| Message ID | 20230403113552.2857693-4-revest@chromium.org (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Add ftrace direct call for arm64 | expand |
On Mon, Apr 03, 2023 at 01:35:51PM +0200, Florent Revest wrote: > The ftrace samples need per-architecture trampoline implementations > to save and restore argument registers around the calls to > my_direct_func* and to restore polluted registers (eg: x30). > > These samples also include <asm/asm-offsets.h> which, on arm64, is not > necessary and redefines previously defined macros (resulting in > warnings) so these includes are guarded by !CONFIG_ARM64. > > Signed-off-by: Florent Revest <revest@chromium.org> Overall this looks pretty good! I spotted a few bugs below while testing, and I've suggested some fixups below. w.r.t. the asm-offsets include guards. I took a look at fixing arm64's asm-offsets.c to not be problematic, but it requires some invasive refactoring, so I'd like to clean that up as a separate series. I don't think that should block this series, and I think that the include guards are fine for now. > --- > arch/arm64/Kconfig | 2 ++ > samples/ftrace/ftrace-direct-modify.c | 34 ++++++++++++++++++ > samples/ftrace/ftrace-direct-multi-modify.c | 38 +++++++++++++++++++++ > samples/ftrace/ftrace-direct-multi.c | 23 +++++++++++++ > samples/ftrace/ftrace-direct-too.c | 26 ++++++++++++++ > samples/ftrace/ftrace-direct.c | 24 +++++++++++++ > 6 files changed, 147 insertions(+) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index f3503d0cc1b8..c2bf28099abd 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -194,6 +194,8 @@ config ARM64 > !CC_OPTIMIZE_FOR_SIZE) > select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ > if DYNAMIC_FTRACE_WITH_ARGS > + select HAVE_SAMPLE_FTRACE_DIRECT > + select HAVE_SAMPLE_FTRACE_DIRECT_MULTI > select HAVE_EFFICIENT_UNALIGNED_ACCESS > select HAVE_FAST_GUP > select HAVE_FTRACE_MCOUNT_RECORD > diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c > index 25fba66f61c0..98d1b7385f08 100644 > --- a/samples/ftrace/ftrace-direct-modify.c > +++ b/samples/ftrace/ftrace-direct-modify.c > @@ -2,7 +2,9 @@ > #include <linux/module.h> > #include <linux/kthread.h> > #include <linux/ftrace.h> > +#ifndef CONFIG_ARM64 > #include <asm/asm-offsets.h> > +#endif > > extern void my_direct_func1(void); > extern void my_direct_func2(void); > @@ -96,6 +98,38 @@ asm ( > > #endif /* CONFIG_S390 */ > > +#ifdef CONFIG_ARM64 > + > +asm ( > +" .pushsection .text, \"ax\", @progbits\n" > +" .type my_tramp1, @function\n" > +" .globl my_tramp1\n" > +" my_tramp1:" > +" bti c\n" > +" sub sp, sp, #16\n" > +" stp x9, x30, [sp]\n" > +" bl my_direct_func1\n" > +" ldp x30, x9, [sp]\n" > +" add sp, sp, #16\n" > +" ret x9\n" > +" .size my_tramp1, .-my_tramp1\n" > + > +" .type my_tramp2, @function\n" > +" .globl my_tramp2\n" > +" my_tramp2:" > +" bti c\n" > +" sub sp, sp, #16\n" > +" stp x9, x30, [sp]\n" > +" bl my_direct_func2\n" > +" ldp x30, x9, [sp]\n" > +" add sp, sp, #16\n" > +" ret x9\n" > +" .size my_tramp2, .