ftrace/recordmcount: Make ignored mcount calls into nops at compile time

[platform/adaptation/renesas_rcar/renesas_kernel.git] / scripts / recordmcount.h

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 7f8d5c4..657dbed 100644 (file)
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -23,6 +23,7 @@
 #undef fn_is_fake_mcount
 #undef MIPS_is_fake_mcount
 #undef sift_rel_mcount
+#undef nop_mcount
 #undef find_secsym_ndx
 #undef __has_rel_mcount
 #undef has_rel_mcount
@@ -49,6 +50,7 @@
 #ifdef RECORD_MCOUNT_64
 # define append_func           append64
 # define sift_rel_mcount       sift64_rel_mcount
+# define nop_mcount            nop_mcount_64
 # define find_secsym_ndx       find64_secsym_ndx
 # define __has_rel_mcount      __has64_rel_mcount
 # define has_rel_mcount                has64_rel_mcount
@@ -77,6 +79,7 @@
 #else
 # define append_func           append32
 # define sift_rel_mcount       sift32_rel_mcount
+# define nop_mcount            nop_mcount_32
 # define find_secsym_ndx       find32_secsym_ndx
 # define __has_rel_mcount      __has32_rel_mcount
 # define has_rel_mcount                has32_rel_mcount
@@ -304,6 +307,70 @@ static uint_t *sift_rel_mcount(uint_t *mlocp,
        return mlocp;
 }
 
+/*
+ * Read the relocation table again, but this time its called on sections
+ * that are not going to be traced. The mcount calls here will be converted
+ * into nops.
+ */
+static void nop_mcount(Elf_Shdr const *const relhdr,
+                      Elf_Ehdr const *const ehdr)
+{
+       Elf_Shdr *const shdr0 = (Elf_Shdr *)(_w(ehdr->e_shoff)
+               + (void *)ehdr);
+       unsigned const symsec_sh_link = w(relhdr->sh_link);
+       Elf_Shdr const *const symsec = &shdr0[symsec_sh_link];
+       Elf_Sym const *const sym0 = (Elf_Sym const *)(_w(symsec->sh_offset)
+               + (void *)ehdr);
+
+       Elf_Shdr const *const strsec = &shdr0[w(symsec->sh_link)];
+       char const *const str0 = (char const *)(_w(strsec->sh_offset)
+               + (void *)ehdr);
+
+       Elf_Rel const *const rel0 = (Elf_Rel const *)(_w(relhdr->sh_offset)
+               + (void *)ehdr);
+       unsigned rel_entsize = _w(relhdr->sh_entsize);
+       unsigned const nrel = _w(relhdr->sh_size) / rel_entsize;
+       Elf_Rel const *relp = rel0;
+
+       Elf_Shdr const *const shdr = &shdr0[w(relhdr->sh_info)];
+
+       unsigned mcountsym = 0;
+       unsigned t;
+
+       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 == Elf_r_sym(relp) && !is_fake_mcount(relp))
+                       ret = make_nop((void *)ehdr, shdr->sh_offset + relp->r_offset);
+
+               /*
+                * If we successfully removed the mcount, mark the relocation
+                * as a nop (don't do anything with it).
+                */
+               if (!ret) {
+                       Elf_Rel rel;
+                       rel = *(Elf_Rel *)relp;
+                       Elf_r_info(&rel, Elf_r_sym(relp), rel_type_nop);
+                       ulseek(fd_map, (void *)relp - (void *)ehdr, SEEK_SET);
+                       uwrite(fd_map, &rel, sizeof(rel));
+               }
+               relp = (Elf_Rel const *)(rel_entsize + (void *)relp);
+       }
+}
+
 
 /*
  * Find a symbol in the given section, to be used as the base for relocating
@@ -360,8 +427,7 @@ __has_rel_mcount(Elf_Shdr const *const relhdr,  /* is SHT_REL or SHT_RELA */
                succeed_file();
        }
        if (w(txthdr->sh_type) != SHT_PROGBITS ||
-           !(w(txthdr->sh_flags) & SHF_EXECINSTR) ||
-           !is_mcounted_section_name(txtname))
+           !(w(txthdr->sh_flags) & SHF_EXECINSTR))
                return NULL;
        return txtname;
 }
@@ -384,9 +450,11 @@ static unsigned tot_relsize(Elf_Shdr const *const shdr0,
 {
        unsigned totrelsz = 0;
        Elf_Shdr const *shdrp = shdr0;
+       char const *txtname;
 
        for (; nhdr; --nhdr, ++shdrp) {
-               if (has_rel_mcount(shdrp, shdr0, shstrtab, fname))
+               txtname = has_rel_mcount(shdrp, shdr0, shstrtab, fname);
+               if (txtname && is_mcounted_section_name(txtname))
                        totrelsz += _w(shdrp->sh_size);
        }
        return totrelsz;
@@ -422,7 +490,7 @@ do_func(Elf_Ehdr *const ehdr, char const *const fname, unsigned const reltype)
        for (relhdr = shdr0, k = nhdr; k; --k, ++relhdr) {
                char const *const txtname = has_rel_mcount(relhdr, shdr0,
                        shstrtab, fname);
-               if (txtname) {
+               if (txtname && is_mcounted_section_name(txtname)) {
                        uint_t recval = 0;
                        unsigned const recsym = find_secsym_ndx(
                                w(relhdr->sh_info), txtname, &recval,
@@ -433,6 +501,12 @@ 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) {
+                       /*
+                        * This section is ignored by ftrace, but still
+                        * has mcount calls. Convert them to nops now.
+                        */
+                       nop_mcount(relhdr, ehdr);
                }
        }
        if (mloc0 != mlocp) {