| Message ID | 173519011487.391279.5450806886342723151.stgit@devnote2 (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | tracing: fprobe: function_graph: Multi-function graph and fprobe on fgraph | expand |
Hello, I got errors building Linux 6.14-rc1 that were solved by reverting this patch and the one after (19/20 and 20/20). Errors look like: In file included from ./arch/x86/include/asm/asm-prototypes.h:2, from <stdin>:3: ./arch/x86/include/asm/ftrace.h: In function 'arch_ftrace_get_symaddr': ./arch/x86/include/asm/ftrace.h:46:21: error: implicit declaration of function 'get_kernel_nofault' [-Wimplicit-function-declaration] 46 | if (get_kernel_nofault(instr, (u32 *)(fentry_ip - ENDBR_INSN_SIZE))) | ^~~~~~~~~~~~~~~~~~ Will send .config on request if needed. Le 26/12/2024 à 06:15, Masami Hiramatsu (Google) a écrit : > From: Masami Hiramatsu (Google) <mhiramat@kernel.org> > > This introduces ftrace_get_symaddr() which tries to convert fentry_ip > passed by ftrace or fgraph callback to symaddr without calling > kallsyms API. It returns the symbol address or 0 if it fails to > convert it. > > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> > Reported-by: kernel test robot <lkp@intel.com> > Closes: https://lore.kernel.org/oe-kbuild-all/202412061423.K79V55Hd-lkp@intel.com/ > Closes: https://lore.kernel.org/oe-kbuild-all/202412061804.5VRzF14E-lkp@intel.com/ > --- > Changes in v21: > - On arm64, fix the macro name to ftrace_get_symaddr() correctly. > - Define ftrace_get_symaddr() outside of CONFIG_DYNAMIC_FTRACE. > Changes in v19: > - Newly added. > --- > arch/arm64/include/asm/ftrace.h | 2 + > arch/arm64/kernel/ftrace.c | 63 +++++++++++++++++++++++++++++++++++++++ > arch/x86/include/asm/ftrace.h | 21 +++++++++++++ > include/linux/ftrace.h | 13 ++++++++ > 4 files changed, 99 insertions(+) > > diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h > index 876e88ad4119..bfe3ce9df197 100644 > --- a/arch/arm64/include/asm/ftrace.h > +++ b/arch/arm64/include/asm/ftrace.h > @@ -52,6 +52,8 @@ extern unsigned long ftrace_graph_call; > extern void return_to_handler(void); > > unsigned long ftrace_call_adjust(unsigned long addr); > +unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip); > +#define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) > > #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS > #define HAVE_ARCH_FTRACE_REGS > diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c > index 570c38be833c..d7c0d023dfe5 100644 > --- a/arch/arm64/kernel/ftrace.c > +++ b/arch/arm64/kernel/ftrace.c > @@ -143,6 +143,69 @@ unsigned long ftrace_call_adjust(unsigned long addr) > return addr; > } > > +/* Convert fentry_ip to the symbol address without kallsyms */ > +unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) > +{ > + u32 insn; > + > + /* > + * When using patchable-function-entry without pre-function NOPS, ftrace > + * entry is the address of the first NOP after the function entry point. > + * > + * The compiler has either generated: > + * > + * func+00: func: NOP // To be patched to MOV X9, LR > + * func+04: NOP // To be patched to BL <caller> > + * > + * Or: > + * > + * func-04: BTI C > + * func+00: func: NOP // To be patched to MOV X9, LR > + * func+04: NOP // To be patched to BL <caller> > + * > + * The fentry_ip is the address of `BL <caller>` which is at `func + 4` > + * bytes in either case. > + */ > + if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS)) > + return fentry_ip - AARCH64_INSN_SIZE; > + > + /* > + * When using patchable-function-entry with pre-function NOPs, BTI is > + * a bit different. > + * > + * func+00: func: NOP // To be patched to MOV X9, LR > + * func+04: NOP // To be patched to BL <caller> > + * > + * Or: > + * > + * func+00: func: BTI C > + * func+04: NOP // To be patched to MOV X9, LR > + * func+08: NOP // To be patched to BL <caller> > + * > + * The fentry_ip is the address of `BL <caller>` which is at either > + * `func + 4` or `func + 8` depends on whether there is a BTI. > + */ > + > + /* If there is no BTI, the func address should be one instruction before. */ > + if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) > + return