ftrace/recordmcount: Remove duplicate code to find mcount symbol

[mirror_ubuntu-bionic-kernel.git] / scripts / recordmcount.h

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 657dbedd1c7f882e41a790c6bfc864601c90a922..deb6a517638cb6abd04057d86f24e365c8ed947a 100644 (file)
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -28,6 +28,7 @@
 #undef __has_rel_mcount
 #undef has_rel_mcount
 #undef tot_relsize
+#undef get_mcountsym
 #undef do_func
 #undef Elf_Addr
 #undef Elf_Ehdr
@@ -56,6 +57,7 @@
 # define has_rel_mcount                has64_rel_mcount
 # define tot_relsize           tot64_relsize
 # define do_func               do64
+# define get_mcountsym         get_mcountsym_64
 # define is_fake_mcount                is_fake_mcount64
 # define fn_is_fake_mcount     fn_is_fake_mcount64
 # define MIPS_is_fake_mcount   MIPS64_is_fake_mcount
@@ -85,6 +87,7 @@
 # define has_rel_mcount                has32_rel_mcount
 # define tot_relsize           tot32_relsize
 # define do_func               do32
+# define get_mcountsym         get_mcountsym_32
 # define is_fake_mcount                is_fake_mcount32
 # define fn_is_fake_mcount     fn_is_fake_mcount32
 # define MIPS_is_fake_mcount   MIPS32_is_fake_mcount
@@ -237,6 +240,26 @@ static void append_func(Elf_Ehdr *const ehdr,
        uwrite(fd_map, ehdr, sizeof(*ehdr));
 }
 
+static unsigned get_mcountsym(Elf_Sym const *const sym0,
+                             Elf_Rel const *relp,
+                             char const *const str0)
+{
+       unsigned mcountsym = 0;
+
+       Elf_Sym const *const symp =
+               &sym0[Elf_r_sym(relp)];
+       char const *symname = &str0[w(symp->st_name)];
+       char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
+
+       if (symname[0] == '.')
+               ++symname;  /* ppc64 hack */
+       if (strcmp(mcount, symname) == 0 ||
+           (altmcount && strcmp(altmcount, symname) == 0))
+               mcountsym = Elf_r_sym(relp);
+
+       return mcountsym;
+}
+
 /*
  * Look at the relocations in order to find the calls to mcount.
  * Accumulate the section offsets that are found, and their relocation info,
@@ -274,18 +297,8 @@ static uint_t *sift_rel_mcount(uint_t *mlocp,
        unsigned t;
 
        for (t = nrel; t; --t) {
-               if (!mcountsym) {
-                       Elf_Sym const *const symp =
-                               &sym0[Elf_r_sym(relp)];
-                       char const *symname = &str0[w(symp->st_name)];
-                       char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
-
-                       if (symname[0] == '.')
-                               ++symname;  /* ppc64 hack */
-                       if (strcmp(mcount, symname) == 0 ||
-                           (altmcount && strcmp(altmcount, symname) == 0))
-                               mcountsym = Elf_r_sym(relp);
-               }
+               if (!mcountsym)
+                       mcountsym = get_mcountsym(sym0, relp, str0);
 
                if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
                        uint_t const addend = _w(_w(relp->r_offset) - recval);
@@ -313,7 +326,8 @@ static uint_t *sift_rel_mcount(uint_t *mlocp,
  * into nops.
  */
 static void nop_mcount(Elf_Shdr const *const relhdr,
-                      Elf_Ehdr const *const ehdr)
+                      Elf_Ehdr const *const ehdr,
+                      const char *const txtname)
 {
        Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
                + (void *)ehdr);
@@ -336,25 +350,26 @@ static void nop_mcount(Elf_Shdr const *const relhdr,
 
        unsigned mcountsym = 0;
        unsigned t;
+       int once = 0;
 
        for (t = nrel; t; --t) {
                int ret = -1;
 
-               if (!mcountsym) {
-                       Elf_Sym const *const symp =
-                               &sym0[Elf_r_sym(relp)];
-                       char const *symname = &str0[w(symp->st_name)];
-                       char const *mcount = gpfx == '_' ? "_mcount" : "mcount";
-
-                       if (symname[0] == '.')
-                               ++symname;  /* ppc64 hack */
-                       if (strcmp(mcount, symname) == 0 ||
-                           (altmcount && strcmp(altmcount, symname) == 0))
-                               mcountsym = Elf_r_sym(relp);
-               }
+               if (!mcountsym)
+                       mcountsym = get_mcountsym(sym0, relp, str0);
 
-               if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp))
-                       ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
+               if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
+                       if (make_nop)
+                               ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
+                       if (warn_on_notrace_sect && !once) {
+                               printf("Section %s has mcount callers being ignored\n",
+                                      txtname);
+                               once = 1;
+                               /* just warn? */
+                               if (!make_nop)
+                                       return;
+                       }
+               }
 
                /*
                 * If we successfully removed the mcount, mark the relocation
@@ -501,12 +516,12 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
                        mlocp = sift_rel_mcount(mlocp,
                                (void *)mlocp - (void *)mloc0, &mrelp,
                                relhdr, ehdr, recsym, recval, reltype);
-               } else if (make_nop && txtname) {
+               } else if (txtname && (warn_on_notrace_sect || make_nop)) {
                        /*
                         * This section is ignored by ftrace, but still
                         * has mcount calls. Convert them to nops now.
                         */
-                       nop_mcount(relhdr, ehdr);
+                       nop_mcount(relhdr, ehdr, txtname);
                }
        }
        if (mloc0 != mlocp) {