ARM: 6511/1: ftrace: add ARM support for C version of recordmcount

Depending on the compiler version, ARM GCC calls the mcount function
either __gnu_mcount_nc or mcount.

Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index db524e7..a7b9070 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -23,6 +23,7 @@ config ARM
        select PERF_USE_VMALLOC
        select HAVE_REGS_AND_STACK_ACCESS_API
        select HAVE_HW_BREAKPOINT if (PERF_EVENTS && (CPU_V6 || CPU_V7))
+       select HAVE_C_RECORDMCOUNT
        help
          The ARM series is a line of low-power-consumption RISC chip designs
          licensed by ARM Ltd and targeted at embedded applications and

diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index ac6e51c..038b3d1 100644 (file)
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -38,6 +38,7 @@ static void *ehdr_curr; /* current ElfXX_Ehdr *  for resource cleanup */
 static char gpfx;      /* prefix for global symbol name (sometimes '_') */
 static struct stat sb; /* Remember .st_size, etc. */
 static jmp_buf jmpenv; /* setjmp/longjmp per-file error escape */
+static const char *altmcount;  /* alternate mcount symbol name */
 
 /* setjmp() return values */
 enum {
@@ -299,7 +300,9 @@ do_file(char const *const fname)
                fail_file();
        } break;
        case EM_386:     reltype = R_386_32;                   break;
-       case EM_ARM:     reltype = R_ARM_ABS32;                break;
+       case EM_ARM:     reltype = R_ARM_ABS32;
+                        altmcount = "__gnu_mcount_nc";
+                        break;
        case EM_IA_64:   reltype = R_IA64_IMM64;   gpfx = '_'; break;
        case EM_MIPS:    /* reltype: e_class    */ gpfx = '_'; break;
        case EM_PPC:     reltype = R_PPC_ADDR32;   gpfx = '_'; break;

diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 58e933a..8087bc8 100644 (file)
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -275,11 +275,12 @@ static uint_t *sift_rel_mcount(uint_t *mlocp,
                        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 (0 == strcmp((('_' == gpfx) ? "_mcount" : "mcount"),
-                                       symname))
+                       if (0 == strcmp(mcount, symname) ||
+                           (altmcount && 0 == strcmp(altmcount, symname)))
                                mcountsym = Elf_r_sym(relp);
                }