From: rostedt at goodmis.org (Steven Rostedt) Subject: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions Date: Wed, 01 May 2019 16:28:31 -0400 [thread overview] Message-ID: <20190501203152.397154664@goodmis.org> (raw) In-Reply-To: 20190501202830.347656894@goodmis.org From: Peter Zijlstra <peterz at infradead.org> In order to allow breakpoints to emulate call functions, they need to push the return address onto the stack. But because the breakpoint exception frame is added to the stack when the breakpoint is hit, there's no room to add the address onto the stack and return to the address of the emulated called funtion. To handle this, copy the exception frame on entry of the breakpoint handler and have leave a gap that can be used to add a return address to the stack frame and return from the breakpoint to the emulated called function, allowing for that called function to return back to the location after the breakpoint was placed. The helper functions were also added: int3_emulate_push(): to push the address onto the gap in the stack int3_emulate_jmp(): changes the location of the regs->ip to return there. int3_emulate_call(): push the return address and change regs->ip Cc: Andy Lutomirski <luto at kernel.org> Cc: Nicolai Stange <nstange at suse.de> Cc: Thomas Gleixner <tglx at linutronix.de> Cc: Ingo Molnar <mingo at redhat.com> Cc: Borislav Petkov <bp at alien8.de> Cc: "H. Peter Anvin" <hpa at zytor.com> Cc: the arch/x86 maintainers <x86 at kernel.org> Cc: Josh Poimboeuf <jpoimboe at redhat.com> Cc: Jiri Kosina <jikos at kernel.org> Cc: Miroslav Benes <mbenes at suse.cz> Cc: Petr Mladek <pmladek at suse.com> Cc: Joe Lawrence <joe.lawrence at redhat.com> Cc: Shuah Khan <shuah at kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com> Cc: Tim Chen <tim.c.chen at linux.intel.com> Cc: Sebastian Andrzej Siewior <bigeasy at linutronix.de> Cc: Mimi Zohar <zohar at linux.ibm.com> Cc: Juergen Gross <jgross at suse.com> Cc: Nick Desaulniers <ndesaulniers at google.com> Cc: Nayna Jain <nayna at linux.ibm.com> Cc: Masahiro Yamada <yamada.masahiro at socionext.com> Cc: Joerg Roedel <jroedel at suse.de> Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest at vger.kernel.org> Cc: stable at vger.kernel.org Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching") Signed-off-by: *** Need Peter Zijlstra's SoB here! *** Signed-off-by: Steven Rostedt (VMware) <rostedt at goodmis.org> --- arch/x86/entry/entry_32.S | 11 +++++++++++ arch/x86/entry/entry_64.S | 14 ++++++++++++-- arch/x86/include/asm/text-patching.h | 20 ++++++++++++++++++++ 3 files changed, 43 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index d309f30cf7af..50bbf4035baf 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1478,6 +1478,17 @@ ENTRY(int3) ASM_CLAC pushl $-1 # mark this as an int +#ifdef CONFIG_VM86 + testl $X86_EFLAGS_VM, PT_EFLAGS(%esp) + jnz .Lfrom_usermode_no_gap +#endif + 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 1f0efdb7b629..834ec1397dab 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -879,7 +879,7 @@ 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 +.