| Message ID | 20240403150154.667649-4-mark.rutland@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | kprobes: permit use without modules | expand |
On Wed Apr 3, 2024 at 6:01 PM EEST, Mark Rutland wrote: > Currently architectures can override kprobes_alloc_insn_page(), but > kprobes_free_insn_page() is always implemented using module_memfree(), > which might not be what an architecture needs, especially as we'd like > to make it possible to use kprobes without requiring MODULES. > > It would be nicer if architectures either: > > (a) Used only the generic kprobes_alloc_insn_page() and > kprobes_free_insn_page(), implicitly depending on MODULES. > > (b) Provided their own implementation of both kprobes_alloc_insn_page() > and kprobes_free_insn_page(), handling the relevant dependencies > themselves. > > This patch applies that split treewide: > > (a) Architectures using the generic kprobes_free_insn_page() and > kprobes_free_insn_page() are left as-is. The __weak annotation is > removed from the generic implementations so that accidental > overrides/misuse can be detected easily. > > (b) Architectures which provide their own kprobes_free_insn_page() are > given a matching implementation of kprobes_free_insn_page(), and > select HAVE_KPROBES_ALLOC. > > This new Kconfig symbol will allow subsequent patches to relax the > dependency on MODULES to (MODULES || HAVE_KPROBES_ALLOC) once other > module dependencies in the core kprobes code are cleaned up. > > Architectures which use module_alloc() are given an implementation > using module_memfree() along with an explicit dependency on MODULES. > > Architectures using __vmalloc_node_range() are given an > implementation using vfree(). This loses the warning for > in_interrupt(), but vfree() can handle this via vfree_atomic(), so > the warning isn't necessary. > > On riscv, the allocator depends on !XIP_KERNEL, which is already a > dependency for HAVE_KPROBES in arch/riscv/Kconfig. > > As of this patch arm64 and riscv have kprobe allocation functions which > do not explicitly depend on MODULES. The core kprobes code still depends > on MODULES. > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Cc: Albert Ou <aou@eecs.berkeley.edu> > Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: David S. Miller <davem@davemloft.net> > Cc: Jarkko Sakkinen <jarkko@kernel.org> > Cc: Masami Hiramatsu <mhiramat@kernel.org> > Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> > Cc: Palmer Dabbelt <palmer@dabbelt.com> > Cc: Paul Walmsley <paul.walmsley@sifive.com> > Cc: Will Deacon <will@kernel.org> > --- > arch/Kconfig | 3 +++ > arch/arm64/Kconfig | 1 + > arch/arm64/kernel/probes/kprobes.c | 5 +++++ > arch/powerpc/Kconfig | 3 ++- > arch/powerpc/kernel/kprobes.c | 5 +++++ > arch/riscv/Kconfig | 1 + > arch/riscv/kernel/probes/kprobes.c | 5 +++++ > arch/s390/Kconfig | 3 ++- > arch/s390/kernel/kprobes.c | 5 +++++ > arch/x86/Kconfig | 3 ++- > arch/x86/kernel/kprobes/core.c | 5 +++++ > include/linux/kprobes.h | 1 + > kernel/kprobes.c | 6 ++++-- > 13 files changed, 41 insertions(+), 5 deletions(-) > > diff --git a/arch/Kconfig b/arch/Kconfig > index 9f066785bb71d..85bb59f7b8c07 100644 > --- a/arch/Kconfig > +++ b/arch/Kconfig > @@ -206,6 +206,9 @@ config HAVE_IOREMAP_PROT > config HAVE_KPROBES > bool > > +config HAVE_KPROBES_ALLOC > + bool > + > config HAVE_KRETPROBES > bool > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 7b11c98b3e84b..bda7913d6c9b8 