[PATCH v6 16/16] objtool/powerpc: Add --mcount specific implementation

[Sathvika Vasireddy]

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

Tested-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
Reviewed-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
Reviewed-by: Christophe Leroy <christophe.le...@csgroup.eu>
Acked-by: Josh Poimboeuf <jpoim...@kernel.org>
Signed-off-by: Sathvika Vasireddy <s...@linux.ibm.com>
---
 arch/powerpc/Kconfig                          |  1 +
 tools/objtool/arch/powerpc/decode.c           | 16 ++++++++++++++++
 tools/objtool/arch/powerpc/include/arch/elf.h |  2 ++
 3 files changed, 19 insertions(+)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 82e3e5e175ae..170a3a354a4a 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -240,6 +240,7 @@ config PPC
        select HAVE_NMI                         if PERF_EVENTS || (PPC64 && 
PPC_BOOK3S)
        select HAVE_OPTPROBES
        select HAVE_OBJTOOL                     if PPC32 || MPROFILE_KERNEL
+       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 dcd0975cad6b..01cade98b49e 100644
--- a/tools/objtool/arch/powerpc/decode.c
+++ b/tools/objtool/arch/powerpc/decode.c
@@ -9,6 +9,11 @@
 #include <objtool/builtin.h>
 #include <objtool/endianness.h>
 
+int arch_ftrace_match(char *name)
+{
+       return !strcmp(name, "_mcount");
+}
+
 unsigned long arch_dest_reloc_offset(int addend)
 {
        return addend;
@@ -50,6 +55,17 @@ int arch_decode_instruction(struct objtool_file *file, const 
struct section *sec
        typ = INSN_OTHER;
        imm = 0;
 
+       switch (opcode) {
+       case 18: /* b[l][a] */
+               if ((insn & 3) == 1) /* bl */
+                       typ = INSN_CALL;
+
+               imm = insn & 0x3fffffc;
+               if (imm & 0x2000000)
+                       imm -= 0x4000000;
+               break;
+       }
+
        if (opcode == 1)
                *len = 8;
        else
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 */
-- 
2.31.1