diff options
| author | Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> | 2020-04-21 20:35:44 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-06-02 13:59:15 +0300 |
| commit | 1f2aaed2db03150428dbcd2ddee02ae6cb4bac52 (patch) | |
| tree | 1d71fad74ebfd725281796b2ec2904a6897f25ba /arch/powerpc/kernel/module_64.c | |
| parent | 03b51416e876aea5e7638947e50831b6c988c246 (diff) | |
| download | linux-1f2aaed2db03150428dbcd2ddee02ae6cb4bac52.tar.xz | |
powerpc/module_64: Simplify check for -mprofile-kernel ftrace relocations
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.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7d9c316adfa1fb787ad268bb4691e7e4059ff2d5.1587488954.git.naveen.n.rao@linux.vnet.ibm.com
Diffstat (limited to 'arch/powerpc/kernel/module_64.c')
| -rw-r--r-- | arch/powerpc/kernel/module_64.c | 18 |
1 files changed, 4 insertions, 14 deletions
diff --git a/arch/powerpc/kernel/module_64.c b/arch/powerpc/kernel/module_64.c index 0acec12d0985..de317c158f38 100644 --- a/arch/powerpc/kernel/module_64.c +++ b/arch/powerpc/kernel/module_64.c @@ -400,19 +400,9 @@ 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; @@ -436,7 +426,7 @@ 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; } @@ -448,7 +438,7 @@ 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; /* |