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -233,6 +233,7 @@ config ARM64 > select HAVE_STACKPROTECTOR > select HAVE_SYSCALL_TRACEPOINTS > select HAVE_KPROBES > + select HAVE_KPROBES_ALLOC > select HAVE_KRETPROBES > select HAVE_GENERIC_VDSO > select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU > diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c > index 4b6ab7b1fa211..69d19a390cd48 100644 > --- a/arch/arm64/kernel/probes/kprobes.c > +++ b/arch/arm64/kernel/probes/kprobes.c > @@ -136,6 +136,11 @@ void *kprobes_alloc_insn_page(void) > NUMA_NO_NODE, __builtin_return_address(0)); > } > > +void kprobes_free_insn_page(void *page) > +{ > + vfree(page); > +} > + > /* arm kprobe: install breakpoint in text */ > void __kprobes arch_arm_kprobe(struct kprobe *p) > { > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > index 1c4be33736860..13e0fc51dcdcf 100644 > --- a/arch/powerpc/Kconfig > +++ b/arch/powerpc/Kconfig > @@ -254,7 +254,8 @@ config PPC > select HAVE_KERNEL_LZMA if DEFAULT_UIMAGE > select HAVE_KERNEL_LZO if DEFAULT_UIMAGE > select HAVE_KERNEL_XZ if PPC_BOOK3S || 44x > - select HAVE_KPROBES > + select HAVE_KPROBES if MODULES > + select HAVE_KPROBES_ALLOC > select HAVE_KPROBES_ON_FTRACE > select HAVE_KRETPROBES > select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if HAVE_OBJTOOL_MCOUNT && (!ARCH_USING_PATCHABLE_FUNCTION_ENTRY || (!CC_IS_GCC || GCC_VERSION >= 110100)) > diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c > index 0b297718d5de6..d0332aaebab09 100644 > --- a/arch/powerpc/kernel/kprobes.c > +++ b/arch/powerpc/kernel/kprobes.c > @@ -146,6 +146,11 @@ void *kprobes_alloc_insn_page(void) > return NULL; > } > > +void kprobes_free_insn_page(void *page) > +{ > + module_memfree(page); > +} > + > int arch_prepare_kprobe(struct kprobe *p) > { > int ret = 0; > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index be09c8836d56b..4e22549a522a5 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -139,6 +139,7 @@ config RISCV > select HAVE_GENERIC_VDSO if MMU && 64BIT > select HAVE_IRQ_TIME_ACCOUNTING > select HAVE_KPROBES if !XIP_KERNEL > + select HAVE_KPROBES_ALLOC > select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL > select HAVE_KRETPROBES if !XIP_KERNEL > # https://github.com/ClangBuiltLinux/linux/issues/1881 > diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c > index 75201ce721057..37fdfa952d999 100644 > --- a/arch/riscv/kernel/probes/kprobes.c > +++ b/arch/riscv/kernel/probes/kprobes.c > @@ -112,6 +112,11 @@ void *kprobes_alloc_insn_page(void) > VM_FLUSH_RESET_PERMS, NUMA_NO_NODE, > __builtin_return_address(0)); > } > + > +void kprobes_free_insn_page(void *page) > +{ > + vfree(page); > +} > #endif > > /* install breakpoint in text */ > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig > index 8f01ada6845e3..635eddc3fce80 100644 > --- a/arch/s390/Kconfig > +++ b/arch/s390/Kconfig > @@ -193,7 +193,8 @@ config S390 > select HAVE_KERNEL_UNCOMPRESSED > select HAVE_KERNEL_XZ > select HAVE_KERNEL_ZSTD > - select HAVE_KPROBES > + select HAVE_KPROBES if MODULES > + select HAVE_KPROBES_ALLOC > select HAVE_KPROBES_ON_FTRACE > select HAVE_KRETPROBES > select HAVE_LIVEPATCH > diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c > index 91ca4d501d4ef..a5b142b8eb0f7 100644 > --- a/arch/s390/kernel/kprobes.c > +++ b/arch/s390/kernel/kprobes.c > @@ -45,6 +45,11 @@ void *kprobes_alloc_insn_page(void) > return page; > } > > +void kprobes_free_insn_page(void *page) > +{ > + module_memfree(page); > +} > + > static