klp_func *func)
{
struct klp_ops *ops;
+ int ret;
+ unsigned long ip;

WARN_ON(func->state != KLP_ENABLED);
WARN_ON(!func->old_addr);
@@ -347,8 +351,9 @@ static void klp_disable_func(struct klp_func *func)
return;

if (list_is_singular(&ops->func_stack)) {
- WARN_ON(unregister_ftrace_function(&ops->fops));
- WARN_ON(ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0));
+ ip = ftrace_function_stub_ip(func->old_addr);
+ WARN_ON(unregister_ftrace_function(&ops->fops));
+ WARN_ON(ftrace_set_filter_ip(&ops->fops, ip, 1, 0));

list_del_rcu(&func->stack_node);
list_del(&ops->node);
@@ -364,6 +369,7 @@ static int klp_enable_func(struct klp_func *func)
{
struct klp_ops *ops;
int ret;
+ unsigned long ip;

if (WARN_ON(!func->old_addr))
return -EINVAL;
@@ -387,7 +393,8 @@ static int klp_enable_func(struct klp_func *func)
INIT_LIST_HEAD(&ops->func_stack);
list_add_rcu(&func->stack_node, &ops->func_stack);

- ret = ftrace_set_filter_ip(&ops->fops, func->old_addr, 0, 0);
+ ip = ftrace_function_stub_ip(func->old_addr);
+ ret = ftrace_set_filter_ip(&ops->fops, ip, 0, 0);
if (ret) {
pr_err("failed to set ftrace filter for function '%s' (%d)\n",
func->old_name, ret);
@@ -398,7 +405,7 @@ static int klp_enable_func(struct klp_func *func)
if (ret) {
pr_err("failed to register ftrace handler for function '%s' (%d)\n",
func->old_name, ret);
- ftrace_set_filter_ip(&ops->fops, func->old_addr, 1, 0);
+ ftrace_set_filter_ip(&ops->fops, ip, 1, 0);
goto err;
}

--
1.7.1


\
 
 \ /
  Last update: 2015-05-28 08:21    [W:0.099 / U:54.800 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site