From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: [PATCH v4 18/27] x86/int3: Ensure that poke_int3_handler() is not traced Date: Fri, 21 Feb 2020 14:34:34 +0100 Message-ID: <20200221134216.251192105@infradead.org> References: <20200221133416.777099322@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.org Cc: peterz@infradead.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, frederic@kernel.org, dan.carpenter@oracle.com, mhiramat@kernel.org List-Id: linux-arch.vger.kernel.org From: Thomas Gleixner In order to ensure poke_int3_handler() is completely self contained -- we call this while we're modifying other text, imagine the fun of hitting another INT3 -- ensure that everything it uses is not traced. The primary means here is to force inlining; bsearch() is notrace because all of lib/ is. Not-Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/ptrace.h | 2 +- arch/x86/include/asm/text-patching.h | 11 +++++++---- arch/x86/kernel/alternative.c | 11 +++++++---- 3 files changed, 15 insertions(+), 9 deletions(-) Index: linux-2.6/arch/x86/include/asm/ptrace.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/ptrace.h +++ linux-2.6/arch/x86/include/asm/ptrace.h @@ -123,7 +123,7 @@ static inline void regs_set_return_value * On x86_64, vm86 mode is mercifully nonexistent, and we don't need * the extra check. */ -static inline int user_mode(struct pt_regs *regs) +static __always_inline int user_mode(struct pt_regs *regs) { #ifdef CONFIG_X86_32 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; Index: linux-2.6/arch/x86/include/asm/text-patching.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/text-patching.h +++ linux-2.6/arch/x86/include/asm/text-patching.h @@ -64,7 +64,7 @@ extern void text_poke_finish(void); #define DISP32_SIZE 4 -static inline int text_opcode_size(u8 opcode) +static __always_inline int text_opcode_size(u8 opcode) { int size = 0; @@ -118,12 +118,14 @@ extern __ro_after_init struct mm_struct extern __ro_after_init unsigned long poking_addr; #ifndef CONFIG_UML_X86 -static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) +static __always_inline +void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) { regs->ip = ip; } -static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val) +static __always_inline +void int3_emulate_push(struct pt_regs *regs, unsigned long val) { /* * The int3 handler in entry_64.S adds a gap between the @@ -138,7 +140,8 @@ static inline void int3_emulate_push(str *(unsigned long *)regs->sp = val; } -static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func) +static __always_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); Index: linux-2.6/arch/x86/kernel/alternative.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/alternative.c +++ linux-2.6/arch/x86/kernel/alternative.c @@ -956,7 +956,8 @@ struct bp_patching_desc { static struct bp_patching_desc *bp_desc; -static inline struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp) +static __always_inline +struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp) { struct bp_patching_desc *desc = READ_ONCE(*descp); /* rcu_dereference */ @@ -966,13 +967,13 @@ static inline struct bp_patching_desc *t return desc; } -static inline void put_desc(struct bp_patching_desc *desc) +static __always_inline void put_desc(struct bp_patching_desc *desc) { smp_mb__before_atomic(); atomic_dec(&desc->refs); } -static inline void *text_poke_addr(struct text_poke_loc *tp) +static __always_inline void *text_poke_addr(struct text_poke_loc *tp) { return _stext + tp->rel_addr; } From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bombadil.infradead.org ([198.137.202.133]:56342 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728496AbgBUNu3 (ORCPT ); Fri, 21 Feb 2020 08:50:29 -0500 Message-ID: <20200221134216.251192105@infradead.org> Date: Fri, 21 Feb 2020 14:34:34 +0100 From: Peter Zijlstra Subject: [PATCH v4 18/27] x86/int3: Ensure that poke_int3_handler() is not traced References: <20200221133416.777099322@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, rostedt@goodmis.org Cc: peterz@infradead.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, paulmck@kernel.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, frederic@kernel.org, dan.carpenter@oracle.com, mhiramat@kernel.org Message-ID: <20200221133434.3OoBEsctUjFknwWDt5uYIgGcKMvZsNB58TnEjGn25iQ@z> From: Thomas Gleixner In order to ensure poke_int3_handler() is completely self contained -- we call this while we're modifying other text, imagine the fun of hitting another INT3 -- ensure that everything it uses is not traced. The primary means here is to force inlining; bsearch() is notrace because all of lib/ is. Not-Signed-off-by: Thomas Gleixner Signed-off-by: Peter Zijlstra (Intel) --- arch/x86/include/asm/ptrace.h | 2 +- arch/x86/include/asm/text-patching.h | 11 +++++++---- arch/x86/kernel/alternative.c | 11 +++++++---- 3 files changed, 15 insertions(+), 9 deletions(-) Index: linux-2.6/arch/x86/include/asm/ptrace.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/ptrace.h +++ linux-2.6/arch/x86/include/asm/ptrace.h @@ -123,7 +123,7 @@ static inline void regs_set_return_value * On x86_64, vm86 mode is mercifully nonexistent, and we don't need * the extra check. */ -static inline int user_mode(struct pt_regs *regs) +static __always_inline int user_mode(struct pt_regs *regs) { #ifdef CONFIG_X86_32 return ((regs->cs & SEGMENT_RPL_MASK) | (regs->flags & X86_VM_MASK)) >= USER_RPL; Index: linux-2.6/arch/x86/include/asm/text-patching.h =================================================================== --- linux-2.6.orig/arch/x86/include/asm/text-patching.h +++ linux-2.6/arch/x86/include/asm/text-patching.h @@ -64,7 +64,7 @@ extern void text_poke_finish(void); #define DISP32_SIZE 4 -static inline int text_opcode_size(u8 opcode) +static __always_inline int text_opcode_size(u8 opcode) { int size = 0; @@ -118,12 +118,14 @@ extern __ro_after_init struct mm_struct extern __ro_after_init unsigned long poking_addr; #ifndef CONFIG_UML_X86 -static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) +static __always_inline +void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip) { regs->ip = ip; } -static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val) +static __always_inline +void int3_emulate_push(struct pt_regs *regs, unsigned long val) { /* * The int3 handler in entry_64.S adds a gap between the @@ -138,7 +140,8 @@ static inline void int3_emulate_push(str *(unsigned long *)regs->sp = val; } -static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func) +static __always_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); Index: linux-2.6/arch/x86/kernel/alternative.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/alternative.c +++ linux-2.6/arch/x86/kernel/alternative.c @@ -956,7 +956,8 @@ struct bp_patching_desc { static struct bp_patching_desc *bp_desc; -static inline struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp) +static __always_inline +struct bp_patching_desc *try_get_desc(struct bp_patching_desc **descp) { struct bp_patching_desc *desc = READ_ONCE(*descp); /* rcu_dereference */ @@ -966,13 +967,13 @@ static inline struct bp_patching_desc *t return desc; } -static inline void put_desc(struct bp_patching_desc *desc) +static __always_inline void put_desc(struct bp_patching_desc *desc) { smp_mb__before_atomic(); atomic_dec(&desc->refs); } -static inline void *text_poke_addr(struct text_poke_loc *tp) +static __always_inline void *text_poke_addr(struct text_poke_loc *tp) { return _stext + tp->rel_addr; }