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 create_gap=0 ENTRY(\sym) UNWIND_HINT_IRET_REGS offset=\has_error_code*8 @@ -899,6 +899,16 @@ 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 @@ -1130,7 +1140,7 @@ apicinterrupt3 HYPERV_STIMER0_VECTOR \ #endif /* CONFIG_HYPERV */ idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK -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 */ -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: rostedt@goodmis.org (Steven Rostedt) Subject: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions Date: Wed, 01 May 2019 16:28:31 -0400 [thread overview] Message-ID: <20190501203152.397154664@goodmis.org> (raw) Message-ID: <20190501202831.F8zRsmTMVq5yNkPMiXuG9DHxenqXNothu3_fyuBqa-c@z> (raw) In-Reply-To: 20190501202830.347656894@goodmis.org From: Peter Zijlstra <peterz@infradead.org> In order to allow breakpoints to emulate call functions, they need to push the return address onto the stack. But because the breakpoint exception frame is added to the stack when the breakpoint is hit, there's no room to add the address onto the stack and return to the address of the emulated called funtion. To handle this, copy the exception frame on entry of the breakpoint handler and have leave a gap that can be used to add a return address to the stack frame and return from the breakpoint to the emulated called function, allowing for that called function to return back to the location after the breakpoint was placed. The helper functions were also added: int3_emulate_push(): to push the address onto the gap in the stack int3_emulate_jmp(): changes the location of the regs->ip to return there. int3_emulate_call(): push the return address and change regs->ip Cc: Andy Lutomirski <luto at kernel.org> Cc: Nicolai Stange <nstange at suse.de> Cc: Thomas Gleixner <tglx at linutronix.de> Cc: Ingo Molnar <mingo at redhat.com> Cc: Borislav Petkov <bp at alien8.de> Cc: "H. Peter Anvin" <hpa at zytor.com> Cc: the arch/x86 maintainers <x86 at kernel.org> Cc: Josh Poimboeuf <jpoimboe at redhat.com> Cc: Jiri Kosina <jikos at kernel.org> Cc: Miroslav Benes <mbenes at suse.cz> Cc: Petr Mladek <pmladek at suse.com> Cc: Joe Lawrence <joe.lawrence at redhat.com> Cc: Shuah Khan <shuah at kernel.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk at oracle.com> Cc: Tim Chen <tim.c.chen at linux.intel.com> Cc: Sebastian Andrzej Siewior <bigeasy at linutronix.de> Cc: Mimi Zohar <zohar at linux.ibm.com> Cc: Juergen Gross <jgross at suse.com> Cc: Nick Desaulniers <ndesaulniers at google.com> Cc: Nayna Jain <nayna at linux.ibm.com> Cc: Masahiro Yamada <yamada.masahiro at socionext.com> Cc: Joerg Roedel <jroedel at suse.de> Cc: "open list:KERNEL SELFTEST FRAMEWORK" <linux-kselftest at vger.kernel.org> Cc: stable at vger.kernel.org Fixes: b700e7f03df5 ("livepatch: kernel: add support for live patching") Signed-off-by: *** Need Peter Zijlstra's SoB here! *** Signed-off-by: Steven Rostedt (VMware) <rostedt at goodmis.org> --- arch/x86/entry/entry_32.S | 11 +++++++++++ arch/x86/entry/entry_64.S | 14 ++++++++++++-- arch/x86/include/asm/text-patching.h | 20 ++++++++++++++++++++ 3 files changed, 43 insertions(+), 2 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index d309f30cf7af..50bbf4035baf 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -1478,6 +1478,17 @@ ENTRY(int3) ASM_CLAC pushl $-1 # mark this as an int +#ifdef CONFIG_VM86 + testl $X86_EFLAGS_VM, PT_EFLAGS(%esp) + jnz .Lfrom_usermode_no_gap +#endif + 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 1f0efdb7b629..834ec1397dab 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -879,7 +879,7 @@ 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 +.macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 create_gap=0 ENTRY(\sym) UNWIND_HINT_IRET_REGS offset=\has_error_code*8 @@ -899,6 +899,16 @@ 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 @@ -1130,7 +1140,7 @@ apicinterrupt3 HYPERV_STIMER0_VECTOR \ #endif /* CONFIG_HYPERV */ idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK -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 */ -- 2.20.1
