powerpc/xmon: Remove store_inst() for patch_instruction()

For modifying instructions in xmon, patch_instruction() can serve the
same role that store_inst() is performing with the advantage of not
being specific to xmon. In some places patch_instruction() is already
being using followed by store_inst(). In these cases just remove the
store_inst(). Otherwise replace store_inst() with patch_instruction().

Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Link: https://lore.kernel.org/r/20200506034050.24806-2-jniethe5@gmail.com

arch/powerpc/xmon/xmon.c

@@ -326,11 +326,6 @@ static inline void sync(void)
 	asm volatile("sync; isync");
 }
 
-static inline void store_inst(void *p)
-{
-	asm volatile ("dcbst 0,%0; sync; icbi 0,%0; isync" : : "r" (p));
-}
-
 static inline void cflush(void *p)
 {
 	asm volatile ("dcbf 0,%0; icbi 0,%0" : : "r" (p));
@@ -882,8 +877,7 @@ static struct bpt *new_breakpoint(unsigned long a)
 	for (bp = bpts; bp < &bpts[NBPTS]; ++bp) {
 		if (!bp->enabled && atomic_read(&bp->ref_count) == 0) {
 			bp->address = a;
-			bp->instr[1] = bpinstr;
-			store_inst(&bp->instr[1]);
+			patch_instruction(&bp->instr[1], bpinstr);
 			return bp;
 		}
 	}
@@ -895,25 +889,26 @@ static struct bpt *new_breakpoint(unsigned long a)
 static void insert_bpts(void)
 {
 	int i;
+	unsigned int instr;
 	struct bpt *bp;
 
 	bp = bpts;
 	for (i = 0; i < NBPTS; ++i, ++bp) {
 		if ((bp->enabled & (BP_TRAP|BP_CIABR)) == 0)
 			continue;
-		if (mread(bp->address, &bp->instr[0], 4) != 4) {
+		if (mread(bp->address, &instr, 4) != 4) {
 			printf("Couldn't read instruction at %lx, "
 			       "disabling breakpoint there\n", bp->address);
 			bp->enabled = 0;
 			continue;
 		}
-		if (IS_MTMSRD(bp->instr[0]) || IS_RFID(bp->instr[0])) {
+		if (IS_MTMSRD(instr) || IS_RFID(instr)) {
 			printf("Breakpoint at %lx is on an mtmsrd or rfid "
 			       "instruction, disabling it\n", bp->address);
 			bp->enabled = 0;
 			continue;
 		}
-		store_inst(&bp->instr[0]);
+		patch_instruction(bp->instr, instr);
 		if (bp->enabled & BP_CIABR)
 			continue;
 		if (patch_instruction((unsigned int *)bp->address,
@@ -923,7 +918,6 @@ static void insert_bpts(void)
 			bp->enabled &= ~BP_TRAP;
 			continue;
 		}
-		store_inst((void *)bp->address);
 	}
 }
 
@@ -958,8 +952,6 @@ static void remove_bpts(void)
 			(unsigned int *)bp->address, bp->instr[0]) != 0)
 			printf("Couldn't remove breakpoint at %lx\n",
 			       bp->address);
-		else
-			store_inst((void *)bp->address);
 	}
 }