powerpc/watchpoint: Fix DAWR exception for CACHEOP

'ea' returned by analyse_instr() needs to be aligned down to cache
block size for CACHEOP instructions. analyse_instr() does not set
size for CACHEOP, thus size also needs to be calculated manually.

Fixes: 27985b2a640e ("powerpc/watchpoint: Don't ignore extraneous exceptions blindly")
Fixes: 74c6881019b7 ("powerpc/watchpoint: Prepare handler to handle more than one watchpoint")
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200723090813.303838-4-ravi.bangoria@linux.ibm.com

diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index a971e22..c55e67b 100644 (file)
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -538,7 +538,12 @@ static bool check_dawrx_constraints(struct pt_regs *regs, int type,
        if (OP_IS_LOAD(type) && !(info->type & HW_BRK_TYPE_READ))
                return false;
 
-       if (OP_IS_STORE(type) && !(info->type & HW_BRK_TYPE_WRITE))
+       /*
+        * The Cache Management instructions other than dcbz never
+        * cause a match. i.e. if type is CACHEOP, the instruction
+        * is dcbz, and dcbz is treated as Store.
+        */
+       if ((OP_IS_STORE(type) || type == CACHEOP) && !(info->type & HW_BRK_TYPE_WRITE))
                return false;
 
        if (is_kernel_addr(regs->nip) && !(info->type & HW_BRK_TYPE_KERNEL))
@@ -601,6 +606,15 @@ static bool check_constraints(struct pt_regs *regs, struct ppc_inst instr,
        return false;
 }
 
+static int cache_op_size(void)
+{
+#ifdef __powerpc64__
+       return ppc64_caches.l1d.block_size;
+#else
+       return L1_CACHE_BYTES;
+#endif
+}
+
 static void get_instr_detail(struct pt_regs *regs, struct ppc_inst *instr,
                             int *type, int *size, unsigned long *ea)
 {
@@ -616,7 +630,12 @@ static void get_instr_detail(struct pt_regs *regs, struct ppc_inst *instr,
        if (!(regs->msr & MSR_64BIT))
                *ea &= 0xffffffffUL;
 #endif
+
        *size = GETSIZE(op.type);
+       if (*type == CACHEOP) {
+               *size = cache_op_size();
+               *ea &= ~(*size - 1);
+       }
 }
 
 static bool is_larx_stcx_instr(int type)