Commit 303e6a9d authored by Ravi Bangoria's avatar Ravi Bangoria Committed by Michael Ellerman
Browse files

powerpc/watchpoint: Convert thread_struct->hw_brk to an array 



So far powerpc hw supported only one watchpoint. But Power10 is
introducing 2nd DAWR. Convert thread_struct->hw_brk into an array.

Signed-off-by: default avatarRavi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Reviewed-by: default avatarMichael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-10-ravi.bangoria@linux.ibm.com
parent 22a214e4

arch/powerpc/include/asm/processor.h

+1 −1
Original line number Diff line number Diff line
@@ -187,7 +187,7 @@ struct thread_struct { 
	 */

	struct perf_event *last_hit_ubp;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */

	struct arch_hw_breakpoint hw_brk; /* info on the hardware breakpoint */

	struct arch_hw_breakpoint hw_brk[HBP_NUM_MAX]; /* hardware breakpoint info */

	unsigned long	trap_nr;	/* last trap # on this thread */

	u8 load_slb;			/* Ages out SLB preload cache entries */

	u8 load_fp;

arch/powerpc/kernel/process.c

+37 −23
Original line number Diff line number Diff line
@@ -711,21 +711,49 @@ void switch_booke_debug_regs(struct debug_reg *new_debug) 
EXPORT_SYMBOL_GPL(switch_booke_debug_regs);

#else	/* !CONFIG_PPC_ADV_DEBUG_REGS */

#ifndef CONFIG_HAVE_HW_BREAKPOINT

static void set_breakpoint(struct arch_hw_breakpoint *brk)

static void set_breakpoint(int i, struct arch_hw_breakpoint *brk)

{

	preempt_disable();

	__set_breakpoint(0, brk);

	__set_breakpoint(i, brk);

	preempt_enable();

}



static void set_debug_reg_defaults(struct thread_struct *thread)

{

	thread->hw_brk.address = 0;

	thread->hw_brk.type = 0;

	thread->hw_brk.len = 0;

	thread->hw_brk.hw_len = 0;

	int i;

	struct arch_hw_breakpoint null_brk = {0};



	for (i = 0; i < nr_wp_slots(); i++) {

		thread->hw_brk[i] = null_brk;

		if (ppc_breakpoint_available())

		set_breakpoint(&thread->hw_brk);

			set_breakpoint(i, &thread->hw_brk[i]);

	}

}



static inline bool hw_brk_match(struct arch_hw_breakpoint *a,

				struct arch_hw_breakpoint *b)

{

	if (a->address != b->address)

		return false;

	if (a->type != b->type)

		return false;

	if (a->len != b->len)

		return false;

	/* no need to check hw_len. it's calculated from address and len */

	return true;

}



static void switch_hw_breakpoint(struct task_struct *new)

{

	int i;



	for (i = 0; i < nr_wp_slots(); i++) {

		if (likely(hw_brk_match(this_cpu_ptr(&current_brk[i]),

					&new->thread.hw_brk[i])))

			continue;



		__set_breakpoint(i, &new->thread.hw_brk[i]);

	}

}

#endif /* !CONFIG_HAVE_HW_BREAKPOINT */

#endif	/* CONFIG_PPC_ADV_DEBUG_REGS */
@@ -829,19 +857,6 @@ bool ppc_breakpoint_available(void) 
}

EXPORT_SYMBOL_GPL(ppc_breakpoint_available);



static inline bool hw_brk_match(struct arch_hw_breakpoint *a,

			      struct arch_hw_breakpoint *b)

{

	if (a->address != b->address)

		return false;

	if (a->type != b->type)

		return false;

	if (a->len != b->len)

		return false;

	/* no need to check hw_len. it's calculated from address and len */

	return true;

}



#ifdef CONFIG_PPC_TRANSACTIONAL_MEM



static inline bool tm_enabled(struct task_struct *tsk)
@@ -1174,8 +1189,7 @@ struct task_struct *__switch_to(struct task_struct *prev, 
 * schedule DABR

 */

#ifndef CONFIG_HAVE_HW_BREAKPOINT

	if (unlikely(!hw_brk_match(this_cpu_ptr(&current_brk[0]), &new->thread.hw_brk)))

		__set_breakpoint(0, &new->thread.hw_brk);

	switch_hw_breakpoint(new);

#endif /* CONFIG_HAVE_HW_BREAKPOINT */

#endif

arch/powerpc/kernel/ptrace/ptrace-noadv.c

+29 −11
Original line number Diff line number Diff line
@@ -67,11 +67,16 @@ int ptrace_get_debugreg(struct task_struct *child, unsigned long addr, 
	/* We only support one DABR and no IABRS at the moment */

	if (addr > 0)

		return -EINVAL;

	dabr_fake = ((child->thread.hw_brk.address & (~HW_BRK_TYPE_DABR)) |

		     (child->thread.hw_brk.type & HW_BRK_TYPE_DABR));

	dabr_fake = ((child->thread.hw_brk[0].address & (~HW_BRK_TYPE_DABR)) |

		     (child->thread.hw_brk[0].type & HW_BRK_TYPE_DABR));

	return put_user(dabr_fake, datalp);

}



/*

 * ptrace_set_debugreg() fakes DABR and DABR is only one. So even if

 * internal hw supports more than one watchpoint, we support only one

 * watchpoint with this interface.