next parent reply other threads:[~2019-05-01 20:28 UTC|newest] Thread overview: 204+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <20190501202830.347656894@goodmis.org> 2019-05-01 20:28 ` rostedt [this message] 2019-05-01 20:28 ` [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions Steven Rostedt 2019-05-02 3:24 ` rostedt 2019-05-02 3:24 ` Steven Rostedt 2019-05-02 16:21 ` peterz 2019-05-02 16:21 ` Peter Zijlstra 2019-05-02 16:29 ` peterz 2019-05-02 16:29 ` Peter Zijlstra 2019-05-02 18:02 ` torvalds 2019-05-02 18:02 ` Linus Torvalds 2019-05-02 18:18 ` peterz 2019-05-02 18:18 ` Peter Zijlstra 2019-05-02 18:30 ` peterz 2019-05-02 18:30 ` Peter Zijlstra 2019-05-02 18:43 ` torvalds 2019-05-02 18:43 ` Linus Torvalds 2019-05-02 19:28 ` jikos 2019-05-02 19:28 ` Jiri Kosina 2019-05-02 20:25 ` luto 2019-05-02 20:25 ` Andy Lutomirski 2019-05-02 20:21 ` peterz 2019-05-02 20:21 ` Peter Zijlstra 2019-05-02 20:49 ` torvalds 2019-05-02 20:49 ` Linus Torvalds 2019-05-02 21:32 ` peterz 2019-05-02 21:32 ` Peter Zijlstra 2019-05-03 19:24 ` rostedt 2019-05-03 19:24 ` Steven Rostedt 2019-05-03 21:46 ` torvalds 2019-05-03 21:46 ` Linus Torvalds 2019-05-03 22:49 ` rostedt 2019-05-03 22:49 ` Steven Rostedt 2019-05-03 23:07 ` torvalds 2019-05-03 23:07 ` Linus Torvalds 2019-05-04 4:17 ` rostedt 2019-05-04 4:17 ` Steven Rostedt [not found] ` <CAHk-=wiuSFbv_rELND-BLWcP0GSZ0yF=xOAEcf61GE3bU9d=yg@mail.gmail.com> 2019-05-04 18:59 ` torvalds 2019-05-04 18:59 ` Linus Torvalds 2019-05-04 20:12 ` luto 2019-05-04 20:12 ` Andy Lutomirski 2019-05-04 20:28 ` torvalds 2019-05-04 20:28 ` Linus Torvalds 2019-05-04 20:36 ` torvalds 2019-05-04 20:36 ` Linus Torvalds 2019-05-03 22:55 ` luto 2019-05-03 22:55 ` Andy Lutomirski 2019-05-03 23:16 ` torvalds 2019-05-03 23:16 ` Linus Torvalds 2019-05-03 23:32 ` luto 2019-05-03 23:32 ` Andy Lutomirski 2019-05-02 22:52 ` rostedt 2019-05-02 22:52 ` Steven Rostedt 2019-05-02 23:31 ` rostedt 2019-05-02 23:31 ` Steven Rostedt 2019-05-02 23:50 ` rostedt 2019-05-02 23:50 ` Steven Rostedt 2019-05-03 1:51 ` [RFC][PATCH 1/2 v2] " rostedt 2019-05-03 1:51 ` Steven Rostedt 2019-05-03 9:29 ` [RFC][PATCH 1/2] " peterz 2019-05-03 9:29 ` Peter Zijlstra 2019-05-03 13:22 ` rostedt 2019-05-03 13:22 ` Steven Rostedt 2019-05-03 16:20 ` luto 2019-05-03 16:20 ` Andy Lutomirski 2019-05-03 16:31 ` rostedt 2019-05-03 16:31 ` Steven Rostedt 2019-05-03 16:35 ` peterz 2019-05-03 16:35 ` Peter Zijlstra 2019-05-03 16:44 ` luto 2019-05-03 16:44 ` Andy Lutomirski 2019-05-03 16:49 ` rostedt 2019-05-03 16:49 ` Steven Rostedt 2019-05-03 16:32 ` peterz 2019-05-03 16:32 ` Peter Zijlstra 2019-05-03 18:57 ` torvalds 2019-05-03 18:57 ` Linus Torvalds 2019-05-06 8:19 ` peterz 2019-05-06 8:19 ` Peter Zijlstra 2019-05-06 13:56 ` rostedt 2019-05-06 13:56 ` Steven Rostedt 2019-05-06 16:17 ` torvalds 2019-05-06 16:17 ` Linus Torvalds 2019-05-06 16:19 ` torvalds 2019-05-06 16:19 ` Linus Torvalds 2019-05-06 17:06 ` rostedt 2019-05-06 17:06 ` Steven Rostedt 2019-05-06 18:06 ` torvalds 2019-05-06 18:06 ` Linus Torvalds 2019-05-06 18:57 ` rostedt 2019-05-06 18:57 ` Steven Rostedt 2019-05-06 19:46 ` torvalds 2019-05-06 19:46 ` Linus Torvalds 2019-05-06 20:29 ` rostedt 2019-05-06 20:29 ` Steven Rostedt 2019-05-06 20:42 ` torvalds 2019-05-06 20:42 ` Linus