[PATCH v4 16/16] objtool/powerpc: Add --mcount specific implementation

Sathvika Vasireddy
2022-10-02T10:46:44Z

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

Signed-off-by: Sathvika Vasireddy <sv@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 dc05cd23c233..6be2e68fa9eb 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -238,6 +238,7 @@ 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