void *alloc_s390_insn_page(void) > { > if (xchg(&insn_page_in_use, 1) == 1) > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 4fff6ed46e902..0810cd0bdeca9 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -240,7 +240,8 @@ config X86 > select HAVE_KERNEL_LZO > select HAVE_KERNEL_XZ > select HAVE_KERNEL_ZSTD > - select HAVE_KPROBES > + select HAVE_KPROBES if MODULES > + select HAVE_KPROBES_ALLOC > select HAVE_KPROBES_ON_FTRACE > select HAVE_FUNCTION_ERROR_INJECTION > select HAVE_KRETPROBES > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > index 7f01bbbfa9e2a..5f093b94d9b40 100644 > --- a/arch/x86/kernel/kprobes/core.c > +++ b/arch/x86/kernel/kprobes/core.c > @@ -508,6 +508,11 @@ void *kprobes_alloc_insn_page(void) > return page; > } > > +void kprobes_free_insn_page(void *page) > +{ > + module_memfree(page); > +} > + > /* Kprobe x86 instruction emulation - only regs->ip or IF flag modifiers */ > > static void kprobe_emulate_ifmodifiers(struct kprobe *p, struct pt_regs *regs) > diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h > index ad4b561100f9e..651c807727bea 100644 > --- a/include/linux/kprobes.h > +++ b/include/linux/kprobes.h > @@ -431,6 +431,7 @@ int enable_kprobe(struct kprobe *kp); > void dump_kprobe(struct kprobe *kp); > > void *kprobes_alloc_insn_page(void); > +void kprobes_free_insn_page(void *page); > > void *kprobes_alloc_optinsn_page(void); > void kprobes_free_optinsn_page(void *page); > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 35adf56430c9b..fa2ee4e59eca2 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -110,7 +110,8 @@ enum kprobe_slot_state { > SLOT_USED = 2, > }; > > -void __weak *kprobes_alloc_insn_page(void) > +#ifndef CONFIG_HAVE_KPROBES_ALLOC > +void *kprobes_alloc_insn_page(void) > { > /* > * Use module_alloc() so this page is within +/- 2GB of where the > @@ -121,10 +122,11 @@ void __weak *kprobes_alloc_insn_page(void) > return module_alloc(PAGE_SIZE); > } > > -static void kprobes_free_insn_page(void *page) > +void kprobes_free_insn_page(void *page) > { > module_memfree(page); > } > +#endif > > struct kprobe_insn_cache kprobe_insn_slots = { > .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex), Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org> BR, Jarkko
diff --git a/arch/Kconfig b/arch/Kconfig index 9f066785bb71d..85bb59f7b8c07 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -206,6 +206,9 @@ config HAVE_IOREMAP_PROT config HAVE_KPROBES bool +config HAVE_KPROBES_ALLOC + bool + config HAVE_KRETPROBES bool diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7b11c98b3e84b..bda7913d6c9b8 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -233,6 +233,7 @@ config ARM64 select HAVE_STACKPROTECTOR select HAVE_SYSCALL_TRACEPOINTS select HAVE_KPROBES + select HAVE_KPROBES_ALLOC select HAVE_KRETPROBES select HAVE_GENERIC_VDSO select HOTPLUG_CORE_SYNC_DEAD if HOTPLUG_CPU diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c index 4b6ab7b1fa211..69d19a390cd48 100644 --- a/arch/arm64/kernel/probes/kprobes.c +++ b/arch/arm64/kernel/probes/kprobes.c @@ -136,6 +136,11 @@ void *kprobes_alloc_insn_page(void) NUMA_NO_NODE, __builtin_return_address(0)); } +void kprobes_free_insn_page(void *page) +{ + vfree(page); +} + /* arm kprobe: install breakpoint in text */ void __kprobes arch_arm_kprobe(struct kprobe *p) { diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 1c4be33736860..13e0fc51dcdcf 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -254,7 +254,8 @@ config PPC select HAVE_KERNEL_LZMA if DEFAULT_UIMAGE select HAVE_KERNEL_LZO if DEFAULT_UIMAGE select HAVE_KERNEL_XZ if PPC_BOOK3S || 44x - select HAVE_KPROBES + select HAVE_KPROBES if MODULES + select HAVE_KPROBES_ALLOC select HAVE_KPROBES_ON_FTRACE select HAVE_KRETPROBES select HAVE_LD_DEAD_CODE_DATA_ELIMINATION if HAVE_OBJTOOL_MCOUNT && (!ARCH_USING_PATCHABLE_FUNCTION_ENTRY || (!CC_IS_GCC || GCC_VERSION >= 110100)) diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index 0b297718d5de6..d0332aaebab09 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -146,6 +146,11 @@ void *kprobes_alloc_insn_page(void) return NULL; } +void kprobes_free_insn_page(void *page) +{ + module_memfree(page); +} + int arch_prepare_kprobe(struct kprobe *p) { int ret = 0; diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index be09c8836d56b..4e22549a522a5 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -139,6 +139,7 @@ config RISCV select HAVE_GENERIC_VDSO if MMU && 64BIT select HAVE_IRQ_TIME_ACCOUNTING select HAVE_KPROBES if !XIP_KERNEL + select HAVE_KPROBES_ALLOC select HAVE_KPROBES_ON_FTRACE if !XIP_KERNEL select HAVE_KRETPROBES if !XIP_KERNEL # https://github.com/ClangBuiltLinux/linux/issues/1881 diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c index 75201ce721057..37fdfa952d999 100644 --- a/arch/riscv/kernel/probes/kprobes.c +++ b/arch/riscv/kernel/probes/kprobes.c @@ -112,6 +112,11 @@ void *kprobes_alloc_insn_page(void) VM_FLUSH_RESET_PERMS, NUMA_NO_NODE, __builtin_return_address(0)); } + +void kprobes_free_insn_page(void *page) +{ + vfree(page); +} #endif /* install breakpoint in text */ diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 8f01ada6845e3..635eddc3fce80 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -193,7 +193,8 @@ config S390 select HAVE_KERNEL_UNCOMPRESSED select HAVE_KERNEL_XZ select HAVE_KERNEL_ZSTD - select HAVE_KPROBES + select HAVE_KPROBES if MODULES + select HAVE_KPROBES_ALLOC select HAVE_KPROBES_ON_FTRACE select HAVE_KRETPROBES select HAVE_LIVEPATCH diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index 91ca4d501d4ef..a5b142b8eb0f7 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -45,6 +45,11 @@ void *kprobes_alloc_insn_page(void) return page; } +void kprobes_free_insn_page(void *page) +{ + module_memfree(page); +} + static void *alloc_s390_insn_page(void) { if (xchg(&insn_page_in_use, 1) == 1) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 4fff6ed46e902..0810cd0bdeca9 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -240,7 +240,8 @@ config X86 select HAVE_KERNEL_LZO select HAVE_KERNEL_XZ select HAVE_KERNEL_ZSTD - select HAVE_KPROBES + select HAVE_KPROBES if MODULES + select HAVE_KPROBES_ALLOC select HAVE_KPROBES_ON_FTRACE select HAVE_FUNCTION_ERROR_INJECTION select HAVE_KRETPROBES diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 7f01bbbfa9e2a..5f093b94d9b40 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -508,6 +508,11 @@ void *kprobes_alloc_insn_page(void) return page; } +void kprobes_free_insn_page(void *page) +{ + module_memfree(page); +} + /* Kprobe x86 instruction emulation - only regs->ip or IF flag modifiers */ static void kprobe_emulate_ifmodifiers(struct kprobe *p, struct pt_regs *regs) diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index ad4b561100f9e..651c807727bea 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -431,6 +431,7 @@ int enable_kprobe(struct kprobe *kp); void dump_kprobe(struct