-my_tramp2\n" > +" .popsection\n" > +); > + > +#endif /* CONFIG_ARM64 */ These looks functionally correct, given they'll only be attached to schedule() and the direct funcs take no arguments, so there's no arguments to save/restore and nothing to shuffle. As an aside, I believe we'll need to rework the sequences when we add support for RELIABLE_STACKTRACE so that the unwinder can reliably acquire the address of the instrumented function and its caller, but I think for now it's preferable to keep this simple and I'm happy to make that a problem for future me. > diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c > index f72623899602..e39108eb085d 100644 > --- a/samples/ftrace/ftrace-direct-multi-modify.c > +++ b/samples/ftrace/ftrace-direct-multi-modify.c > @@ -2,7 +2,9 @@ > #include <linux/module.h> > #include <linux/kthread.h> > #include <linux/ftrace.h> > +#ifndef CONFIG_ARM64 > #include <asm/asm-offsets.h> > +#endif > > extern void my_direct_func1(unsigned long ip); > extern void my_direct_func2(unsigned long ip); > @@ -103,6 +105,42 @@ asm ( > > #endif /* CONFIG_S390 */ > > +#ifdef CONFIG_ARM64 > + > +asm ( > +" .pushsection .text, \"ax\", @progbits\n" > +" .type my_tramp1, @function\n" > +" .globl my_tramp1\n" > +" my_tramp1:" > +" bti c\n" > +" sub sp, sp, #32\n" > +" stp x9, x30, [sp]\n" > +" str x0, [sp, #16]\n" > +" bl my_direct_func1\n" > +" ldp x30, x9, [sp]\n" > +" ldr x0, [sp, #16]\n" > +" add sp, sp, #32\n" > +" ret x9\n" > +" .size my_tramp1, .-my_tramp1\n" > + > +" .type my_tramp2, @function\n" > +" .globl my_tramp2\n" > +" my_tramp2:" > +" bti c\n" > +" sub sp, sp, #32\n" > +" stp x9, x30, [sp]\n" > +" str x0, [sp, #16]\n" > +" bl my_direct_func2\n" > +" ldp x30, x9, [sp]\n" > +" ldr x0, [sp, #16]\n" > +" add sp, sp, #32\n" > +" ret x9\n" > +" .size my_tramp2, .-my_tramp2\n" > +" .popsection\n" > +); > + > +#endif /* CONFIG_ARM64 */ For both of these trampolines we need to pass the trampoline's return address (i.e. where we'll return to in the instrumented function) as the 'ip' argument to my_direct_func{1,2}(). In both cases, just before the 'bl my_direct_func{1,2}' we'll need to add: mov x0, x30 [...] > diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c > index 1547c2c6be02..5a395d2d2e07 100644 > --- a/samples/ftrace/ftrace-direct-multi.c > +++ b/samples/ftrace/ftrace-direct-multi.c > @@ -4,7 +4,9 @@ > #include <linux/mm.h> /* for handle_mm_fault() */ > #include <linux/ftrace.h> > #include <linux/sched/stat.h> > +#ifndef CONFIG_ARM64 > #include <asm/asm-offsets.h> > +#endif > > extern void my_direct_func(unsigned long ip); > > @@ -66,6 +68,27 @@ asm ( > > #endif /* CONFIG_S390 */ > > +#ifdef CONFIG_ARM64 > + > +asm ( > +" .pushsection .text, \"ax\", @progbits\n" > +" .type my_tramp, @function\n" > +" .globl my_tramp\n" > +" my_tramp:" > +" bti c\n" > +" sub sp, sp, #32\n" > +" stp x9, x30, [sp]\n" > +" str x0, [sp, #16]\n" > +" bl my_direct_func\n" > +" ldp x30, x9, [sp]\n" > +" ldr x0, [sp, #16]\n" > +" add sp, sp, #32\n" > +" ret x9\n" > +" .size my_tramp, .-my_tramp\n" > +" .popsection\n" > +); > + > +#endif /* CONFIG_ARM64 */ > static struct ftrace_ops direct; As with ftrace-direct-multi-modify.c, we need to pass the return address of the trampoline as the 'ip' argument to my_direct_func1(), so just before the 'bl my_direct_func' we'll need to add: mov x0, x30 [...] > diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c > index f28e7b99840f..6e93c45fea86 100644 > --- a/samples/ftrace/ftrace-direct-too.c > +++ b/samples/ftrace/ftrace-direct-too.c > @@ -3,7 +3,9 @@ > > #include <linux/mm.h> /* for handle_mm_fault() */ > #include <linux/ftrace.h> > +#ifndef CONFIG_ARM64 > #include <asm/asm-offsets.h> > +#endif > > extern void my_direct_func(struct vm_area_struct *vma, > unsigned long address, unsigned int flags); This gets