From: rostedt at goodmis.org (Steven Rostedt) Subject: [RFC][PATCH] ftrace/x86: Emulate call function while updating in breakpoint handler Date: Wed, 1 May 2019 14:58:24 -0400 [thread overview] Message-ID: <20190501145824.08aed43a@gandalf.local.home> (raw) In-Reply-To: <20190501131117.GW2623@hirez.programming.kicks-ass.net> On Wed, 1 May 2019 15:11:17 +0200 Peter Zijlstra <peterz at infradead.org> wrote: > On Tue, Apr 30, 2019 at 11:33:21AM -0700, Linus Torvalds wrote: > > Anyway, since Andy really likes the entry code change, can we have > > that patch in parallel and judge the difference that way? Iirc, that > > was x86-64 specific too. > > Here goes, compile tested only... > > It obviously needs a self-test, but that shoulnd't be too hard to > arrange. > I was able to get it applied (with slight tweaking) but it then crashed. But that was due to incorrect updates in the ftrace_int3_handler(). > --- > arch/x86/entry/entry_32.S | 7 +++++++ > arch/x86/entry/entry_64.S | 14 ++++++++++++-- > arch/x86/include/asm/text-patching.h | 20 ++++++++++++++++++++ > arch/x86/kernel/ftrace.c | 24 +++++++++++++++++++----- > 4 files changed, 58 insertions(+), 7 deletions(-) > #endif /* _ASM_X86_TEXT_PATCHING_H */ > diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c > index ef49517f6bb2..90d319687d7e 100644 > --- a/arch/x86/kernel/ftrace.c > +++ b/arch/x86/kernel/ftrace.c > @@ -29,6 +29,7 @@ > #include <asm/kprobes.h> > #include <asm/ftrace.h> > #include <asm/nops.h> > +#include <asm/text-patching.h> > > #ifdef CONFIG_DYNAMIC_FTRACE > > @@ -231,6 +232,7 @@ int ftrace_modify_call(struct dyn_ftrace *rec, > unsigned long old_addr, } > > static unsigned long ftrace_update_func; > +static unsigned long ftrace_update_func_call; > > static int update_ftrace_func(unsigned long ip, void *new) > { > @@ -259,6 +261,8 @@ int ftrace_update_ftrace_func(ftrace_func_t func) > unsigned char *new; > int ret; > > + ftrace_update_func_call = (unsigned long)func; > + > new = ftrace_call_replace(ip, (unsigned long)func); > ret = update_ftrace_func(ip, new); > > @@ -295,12 +299,19 @@ int ftrace_int3_handler(struct pt_regs *regs) > return 0; > > ip = regs->ip - 1; > - if (!ftrace_location(ip) && !is_ftrace_caller(ip)) > - return 0; > - > - regs->ip += MCOUNT_INSN_SIZE - 1; > + if (ftrace_location(ip)) { > + int3_emulate_call(regs, ftrace_update_func_call); Should be: int3_emulate_call(regs, (unsigned long)ftrace_regs_caller); > + return 1; > + } else if (is_ftrace_caller(ip)) { > + if (!ftrace_update_func_call) { > + int3_emulate_jmp(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); I see what you did here, but I think: int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); looks better. But that said, we could in the beginning do: ip = regs->ip - INT3_INSN_SIZE; instead of ip = regs->ip - 1; I made these updates and posted them to Linus. -- Steve > + return 1; > + } > + int3_emulate_call(regs, ftrace_update_func_call); > + return 1; > + } > > - return 1; > + return 0; > } > NOKPROBE_SYMBOL(ftrace_int3_handler); > > @@ -859,6 +870,8 @@ void