powerpc: tracing: Give hypervisor call tracepoints access to arguments

While most users of the hcall tracepoints will only want the opcode
and return code, some will want all the arguments.  To avoid the
complexity of using varargs we pass a pointer to the register save
area, which contains all the arguments.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 29 insertions, 16 deletions

diff --git a/arch/powerpc/platforms/pseries/hvCall.S b/arch/powerpc/platforms/pseries/hvCall.S
index 01e95ab18d35..383a5d0e9818 100644
--- a/arch/powerpc/platforms/pseries/hvCall.S
+++ b/arch/powerpc/platforms/pseries/hvCall.S
@@ -30,7 +30,7 @@ hcall_tracepoint_refcount:
  * in early init (eg when populating the MMU hashtable) by using an
  * unconditional cpu feature.
  */
-#define HCALL_INST_PRECALL                                      \
+#define HCALL_INST_PRECALL(FIRST_REG)                           \
 BEGIN_FTR_SECTION;                                              \
         b       1f;                                             \
 END_FTR_SECTION(0, 1);                                          \
@@ -47,6 +47,7 @@ END_FTR_SECTION(0, 1);						\
         std     r9,STK_PARM(r9)(r1);                            \
         std     r10,STK_PARM(r10)(r1);                          \
         std     r0,16(r1);                                      \
+        addi    r4,r1,STK_PARM(FIRST_REG);                      \
         stdu    r1,-STACK_FRAME_OVERHEAD(r1);                   \
         bl      .__trace_hcall_entry;                           \
         addi    r1,r1,STACK_FRAME_OVERHEAD;                     \
@@ -68,7 +69,7 @@ END_FTR_SECTION(0, 1);						\
  * in early init (eg when populating the MMU hashtable) by using an
  * unconditional cpu feature.
  */
-#define HCALL_INST_POSTCALL                                     \
+#define __HCALL_INST_POSTCALL                                   \
 BEGIN_FTR_SECTION;                                              \
         b       1f;                                             \
 END_FTR_SECTION(0, 1);                                          \
@@ -88,9 +89,19 @@ END_FTR_SECTION(0, 1);						\
         ld      r3,STK_PARM(r3)(r1);                            \
         mtlr    r0;                                             \
 1:
+
+#define HCALL_INST_POSTCALL_NORETS                              \
+        li      r5,0;                                           \
+        __HCALL_INST_POSTCALL
+
+#define HCALL_INST_POSTCALL(BUFREG)                             \
+        mr      r5,BUFREG;                                      \
+        __HCALL_INST_POSTCALL
+
 #else
-#define HCALL_INST_PRECALL
-#define HCALL_INST_POSTCALL
+#define HCALL_INST_PRECALL(FIRST_ARG)
+#define HCALL_INST_POSTCALL_NORETS
+#define HCALL_INST_POSTCALL(BUFREG)
 #endif
 
         .text
@@ -101,11 +112,11 @@ _GLOBAL(plpar_hcall_norets)
         mfcr    r0
         stw     r0,8(r1)
 
-        HCALL_INST_PRECALL
+        HCALL_INST_PRECALL(r4)
 
         HVSC                            /* invoke the hypervisor */
 
-        HCALL_INST_POSTCALL
+        HCALL_INST_POSTCALL_NORETS
 
         lwz     r0,8(r1)
         mtcrf   0xff,r0
@@ -117,7 +128,7 @@ _GLOBAL(plpar_hcall)
         mfcr    r0
         stw     r0,8(r1)
 
-        HCALL_INST_PRECALL
+        HCALL_INST_PRECALL(r5)
 
         std     r4,STK_PARM(r4)(r1)     /* Save ret buffer */
 
@@ -136,7 +147,7 @@ _GLOBAL(plpar_hcall)
         std     r6, 16(r12)
         std     r7, 24(r12)
 
-        HCALL_INST_POSTCALL
+        HCALL_INST_POSTCALL(r12)
 
         lwz     r0,8(r1)
         mtcrf   0xff,r0
@@ -183,7 +194,7 @@ _GLOBAL(plpar_hcall9)
         mfcr    r0
         stw     r0,8(r1)
 
-        HCALL_INST_PRECALL
+        HCALL_INST_PRECALL(r5)
 
         std     r4,STK_PARM(r4)(r1)     /* Save ret buffer */
 
@@ -211,7 +222,7 @@ _GLOBAL(plpar_hcall9)
         std     r11,56(r12)
         std     r0, 64(r12)
 
-        HCALL_INST_POSTCALL
+        HCALL_INST_POSTCALL(r12)
 
         lwz     r0,8(r1)
         mtcrf   0xff,r0
diff --git a/arch/powerpc/platforms/pseries/hvCall_inst.c b/arch/powerpc/platforms/pseries/hvCall_inst.c
index e44e1035f133..2f58c71b7259 100644
--- a/arch/powerpc/platforms/pseries/hvCall_inst.c
+++ b/arch/powerpc/platforms/pseries/hvCall_inst.c
@@ -102,7 +102,7 @@ static const struct file_operations hcall_inst_seq_fops = {
 #define CPU_NAME_BUF_SIZE       32
 
 
-static void probe_hcall_entry(unsigned long opcode)
+static void probe_hcall_entry(unsigned long opcode, unsigned long *args)
 {
         struct hcall_stats *h;
 
@@ -114,7 +114,8 @@ static void probe_hcall_entry(unsigned long opcode)
         h->purr_start = mfspr(SPRN_PURR);
 }
 
-static void probe_hcall_exit(unsigned long opcode, unsigned long retval)
+static void probe_hcall_exit(unsigned long opcode, unsigned long retval,
+                             unsigned long *retbuf)
 {
         struct hcall_stats *h;
 
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index 4b7b6e8e32de..0707653612ba 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -683,13 +683,14 @@ void hcall_tracepoint_unregfunc(void)
         hcall_tracepoint_refcount--;
 }
 
-void __trace_hcall_entry(unsigned long opcode)
+void __trace_hcall_entry(unsigned long opcode, unsigned long *args)
 {
-        trace_hcall_entry(opcode);
+        trace_hcall_entry(opcode, args);
 }
 
-void __trace_hcall_exit(long opcode, unsigned long retval)
+void __trace_hcall_exit(long opcode, unsigned long retval,
+                        unsigned long *retbuf)
 {
-        trace_hcall_exit(opcode, retval);
+        trace_hcall_exit(opcode, retval, retbuf);
 }
 #endif