 */

int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned long data)

{

#ifdef CONFIG_HAVE_HW_BREAKPOINT
@@ -137,7 +142,7 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned l 
			return ret;



		thread->ptrace_bps[0] = bp;

		thread->hw_brk = hw_brk;

		thread->hw_brk[0] = hw_brk;

		return 0;

	}
@@ -159,12 +164,24 @@ int ptrace_set_debugreg(struct task_struct *task, unsigned long addr, unsigned l 
	if (set_bp && (!ppc_breakpoint_available()))

		return -ENODEV;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */

	task->thread.hw_brk = hw_brk;

	task->thread.hw_brk[0] = hw_brk;

	return 0;

}



static int find_empty_hw_brk(struct thread_struct *thread)

{

	int i;



	for (i = 0; i < nr_wp_slots(); i++) {

		if (!thread->hw_brk[i].address)

			return i;

	}

	return -1;

}



long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_info)

{

	int i;

#ifdef CONFIG_HAVE_HW_BREAKPOINT

	int len = 0;

	struct thread_struct *thread = &child->thread;
@@ -223,15 +240,16 @@ long ppc_set_hwdebug(struct task_struct *child, struct ppc_hw_breakpoint *bp_inf 
	if (bp_info->addr_mode != PPC_BREAKPOINT_MODE_EXACT)

		return -EINVAL;



	if (child->thread.hw_brk.address)

	i = find_empty_hw_brk(&child->thread);

	if (i < 0)

		return -ENOSPC;



	if (!ppc_breakpoint_available())

		return -ENODEV;



	child->thread.hw_brk = brk;

	child->thread.hw_brk[i] = brk;



	return 1;

	return i + 1;

}



long ppc_del_hwdebug(struct task_struct *child, long data)
@@ -241,7 +259,7 @@ long ppc_del_hwdebug(struct task_struct *child, long data) 
	struct thread_struct *thread = &child->thread;

	struct perf_event *bp;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */

	if (data != 1)

	if (data < 1 || data > nr_wp_slots())

		return -EINVAL;



#ifdef CONFIG_HAVE_HW_BREAKPOINT
@@ -254,11 +272,11 @@ long ppc_del_hwdebug(struct task_struct *child, long data) 
	}

	return ret;

#else /* CONFIG_HAVE_HW_BREAKPOINT */

	if (child->thread.hw_brk.address == 0)

	if (child->thread.hw_brk[data - 1].address == 0)

		return -ENOENT;



	child->thread.hw_brk.address = 0;

	child->thread.hw_brk.type = 0;

	child->thread.hw_brk[data - 1].address = 0;

	child->thread.hw_brk[data - 1].type = 0;

#endif /* CONFIG_HAVE_HW_BREAKPOINT */



	return 0;

arch/powerpc/kernel/ptrace/ptrace32.c

+2 −2
Original line number Diff line number Diff line
@@ -259,8 +259,8 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request, 
		ret = put_user(child->thread.debug.dac1, (u32 __user *)data);

#else

		dabr_fake = (

			(child->thread.hw_brk.address & (~HW_BRK_TYPE_DABR)) |

			(child->thread.hw_brk.type & HW_BRK_TYPE_DABR));

			(child->thread.hw_brk[0].address & (~HW_BRK_TYPE_DABR)) |

			(child->thread.hw_brk[0].type & HW_BRK_TYPE_DABR));

		ret = put_user(dabr_fake, (u32 __user *)data);

#endif

		break;

arch/powerpc/kernel/signal.c

+9 −4
Original line number Diff line number Diff line
@@ -265,15 +265,20 @@ static void do_signal(struct task_struct *tsk) 
		return;               /* no signals delivered */

	}



#ifndef CONFIG_PPC_ADV_DEBUG_REGS

        /*

	 * Reenable the DABR before delivering the signal to

	 * user space. The DABR will have been cleared if it

	 * triggered inside the kernel.

	 */

	if (tsk->thread.hw_brk.address && tsk->thread.hw_brk.type)

		__set_breakpoint(0, &tsk->thread.hw_brk);

#endif

	if (!IS_ENABLED(CONFIG_PPC_ADV_DEBUG_REGS)) {

		int i;



		for (i = 0; i < nr_wp_slots(); i++) {

			if (tsk->thread.hw_brk[i].address && tsk->thread.hw_brk[i].type)

				__set_breakpoint(i, &tsk->thread.hw_brk[i]);

		}

	}



	/* Re-enable the breakpoints for the signal stack */

	thread_change_pc(tsk, tsk->thread.regs);

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