fentry_ip - AARCH64_INSN_SIZE; > + > + /* We want to be extra safe in case entry ip is on the page edge, > + * but otherwise we need to avoid get_kernel_nofault()'s overhead. > + */ > + if ((fentry_ip & ~PAGE_MASK) < AARCH64_INSN_SIZE * 2) { > + if (get_kernel_nofault(insn, (u32 *)(fentry_ip - AARCH64_INSN_SIZE * 2))) > + return 0; > + } else { > + insn = *(u32 *)(fentry_ip - AARCH64_INSN_SIZE * 2); > + } > + > + if (aarch64_insn_is_bti(le32_to_cpu((__le32)insn))) > + return fentry_ip - AARCH64_INSN_SIZE * 2; > + > + return fentry_ip - AARCH64_INSN_SIZE; > +} > + > /* > * Replace a single instruction, which may be a branch or NOP. > * If @validate == true, a replaced instruction is checked against 'old'. > diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h > index cc92c99ef276..f9cb4d07df58 100644 > --- a/arch/x86/include/asm/ftrace.h > +++ b/arch/x86/include/asm/ftrace.h > @@ -34,6 +34,27 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) > return addr; > } > > +static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) > +{ > +#ifdef CONFIG_X86_KERNEL_IBT > + u32 instr; > + > + /* We want to be extra safe in case entry ip is on the page edge, > + * but otherwise we need to avoid get_kernel_nofault()'s overhead. > + */ > + if ((fentry_ip & ~PAGE_MASK) < ENDBR_INSN_SIZE) { > + if (get_kernel_nofault(instr, (u32 *)(fentry_ip - ENDBR_INSN_SIZE))) > + return fentry_ip; > + } else { > + instr = *(u32 *)(fentry_ip - ENDBR_INSN_SIZE); > + } > + if (is_endbr(instr)) > + fentry_ip -= ENDBR_INSN_SIZE; > +#endif > + return fentry_ip; > +} > +#define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) > + > #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS > > #include <linux/ftrace_regs.h> > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h > index 4c553fe9c026..07092dfb21a4 100644 > --- a/include/linux/ftrace.h > +++ b/include/linux/ftrace.h > @@ -622,6 +622,19 @@ enum { > FTRACE_MAY_SLEEP = (1 << 5), > }; > > +/* Arches can override ftrace_get_symaddr() to convert fentry_ip to symaddr. */ > +#ifndef ftrace_get_symaddr > +/** > + * ftrace_get_symaddr - return the symbol address from fentry_ip > + * @fentry_ip: the address of ftrace location > + * > + * Get the symbol address from @fentry_ip (fast path). If there is no fast > + * search path, this returns 0. > + * User may need to use kallsyms API to find the symbol address. > + */ > +#define ftrace_get_symaddr(fentry_ip) (0) > +#endif > + > #ifdef CONFIG_DYNAMIC_FTRACE > > void ftrace_arch_code_modify_prepare(void); > >
On Mon, 3 Feb 2025 22:33:48 +0100 Gabriel de Perthuis <g2p.code@gmail.com> wrote: > Hello, > > I got errors building Linux 6.14-rc1 that were solved by reverting this > patch and the one after (19/20 and 20/20). > > Errors look like: > > In file included from ./arch/x86/include/asm/asm-prototypes.h:2, > from <stdin>:3: > ./arch/x86/include/asm/ftrace.h: In function 'arch_ftrace_get_symaddr': > ./arch/x86/include/asm/ftrace.h:46:21: error: implicit declaration of > function 'get_kernel_nofault' [-Wimplicit-function-declaration] > 46 | if (get_kernel_nofault(instr, (u32 *)(fentry_ip > - ENDBR_INSN_SIZE))) > | ^~~~~~~~~~~~~~~~~~ > > Will send .config on request if needed. Thanks for the report! -------<arch/x86/include/asm/asm-prototypes.h> /* SPDX-License-Identifier: GPL-2.0 */ #include <asm/ftrace.h> #include <linux/uaccess.h> ----- Ah, that's why... get_kernel_nofault() is defined in linux/uaccess.h. I also found that is_endbr() is in asm/ibt.h. Can you try this? Thank you, diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h index f9cb4d07df58..d24d7c71253f 100644 --- a/arch/x86/include/asm/ftrace.h +++ b/arch/x86/include/asm/ftrace.h @@ -16,24 +16,9 @@ # include <asm/ibt.h> /* Add offset for endbr64 if IBT enabled */ # define FTRACE_MCOUNT_MAX_OFFSET ENDBR_INSN_SIZE -#endif - -#ifdef CONFIG_DYNAMIC_FTRACE -#define ARCH_SUPPORTS_FTRACE_OPS 1 -#endif - -#ifndef __ASSEMBLY__ -extern void __fentry__(void); - -static inline unsigned long ftrace_call_adjust(unsigned long addr) -{ - /* - * addr is the address of the mcount call instruction. - * recordmcount does the necessary offset calculation. - */ - return addr; -} +#include <linux/uaccess.h> +/* This only supports fentry based ftrace. */ static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) { #ifdef CONFIG_X86_KERNEL_IBT @@ -55,6 +40,24 @@ static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) } #define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) +#endif + +#ifdef CONFIG_DYNAMIC_FTRACE +#define ARCH_SUPPORTS_FTRACE_OPS 1 +#endif + +#ifndef __ASSEMBLY__ +extern void __fentry__(void); + +static inline unsigned long ftrace_call_adjust(unsigned long addr) +{ + /* + * addr is the address of the mcount call instruction. + * recordmcount does the necessary offset calculation. + */ + return addr; +} + #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS #include <linux/ftrace_regs.h>
Thank you for the prompt response!
Sorry, this doesn't build.
New, different errors:
AS arch/x86/kernel/ftrace_64.o
In file included from ./include/linux/kcsan-checks.h:13,
from ./include/linux/instrumented.h:12,
from ./include/linux/uaccess.h:6,
from ./arch/x86/include/asm/ftrace.h:20,
from arch/x86/kernel/ftrace_64.S:11:
./include/linux/compiler_attributes.h:91:20: error: missing binary
operator before token "("
91 | #if __has_attribute(__copy__)
| ^
./include/linux/compiler_attributes.h:103:20: error: missing binary
operator before token "("
103 | #if __has_attribute(__diagnose_as_builtin__)
| ^
./include/linux/compiler_attributes.h:126:20: error: missing binary
operator before token "("
126 | #if __has_attribute(__designated_init__)
| ^
./include/linux/compiler_attributes.h:137:20: error: missing binary
operator before token "("
137 | #if __has_attribute(__error__)
| ^
./include/linux/compiler_attributes.h:148:20: error: missing binary
operator before token "("
148 | #if __has_attribute(__externally_visible__)
| ^
./include/linux/compiler_attributes.h:185:20: error: missing binary
operator before token "("
185 | #if __has_attribute(__no_caller_saved_registers__)
| ^
./include/linux/compiler_attributes.h:196:20: error: missing binary
operator before token "("
196 | #if __has_attribute(__noclone__)
| ^
./include/linux/compiler_attributes.h:213:20: error: missing binary
operator before token "("
213 | #if __has_attribute(__fallthrough__)
| ^
./include/linux/compiler_attributes.h:239:20: error: missing binary
operator before token "("
239 | #if __has_attribute(__nonstring__)
| ^
./include/linux/compiler_attributes.h:251:20: error: missing binary
operator before token "("
251 | #if __has_attribute(__no_profile_instrument_function__)
| ^
./include/linux/compiler_attributes.h:270:20: error: missing binary
operator before token "("
270 | #if __has_attribute(__no_stack_protector__)
| ^
./include/linux/compiler_attributes.h:281:20: error: missing binary
operator before token "("
281 | #if __has_attribute(__overloadable__)
| ^
./include/linux/compiler_attributes.h:300:20: error: missing binary
operator before token "("
300 | #if __has_attribute(__pass_dynamic_object_size__)
| ^
./include/linux/compiler_attributes.h:305:20: error: missing binary
operator before token "("
305 | #if __has_attribute(__pass_object_size__)
| ^
./include/linux/compiler_attributes.h:329:20: error: missing binary
operator before token "("
329 | #if __has_attribute(__uninitialized__)
| ^
./include/linux/compiler_attributes.h:375:20: error: missing binary
operator before token "("
375 | #if __has_attribute(__warning__)
| ^
./include/linux/compiler_attributes.h:392:20: error: missing binary
operator before token "("
392 | #if __has_attribute(disable_sanitizer_instrumentation)
| ^
In file included from ./include/linux/mm_types_task.h:11,
from ./include/linux/sched.h:38,
from ./include/linux/uaccess.h:9:
./include/linux/align.h:8:9: warning: "ALIGN" redefined
8 | #define ALIGN(x, a) __ALIGN_KERNEL((x), (a))
| ^~~~~
In file included from ./include/linux/export.h:6,
from arch/x86/kernel/ftrace_64.S:6:
./include/linux/linkage.h:103:9: note: this is the location of the
previous definition
103 | #define ALIGN __ALIGN
| ^~~~~
make[7]: *** [scripts/Makefile.build:339: arch/x86/kernel/ftrace_64.o] Error 1
Am attaching the .config so you can reproduce these easily.
