powerpc/watchpoint/ptrace: Introduce PPC_DEBUG_FEATURE_DATA_BP_ARCH_31

PPC_DEBUG_FEATURE_DATA_BP_ARCH_31 can be used to determine whether
we are running on an ISA 3.1 compliant machine. Which is needed to
determine DAR behaviour, 512 byte boundary limit etc. This was
requested by Pedro Miraglia Franco de Carvalho for extending
watchpoint features in gdb. Note that availability of 2nd DAWR is
independent of this flag and should be checked using
ppc_debug_info->num_data_bps.

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/20200902042945.129369-8-ravi.bangoria@linux.ibm.com

diff --git a/Documentation/powerpc/ptrace.rst b/Documentation/powerpc/ptrace.rst
index 864d4b6..77725d6 100644 (file)
--- a/Documentation/powerpc/ptrace.rst
+++ b/Documentation/powerpc/ptrace.rst
@@ -46,6 +46,7 @@ features will have bits indicating whether there is support for::
   #define PPC_DEBUG_FEATURE_DATA_BP_RANGE              0x4
   #define PPC_DEBUG_FEATURE_DATA_BP_MASK               0x8
   #define PPC_DEBUG_FEATURE_DATA_BP_DAWR               0x10
+  #define PPC_DEBUG_FEATURE_DATA_BP_ARCH_31            0x20
 
 2. PTRACE_SETHWDEBUG
 

diff --git a/arch/powerpc/include/uapi/asm/ptrace.h b/arch/powerpc/include/uapi/asm/ptrace.h
index f5f1ccc..7004cfe 100644 (file)
--- a/arch/powerpc/include/uapi/asm/ptrace.h
+++ b/arch/powerpc/include/uapi/asm/ptrace.h
@@ -222,6 +222,7 @@ struct ppc_debug_info {
 #define PPC_DEBUG_FEATURE_DATA_BP_RANGE                0x0000000000000004
 #define PPC_DEBUG_FEATURE_DATA_BP_MASK         0x0000000000000008
 #define PPC_DEBUG_FEATURE_DATA_BP_DAWR         0x0000000000000010
+#define PPC_DEBUG_FEATURE_DATA_BP_ARCH_31      0x0000000000000020
 
 #ifndef __ASSEMBLY__
 

diff --git a/arch/powerpc/kernel/ptrace/ptrace-noadv.c b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
index 48c5242..aa36fca 100644 (file)
--- a/arch/powerpc/kernel/ptrace/ptrace-noadv.c
+++ b/arch/powerpc/kernel/ptrace/ptrace-noadv.c
@@ -57,6 +57,8 @@ void ppc_gethwdinfo(struct ppc_debug_info *dbginfo)
        } else {
                dbginfo->features = 0;
        }
+       if (cpu_has_feature(CPU_FTR_ARCH_31))
+               dbginfo->features |= PPC_DEBUG_FEATURE_DATA_BP_ARCH_31;
 }
 
 int ptrace_get_debugreg(struct task_struct *child, unsigned long addr,