attached to handle_mm_fault(), whose prototype is currently: vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, unsigned int flags, struct pt_regs *regs) i.e. it has 4 arguments, in x0 to x3. > @@ -70,6 +72,30 @@ asm ( > > #endif /* CONFIG_S390 */ > > +#ifdef CONFIG_ARM64 > + > +asm ( > +" .pushsection .text, \"ax\", @progbits\n" > +" .type my_tramp, @function\n" > +" .globl my_tramp\n" > +" my_tramp:" > +" bti c\n" > +" sub sp, sp, #48\n" > +" stp x9, x30, [sp]\n" > +" stp x0, x1, [sp, #16]\n" > +" str x2, [sp, #32]\n" > +" bl my_direct_func\n" > +" ldp x30, x9, [sp]\n" > +" ldp x0, x1, [sp, #16]\n" > +" ldr x2, [sp, #32]\n" So here we need to save+restore x3 also. We already have the space reserved, so that should just be a matter of using stp/ldp for x2 and x3. > +" add sp, sp, #48\n" > +" ret x9\n" > +" .size my_tramp, .-my_tramp\n" > +" .popsection\n" > +); > + > +#endif /* CONFIG_ARM64 */ > + > static struct ftrace_ops direct; > > static int __init ftrace_direct_init(void) > diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c > index d81a9473b585..e5312f9c15d3 100644 > --- a/samples/ftrace/ftrace-direct.c > +++ b/samples/ftrace/ftrace-direct.c > @@ -3,7 +3,9 @@ > > #include <linux/sched.h> /* for wake_up_process() */ > #include <linux/ftrace.h> > +#ifndef CONFIG_ARM64 > #include <asm/asm-offsets.h> > +#endif > > extern void my_direct_func(struct task_struct *p); > > @@ -63,6 +65,28 @@ asm ( > > #endif /* CONFIG_S390 */ > > +#ifdef CONFIG_ARM64 > + > +asm ( > +" .pushsection .text, \"ax\", @progbits\n" > +" .type my_tramp, @function\n" > +" .globl my_tramp\n" > +" my_tramp:" > +" bti c\n" > +" sub sp, sp, #32\n" > +" stp x9, x30, [sp]\n" > +" str x0, [sp, #16]\n" > +" bl my_direct_func\n" > +" ldp x30, x9, [sp]\n" > +" ldr x0, [sp, #16]\n" > +" add sp, sp, #32\n" > +" ret x9\n" > +" .size my_tramp, .-my_tramp\n" > +" .popsection\n" > +); This looks fine. Since my_direct_func() is attached to wake_up_process() and expects its single argument, saving/restoring x0 is sufficient and we don't need any additional register shuffling. Thanks, Mark.
On Mon, Apr 3, 2023 at 7:26 PM Mark Rutland <mark.rutland@arm.com> wrote: > > On Mon, Apr 03, 2023 at 01:35:51PM +0200, Florent Revest wrote: > > The ftrace samples need per-architecture trampoline implementations > > to save and restore argument registers around the calls to > > my_direct_func* and to restore polluted registers (eg: x30). > > > > These samples also include <asm/asm-offsets.h> which, on arm64, is not > > necessary and redefines previously defined macros (resulting in > > warnings) so these includes are guarded by !CONFIG_ARM64. > > > > Signed-off-by: Florent Revest <revest@chromium.org> > > Overall this looks pretty good! > > I spotted a few bugs below while testing, and I've suggested some fixups below. > > w.r.t. the asm-offsets include guards. I took a look at fixing arm64's > asm-offsets.c to not be problematic, but it requires some invasive refactoring, > so I'd like to clean that up as a separate series. I don't think that should > block this series, and I think that the include guards are fine for now. Sounds great! Thank you Mark :) > > --- > > arch/arm64/Kconfig | 2 ++ > > samples/ftrace/ftrace-direct-modify.c | 34 ++++++++++++++++++ > > samples/ftrace/ftrace-direct-multi-modify.c | 38 +++++++++++++++++++++ > > samples/ftrace/ftrace-direct-multi.c | 23 +++++++++++++ > > samples/ftrace/ftrace-direct-too.c | 26 ++++++++++++++ > > samples/ftrace/ftrace-direct.c | 24 +++++++++++++ > > 6 files changed, 147 insertions(+) > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index f3503d0cc1b8..c2bf28099abd 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -194,6 +194,8 @@ config ARM64 > > !CC_OPTIMIZE_FOR_SIZE) > > select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ > > if DYNAMIC_FTRACE_WITH_ARGS > > + select HAVE_SAMPLE_FTRACE_DIRECT > > + select HAVE_SAMPLE_FTRACE_DIRECT_MULTI > > select HAVE_EFFICIENT_UNALIGNED_ACCESS > > select HAVE_FAST_GUP > > select HAVE_FTRACE_MCOUNT_RECORD > > diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c > > index 25fba66f61c0..98d1b7385f08 100644 > > --- a/samples/ftrace/ftrace-direct-modify.c > > +++ b/samples/ftrace/ftrace-direct-modify.c > > @@ -2,7 +2,9 @@ > > #include <linux/module.h> > > #include <linux/kthread.h> > > #include <linux/ftrace.h> > > +#ifndef CONFIG_ARM64 > > #include <asm/asm-offsets.h> > > +#endif > > > > extern void my_direct_func1(void); > > extern void my_direct_func2(void); > > @@ -96,6 +98,38 @@ asm ( > > > > #endif /* CONFIG_S390 */ > > > > +#ifdef CONFIG_ARM64 > > + > > +asm ( > > +" .pushsection .text, \"ax\", @progbits\n" > > +" .type my_tramp1, @function\n" > > +" .globl my_tramp1\n" > > +" my_tramp1:" > > +" bti c\n" > > +" sub sp, sp, #16\n" > > +" stp x9, x30, [sp]\n" > > +" bl my_direct_func1\n" > > +" ldp x30, x9, [sp]\n" > > +" add sp, sp, #16\n" > > +" ret x9\n" > > +" .size my_tramp1, .-my_tramp1\n" > > + > > +" .type my_tramp2, @function\n" > > +" .globl my_tramp2\n" > > +" my_tramp2:" > > +" bti c\n" > > +" sub sp, sp, #16\n" > > +" stp x9, x30, [sp]\n" > > +" bl my_direct_func2\n" > > +" ldp x30, x9, [sp]\n" > > +" add sp, sp, #16\n" > > +" ret x9\n" > > +" .size my_tramp2, .-my_tramp2\n" > > +" .popsection\n" > > +); > > + > > +#endif /* CONFIG_ARM64 */ > > These looks functionally correct, given they'll only be attached to schedule() > and the direct funcs take no arguments, so there's no arguments to save/restore > and nothing to shuffle. > > As an aside, I believe we'll need to rework the sequences when we add support > for RELIABLE_STACKTRACE so that the unwinder can reliably acquire the address > of the instrumented function and its caller, but I think for now it's > preferable to keep this simple and I'm happy to make that a problem for future > me. Ah, interesting. I'd be happy to help when that time comes! :) > > diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c > > index f72623899602..e39108eb085d 100644 > > --- a/samples/ftrace/ftrace-direct-multi-modify.c > > +++ b/samples/ftrace/ftrace-direct-multi-modify.c > > @@ -2,7 +2,9 @@ > > #include <linux/module.h> > > #include <linux/kthread.h> > > #include <linux/ftrace.h> > > +#ifndef CONFIG_ARM64 > > #include <asm/asm-offsets.h> > > +#endif > > > > extern void my_direct_func1(unsigned long ip); > > extern void my_direct_func2(unsigned long ip); > > @@ -103,6 +105,42 @@ asm ( > > > > #endif /* CONFIG_S390 */ > > > > +#ifdef CONFIG_ARM64 > > + > > +asm ( > > +" .pushsection .text, \"ax\", @progbits\n" > > +" .type my_tramp1, @function\n" > > +" .globl my_tramp1\n" > > +" my_tramp1:" > > +" bti c\n" > > +" sub sp, sp, #32\n" > > +" stp x9, x30, [sp]\n" > > +" str x0, [sp, #16]\n" > > +" bl my_direct_func1\n" > > +" ldp x30, x9, [sp]\n" > > +" ldr x0, [sp, #16]\n" > > +" add sp, sp, #32\n" > > +" ret x9\n" > > +" .size my_tramp1, .