Le mar. 4 févr. 2025 à 10:19, Masami Hiramatsu <mhiramat@kernel.org> a écrit :
>
> On Mon, 3 Feb 2025 22:33:48 +0100
> Gabriel de Perthuis <g2p.code@gmail.com> wrote:
>
> > Hello,
> >
> > I got errors building Linux 6.14-rc1 that were solved by reverting this
> > patch and the one after (19/20 and 20/20).
> >
> > Errors look like:
> >
> > In file included from ./arch/x86/include/asm/asm-prototypes.h:2,
> > from <stdin>:3:
> > ./arch/x86/include/asm/ftrace.h: In function 'arch_ftrace_get_symaddr':
> > ./arch/x86/include/asm/ftrace.h:46:21: error: implicit declaration of
> > function 'get_kernel_nofault' [-Wimplicit-function-declaration]
> > 46 | if (get_kernel_nofault(instr, (u32 *)(fentry_ip
> > - ENDBR_INSN_SIZE)))
> > | ^~~~~~~~~~~~~~~~~~
> >
> > Will send .config on request if needed.
>
>
> Thanks for the report!
>
> -------<arch/x86/include/asm/asm-prototypes.h>
> /* SPDX-License-Identifier: GPL-2.0 */
> #include <asm/ftrace.h>
> #include <linux/uaccess.h>
> -----
>
> Ah, that's why... get_kernel_nofault() is defined in linux/uaccess.h.
> I also found that is_endbr() is in asm/ibt.h.
>
> Can you try this?
>
> Thank you,
>
> diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
> index f9cb4d07df58..d24d7c71253f 100644
> --- a/arch/x86/include/asm/ftrace.h
> +++ b/arch/x86/include/asm/ftrace.h
> @@ -16,24 +16,9 @@
> # include <asm/ibt.h>
> /* Add offset for endbr64 if IBT enabled */
> # define FTRACE_MCOUNT_MAX_OFFSET ENDBR_INSN_SIZE
> -#endif
> -
> -#ifdef CONFIG_DYNAMIC_FTRACE
> -#define ARCH_SUPPORTS_FTRACE_OPS 1
> -#endif
> -
> -#ifndef __ASSEMBLY__
> -extern void __fentry__(void);
> -
> -static inline unsigned long ftrace_call_adjust(unsigned long addr)
> -{
> - /*
> - * addr is the address of the mcount call instruction.
> - * recordmcount does the necessary offset calculation.
> - */
> - return addr;
> -}
>
> +#include <linux/uaccess.h>
> +/* This only supports fentry based ftrace. */
> static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip)
> {
> #ifdef CONFIG_X86_KERNEL_IBT
> @@ -55,6 +40,24 @@ static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip)
> }
> #define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip)
>
> +#endif
> +
> +#ifdef CONFIG_DYNAMIC_FTRACE
> +#define ARCH_SUPPORTS_FTRACE_OPS 1
> +#endif
> +
> +#ifndef __ASSEMBLY__
> +extern void __fentry__(void);
> +
> +static inline unsigned long ftrace_call_adjust(unsigned long addr)
> +{
> + /*
> + * addr is the address of the mcount call instruction.
