Re: [PATCH v5 4/8] powerpc/watchpoint: Move DAWR detection logic outside of hw_breakpoint.c

[Christophe Leroy]

Le 25/08/2020 à 06:36, Ravi Bangoria a écrit :

Power10 hw has multiple DAWRs but hw doesn't tell which DAWR caused
the exception. So we have a sw logic to detect that in hw_breakpoint.c.
But hw_breakpoint.c gets compiled only with CONFIG_HAVE_HW_BREAKPOINT=Y.
Move DAWR detection logic outside of hw_breakpoint.c so that it can be
reused when CONFIG_HAVE_HW_BREAKPOINT is not set.

Signed-off-by: Ravi Bangoria <ravi.bango...@linux.ibm.com>
---
  arch/powerpc/include/asm/hw_breakpoint.h      |   8 +
  arch/powerpc/kernel/Makefile                  |   3 +-
  arch/powerpc/kernel/hw_breakpoint.c           | 159 +----------------
  .../kernel/hw_breakpoint_constraints.c        | 162 ++++++++++++++++++
  4 files changed, 174 insertions(+), 158 deletions(-)
  create mode 100644 arch/powerpc/kernel/hw_breakpoint_constraints.c

[...]

diff --git a/arch/powerpc/kernel/hw_breakpoint_constraints.c 
b/arch/powerpc/kernel/hw_breakpoint_constraints.c
new file mode 100644
index 000000000000..867ee4aa026a
--- /dev/null
+++ b/arch/powerpc/kernel/hw_breakpoint_constraints.c
@@ -0,0 +1,162 @@

[...]

+
+static int cache_op_size(void)
+{
+#ifdef __powerpc64__
+       return ppc64_caches.l1d.block_size;
+#else
+       return L1_CACHE_BYTES;
+#endif
+}

You've got l1_dcache_bytes() in arch/powerpc/include/asm/cache.h to do that.

+
+void wp_get_instr_detail(struct pt_regs *regs, struct ppc_inst *instr,
+                        int *type, int *size, unsigned long *ea)
+{
+       struct instruction_op op;
+
+       if (__get_user_instr_inatomic(*instr, (void __user *)regs->nip))
+               return;
+
+       analyse_instr(&op, regs, *instr);
+       *type = GETTYPE(op.type);
+       *ea = op.ea;
+#ifdef __powerpc64__
+       if (!(regs->msr & MSR_64BIT))
+               *ea &= 0xffffffffUL;
+#endif

This #ifdef is unneeded, it should build fine on a 32 bits too.

+
+       *size = GETSIZE(op.type);
+       if (*type == CACHEOP) {
+               *size = cache_op_size();
+               *ea &= ~(*size - 1);
+       } else if (*type == LOAD_VMX || *type == STORE_VMX) {
+               *ea &= ~(*size - 1);
+       }
+}

Christophe