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-rw-r--r--scripts/recordmcount.c5
-rw-r--r--scripts/recordmcount.h56
2 files changed, 57 insertions, 4 deletions
diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c
index 2d32b9ced20..f2f32eee2c5 100644
--- a/scripts/recordmcount.c
+++ b/scripts/recordmcount.c
@@ -325,8 +325,10 @@ do_file(char const *const fname)
}
if (EM_S390 == w2(ehdr->e_machine))
reltype = R_390_32;
- if (EM_MIPS == w2(ehdr->e_machine))
+ if (EM_MIPS == w2(ehdr->e_machine)) {
reltype = R_MIPS_32;
+ is_fake_mcount32 = MIPS32_is_fake_mcount;
+ }
do32(ehdr, fname, reltype);
} break;
case ELFCLASS64: {
@@ -343,6 +345,7 @@ do_file(char const *const fname)
reltype = R_MIPS_64;
Elf64_r_sym = MIPS64_r_sym;
Elf64_r_info = MIPS64_r_info;
+ is_fake_mcount64 = MIPS64_is_fake_mcount;
}
do64(ghdr, fname, reltype);
} break;
diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
index 190fd18dc85..58e933a2054 100644
--- a/scripts/recordmcount.h
+++ b/scripts/recordmcount.h
@@ -19,12 +19,16 @@
* Licensed under the GNU General Public License, version 2 (GPLv2).
*/
#undef append_func
+#undef is_fake_mcount
+#undef fn_is_fake_mcount
+#undef MIPS_is_fake_mcount
#undef sift_rel_mcount
#undef find_secsym_ndx
#undef __has_rel_mcount
#undef has_rel_mcount
#undef tot_relsize
#undef do_func
+#undef Elf_Addr
#undef Elf_Ehdr
#undef Elf_Shdr
#undef Elf_Rel
@@ -50,6 +54,10 @@
# define has_rel_mcount has64_rel_mcount
# define tot_relsize tot64_relsize
# define do_func do64
+# 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
+# define Elf_Addr Elf64_Addr
# define Elf_Ehdr Elf64_Ehdr
# define Elf_Shdr Elf64_Shdr
# define Elf_Rel Elf64_Rel
@@ -74,6 +82,10 @@
# define has_rel_mcount has32_rel_mcount
# define tot_relsize tot32_relsize
# define do_func do32
+# 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
+# define Elf_Addr Elf32_Addr
# define Elf_Ehdr Elf32_Ehdr
# define Elf_Shdr Elf32_Shdr
# define Elf_Rel Elf32_Rel
@@ -92,7 +104,13 @@
# define _size 4
#endif
-/* Functions and pointers that 64-bit EM_MIPS can override. */
+/* Functions and pointers that do_file() may override for specific e_machine. */
+static int fn_is_fake_mcount(Elf_Rel const *rp)
+{
+ return 0;
+}
+static int (*is_fake_mcount)(Elf_Rel const *rp) = fn_is_fake_mcount;
+
static uint_t fn_ELF_R_SYM(Elf_Rel const *rp)
{
return ELF_R_SYM(_w(rp->r_info));
@@ -105,6 +123,39 @@ static void fn_ELF_R_INFO(Elf_Rel *const rp, unsigned sym, unsigned type)
}
static void (*Elf_r_info)(Elf_Rel *const rp, unsigned sym, unsigned type) = fn_ELF_R_INFO;
+/*
+ * MIPS mcount long call has 2 _mcount symbols, only the position of the 1st
+ * _mcount symbol is needed for dynamic function tracer, with it, to disable
+ * tracing(ftrace_make_nop), the instruction in the position is replaced with
+ * the "b label" instruction, to enable tracing(ftrace_make_call), replace the
+ * instruction back. So, here, we set the 2nd one as fake and filter it.
+ *
+ * c: 3c030000 lui v1,0x0 <--> b label
+ * c: R_MIPS_HI16 _mcount
+ * c: R_MIPS_NONE *ABS*
+ * c: R_MIPS_NONE *ABS*
+ * 10: 64630000 daddiu v1,v1,0
+ * 10: R_MIPS_LO16 _mcount
+ * 10: R_MIPS_NONE *ABS*
+ * 10: R_MIPS_NONE *ABS*
+ * 14: 03e0082d move at,ra
+ * 18: 0060f809 jalr v1
+ * label:
+ */
+#define MIPS_FAKEMCOUNT_OFFSET 4
+
+static int MIPS_is_fake_mcount(Elf_Rel const *rp)
+{
+ static Elf_Addr old_r_offset;
+ Elf_Addr current_r_offset = _w(rp->r_offset);
+ int is_fake;
+
+ is_fake = old_r_offset &&
+ (current_r_offset - old_r_offset == MIPS_FAKEMCOUNT_OFFSET);
+ old_r_offset = current_r_offset;
+
+ return is_fake;
+}
/* Append the new shstrtab, Elf_Shdr[], __mcount_loc and its relocations. */
static void append_func(Elf_Ehdr *const ehdr,
@@ -183,7 +234,6 @@ static void append_func(Elf_Ehdr *const ehdr,
uwrite(fd_map, ehdr, sizeof(*ehdr));
}
-
/*
* Look at the relocations in order to find the calls to mcount.
* Accumulate the section offsets that are found, and their relocation info,
@@ -233,7 +283,7 @@ static uint_t *sift_rel_mcount(uint_t *mlocp,
mcountsym = Elf_r_sym(relp);
}
- if (mcountsym == Elf_r_sym(relp)) {
+ if (mcountsym == Elf_r_sym(relp) && !is_fake_mcount(relp)) {
uint_t const addend = _w(_w(relp->r_offset) - recval);
mrelp->r_offset = _w(offbase