arch_ftrace_update_trampoline(struct > ftrace_ops *ops) > func = ftrace_ops_get_func(ops); > > + ftrace_update_func_call = (unsigned long)func; > + > /* Do a safe modify in case the trampoline is executing */ > new = ftrace_call_replace(ip, (unsigned long)func); > ret = update_ftrace_func(ip, new); > @@ -960,6 +973,7 @@ static int ftrace_mod_jmp(unsigned long ip, void > *func) { > unsigned char *new; > > + ftrace_update_func_call = 0UL; > new = ftrace_jmp_replace(ip, (unsigned long)func); > > return update_ftrace_func(ip, new);
WARNING: multiple messages have this Message-ID (diff)
From: rostedt@goodmis.org (Steven Rostedt) Subject: [RFC][PATCH] ftrace/x86: Emulate call function while updating in breakpoint handler Date: Wed, 1 May 2019 14:58:24 -0400 [thread overview] Message-ID: <20190501145824.08aed43a@gandalf.local.home> (raw) Message-ID: <20190501185824.yc8RJCjQNau-I60Y3ri2XjQ0UirBLe1qVaHTVai5fPw@z> (raw) In-Reply-To: <20190501131117.GW2623@hirez.programming.kicks-ass.net> On Wed, 1 May 2019 15:11:17 +0200 Peter Zijlstra <peterz@infradead.org> wrote: > On Tue, Apr 30, 2019@11:33:21AM -0700, Linus Torvalds wrote: > > Anyway, since Andy really likes the entry code change, can we have > > that patch in parallel and judge the difference that way? Iirc, that > > was x86-64 specific too. > > Here goes, compile tested only... > > It obviously needs a self-test, but that shoulnd't be too hard to > arrange. > I was able to get it applied (with slight tweaking) but it then crashed. But that was due to incorrect updates in the ftrace_int3_handler(). > --- > arch/x86/entry/entry_32.S | 7 +++++++ > arch/x86/entry/entry_64.S | 14 ++++++++++++-- > arch/x86/include/asm/text-patching.h | 20 ++++++++++++++++++++ > arch/x86/kernel/ftrace.c | 24 +++++++++++++++++++----- > 4 files changed, 58 insertions(+), 7 deletions(-) > #endif /* _ASM_X86_TEXT_PATCHING_H */ > diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c > index ef49517f6bb2..90d319687d7e 100644 > --- a/arch/x86/kernel/ftrace.c > +++ b/arch/x86/kernel/ftrace.c > @@ -29,6 +29,7 @@ > #include <asm/kprobes.h> > #include <asm/ftrace.h> > #include <asm/nops.h> > +#include <asm/text-patching.h> > > #ifdef CONFIG_DYNAMIC_FTRACE > > @@ -231,6 +232,7 @@ int ftrace_modify_call(struct dyn_ftrace *rec, > unsigned long old_addr, } > > static unsigned long ftrace_update_func; > +static unsigned long ftrace_update_func_call; > > static int update_ftrace_func(unsigned long ip, void *new) > { > @@ -259,6 +261,8 @@ int ftrace_update_ftrace_func(ftrace_func_t func) > unsigned char *new; > int ret; > > + ftrace_update_func_call = (unsigned long)func; > + > new = ftrace_call_replace(ip, (unsigned long)func); > ret = update_ftrace_func(ip, new); > > @@ -295,12 +299,19 @@ int ftrace_int3_handler(struct pt_regs *regs) > return 0; > > ip = regs->ip - 1; > - if (!ftrace_location(ip) && !is_ftrace_caller(ip)) > - return 0; > - > - regs->ip += MCOUNT_INSN_SIZE - 1; > + if (ftrace_location(ip)) { > + int3_emulate_call(regs, ftrace_update_func_call); Should be: int3_emulate_call(regs, (unsigned