From 74ca317c26a3f8543203b61d262c0ab2e30c384e Mon Sep 17 00:00:00 2001 From: Vivek Goyal Date: Fri, 29 Aug 2014 15:18:46 -0700 Subject: [PATCH] kexec: create a new config option CONFIG_KEXEC_FILE for new syscall Currently new system call kexec_file_load() and all the associated code compiles if CONFIG_KEXEC=y. But new syscall also compiles purgatory code which currently uses gcc option -mcmodel=large. This option seems to be available only gcc 4.4 onwards. Hiding new functionality behind a new config option will not break existing users of old gcc. Those who wish to enable new functionality will require new gcc. Having said that, I am trying to figure out how can I move away from using -mcmodel=large but that can take a while. I think there are other advantages of introducing this new config option. As this option will be enabled only on x86_64, other arches don't have to compile generic kexec code which will never be used. This new code selects CRYPTO=y and CRYPTO_SHA256=y. And all other arches had to do this for CONFIG_KEXEC. Now with introduction of new config option, we can remove crypto dependency from other arches. Now CONFIG_KEXEC_FILE is available only on x86_64. So whereever I had CONFIG_X86_64 defined, I got rid of that. For CONFIG_KEXEC_FILE, instead of doing select CRYPTO=y, I changed it to "depends on CRYPTO=y". This should be safer as "select" is not recursive. Signed-off-by: Vivek Goyal Cc: Eric Biederman Cc: H. Peter Anvin Tested-by: Shaun Ruffell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/Kbuild | 4 +--- arch/x86/Kconfig | 18 ++++++++++++++---- arch/x86/Makefile | 5 +---- arch/x86/kernel/Makefile | 2 +- arch/x86/kernel/crash.c | 6 ++---- arch/x86/kernel/machine_kexec_64.c | 11 +++++++++++ arch/x86/purgatory/Makefile | 5 +---- kernel/kexec.c | 11 +++++++++++ 8 files changed, 42 insertions(+), 20 deletions(-) diff --git a/arch/x86/Kbuild b/arch/x86/Kbuild index 61b6d51866f8..3942f74c92d7 100644 --- a/arch/x86/Kbuild +++ b/arch/x86/Kbuild @@ -17,6 +17,4 @@ obj-$(CONFIG_IA32_EMULATION) += ia32/ obj-y += platform/ obj-y += net/ -ifeq ($(CONFIG_X86_64),y) -obj-$(CONFIG_KEXEC) += purgatory/ -endif +obj-$(CONFIG_KEXEC_FILE) += purgatory/ diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 5d0bf1aa9dcb..778178f4c7d1 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1585,9 +1585,6 @@ source kernel/Kconfig.hz config KEXEC bool "kexec system call" - select BUILD_BIN2C - select CRYPTO - select CRYPTO_SHA256 ---help--- kexec is a system call that implements the ability to shutdown your current kernel, and to start another kernel. It is like a reboot @@ -1602,9 +1599,22 @@ config KEXEC interface is strongly in flux, so no good recommendation can be made. +config KEXEC_FILE + bool "kexec file based system call" + select BUILD_BIN2C + depends on KEXEC + depends on X86_64 + depends on CRYPTO=y + depends on CRYPTO_SHA256=y + ---help--- + This is new version of kexec system call. This system call is + file based and takes file descriptors as system call argument + for kernel and initramfs as opposed to list of segments as + accepted by previous system call. + config KEXEC_VERIFY_SIG bool "Verify kernel signature during kexec_file_load() syscall" - depends on KEXEC + depends on KEXEC_FILE ---help--- This option makes kernel signature verification mandatory for kexec_file_load() syscall. If kernel is signature can not be diff --git a/arch/x86/Makefile b/arch/x86/Makefile index c1aa36887843..c96bcec544fc 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -184,11 +184,8 @@ archheaders: $(Q)$(MAKE) $(build)=arch/x86/syscalls all archprepare: -ifeq ($(CONFIG_KEXEC),y) -# Build only for 64bit. No loaders for 32bit yet. - ifeq ($(CONFIG_X86_64),y) +ifeq ($(CONFIG_KEXEC_FILE),y) $(Q)$(MAKE) $(build)=arch/x86/purgatory arch/x86/purgatory/kexec-purgatory.c - endif endif ### diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index b5ea75c4a4b4..ada2e2d6be3e 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -71,6 +71,7 @@ obj-$(CONFIG_FTRACE_SYSCALLS) += ftrace.o obj-$(CONFIG_X86_TSC) += trace_clock.o obj-$(CONFIG_KEXEC) += machine_kexec_$(BITS).o obj-$(CONFIG_KEXEC) += relocate_kernel_$(BITS).o crash.o +obj-$(CONFIG_KEXEC_FILE) += kexec-bzimage64.o obj-$(CONFIG_CRASH_DUMP) += crash_dump_$(BITS).o