-my_tramp1\n" > > + > > +" .type my_tramp2, @function\n" > > +" .globl my_tramp2\n" > > +" my_tramp2:" > > +" bti c\n" > > +" sub sp, sp, #32\n" > > +" stp x9, x30, [sp]\n" > > +" str x0, [sp, #16]\n" > > +" bl my_direct_func2\n" > > +" ldp x30, x9, [sp]\n" > > +" ldr x0, [sp, #16]\n" > > +" add sp, sp, #32\n" > > +" ret x9\n" > > +" .size my_tramp2, .-my_tramp2\n" > > +" .popsection\n" > > +); > > + > > +#endif /* CONFIG_ARM64 */ > > For both of these trampolines we need to pass the trampoline's return address > (i.e. where we'll return to in the instrumented function) as the 'ip' argument > to my_direct_func{1,2}(). > > In both cases, just before the 'bl my_direct_func{1,2}' we'll need to add: > > mov x0, x30 Oopsie, yes! Very good catch! > > diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c > > index 1547c2c6be02..5a395d2d2e07 100644 > > --- a/samples/ftrace/ftrace-direct-multi.c > > +++ b/samples/ftrace/ftrace-direct-multi.c > > @@ -4,7 +4,9 @@ > > #include <linux/mm.h> /* for handle_mm_fault() */ > > #include <linux/ftrace.h> > > #include <linux/sched/stat.h> > > +#ifndef CONFIG_ARM64 > > #include <asm/asm-offsets.h> > > +#endif > > > > extern void my_direct_func(unsigned long ip); > > > > @@ -66,6 +68,27 @@ asm ( > > > > #endif /* CONFIG_S390 */ > > > > +#ifdef CONFIG_ARM64 > > + > > +asm ( > > +" .pushsection .text, \"ax\", @progbits\n" > > +" .type my_tramp, @function\n" > > +" .globl my_tramp\n" > > +" my_tramp:" > > +" bti c\n" > > +" sub sp, sp, #32\n" > > +" stp x9, x30, [sp]\n" > > +" str x0, [sp, #16]\n" > > +" bl my_direct_func\n" > > +" ldp x30, x9, [sp]\n" > > +" ldr x0, [sp, #16]\n" > > +" add sp, sp, #32\n" > > +" ret x9\n" > > +" .size my_tramp, .-my_tramp\n" > > +" .popsection\n" > > +); > > + > > +#endif /* CONFIG_ARM64 */ > > static struct ftrace_ops direct; > > As with ftrace-direct-multi-modify.c, we need to pass the return address of the > trampoline as the 'ip' argument to my_direct_func1(), so just before the 'bl > my_direct_func' we'll need to add: > > mov x0, x30 Will do :) > > diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c > > index f28e7b99840f..6e93c45fea86 100644 > > --- a/samples/ftrace/ftrace-direct-too.c > > +++ b/samples/ftrace/ftrace-direct-too.c > > @@ -3,7 +3,9 @@ > > > > #include <linux/mm.h> /* for handle_mm_fault() */ > > #include <linux/ftrace.h> > > +#ifndef CONFIG_ARM64 > > #include <asm/asm-offsets.h> > > +#endif > > > > extern void my_direct_func(struct vm_area_struct *vma, > > unsigned long address, unsigned int flags); > > This gets attached to handle_mm_fault(), whose prototype is currently: > > vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, > unsigned int flags, struct pt_regs *regs) > > i.e. it has 4 arguments, in x0 to x3. > > > @@ -70,6 +72,30 @@ asm ( > > > > #endif /* CONFIG_S390 */ > > > > +#ifdef CONFIG_ARM64 > > + > > +asm ( > > +" .pushsection .text, \"ax\", @progbits\n" > > +" .type my_tramp, @function\n" > > +" .globl my_tramp\n" > > +" my_tramp:" > > +" bti c\n" > > +" sub sp, sp, #48\n" > > +" stp x9, x30, [sp]\n" > > +" stp x0, x1, [sp, #16]\n" > > +" str x2, [sp, #32]\n" > > +" bl my_direct_func\n" > > +" ldp x30, x9, [sp]\n" > > +" ldp x0, x1, [sp, #16]\n" > > +" ldr x2, [sp, #32]\n" > > So here we need to save+restore x3 also. > > We already have the space reserved, so that should just be a matter of using > stp/ldp for x2 and x3. That's also a very