long)ftrace_regs_caller); > + return 1; > + } else if (is_ftrace_caller(ip)) { > + if (!ftrace_update_func_call) { > + int3_emulate_jmp(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); I see what you did here, but I think: int3_emulate_jmp(regs, ip + CALL_INSN_SIZE); looks better. But that said, we could in the beginning do: ip = regs->ip - INT3_INSN_SIZE; instead of ip = regs->ip - 1; I made these updates and posted them to Linus. -- Steve > + return 1; > + } > + int3_emulate_call(regs, ftrace_update_func_call); > + return 1; > + } > > - return 1; > + return 0; > } > NOKPROBE_SYMBOL(ftrace_int3_handler); > > @@ -859,6 +870,8 @@ void arch_ftrace_update_trampoline(struct > ftrace_ops *ops) > func = ftrace_ops_get_func(ops); > > + ftrace_update_func_call = (unsigned long)func; > + > /* Do a safe modify in case the trampoline is executing */ > new = ftrace_call_replace(ip, (unsigned long)func); > ret = update_ftrace_func(ip, new); > @@ -960,6 +973,7 @@ static int ftrace_mod_jmp(unsigned long ip, void > *func) { > unsigned char *new; > > + ftrace_update_func_call = 0UL; > new = ftrace_jmp_replace(ip, (unsigned long)func); > > return update_ftrace_func(ip, new);
next prev parent reply other threads:[~2019-05-01 18:58 UTC|newest] Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-04-27 10:06 [PATCH 0/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation nstange 2019-04-27 10:06 ` Nicolai Stange 2019-04-27 10:06 ` [PATCH 1/4] x86/thread_info: introduce ->ftrace_int3_stack member nstange 2019-04-27 10:06 ` Nicolai Stange 2019-04-28 17:41 ` luto 2019-04-28 17:41 ` Andy Lutomirski 2019-04-28 17:51 ` rostedt 2019-04-28 17:51 ` Steven Rostedt 2019-04-28 18:08 ` luto 2019-04-28 18:08 ` Andy Lutomirski 2019-04-28 19:43 ` rostedt 2019-04-28 19:43 ` Steven Rostedt 2019-04-28 20:56 ` luto 2019-04-28 20:56 ` Andy Lutomirski 2019-04-28 21:22 ` nstange 2019-04-28 21:22 ` Nicolai Stange 2019-04-28 23:27 ` luto 2019-04-28 23:27 ` Andy Lutomirski 2019-04-27 10:06 ` [PATCH 2/4] ftrace: drop 'static' qualifier from ftrace_ops_list_func() nstange 2019-04-27 10:06 ` Nicolai Stange 2019-04-27 10:06 ` [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation nstange 2019-04-27 10:06 ` Nicolai Stange 2019-04-27 10:26 ` peterz 2019-04-27 10:26 ` Peter Zijlstra 2019-04-28 17:38 ` rostedt 2019-04-28 17:38 ` Steven Rostedt 2019-04-29 18:06 ` torvalds 2019-04-29 18:06 ` Linus Torvalds 2019-04-29 18:22 ` torvalds 2019-04-29 18:22 ` Linus Torvalds 2019-04-29 18:42 ` luto 2019-04-29 18:42 ` Andy Lutomirski [not found] ` <CAHk-=whtt4K2f0KPtG-4Pykh3FK8UBOjD8jhXCUKB5nWDj_YRA@mail.gmail.com> 2019-04-29 18:56 ` luto 2019-04-29 18:56 ` Andy Lutomirski [not found] ` <CAHk-=wgewK4eFhF3=0RNtk1KQjMANFH6oDE=8m=84RExn2gxhw@mail.gmail.com> [not found] ` <CAHk-=whay7eN6+2gZjY-ybRbkbcqAmgrLwwszzHx8ws3c=S-MA@mail.gmail.com> 2019-04-29 19:24 ` luto 2019-04-29 19:24 ` Andy Lutomirski 2019-04-29 20:07 ` torvalds 2019-04-29 20:07 ` Linus Torvalds 2019-04-30 13:56 ` peterz 2019-04-30 13:56 ` Peter Zijlstra 2019-04-30 16:06 ` torvalds 2019-04-30 16:06 ` Linus