obj-y += kprobes/ obj-$(CONFIG_MODULES) += module.o @@ -118,5 +119,4 @@ ifeq ($(CONFIG_X86_64),y) obj-$(CONFIG_PCI_MMCONFIG) += mmconf-fam10h_64.o obj-y += vsmp_64.o - obj-$(CONFIG_KEXEC) += kexec-bzimage64.o endif diff --git a/arch/x86/kernel/crash.c b/arch/x86/kernel/crash.c index 0553a34fa0df..a618fcd2c07d 100644 --- a/arch/x86/kernel/crash.c +++ b/arch/x86/kernel/crash.c @@ -182,8 +182,7 @@ void native_machine_crash_shutdown(struct pt_regs *regs) crash_save_cpu(regs, safe_smp_processor_id()); } -#ifdef CONFIG_X86_64 - +#ifdef CONFIG_KEXEC_FILE static int get_nr_ram_ranges_callback(unsigned long start_pfn, unsigned long nr_pfn, void *arg) { @@ -696,5 +695,4 @@ int crash_load_segments(struct kimage *image) return ret; } - -#endif /* CONFIG_X86_64 */ +#endif /* CONFIG_KEXEC_FILE */ diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c index 8b04018e5d1f..485981059a40 100644 --- a/arch/x86/kernel/machine_kexec_64.c +++ b/arch/x86/kernel/machine_kexec_64.c @@ -25,9 +25,11 @@ #include #include +#ifdef CONFIG_KEXEC_FILE static struct kexec_file_ops *kexec_file_loaders[] = { &kexec_bzImage64_ops, }; +#endif static void free_transition_pgtable(struct kimage *image) { @@ -178,6 +180,7 @@ static void load_segments(void) ); } +#ifdef CONFIG_KEXEC_FILE /* Update purgatory as needed after various image segments have been prepared */ static int arch_update_purgatory(struct kimage *image) { @@ -209,6 +212,12 @@ static int arch_update_purgatory(struct kimage *image) return ret; } +#else /* !CONFIG_KEXEC_FILE */ +static inline int arch_update_purgatory(struct kimage *image) +{ + return 0; +} +#endif /* CONFIG_KEXEC_FILE */ int machine_kexec_prepare(struct kimage *image) { @@ -329,6 +338,7 @@ void arch_crash_save_vmcoreinfo(void) /* arch-dependent functionality related to kexec file-based syscall */ +#ifdef CONFIG_KEXEC_FILE int arch_kexec_kernel_image_probe(struct kimage *image, void *buf, unsigned long buf_len) { @@ -522,3 +532,4 @@ overflow: (int)ELF64_R_TYPE(rel[i].r_info), value); return -ENOEXEC; } +#endif /* CONFIG_KEXEC_FILE */ diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile index 7fde9ee438a4..c4ae06e4ae74 100644 --- a/arch/x86/purgatory/Makefile +++ b/arch/x86/purgatory/Makefile @@ -24,7 +24,4 @@ $(obj)/kexec-purgatory.c: $(obj)/purgatory.ro FORCE $(call if_changed,bin2c) -# No loaders for 32bits yet. -ifeq ($(CONFIG_X86_64),y) - obj-$(CONFIG_KEXEC) += kexec-purgatory.o -endif +obj-$(CONFIG_KEXEC_FILE) += kexec-purgatory.o diff --git a/kernel/kexec.c b/kernel/kexec.c index 0b49a0a58102..2bee072268d9 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -64,7 +64,9 @@ bool kexec_in_progress = false; char __weak kexec_purgatory[0]; size_t __weak kexec_purgatory_size = 0; +#ifdef CONFIG_KEXEC_FILE static int kexec_calculate_store_digests(struct kimage *image); +#endif /* Location of the reserved area for the crash kernel */ struct resource crashk_res = { @@ -341,6 +343,7 @@ out_free_image: return ret; } +#ifdef CONFIG_KEXEC_FILE static int copy_file_from_fd(int fd, void **buf, unsigned long *buf_len) { struct fd f = fdget(fd); @@ -612,6 +615,9 @@ out_free_image: kfree(image); return ret; } +#else /* CONFIG_KEXEC_FILE */ +static inline void kimage_file_post_load_cleanup(struct kimage *image) { } +#endif /* CONFIG_KEXEC_FILE */ static int kimage_is_destination_range(struct kimage *image, unsigned long start, @@ -1375,6 +1381,7 @@ COMPAT_SYSCALL_DEFINE4(kexec_load, compat_ulong_t, entry, } #endif +#ifdef CONFIG_KEXEC_FILE SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, unsigned long, cmdline_len, const char __user *, cmdline_ptr, unsigned long, flags) @@ -1451,6 +1458,8 @@ out: return ret; } +#endif /* CONFIG_KEXEC_FILE */ + void crash_kexec(struct pt_regs *regs) { /* Take the kexec_mutex here to prevent sys_kexec_load @@ -2006,6 +2015,7 @@ static int __init crash_save_vmcoreinfo_init(void) subsys_initcall(crash_save_vmcoreinfo_init); +#ifdef CONFIG_KEXEC_FILE static int __kexec_add_segment(struct kimage *image, char *buf, unsigned long bufsz, unsigned long mem, unsigned long memsz) @@ -2682,6 +2692,7 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name, return 0; } +#endif /* CONFIG_KEXEC_FILE */ /* * Move into place and start executing a preloaded standalone -- 2.34.1