good catch. It looks like it's an issue for the sample trampoline on x86_64 as well, I'll fix it too in a separate patch as part of v6. (if i understand s390 asm correctly, the stmg already saves all arg registers in one instruction so s390 doesn't need to change)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index f3503d0cc1b8..c2bf28099abd 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -194,6 +194,8 @@ config ARM64 !CC_OPTIMIZE_FOR_SIZE) select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ if DYNAMIC_FTRACE_WITH_ARGS + select HAVE_SAMPLE_FTRACE_DIRECT + select HAVE_SAMPLE_FTRACE_DIRECT_MULTI select HAVE_EFFICIENT_UNALIGNED_ACCESS select HAVE_FAST_GUP select HAVE_FTRACE_MCOUNT_RECORD diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c index 25fba66f61c0..98d1b7385f08 100644 --- a/samples/ftrace/ftrace-direct-modify.c +++ b/samples/ftrace/ftrace-direct-modify.c @@ -2,7 +2,9 @@ #include <linux/module.h> #include <linux/kthread.h> #include <linux/ftrace.h> +#ifndef CONFIG_ARM64 #include <asm/asm-offsets.h> +#endif extern void my_direct_func1(void); extern void my_direct_func2(void); @@ -96,6 +98,38 @@ asm ( #endif /* CONFIG_S390 */ +#ifdef CONFIG_ARM64 + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp1, @function\n" +" .globl my_tramp1\n" +" my_tramp1:" +" bti c\n" +" sub sp, sp, #16\n" +" stp x9, x30, [sp]\n" +" bl my_direct_func1\n" +" ldp x30, x9, [sp]\n" +" add sp, sp, #16\n" +" ret x9\n" +" .size my_tramp1, .-my_tramp1\n" + +" .type my_tramp2, @function\n" +" .globl my_tramp2\n" +" my_tramp2:" +" bti c\n" +" sub sp, sp, #16\n" +" stp x9, x30, [sp]\n" +" bl my_direct_func2\n" +" ldp x30, x9, [sp]\n" +" add sp, sp, #16\n" +" ret x9\n" +" .size my_tramp2, .-my_tramp2\n" +" .popsection\n" +); + +#endif /* CONFIG_ARM64 */ + static struct ftrace_ops direct; static unsigned long my_tramp = (unsigned long)my_tramp1; diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c index f72623899602..e39108eb085d 100644 --- a/samples/ftrace/ftrace-direct-multi-modify.c +++ b/samples/ftrace/ftrace-direct-multi-modify.c @@ -2,7 +2,9 @@ #include <linux/module.h> #include <linux/kthread.h> #include <linux/ftrace.h> +#ifndef CONFIG_ARM64 #include <asm/asm-offsets.h> +#endif extern void my_direct_func1(unsigned long ip); extern void my_direct_func2(unsigned long ip); @@ -103,6 +105,42 @@ asm ( #endif /* CONFIG_S390 */ +#ifdef CONFIG_ARM64 + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp1, @function\n" +" .globl my_tramp1\n" +" my_tramp1:" +" bti c\n" +" sub sp, sp, #32\n" +" stp x9, x30, [sp]\n" +" str x0, [sp, #16]\n" +" bl my_direct_func1\n" +" ldp x30, x9, [sp]\n" +" ldr x0, [sp, #16]\n" +" add sp, sp, #32\n" +" ret x9\n" +" .size my_tramp1, .-my_tramp1\n" + +" .type my_tramp2, @function\n" +" .globl my_tramp2\n" +" my_tramp2:" +" bti c\n" +" sub sp, sp, #32\n" +" stp x9, x30, [sp]\n" +" str x0, [sp, #16]\n" +" bl my_direct_func2\n" +" ldp x30, x9, [sp]\n" +" ldr x0, [sp, #16]\n" +" add sp, sp, #32\n" +" ret x9\n" +" .size my_tramp2, .