> + * recordmcount does the necessary offset calculation.
> + */
> + return addr;
> +}
> +
> #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
>
> #include <linux/ftrace_regs.h>
>
>
> --
> Masami Hiramatsu (Google) <mhiramat@kernel.org>
On Tue, 4 Feb 2025 15:19:45 +0100 Gabriel de Perthuis <g2p.code@gmail.com> wrote: > Thank you for the prompt response! > Sorry, this doesn't build. Thanks for testing! OK, so including linux/uaccess.h in asm/ftrace.h will cause another issue. This is a good information! I'll move the ftrace_call_adjust() to arch/x86/kernel/ftrace.c then. Thank you! > New, different errors: > > AS arch/x86/kernel/ftrace_64.o > In file included from ./include/linux/kcsan-checks.h:13, > from ./include/linux/instrumented.h:12, > from ./include/linux/uaccess.h:6, > from ./arch/x86/include/asm/ftrace.h:20, > from arch/x86/kernel/ftrace_64.S:11: > ./include/linux/compiler_attributes.h:91:20: error: missing binary > operator before token "(" > 91 | #if __has_attribute(__copy__) > | ^ > ./include/linux/compiler_attributes.h:103:20: error: missing binary > operator before token "(" > 103 | #if __has_attribute(__diagnose_as_builtin__) > | ^ > ./include/linux/compiler_attributes.h:126:20: error: missing binary > operator before token "(" > 126 | #if __has_attribute(__designated_init__) > | ^ > ./include/linux/compiler_attributes.h:137:20: error: missing binary > operator before token "(" > 137 | #if __has_attribute(__error__) > | ^ > ./include/linux/compiler_attributes.h:148:20: error: missing binary > operator before token "(" > 148 | #if __has_attribute(__externally_visible__) > | ^ > ./include/linux/compiler_attributes.h:185:20: error: missing binary > operator before token "(" > 185 | #if __has_attribute(__no_caller_saved_registers__) > | ^ > ./include/linux/compiler_attributes.h:196:20: error: missing binary > operator before token "(" > 196 | #if __has_attribute(__noclone__) > | ^ > ./include/linux/compiler_attributes.h:213:20: error: missing binary > operator before token "(" > 213 | #if __has_attribute(__fallthrough__) > | ^ > ./include/linux/compiler_attributes.h:239:20: error: missing binary > operator before token "(" > 239 | #if __has_attribute(__nonstring__) > | ^ > ./include/linux/compiler_attributes.h:251:20: error: missing binary > operator before token "(" > 251 | #if __has_attribute(__no_profile_instrument_function__) > | ^ > ./include/linux/compiler_attributes.h:270:20: error: missing binary > operator before token "(" > 270 | #if __has_attribute(__no_stack_protector__) > | ^ > ./include/linux/compiler_attributes.h:281:20: error: missing binary > operator before token "(" > 281 | #if __has_attribute(__overloadable__) > | ^ > ./include/linux/compiler_attributes.h:300:20: error: missing binary > operator before token "(" > 300 | #if __has_attribute(__pass_dynamic_object_size__) > | ^ > ./include/linux/compiler_attributes.h:305:20: error: missing binary > operator before token "(" > 305 | #if __has_attribute(__pass_object_size__) > | ^ > ./include/linux/compiler_attributes.h:329:20: error: missing binary > operator before token "(" > 329 | #if __has_attribute(__uninitialized__) > | ^ > ./include/linux/compiler_attributes.h:375:20: error: missing binary > operator before token "(" > 375 | #if __has_attribute(__warning__) > | ^ > ./include/linux/compiler_attributes.h:392:20: error: missing binary > operator before token "(" > 392 | #if __has_attribute(disable_sanitizer_instrumentation) > | ^ > In file included from ./include/linux/mm_types_task.h:11, > from ./include/linux/sched.h:38, > from ./include/linux/uaccess.h:9: > ./include/linux/align.h:8:9: warning: "ALIGN" redefined > 8 | #define ALIGN(x, a) __ALIGN_KERNEL((x), (a)) > | ^~~~~ > In file included from ./include/linux/export.h:6, > from arch/x86/kernel/ftrace_64.S:6: > ./include/linux/linkage.h:103:9: note: this is the location of the > previous definition > 103 | #define ALIGN __ALIGN > | ^~~~~ > make[7]: *** [scripts/Makefile.build:339: arch/x86/kernel/ftrace_64.o] Error 1 > > Am attaching the .config so you can reproduce these easily. > > Le mar. 4 févr. 2025 à 10:19, Masami Hiramatsu <mhiramat@kernel.org> a écrit : > > > > On Mon, 3 Feb 2025 22:33:48 +0100 > > Gabriel de Perthuis <g2p.code@gmail.com> wrote: > > > > > Hello, > > > > > > I got errors building Linux 6.14-rc1 that were solved by reverting this > > > patch and the one after (19/20 and 20/20). > > > > > > Errors look like: > > > > > > In file included from ./arch/x86/include/asm/asm-prototypes.h:2, > > > from <stdin>:3: > > > ./arch/x86/include/asm/ftrace.h: In function 'arch_ftrace_get_symaddr': > > > ./arch/x86/include/asm/ftrace.h:46:21: error: implicit declaration of > > > function 'get_kernel_nofault' [-Wimplicit-function-declaration] > > > 46 | if (get_kernel_nofault(instr, (u32 *)(fentry_ip > > > - ENDBR_INSN_SIZE))) > > > | ^~~~~~~~~~~~~~~~~~ > > > > > > Will send .config on request if needed. > > > > > > Thanks for the report! > > > > -------<arch/x86/include/asm/asm-prototypes.h> > > /* SPDX-License-Identifier: GPL-2.0 */ > > #include <asm/ftrace.h> > > #include <linux/uaccess.h> > > ----- > > > > Ah, that's why... get_kernel_nofault() is defined in linux/uaccess.h. > > I also found that is_endbr() is in asm/ibt.h. > > > > Can you try this? > > > > Thank you, > > > > diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h > > index f9cb4d07df58..d24d7c71253f 100644 > > --- a/arch/x86/include/asm/ftrace.h > > +++ b/arch/x86/include/asm/ftrace.h > > @@ -16,24 +16,9 @@ > > # include <asm/ibt.h> > > /* Add offset for endbr64 if IBT enabled */ > > # define FTRACE_MCOUNT_MAX_OFFSET ENDBR_INSN_SIZE > > -#endif > > - > > -#ifdef CONFIG_DYNAMIC_FTRACE > > -#define ARCH_SUPPORTS_FTRACE_OPS 1 > > -#endif > > - > > -#ifndef __ASSEMBLY__ > > -extern void __fentry__(void); > > - > > -static inline unsigned long ftrace_call_adjust(unsigned long addr) > > -{ > > - /* > > - * addr is the address of the mcount call instruction. > > - * recordmcount does the necessary offset calculation. > > - */ > > - return addr; > > -} > > > > +#include <linux/uaccess.h> > > +/* This only supports fentry based ftrace. */ > > static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) > > { > > #ifdef CONFIG_X86_KERNEL_IBT > > @@ -55,6 +40,24 @@ static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) > > } > > #define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) > > > > +#endif > > + > > +#ifdef CONFIG_DYNAMIC_FTRACE > > +#define ARCH_SUPPORTS_FTRACE_OPS 1 > > +#endif > > + > > +#ifndef __ASSEMBLY__ > > +extern void __fentry__(void); > > + > > +static inline unsigned long ftrace_call_adjust(unsigned long addr) > > +{ > > + /* > > + * addr is the address of the mcount call instruction. > > + * recordmcount does the necessary offset calculation. > > + */ > > + return addr; > > +} > > + > > #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS > > > > #include <linux/ftrace_regs.h> > > > > > > -- > > Masami Hiramatsu (Google) <mhiramat@kernel.org>
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 876e88ad4119..bfe3ce9df197 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -52,6 +52,8 @@ extern unsigned long ftrace_graph_call; extern void return_to_handler(void); unsigned long ftrace_call_adjust(unsigned long addr); +unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip); +#define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) #ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS #define HAVE_ARCH_FTRACE_REGS diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 570c38be833c..d7c0d023dfe5 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -143,6 +143,69 @@ unsigned long ftrace_call_adjust(unsigned