Re: [PATCH] x86: Remove 'e' from kprope structure members

[Jeremy Fitzhardinge]

Harvey Harrison wrote:
> Some kprobe structure members had a superfluous e in their
> name.
>
> eflags -> flags
> esp -> sp
>   

eflags and esp are the actual machine register names (at least in
32-bit), and therefore more distinctive than just "flags". 

If this is in preparation for a unification then OK, but I disagree if
not (and technically 64-bit should be using rsp/rflags).

    J

> Signed-off-by: Harvey Harrison <harvey.harrison@xxxxxxxxx>
> ---
> Ingo, this applies on top of my kprobes unification patch.
>
>  arch/x86/kernel/kprobes_32.c |   34 +++++++++++++++++-----------------
>  arch/x86/kernel/kprobes_64.c |   34 +++++++++++++++++-----------------
>  include/asm-x86/kprobes.h    |   10 +++++-----
>  3 files changed, 39 insertions(+), 39 deletions(-)
>
> diff --git a/arch/x86/kernel/kprobes_32.c b/arch/x86/kernel/kprobes_32.c
> index 6585ec5..44bc600 100644
> --- a/arch/x86/kernel/kprobes_32.c
> +++ b/arch/x86/kernel/kprobes_32.c
> @@ -195,26 +195,26 @@ static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
>  {
>  	kcb->prev_kprobe.kp = kprobe_running();
>  	kcb->prev_kprobe.status = kcb->kprobe_status;
> -	kcb->prev_kprobe.old_eflags = kcb->kprobe_old_eflags;
> -	kcb->prev_kprobe.saved_eflags = kcb->kprobe_saved_eflags;
> +	kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags;
> +	kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
>  }
>  
>  static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
>  {
>  	__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
>  	kcb->kprobe_status = kcb->prev_kprobe.status;
> -	kcb->kprobe_old_eflags = kcb->prev_kprobe.old_eflags;
> -	kcb->kprobe_saved_eflags = kcb->prev_kprobe.saved_eflags;
> +	kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
> +	kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
>  }
>  
>  static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
>  				struct kprobe_ctlblk *kcb)
>  {
>  	__get_cpu_var(current_kprobe) = p;
> -	kcb->kprobe_saved_eflags = kcb->kprobe_old_eflags
> +	kcb->kprobe_saved_flags = kcb->kprobe_old_flags
>  		= (regs->flags & (TF_MASK | IF_MASK));
>  	if (is_IF_modifier(p->opcode))
> -		kcb->kprobe_saved_eflags &= ~IF_MASK;
> +		kcb->kprobe_saved_flags &= ~IF_MASK;
>  }
>  
>  static __always_inline void clear_btf(void)
> @@ -280,7 +280,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
>  			if (kcb->kprobe_status == KPROBE_HIT_SS &&
>  				*p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
>  				regs->flags &= ~TF_MASK;
> -				regs->flags |= kcb->kprobe_saved_eflags;
> +				regs->flags |= kcb->kprobe_saved_flags;
>  				goto no_kprobe;
>  			}
>  			/* We have reentered the kprobe_handler(), since
> @@ -501,7 +501,7 @@ static void __kprobes resume_execution(struct kprobe *p,
>  	switch (p->ainsn.insn[0]) {
>  	case 0x9c:		/* pushfl */
>  		*tos &= ~(TF_MASK | IF_MASK);
> -		*tos |= kcb->kprobe_old_eflags;
> +		*tos |= kcb->kprobe_old_flags;
>  		break;
>  	case 0xc2:		/* iret/ret/lret */
>  	case 0xc3:
> @@ -578,7 +578,7 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
>  	}
>  
>  	resume_execution(cur, regs, kcb);
> -	regs->flags |= kcb->kprobe_saved_eflags;
> +	regs->flags |= kcb->kprobe_saved_flags;
>  	trace_hardirqs_fixup_flags(regs->flags);
>  
>  	/*Restore back the original saved kprobes variables and continue. */
> @@ -617,7 +617,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
>  		 * normal page fault.
>  		 */
>  		regs->ip = (unsigned long)cur->addr;
> -		regs->flags |= kcb->kprobe_old_eflags;
> +		regs->flags |= kcb->kprobe_old_flags;
>  		if (kcb->kprobe_status == KPROBE_REENTER)
