[RFC PATCH v3 10/12] objtool/powerpc: Add --mcount specific implementation

[Sathvika Vasireddy]

This patch enables objtool --mcount on powerpc, and
adds implementation specific to powerpc.

Signed-off-by: Sathvika Vasireddy <s...@linux.ibm.com>
---
 arch/powerpc/Kconfig                          |  1 +
 tools/objtool/arch/powerpc/decode.c           | 22 +++++++++++++++++++
 tools/objtool/arch/powerpc/include/arch/elf.h |  2 ++
 3 files changed, 25 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 732a3f91ee5e..3373d44a1298 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -233,6 +233,7 @@ config PPC
        select HAVE_NMI                         if PERF_EVENTS || (PPC64 && 
PPC_BOOK3S)
        select HAVE_OPTPROBES
        select HAVE_OBJTOOL                     if PPC64
+       select HAVE_OBJTOOL_MCOUNT              if HAVE_OBJTOOL
        select HAVE_PERF_EVENTS
        select HAVE_PERF_EVENTS_NMI             if PPC64
        select HAVE_PERF_REGS
diff --git a/tools/objtool/arch/powerpc/decode.c 
b/tools/objtool/arch/powerpc/decode.c
index 8b6a14680da7..06fc0206bf8e 100644
--- a/tools/objtool/arch/powerpc/decode.c
+++ b/tools/objtool/arch/powerpc/decode.c
@@ -9,6 +9,14 @@
 #include <objtool/builtin.h>
 #include <objtool/endianness.h>
 
+bool arch_ftrace_match(char *name)
+{
+       if ((!strcmp(name, "_mcount")) || (!strcmp(name, "._mcount")))
+               return true;
+
+       return false;
+}
+
 unsigned long arch_dest_reloc_offset(int addend)
 {
        return addend;
@@ -41,12 +49,26 @@ int arch_decode_instruction(struct objtool_file *file, 
const struct section *sec
                            struct list_head *ops_list)
 {
        u32 insn;
+       unsigned int opcode;
 
        *immediate = 0;
        insn = bswap_if_needed(file->elf, *(u32 *)(sec->data->d_buf + offset));
        *len = 4;
        *type = INSN_OTHER;
 
+       opcode = insn >> 26;
+
+       switch (opcode) {
+       case 18: /* bl */
+               if ((insn & 3) == 1) {
+                       *type = INSN_CALL;
+                       *immediate = insn & 0x3fffffc;
+                       if (*immediate & 0x2000000)
+                               *immediate -= 0x4000000;
+               }
+               break;
+       }
+
        return 0;
 }
 
diff --git a/tools/objtool/arch/powerpc/include/arch/elf.h 
b/tools/objtool/arch/powerpc/include/arch/elf.h
index 3c8ebb7d2a6b..73f9ae172fe5 100644
--- a/tools/objtool/arch/powerpc/include/arch/elf.h
+++ b/tools/objtool/arch/powerpc/include/arch/elf.h
@@ -4,5 +4,7 @@
 #define _OBJTOOL_ARCH_ELF
 
 #define R_NONE R_PPC_NONE
+#define R_ABS64 R_PPC64_ADDR64
+#define R_ABS32 R_PPC_ADDR32
 
 #endif /* _OBJTOOL_ARCH_ELF */
-- 
2.25.1