powerpc: Dynamically calculate the dabrx based on kernel/user/hypervisor

Currently we mark the DABRX to interrupt on all matches
(hypervisor/kernel/user and then filter in software.  We can be a lot
smarter now that we can set the DABRX dynamically.

This sets the DABRX based on the flags passed by the user.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 11 insertions, 4 deletions

diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 6891d79ecef6..a89cae481b04 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -73,7 +73,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
          * If so, DABR will be populated in single_step_dabr_instruction().
          */
         if (current->thread.last_hit_ubp != bp)
-                set_dabr(info->address | info->type | DABR_TRANSLATION, DABRX_ALL);
+                set_dabr(info->address | info->type | DABR_TRANSLATION, info->dabrx);
 
         return 0;
 }
@@ -170,6 +170,13 @@ int arch_validate_hwbkpt_settings(struct perf_event *bp)
 
         info->address = bp->attr.bp_addr;
         info->len = bp->attr.bp_len;
+        info->dabrx = DABRX_ALL;
+        if (bp->attr.exclude_user)
+                info->dabrx &= ~DABRX_USER;
+        if (bp->attr.exclude_kernel)
+                info->dabrx &= ~DABRX_KERNEL;
+        if (bp->attr.exclude_hv)
+                info->dabrx &= ~DABRX_HYP;
 
         /*
          * Since breakpoint length can be a maximum of HW_BREAKPOINT_LEN(8)
@@ -197,7 +204,7 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)
 
         info = counter_arch_bp(tsk->thread.last_hit_ubp);
         regs->msr &= ~MSR_SE;
-        set_dabr(info->address | info->type | DABR_TRANSLATION, DABRX_ALL);
+        set_dabr(info->address | info->type | DABR_TRANSLATION, info->dabrx);
         tsk->thread.last_hit_ubp = NULL;
 }
 
@@ -281,7 +288,7 @@ int __kprobes hw_breakpoint_handler(struct die_args *args)
         if (!info->extraneous_interrupt)
                 perf_bp_event(bp, regs);
 
-        set_dabr(info->address | info->type | DABR_TRANSLATION, DABRX_ALL);
+        set_dabr(info->address | info->type | DABR_TRANSLATION, info->dabrx);
 out:
         rcu_read_unlock();
         return rc;
@@ -313,7 +320,7 @@ int __kprobes single_step_dabr_instruction(struct die_args *args)
         if (!info->extraneous_interrupt)
                 perf_bp_event(bp, regs);
 
-        set_dabr(info->address | info->type | DABR_TRANSLATION, DABRX_ALL);
+        set_dabr(info->address | info->type | DABR_TRANSLATION, info->dabrx);
         current->thread.last_hit_ubp = NULL;
 
         /*