From: YunQiang Su <[email protected]>
Currently, almost all of the shared libraries of MIPS, rely on $t9
to get the address of current function, instead of PCREL instructions,
even on MIPSr6. So we have to set $t9 properly.
To get the address of preemptible function, we need the help of GOT.
MIPS/O32 has .cpload, which can help to generate 3 instructions to get GOT.
For __mips64, we can get GOT by:
lui $t8, %hi(%neg(%gp_rel(SANITIZER_STRINGIFY(TRAMPOLINE(func)))))
daddu $t8, $t8, $t9
daddiu $t8, $t8, %hi(%neg(%gp_rel(SANITIZER_STRINGIFY(TRAMPOLINE(func)))))
And then get the address of __interceptor_func, and jump to it
ld $t9, %got_disp(_interceptor" SANITIZER_STRINGIFY(func) ")($t8)
jr $t9
Upstream-Commit: 0a64367a72f1634321f5051221f05f2f364bd882
libsanitizer
* interception/interception.h (substitution_##func_name):
Use macro C_ASM_TAIL_CALL.
* sanitizer_common/sanitizer_asm.h: Define C_ASM_TAIL_CALL
for MIPS with help of t9.
---
libsanitizer/interception/interception.h | 5 ++--
libsanitizer/sanitizer_common/sanitizer_asm.h | 23 +++++++++++++++++++
2 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/libsanitizer/interception/interception.h
b/libsanitizer/interception/interception.h
index 9d8b60b2eef..58e969378a9 100644
--- a/libsanitizer/interception/interception.h
+++ b/libsanitizer/interception/interception.h
@@ -205,8 +205,9 @@ const interpose_substitution substitution_##func_name[]
\
ASM_TYPE_FUNCTION_STR "\n"
\
SANITIZER_STRINGIFY(TRAMPOLINE(func)) ":\n"
\
SANITIZER_STRINGIFY(CFI_STARTPROC) "\n"
\
- SANITIZER_STRINGIFY(ASM_TAIL_CALL) " __interceptor_"
\
- SANITIZER_STRINGIFY(ASM_PREEMPTIBLE_SYM(func)) "\n"
\
+ C_ASM_TAIL_CALL(SANITIZER_STRINGIFY(TRAMPOLINE(func)),
\
+ "__interceptor_"
\
+ SANITIZER_STRINGIFY(ASM_PREEMPTIBLE_SYM(func))) "\n"
\
SANITIZER_STRINGIFY(CFI_ENDPROC) "\n"
\
".size " SANITIZER_STRINGIFY(TRAMPOLINE(func)) ", "
\
".-" SANITIZER_STRINGIFY(TRAMPOLINE(func)) "\n"
\
diff --git a/libsanitizer/sanitizer_common/sanitizer_asm.h
b/libsanitizer/sanitizer_common/sanitizer_asm.h
index bbb18cfbdf1..3af66a4e449 100644
--- a/libsanitizer/sanitizer_common/sanitizer_asm.h
+++ b/libsanitizer/sanitizer_common/sanitizer_asm.h
@@ -53,6 +53,29 @@
# define ASM_TAIL_CALL tail
#endif
+// Currently, almost all of the shared libraries rely on the value of
+// $t9 to get the address of current function, instead of PCREL, even
+// on MIPSr6. To be compatiable with them, we have to set $t9 properly.
+// MIPS uses GOT to get the address of preemptible functions.
+#if defined(__mips64)
+# define C_ASM_TAIL_CALL(t_func, i_func) \
+ "lui $t8, %hi(%neg(%gp_rel(" t_func ")))\n" \
+ "daddu $t8, $t8, $t9\n" \
+ "daddiu $t8, $t8, %lo(%neg(%gp_rel(" t_func ")))\n" \
+ "ld $t9, %got_disp(" i_func ")($t8)\n" \
+ "jr $t9\n"
+#elif defined(__mips__)
+# define C_ASM_TAIL_CALL(t_func, i_func) \
+ ".set noreorder\n" \
+ ".cpload $t9\n" \
+ ".set reorder\n" \
+ "lw $t9, %got(" i_func ")($gp)\n" \
+ "jr $t9\n"
+#elif defined(ASM_TAIL_CALL)
+# define C_ASM_TAIL_CALL(t_func, i_func) \
+ SANITIZER_STRINGIFY(ASM_TAIL_CALL) " " i_func
+#endif
+
#if defined(__ELF__) && defined(__x86_64__) || defined(__i386__) || \
defined(__riscv)
# define ASM_PREEMPTIBLE_SYM(sym) sym@plt
--
2.39.2