Torvalds 2019-05-06 20:44 ` torvalds 2019-05-06 20:44 ` Linus Torvalds 2019-05-06 21:45 ` rostedt 2019-05-06 21:45 ` Steven Rostedt 2019-05-06 22:06 ` torvalds 2019-05-06 22:06 ` Linus Torvalds 2019-05-06 22:31 ` torvalds 2019-05-06 22:31 ` Linus Torvalds 2019-05-07 0:10 ` rostedt 2019-05-07 0:10 ` Steven Rostedt 2019-05-07 1:06 ` torvalds 2019-05-07 1:06 ` Linus Torvalds 2019-05-07 1:04 ` rostedt 2019-05-07 1:04 ` Steven Rostedt 2019-05-07 1:34 ` rostedt 2019-05-07 1:34 ` Steven Rostedt 2019-05-07 1:34 ` torvalds 2019-05-07 1:34 ` Linus Torvalds 2019-05-07 1:53 ` rostedt 2019-05-07 1:53 ` Steven Rostedt 2019-05-07 2:22 ` torvalds 2019-05-07 2:22 ` Linus Torvalds 2019-05-07 2:58 ` rostedt 2019-05-07 2:58 ` Steven Rostedt 2019-05-07 3:05 ` torvalds 2019-05-07 3:05 ` Linus Torvalds 2019-05-07 3:21 ` rostedt 2019-05-07 3:21 ` Steven Rostedt 2019-05-07 3:28 ` torvalds 2019-05-07 3:28 ` Linus Torvalds 2019-05-07 14:54 ` torvalds 2019-05-07 14:54 ` Linus Torvalds 2019-05-07 15:12 ` rostedt 2019-05-07 15:12 ` Steven Rostedt 2019-05-07 15:25 ` rostedt 2019-05-07 15:25 ` Steven Rostedt 2019-05-07 16:25 ` rostedt 2019-05-07 16:25 ` Steven Rostedt 2019-05-07 15:31 ` torvalds 2019-05-07 15:31 ` Linus Torvalds 2019-05-07 15:45 ` rostedt 2019-05-07 15:45 ` Steven Rostedt 2019-05-07 16:34 ` peterz 2019-05-07 16:34 ` Peter Zijlstra 2019-05-07 17:08 ` torvalds 2019-05-07 17:08 ` Linus Torvalds 2019-05-07 17:21 ` jpoimboe 2019-05-07 17:21 ` Josh Poimboeuf 2019-05-07 21:24 ` rostedt 2019-05-07 21:24 ` Steven Rostedt 2019-05-08 4:50 ` torvalds 2019-05-08 4:50 ` Linus Torvalds 2019-05-08 16:37 ` rostedt 2019-05-08 16:37 ` Steven Rostedt 2019-05-07 17:38 ` peterz 2019-05-07 17:38 ` Peter Zijlstra 2019-05-07 9:51 ` peterz 2019-05-07 9:51 ` Peter Zijlstra 2019-05-07 14:48 ` luto 2019-05-07 14:48 ` Andy Lutomirski 2019-05-07 14:57 ` torvalds 2019-05-07 14:57 ` Linus Torvalds 2019-05-07 14:13 ` mhiramat 2019-05-07 14:13 ` Masami Hiramatsu 2019-05-07 17:15 ` mhiramat 2019-05-07 17:15 ` Masami Hiramatsu 2019-05-06 14:22 ` peterz 2019-05-06 14:22 ` Peter Zijlstra 2019-05-07 8:57 ` peterz 2019-05-07 8:57 ` Peter Zijlstra 2019-05-07 9:18 ` David.Laight 2019-05-07 9:18 ` David Laight 2019-05-07 11:30 ` peterz 2019-05-07 11:30 ` Peter Zijlstra 2019-05-07 12:57 ` David.Laight 2019-05-07 12:57 ` David Laight 2019-05-07 13:14 ` rostedt 2019-05-07 13:14 ` Steven Rostedt 2019-05-07 14:50 ` David.Laight 2019-05-07 14:50 ` David Laight 2019-05-07 14:57 ` rostedt 2019-05-07 14:57 ` Steven Rostedt 2019-05-07 15:46 ` David.Laight 2019-05-07 15:46 ` David Laight 2019-05-07 13:32 ` peterz 2019-05-07 13:32 ` Peter Zijlstra 2019-05-07 9:27 ` peterz 2019-05-07 9:27 ` Peter Zijlstra 2019-05-07 12:27 ` rostedt 2019-05-07 12:27 ` Steven Rostedt 2019-05-07 12:41 ` peterz 2019-05-07 12:41 ` Peter Zijlstra 2019-05-07 12:54 ` rostedt 2019-05-07 12:54 ` Steven Rostedt 2019-05-07 17:22 ` masami.hiramatsu 2019-05-07 17:22 ` Masami Hiramatsu 2019-05-07 14:28 ` peterz 2019-05-07 14:28 ` Peter Zijlstra 2019-05-02 20:48 ` rostedt 2019-05-02 20:48 ` Steven Rostedt 2019-05-06 15:14 ` jpoimboe 2019-05-06 15:14 ` Josh Poimboeuf 2019-05-01 20:28 ` [RFC][PATCH 2/2] ftrace/x86: Emulate call function while updating in breakpoint handler rostedt 2019-05-01 20:28 ` Steven Rostedt 2019-05-03 10:22 ` [RFC][PATCH 1.5/2] x86: Add int3_emulate_call() selftest peterz 2019-05-03 10:22 ` Peter Zijlstra 2019-05-03 18:46 ` rostedt 2019-05-03 18:46 ` Steven Rostedt
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