long addr) return addr; } +/* Convert fentry_ip to the symbol address without kallsyms */ +unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) +{ + u32 insn; + + /* + * When using patchable-function-entry without pre-function NOPS, ftrace + * entry is the address of the first NOP after the function entry point. + * + * The compiler has either generated: + * + * func+00: func: NOP // To be patched to MOV X9, LR + * func+04: NOP // To be patched to BL <caller> + * + * Or: + * + * func-04: BTI C + * func+00: func: NOP // To be patched to MOV X9, LR + * func+04: NOP // To be patched to BL <caller> + * + * The fentry_ip is the address of `BL <caller>` which is at `func + 4` + * bytes in either case. + */ + if (!IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS)) + return fentry_ip - AARCH64_INSN_SIZE; + + /* + * When using patchable-function-entry with pre-function NOPs, BTI is + * a bit different. + * + * func+00: func: NOP // To be patched to MOV X9, LR + * func+04: NOP // To be patched to BL <caller> + * + * Or: + * + * func+00: func: BTI C + * func+04: NOP // To be patched to MOV X9, LR + * func+08: NOP // To be patched to BL <caller> + * + * The fentry_ip is the address of `BL <caller>` which is at either + * `func + 4` or `func + 8` depends on whether there is a BTI. + */ + + /* If there is no BTI, the func address should be one instruction before. */ + if (!IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) + return fentry_ip - AARCH64_INSN_SIZE; + + /* We want to be extra safe in case entry ip is on the page edge, + * but otherwise we need to avoid get_kernel_nofault()'s overhead. + */ + if ((fentry_ip & ~PAGE_MASK) < AARCH64_INSN_SIZE * 2) { + if (get_kernel_nofault(insn, (u32 *)(fentry_ip - AARCH64_INSN_SIZE * 2))) + return 0; + } else { + insn = *(u32 *)(fentry_ip - AARCH64_INSN_SIZE * 2); + } + + if (aarch64_insn_is_bti(le32_to_cpu((__le32)insn))) + return fentry_ip - AARCH64_INSN_SIZE * 2; + + return fentry_ip - AARCH64_INSN_SIZE; +} + /* * Replace a single instruction, which may be a branch or NOP. * If @validate == true, a replaced instruction is checked against 'old'. diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h index cc92c99ef276..f9cb4d07df58 100644 --- a/arch/x86/include/asm/ftrace.h +++ b/arch/x86/include/asm/ftrace.h @@ -34,6 +34,27 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) return addr; } +static inline unsigned long arch_ftrace_get_symaddr(unsigned long fentry_ip) +{ +#ifdef CONFIG_X86_KERNEL_IBT + u32 instr; + + /* We want to be extra safe in case entry ip is on the page edge, + * but otherwise we need to avoid get_kernel_nofault()'s overhead. + */ + if ((fentry_ip & ~PAGE_MASK) < ENDBR_INSN_SIZE) { + if (get_kernel_nofault(instr, (u32 *)(fentry_ip - ENDBR_INSN_SIZE))) + return fentry_ip; + } else { + instr = *(u32 *)(fentry_ip - ENDBR_INSN_SIZE); + } + if (is_endbr(instr)) + fentry_ip -= ENDBR_INSN_SIZE; +#endif + return fentry_ip; +} +#define ftrace_get_symaddr(fentry_ip) arch_ftrace_get_symaddr(fentry_ip) + #ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS #include <linux/ftrace_regs.h> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 4c553fe9c026..07092dfb21a4 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -622,6 +622,19 @@ enum { FTRACE_MAY_SLEEP = (1 << 5), }; +/* Arches can override ftrace_get_symaddr() to convert fentry_ip to symaddr. */ +#ifndef ftrace_get_symaddr +/** + * ftrace_get_symaddr - return the symbol address from fentry_ip + * @fentry_ip: the address of ftrace location + * + * Get the symbol address from @fentry_ip (fast path). If there is no fast + * search path, this returns 0. + * User may need to use kallsyms API to find the symbol address. + */ +#define ftrace_get_symaddr(fentry_ip) (0) +#endif + #ifdef CONFIG_DYNAMIC_FTRACE void ftrace_arch_code_modify_prepare(void);