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@xxxxxxxxxx> --- 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@xxxxxxxxxx> + * + * 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@xxxxxxxxxx> + * + * 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 -- To unsubscribe from this list: send the line "unsubscribe live-patching" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