>  			restore_previous_kprobe(kcb);
>  		else
> @@ -703,8 +703,8 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
>  	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
>  
>  	kcb->jprobe_saved_regs = *regs;
> -	kcb->jprobe_saved_esp = &regs->sp;
> -	addr = (unsigned long)(kcb->jprobe_saved_esp);
> +	kcb->jprobe_saved_sp = &regs->sp;
> +	addr = (unsigned long)(kcb->jprobe_saved_sp);
>  
>  	/*
>  	 * TBD: As Linus pointed out, gcc assumes that the callee
> @@ -730,23 +730,23 @@ void __kprobes jprobe_return(void)
>  		      "       .globl jprobe_return_end	\n"
>  		      "       jprobe_return_end:	\n"
>  		      "       nop			\n"::"b"
> -		      (kcb->jprobe_saved_esp):"memory");
> +		      (kcb->jprobe_saved_sp):"memory");
>  }
>  
>  int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
>  {
>  	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
>  	u8 *addr = (u8 *) (regs->ip - 1);
> -	unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_esp);
> +	unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_sp);
>  	struct jprobe *jp = container_of(p, struct jprobe, kp);
>  
>  	if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
> -		if (&regs->sp != kcb->jprobe_saved_esp) {
> +		if (&regs->sp != kcb->jprobe_saved_sp) {
>  			struct pt_regs *saved_regs =
> -			    container_of(kcb->jprobe_saved_esp,
> +			    container_of(kcb->jprobe_saved_sp,
>  					    struct pt_regs, sp);
>  			printk("current sp %p does not match saved sp %p\n",
> -			       &regs->sp, kcb->jprobe_saved_esp);
> +			       &regs->sp, kcb->jprobe_saved_sp);
>  			printk("Saved registers for jprobe %p\n", jp);
>  			show_registers(saved_regs);
>  			printk("Current registers\n");
> diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes_64.c
> index a0ec7c2..3d1f1fa 100644
> --- a/arch/x86/kernel/kprobes_64.c
> +++ b/arch/x86/kernel/kprobes_64.c
> @@ -234,26 +234,26 @@ static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
>  {
>  	kcb->prev_kprobe.kp = kprobe_running();
>  	kcb->prev_kprobe.status = kcb->kprobe_status;
> -	kcb->prev_kprobe.old_eflags = kcb->kprobe_old_eflags;
> -	kcb->prev_kprobe.saved_eflags = kcb->kprobe_saved_eflags;
> +	kcb->prev_kprobe.old_flags = kcb->kprobe_old_flags;
> +	kcb->prev_kprobe.saved_flags = kcb->kprobe_saved_flags;
>  }
>  
>  static void __kprobes restore_previous_kprobe(struct kprobe_ctlblk *kcb)
>  {
>  	__get_cpu_var(current_kprobe) = kcb->prev_kprobe.kp;
>  	kcb->kprobe_status = kcb->prev_kprobe.status;
> -	kcb->kprobe_old_eflags = kcb->prev_kprobe.old_eflags;
> -	kcb->kprobe_saved_eflags = kcb->prev_kprobe.saved_eflags;
> +	kcb->kprobe_old_flags = kcb->prev_kprobe.old_flags;
> +	kcb->kprobe_saved_flags = kcb->prev_kprobe.saved_flags;
>  }
>  
>  static void __kprobes set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
>  				struct kprobe_ctlblk *kcb)
>  {
>  	__get_cpu_var(current_kprobe) = p;
> -	kcb->kprobe_saved_eflags = kcb->kprobe_old_eflags
> +	kcb->kprobe_saved_flags = kcb->kprobe_old_flags
>  		= (regs->flags & (TF_MASK | IF_MASK));
>  	if (is_IF_modifier(p->ainsn.insn))
> -		kcb->kprobe_saved_eflags &= ~IF_MASK;
> +		kcb->kprobe_saved_flags &= ~IF_MASK;
>  }
>  
>  static __always_inline void clear_btf(void)
> @@ -312,7 +312,7 @@ static int __kprobes kprobe_handler(struct pt_regs *regs)
>  			if (kcb->kprobe_status == KPROBE_HIT_SS &&
>  				*p->ainsn.insn == BREAKPOINT_INSTRUCTION) {
>  				regs->flags &= ~TF_MASK;
> -				regs->flags |= kcb->kprobe_saved_eflags;
> +				regs->flags |= kcb->kprobe_saved_flags;
>  				goto no_kprobe;
>  			} else if (kcb->kprobe_status == KPROBE_HIT_SSDONE) {
>  				/* TODO: Provide re-entrancy from
