powerpc/watchpoint: Provide DAWR number to set_dawr

Introduce new parameter 'nr' to set_dawr() which indicates which DAWR
should be programed.
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Michael Neuling <mikey@neuling.org>
Link: https://lore.kernel.org/r/20200514111741.97993-6-ravi.bangoria@linux.ibm.com

arch/powerpc/include/asm/hw_breakpoint.h

@@ -104,10 +104,10 @@ static inline bool dawr_enabled(void)
 {
 	return dawr_force_enable;
 }
-int set_dawr(struct arch_hw_breakpoint *brk);
+int set_dawr(int nr, struct arch_hw_breakpoint *brk);
 #else
 static inline bool dawr_enabled(void) { return false; }
-static inline int set_dawr(struct arch_hw_breakpoint *brk) { return -1; }
+static inline int set_dawr(int nr, struct arch_hw_breakpoint *brk) { return -1; }
 #endif
 
 #endif	/* __KERNEL__ */

arch/powerpc/kernel/dawr.c

@@ -16,7 +16,7 @@
 bool dawr_force_enable;
 EXPORT_SYMBOL_GPL(dawr_force_enable);
 
-int set_dawr(struct arch_hw_breakpoint *brk)
+int set_dawr(int nr, struct arch_hw_breakpoint *brk)
 {
 	unsigned long dawr, dawrx, mrd;
 
@@ -39,15 +39,20 @@ int set_dawr(struct arch_hw_breakpoint *brk)
 	if (ppc_md.set_dawr)
 		return ppc_md.set_dawr(dawr, dawrx);
 
-	mtspr(SPRN_DAWR0, dawr);
-	mtspr(SPRN_DAWRX0, dawrx);
+	if (nr == 0) {
+		mtspr(SPRN_DAWR0, dawr);
+		mtspr(SPRN_DAWRX0, dawrx);
+	} else {
+		mtspr(SPRN_DAWR1, dawr);
+		mtspr(SPRN_DAWRX1, dawrx);
+	}
 
 	return 0;
 }
 
 static void set_dawr_cb(void *info)
 {
-	set_dawr(info);
+	set_dawr(0, info);
 }
 
 static ssize_t dawr_write_file_bool(struct file *file,
@@ -60,7 +65,7 @@ static ssize_t dawr_write_file_bool(struct file *file,
 	/* Send error to user if they hypervisor won't allow us to write DAWR */
 	if (!dawr_force_enable &&
 	    firmware_has_feature(FW_FEATURE_LPAR) &&
-	    set_dawr(&null_brk) != H_SUCCESS)
+	    set_dawr(0, &null_brk) != H_SUCCESS)
 		return -ENODEV;
 
 	rc = debugfs_write_file_bool(file, user_buf, count, ppos);

arch/powerpc/kernel/process.c

@@ -806,7 +806,7 @@ void __set_breakpoint(struct arch_hw_breakpoint *brk)
 
 	if (dawr_enabled())
 		// Power8 or later
-		set_dawr(brk);
+		set_dawr(0, brk);
 	else if (IS_ENABLED(CONFIG_PPC_8xx))
 		set_breakpoint_8xx(brk);
 	else if (!cpu_has_feature(CPU_FTR_ARCH_207S))