dtrace: support passing offset as arg0 to FBT return probes

FBT return probes pass the offset from the function start (in bytes)
as arg0.  To make that possible, we pass the offset value in the call
to fbt_add_probe.  For FBT entry probes we pass 0 (which is ignored).

Orabug: 25949086
Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
Acked-by: Nick Alcock <nick.alcock@oracle.com>

diff --git a/arch/sparc/kernel/dtrace_fbt.c b/arch/sparc/kernel/dtrace_fbt.c
index 5ab8e363aebf5f7d4aa63925107d95ab841210d1..2178e7736f7f39ff5b89a02ad59bbaac3b1eed67 100644 (file)
--- a/arch/sparc/kernel/dtrace_fbt.c
+++ b/arch/sparc/kernel/dtrace_fbt.c
@@ -280,7 +280,7 @@ void dtrace_fbt_init(fbt_add_probe_fn fbt_add_probe)
                                continue;
 
                        fbt_add_probe(dtrace_kmod, sym.name, FBT_ENTRY, 32,
-                                     addr + 1, NULL);
+                                     addr + 1, 0, NULL);
                } else
                        continue;
        }

diff --git a/arch/x86/kernel/dtrace_fbt.c b/arch/x86/kernel/dtrace_fbt.c
index e84344e53d3821ba0889c7bb1a4ef17230ee81a6..43f0b83af80cfb5ac8ff8905f2d20cbe0a2314be 100644 (file)
--- a/arch/x86/kernel/dtrace_fbt.c
+++ b/arch/x86/kernel/dtrace_fbt.c
@@ -155,7 +155,8 @@ void dtrace_fbt_init(fbt_add_probe_fn fbt_add_probe)
                                if (*addr == FBT_PUSHL_EBP) {
                                        fbt_add_probe(
                                                dtrace_kmod, sym.name,
-                                               FBT_ENTRY, *addr, addr, NULL);
+                                               FBT_ENTRY, *addr, addr, 0,
+                                               NULL);
                                        state = 1;
                                } else if (insc > 2)
                                        state = 2;
@@ -164,9 +165,13 @@ void dtrace_fbt_init(fbt_add_probe_fn fbt_add_probe)
                                if (*addr == FBT_RET &&
                                    (*(addr + 1) == FBT_PUSHL_EBP ||
                                     *(addr + 1) == FBT_NOP)) {
+                                       uintptr_t       off;
+
+                                       off = addr - (asm_instr_t *)sym.value;
                                        fbt_add_probe(
                                                dtrace_kmod, sym.name,
-                                               FBT_RETURN, *addr, addr, fbtp);
+                                               FBT_RETURN, *addr, addr, off,
+                                               fbtp);
                                        state = 2;
                                }
                                break;

diff --git a/include/linux/dtrace_fbt.h b/include/linux/dtrace_fbt.h
index 3bc8b771386f915db7032ac606e7ca55c26cd1be..a7789eb84ec090ba5105915c1385f5053ffc635f 100644 (file)
--- a/include/linux/dtrace_fbt.h
+++ b/include/linux/dtrace_fbt.h
@@ -26,7 +26,7 @@ extern unsigned long dtrace_fbt_nfuncs __attribute__((weak));
 #define FBT_RETURN     1
 
 typedef void *(*fbt_add_probe_fn)(struct module *, char *, int, int,
-                                 asm_instr_t *, void *);
+                                 asm_instr_t *, uintptr_t, void *);
 extern void dtrace_fbt_init(fbt_add_probe_fn);
 
 #endif /* _LINUX_DTRACE_FBT_H */