-my_tramp2\n" +" .popsection\n" +); + +#endif /* CONFIG_ARM64 */ + static unsigned long my_tramp = (unsigned long)my_tramp1; static unsigned long tramps[2] = { (unsigned long)my_tramp1, diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c index 1547c2c6be02..5a395d2d2e07 100644 --- a/samples/ftrace/ftrace-direct-multi.c +++ b/samples/ftrace/ftrace-direct-multi.c @@ -4,7 +4,9 @@ #include <linux/mm.h> /* for handle_mm_fault() */ #include <linux/ftrace.h> #include <linux/sched/stat.h> +#ifndef CONFIG_ARM64 #include <asm/asm-offsets.h> +#endif extern void my_direct_func(unsigned long ip); @@ -66,6 +68,27 @@ asm ( #endif /* CONFIG_S390 */ +#ifdef CONFIG_ARM64 + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp, @function\n" +" .globl my_tramp\n" +" my_tramp:" +" bti c\n" +" sub sp, sp, #32\n" +" stp x9, x30, [sp]\n" +" str x0, [sp, #16]\n" +" bl my_direct_func\n" +" ldp x30, x9, [sp]\n" +" ldr x0, [sp, #16]\n" +" add sp, sp, #32\n" +" ret x9\n" +" .size my_tramp, .-my_tramp\n" +" .popsection\n" +); + +#endif /* CONFIG_ARM64 */ static struct ftrace_ops direct; static int __init ftrace_direct_multi_init(void) diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c index f28e7b99840f..6e93c45fea86 100644 --- a/samples/ftrace/ftrace-direct-too.c +++ b/samples/ftrace/ftrace-direct-too.c @@ -3,7 +3,9 @@ #include <linux/mm.h> /* for handle_mm_fault() */ #include <linux/ftrace.h> +#ifndef CONFIG_ARM64 #include <asm/asm-offsets.h> +#endif extern void my_direct_func(struct vm_area_struct *vma, unsigned long address, unsigned int flags); @@ -70,6 +72,30 @@ asm ( #endif /* CONFIG_S390 */ +#ifdef CONFIG_ARM64 + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp, @function\n" +" .globl my_tramp\n" +" my_tramp:" +" bti c\n" +" sub sp, sp, #48\n" +" stp x9, x30, [sp]\n" +" stp x0, x1, [sp, #16]\n" +" str x2, [sp, #32]\n" +" bl my_direct_func\n" +" ldp x30, x9, [sp]\n" +" ldp x0, x1, [sp, #16]\n" +" ldr x2, [sp, #32]\n" +" add sp, sp, #48\n" +" ret x9\n" +" .size my_tramp, .-my_tramp\n" +" .popsection\n" +); + +#endif /* CONFIG_ARM64 */ + static struct ftrace_ops direct; static int __init ftrace_direct_init(void) diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c index d81a9473b585..e5312f9c15d3 100644 --- a/samples/ftrace/ftrace-direct.c +++ b/samples/ftrace/ftrace-direct.c @@ -3,7 +3,9 @@ #include <linux/sched.h> /* for wake_up_process() */ #include <linux/ftrace.h> +#ifndef CONFIG_ARM64 #include <asm/asm-offsets.h> +#endif extern void my_direct_func(struct task_struct *p); @@ -63,6 +65,28 @@ asm ( #endif /* CONFIG_S390 */ +#ifdef CONFIG_ARM64 + +asm ( +" .pushsection .text, \"ax\", @progbits\n" +" .type my_tramp, @function\n" +" .globl my_tramp\n" +" my_tramp:" +" bti c\n" +" sub sp, sp, #32\n" +" stp x9, x30, [sp]\n" +" str x0, [sp, #16]\n" +" bl my_direct_func\n" +" ldp x30, x9, [sp]\n" +" ldr x0, [sp, #16]\n" +" add sp, sp, #32\n" +" ret x9\n" +" .size my_tramp, .-my_tramp\n" +" .popsection\n" +); + +#endif /* CONFIG_ARM64 */ + static struct ftrace_ops direct; static int __init ftrace_direct_init(void)
The ftrace samples need per-architecture trampoline implementations to save and restore argument registers around the calls to my_direct_func* and to restore polluted registers (eg: x30). These samples also include <asm/asm-offsets.h> which, on arm64, is not necessary and redefines previously defined macros (resulting in warnings) so these includes are guarded by !CONFIG_ARM64. Signed-off-by: Florent Revest <revest@chromium.org> --- arch/arm64/Kconfig | 2 ++ samples/ftrace/ftrace-direct-modify.c | 34 ++++++++++++++++++ samples/ftrace/ftrace-direct-multi-modify.c | 38 +++++++++++++++++++++ samples/ftrace/ftrace-direct-multi.c | 23 +++++++++++++ samples/ftrace/ftrace-direct-too.c | 26 ++++++++++++++ samples/ftrace/ftrace-direct.c | 24 +++++++++++++ 6 files changed, 147 insertions(+)