From: peterz at infradead.org (Peter Zijlstra) Subject: [RFC][PATCH] ftrace/x86: Emulate call function while updating in breakpoint handler Date: Wed, 1 May 2019 15:11:17 +0200 [thread overview] Message-ID: <20190501131117.GW2623@hirez.programming.kicks-ass.net> (raw) In-Reply-To: <CAHk-=wjJ8D74+FDcXGL65Q9aB0cc7B4vr2s2rS6V4d4a3hU-1Q@mail.gmail.com> 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. --- 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(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 7b23431be5cb..d246302085a3 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1479,6 +1479,13 @@ ENTRY(int3) ASM_CLAC pushl $-1 # mark this as an int + testl $SEGMENT_RPL_MASK, PT_CS(%esp) + jnz .Lfrom_usermode_no_gap + .rept 6 + pushl 5*4(%esp) + .endr +.Lfrom_usermode_no_gap: + SAVE_ALL switch_stacks=1 ENCODE_FRAME_POINTER TRACE_IRQS_OFF diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 20e45d9b4e15..268cd9affe04 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -878,7 +878,7 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt * @paranoid == 2 is special: the stub will never switch stacks. This is for * #DF: if the thread stack is somehow unusable, we'll still get a useful OOPS. */ -.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ist_offset=0 +.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ist_offset=0 create_gap=0 ENTRY(\sym) UNWIND_HINT_IRET_REGS offset=\has_error_code*8 @@ -898,6 +898,16 @@ ENTRY(\sym) jnz .Lfrom_usermode_switch_stack_\@ .endif + .if \create_gap == 1 + testb $3, CS-ORIG_RAX(%rsp) + jnz .Lfrom_usermode_no_gap_\@ + .rept 6 + pushq 5*8(%rsp) + .endr + UNWIND_HINT_IRET_REGS offset=8 +.Lfrom_usermode_no_gap_\@: + .endif + .if \paranoid call paranoid_entry .else @@ -1129,7 +1139,7 @@ apicinterrupt3 HYPERV_STIMER0_VECTOR \ #endif /* CONFIG_HYPERV */ idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=IST_INDEX_DB ist_offset=DB_STACK_OFFSET -idtentry int3 do_int3 has_error_code=0 +idtentry int3 do_int3 has_error_code=0 create_gap=1 idtentry stack_segment do_stack_segment has_error_code=1 #ifdef CONFIG_XEN_PV diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index e85ff65c43c3..ba275b6292db 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -39,4 +39,24 @@ extern int poke_int3_handler(struct pt_regs *regs); extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); extern int after_bootmem; +static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val) +{ + regs->sp -= sizeof(unsigned long); + *(unsigned long *)regs->sp = val; +} + +static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) +{ + regs->ip = ip; +} + +#define INT3_INSN_SIZE 1 +#define CALL_INSN_SIZE 5 + +static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func) +{ + int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); + int3_emulate_jmp(regs, func); +} + #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); + 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); + 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: peterz@infradead.org (Peter Zijlstra) Subject: [RFC][PATCH] ftrace/x86: Emulate call function while updating in breakpoint handler Date: Wed, 1 May 2019 15:11:17 +0200 [thread overview] Message-ID: <20190501131117.GW2623@hirez.programming.kicks-ass.net> (raw) Message-ID: <20190501131117.ncGnFPk-I3h5gVA7fZej_iLih7jsg9gqhSxnioHczww@z> (raw) In-Reply-To: <CAHk-=wjJ8D74+FDcXGL65Q9aB0cc7B4vr2s2rS6V4d4a3hU-1Q@mail.gmail.com> 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. --- 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(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 7b23431be5cb..d246302085a3 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1479,6 +1479,13 @@ ENTRY(int3) ASM_CLAC pushl $-1 # mark this as an int + testl $SEGMENT_RPL_MASK, PT_CS(%esp) + jnz .Lfrom_usermode_no_gap + .rept 6 + pushl 5*4(%esp) + .endr +.Lfrom_usermode_no_gap: + SAVE_ALL switch_stacks=1 ENCODE_FRAME_POINTER TRACE_IRQS_OFF diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 20e45d9b4e15..268cd9affe04 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -878,7 +878,7 @@ apicinterrupt IRQ_WORK_VECTOR irq_work_interrupt smp_irq_work_interrupt * @paranoid == 2 is special: the stub will never switch stacks. This is for * #DF: if the thread stack is somehow unusable, we'll still get a useful OOPS. */ -.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ist_offset=0 +.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 ist_offset=0 create_gap=0 ENTRY(\sym) UNWIND_HINT_IRET_REGS offset=\has_error_code*8 @@ -898,6 +898,16 @@ ENTRY(\sym) jnz .Lfrom_usermode_switch_stack_\@ .endif + .if \create_gap == 1 + testb $3, CS-ORIG_RAX(%rsp) + jnz .Lfrom_usermode_no_gap_\@ + .rept 6 + pushq 5*8(%rsp) + .endr + UNWIND_HINT_IRET_REGS offset=8 +.Lfrom_usermode_no_gap_\@: + .endif + .if \paranoid call paranoid_entry .else @@ -1129,7 +1139,7 @@ apicinterrupt3 HYPERV_STIMER0_VECTOR \ #endif /* CONFIG_HYPERV */ idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=IST_INDEX_DB ist_offset=DB_STACK_OFFSET -idtentry int3 do_int3 has_error_code=0 +idtentry int3 do_int3 has_error_code=0 create_gap=1 idtentry stack_segment do_stack_segment has_error_code=1 #ifdef CONFIG_XEN_PV diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h index e85ff65c43c3..ba275b6292db 100644 --- a/arch/x86/include/asm/text-patching.h +++ b/arch/x86/include/asm/text-patching.h @@ -39,4 +39,24 @@ extern int poke_int3_handler(struct pt_regs *regs); extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler); extern int after_bootmem; +static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val) +{ + regs->sp -= sizeof(unsigned long); + *(unsigned long *)regs->sp = val; +} + +static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) +{ + regs->ip = ip; +} + +#define INT3_INSN_SIZE 1 +#define CALL_INSN_SIZE 5 + +static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func) +{ + int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE); + int3_emulate_jmp(regs, func); +} + #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); + 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); + 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 13:11 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 [this message] 2019-05-01 13:11 ` Peter Zijlstra 2019-05-01 18:58 ` rostedt 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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