For -mprofile-kernel, we need special handling when generating stubs for
ftrace calls such as _mcount(). To faciliate this, we check if a
R_PPC64_REL24 relocation is for a symbol named "_mcount()" along with
also checking the instruction sequence. The latter is not really
required since "_mcount()" is an exported symbol and kernel modules
cannot use it. As such, drop the additional checking and simplify the
code. This helps unify stub creation for ftrace stubs with
-mprofile-kernel and aids in code reuse.
Also rename is_mprofile_mcount_callsite() to is_mprofile_ftrace_call()
to reflect the checking being done.
Signed-off-by: Naveen N. Rao <naveen.n....@linux.vnet.ibm.com>
---
arch/powerpc/kernel/module_64.c | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c
index 54d9d830f4a4..7f4cc5346387 100644
--- a/arch/powerpc/kernel/module_64.c
+++ b/arch/powerpc/kernel/module_64.c
@@ -414,19 +414,9 @@ static unsigned long stub_for_addr(const Elf64_Shdr
*sechdrs,
}
#ifdef CONFIG_MPROFILE_KERNEL
-static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
+static bool is_mprofile_ftrace_call(const char *name)
{
- if (strcmp("_mcount", name))
- return false;
-
- /*
- * Check if this is one of the -mprofile-kernel sequences.
- */
- if (instruction[-1] == PPC_INST_STD_LR &&
- instruction[-2] == PPC_INST_MFLR)
- return true;
-
- if (instruction[-1] == PPC_INST_MFLR)
+ if (!strcmp("_mcount", name))
return true;
return false;
@@ -450,7 +440,7 @@ static void squash_toc_save_inst(const char *name, unsigned
long addr)
#else
static void squash_toc_save_inst(const char *name, unsigned long addr) { }
-static bool is_mprofile_mcount_callsite(const char *name, u32 *instruction)
+static bool is_mprofile_ftrace_call(const char *name)
{
return false;
}
@@ -462,7 +452,7 @@ static int restore_r2(const char *name, u32 *instruction,
struct module *me)
{
u32 *prev_insn = instruction - 1;
- if (is_mprofile_mcount_callsite(name, prev_insn))
+ if (is_mprofile_ftrace_call(name))
return 1;
/*
--
2.25.1