Torvalds 2019-04-30 16:33 ` luto 2019-04-30 16:33 ` Andy Lutomirski 2019-04-30 17:03 ` rostedt 2019-04-30 17:03 ` Steven Rostedt 2019-04-30 17:20 ` rostedt 2019-04-30 17:20 ` Steven Rostedt 2019-04-30 17:49 ` [RFC][PATCH] ftrace/x86: Emulate call function while updating in breakpoint handler rostedt 2019-04-30 17:49 ` Steven Rostedt 2019-04-30 18:33 ` torvalds 2019-04-30 18:33 ` Linus Torvalds 2019-04-30 19:00 ` rostedt 2019-04-30 19:00 ` Steven Rostedt 2019-04-30 21:08 ` rostedt 2019-04-30 21:08 ` Steven Rostedt 2019-05-01 13:11 ` peterz 2019-05-01 13:11 ` Peter Zijlstra 2019-05-01 18:58 ` rostedt [this message] 2019-05-01 18:58 ` Steven Rostedt 2019-05-01 19:03 ` peterz 2019-05-01 19:03 ` Peter Zijlstra 2019-05-01 19:03 ` torvalds 2019-05-01 19:03 ` Linus Torvalds 2019-05-01 19:13 ` peterz 2019-05-01 19:13 ` Peter Zijlstra 2019-05-01 19:13 ` rostedt 2019-05-01 19:13 ` Steven Rostedt 2019-05-01 19:33 ` jikos 2019-05-01 19:33 ` Jiri Kosina 2019-05-01 19:41 ` peterz 2019-05-01 19:41 ` Peter Zijlstra 2019-04-30 21:53 ` [RFC][PATCH v2] " rostedt 2019-04-30 21:53 ` Steven Rostedt 2019-05-01 1:35 ` rostedt 2019-05-01 1:35 ` Steven Rostedt 2019-05-01 1:58 ` torvalds 2019-05-01 1:58 ` Linus Torvalds 2019-05-01 8:26 ` nstange 2019-05-01 8:26 ` Nicolai Stange 2019-05-01 13:22 ` rostedt 2019-05-01 13:22 ` Steven Rostedt 2019-04-29 20:16 ` [PATCH 3/4] x86/ftrace: make ftrace_int3_handler() not to skip fops invocation torvalds 2019-04-29 20:16 ` Linus Torvalds 2019-04-29 22:08 ` sean.j.christopherson 2019-04-29 22:08 ` Sean Christopherson 2019-04-29 22:22 ` torvalds 2019-04-29 22:22 ` Linus Torvalds 2019-04-30 0:08 ` sean.j.christopherson 2019-04-30 0:08 ` Sean Christopherson 2019-04-30 0:45 ` sean.j.christopherson 2019-04-30 0:45 ` Sean Christopherson 2019-04-30 2:26 ` torvalds 2019-04-30 2:26 ` Linus Torvalds 2019-04-30 10:40 ` peterz 2019-04-30 10:40 ` Peter Zijlstra 2019-04-30 11:17 ` jikos 2019-04-30 11:17 ` Jiri Kosina 2019-04-29 22:06 ` torvalds 2019-04-29 22:06 ` Linus Torvalds 2019-04-30 11:18 ` peterz 2019-04-30 11:18 ` Peter Zijlstra 2019-04-29 18:52 ` rostedt 2019-04-29 18:52 ` Steven Rostedt [not found] ` <CAHk-=wjm93jLtVxTX4HZs6K4k1Wqh3ujjmapqaYtcibVk_YnzQ@mail.gmail.com> 2019-04-29 19:07 ` rostedt 2019-04-29 19:07 ` Steven Rostedt 2019-04-29 20:06 ` torvalds 2019-04-29 20:06 ` Linus Torvalds 2019-04-29 20:20 ` torvalds 2019-04-29 20:20 ` Linus Torvalds 2019-04-29 20:30 ` rostedt 2019-04-29 20:30 ` Steven Rostedt 2019-04-29 21:38 ` torvalds 2019-04-29 21:38 ` Linus Torvalds 2019-04-29 22:07 ` rostedt 2019-04-29 22:07 ` Steven Rostedt 2019-04-30 9:24 ` nstange 2019-04-30 9:24 ` Nicolai Stange 2019-04-30 10:46 ` peterz 2019-04-30 10:46 ` Peter Zijlstra 2019-04-30 13:44 ` rostedt 2019-04-30 13:44 ` Steven Rostedt 2019-04-30 14:20 ` peterz 2019-04-30 14:20 ` Peter Zijlstra 2019-04-30 14:36 ` rostedt 2019-04-30 14:36 ` Steven Rostedt 2019-04-27 10:06 ` [PATCH 4/4] selftests/livepatch: add "ftrace a live patched function" test nstange 2019-04-27 10:06 ` Nicolai Stange
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