kprobe *kp); void *kprobes_alloc_insn_page(void); +void kprobes_free_insn_page(void *page); void *kprobes_alloc_optinsn_page(void); void kprobes_free_optinsn_page(void *page); diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 35adf56430c9b..fa2ee4e59eca2 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -110,7 +110,8 @@ enum kprobe_slot_state { SLOT_USED = 2, }; -void __weak *kprobes_alloc_insn_page(void) +#ifndef CONFIG_HAVE_KPROBES_ALLOC +void *kprobes_alloc_insn_page(void) { /* * Use module_alloc() so this page is within +/- 2GB of where the @@ -121,10 +122,11 @@ void __weak *kprobes_alloc_insn_page(void) return module_alloc(PAGE_SIZE); } -static void kprobes_free_insn_page(void *page) +void kprobes_free_insn_page(void *page) { module_memfree(page); } +#endif struct kprobe_insn_cache kprobe_insn_slots = { .mutex = __MUTEX_INITIALIZER(kprobe_insn_slots.mutex),
Currently architectures can override kprobes_alloc_insn_page(), but kprobes_free_insn_page() is always implemented using module_memfree(), which might not be what an architecture needs, especially as we'd like to make it possible to use kprobes without requiring MODULES. It would be nicer if architectures either: (a) Used only the generic kprobes_alloc_insn_page() and kprobes_free_insn_page(), implicitly depending on MODULES. (b) Provided their own implementation of both kprobes_alloc_insn_page() and kprobes_free_insn_page(), handling the relevant dependencies themselves. This patch applies that split treewide: (a) Architectures using the generic kprobes_free_insn_page() and kprobes_free_insn_page() are left as-is. The __weak annotation is removed from the generic implementations so that accidental overrides/misuse can be detected easily. (b) Architectures which provide their own kprobes_free_insn_page() are given a matching implementation of kprobes_free_insn_page(), and select HAVE_KPROBES_ALLOC. This new Kconfig symbol will allow subsequent patches to relax the dependency on MODULES to (MODULES || HAVE_KPROBES_ALLOC) once other module dependencies in the core kprobes code are cleaned up. Architectures which use module_alloc() are given an implementation using module_memfree() along with an explicit dependency on MODULES. Architectures using __vmalloc_node_range() are given an implementation using vfree(). This loses the warning for in_interrupt(), but vfree() can handle this via vfree_atomic(), so the warning isn't necessary. On riscv, the allocator depends on !XIP_KERNEL, which is already a dependency for HAVE_KPROBES in arch/riscv/Kconfig. As of this patch arm64 and riscv have kprobe allocation functions which do not explicitly depend on MODULES. The core kprobes code still depends on MODULES. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: David S. Miller <davem@davemloft.net> Cc: Jarkko Sakkinen <jarkko@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Cc: Palmer Dabbelt <palmer@dabbelt.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Will Deacon <will@kernel.org> --- arch/Kconfig | 3 +++ arch/arm64/Kconfig | 1 + arch/arm64/kernel/probes/kprobes.c | 5 +++++ arch/powerpc/Kconfig | 3 ++- arch/powerpc/kernel/kprobes.c | 5 +++++ arch/riscv/Kconfig | 1 + arch/riscv/kernel/probes/kprobes.c | 5 +++++ arch/s390/Kconfig | 3 ++- arch/s390/kernel/kprobes.c | 5 +++++ arch/x86/Kconfig | 3 ++- arch/x86/kernel/kprobes/core.c | 5 +++++ include/linux/kprobes.h | 1 + kernel/kprobes.c | 6 ++++-- 13 files changed, 41 insertions(+), 5 deletions(-)