> @@ -510,7 +510,7 @@ static void __kprobes resume_execution(struct kprobe *p,
>  	switch (*insn) {
>  	case 0x9c:		/* pushfl */
>  		*tos &= ~(TF_MASK | IF_MASK);
> -		*tos |= kcb->kprobe_old_eflags;
> +		*tos |= kcb->kprobe_old_flags;
>  		break;
>  	case 0xc3:		/* ret/lret */
>  	case 0xcb:
> @@ -565,7 +565,7 @@ static int __kprobes post_kprobe_handler(struct pt_regs *regs)
>  	}
>  
>  	resume_execution(cur, regs, kcb);
> -	regs->flags |= kcb->kprobe_saved_eflags;
> +	regs->flags |= kcb->kprobe_saved_flags;
>  	trace_hardirqs_fixup_flags(regs->flags);
>  
>  	/* Restore the original saved kprobes variables and continue. */
> @@ -605,7 +605,7 @@ int __kprobes kprobe_fault_handler(struct pt_regs *regs, int trapnr)
>  		 * normal page fault.
>  		 */
>  		regs->ip = (unsigned long)cur->addr;
> -		regs->flags |= kcb->kprobe_old_eflags;
> +		regs->flags |= kcb->kprobe_old_flags;
>  		if (kcb->kprobe_status == KPROBE_REENTER)
>  			restore_previous_kprobe(kcb);
>  		else
> @@ -694,8 +694,8 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
>  	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
>  
>  	kcb->jprobe_saved_regs = *regs;
> -	kcb->jprobe_saved_esp = (long *) regs->sp;
> -	addr = (unsigned long)(kcb->jprobe_saved_esp);
> +	kcb->jprobe_saved_sp = (long *) regs->sp;
> +	addr = (unsigned long)(kcb->jprobe_saved_sp);
>  	/*
>  	 * As Linus pointed out, gcc assumes that the callee
>  	 * owns the argument space and could overwrite it, e.g.
> @@ -720,23 +720,23 @@ void __kprobes jprobe_return(void)
>  		      "       .globl jprobe_return_end	\n"
>  		      "       jprobe_return_end:	\n"
>  		      "       nop			\n"::"b"
> -		      (kcb->jprobe_saved_esp):"memory");
> +		      (kcb->jprobe_saved_sp):"memory");
>  }
>  
>  int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
>  {
>  	struct kprobe_ctlblk *kcb = get_kprobe_ctlblk();
>  	u8 *addr = (u8 *) (regs->ip - 1);
> -	unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_esp);
> +	unsigned long stack_addr = (unsigned long)(kcb->jprobe_saved_sp);
>  	struct jprobe *jp = container_of(p, struct jprobe, kp);
>  
>  	if ((addr > (u8 *) jprobe_return) && (addr < (u8 *) jprobe_return_end)) {
> -		if ((long *)regs->sp != kcb->jprobe_saved_esp) {
> +		if ((long *)regs->sp != kcb->jprobe_saved_sp) {
>  			struct pt_regs *saved_regs =
> -			    container_of(kcb->jprobe_saved_esp,
> +			    container_of(kcb->jprobe_saved_sp,
>  					    struct pt_regs, sp);
>  			printk("current sp %p does not match saved sp %p\n",
> -			       (long *)regs->sp, kcb->jprobe_saved_esp);
> +			       (long *)regs->sp, kcb->jprobe_saved_sp);
>  			printk("Saved registers for jprobe %p\n", jp);
>  			show_registers(saved_regs);
>  			printk("Current registers\n");
> diff --git a/include/asm-x86/kprobes.h b/include/asm-x86/kprobes.h
> index 074ac7d..87b9d1b 100644
> --- a/include/asm-x86/kprobes.h
> +++ b/include/asm-x86/kprobes.h
> @@ -73,16 +73,16 @@ struct arch_specific_insn {
>  struct prev_kprobe {
>  	struct kprobe *kp;
>  	unsigned long status;
> -	unsigned long old_eflags;
> -	unsigned long saved_eflags;
> +	unsigned long old_flags;
> +	unsigned long saved_flags;
>  };
>  
>  /* per-cpu kprobe control block */
>  struct kprobe_ctlblk {
>  	unsigned long kprobe_status;
> -	unsigned long kprobe_old_eflags;
> -	unsigned long kprobe_saved_eflags;
> -	long *jprobe_saved_esp;
> +	unsigned long kprobe_old_flags;
> +	unsigned long kprobe_saved_flags;
> +	long *jprobe_saved_sp;
>  	struct pt_regs jprobe_saved_regs;
>  	kprobe_opcode_t jprobes_stack[MAX_STACK_SIZE];
>  	struct prev_kprobe prev_kprobe;
>   


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