[PATCH 1/1] LoongArch: Add pointer mangling support.

[caiyinyu <caiyinyu@loongson.cn>]

Tested on LoongArch machine: gcc 13.0.0, Linux kernel 5.19.0 rc2,
binutils branch master 2eb132bdfb9.

[1]
XPASS: conform/UNIX98/ndbm.h/linknamespace
XPASS: conform/XOPEN2K/ndbm.h/linknamespace
XPASS: conform/XOPEN2K8/ndbm.h/linknamespace
XPASS: conform/XPG42/ndbm.h/linknamespace
UNSUPPORTED: crypt/cert
UNSUPPORTED: elf/tst-env-setuid
UNSUPPORTED: elf/tst-env-setuid-tunables
XPASS: elf/tst-protected1a
XPASS: elf/tst-protected1b
UNSUPPORTED: elf/tst-valgrind-smoke
UNSUPPORTED: misc/tst-adjtimex
UNSUPPORTED: misc/tst-clock_adjtime
UNSUPPORTED: misc/tst-ntp_adjtime
UNSUPPORTED: misc/tst-pkey
UNSUPPORTED: misc/tst-rseq
UNSUPPORTED: misc/tst-rseq-disable
UNSUPPORTED: nptl/test-cond-printers
UNSUPPORTED: nptl/test-condattr-printers
UNSUPPORTED: nptl/test-mutex-printers
UNSUPPORTED: nptl/test-mutexattr-printers
UNSUPPORTED: nptl/test-rwlock-printers
UNSUPPORTED: nptl/test-rwlockattr-printers
UNSUPPORTED: nptl/tst-rseq-nptl
UNSUPPORTED: stdlib/tst-secure-getenv
UNSUPPORTED: time/tst-clock_settime
UNSUPPORTED: time/tst-settimeofday
Summary of test results:
   4580 PASS 
     20 UNSUPPORTED
     12 XFAIL 
      6 XPASS

---
 sysdeps/loongarch/__longjmp.S              |  7 +++
 sysdeps/loongarch/setjmp.S                 |  7 +++
 sysdeps/unix/sysv/linux/loongarch/sysdep.h | 63 ++++++++++++++++++++--
 3 files changed, 74 insertions(+), 3 deletions(-)

diff --git a/sysdeps/loongarch/__longjmp.S b/sysdeps/loongarch/__longjmp.S
index 37e7384413..c2c5b56a80 100644
--- a/sysdeps/loongarch/__longjmp.S
+++ b/sysdeps/loongarch/__longjmp.S
@@ -20,8 +20,15 @@
 #include <sys/asm.h>
 
 ENTRY (__longjmp)
+#ifdef PTR_MANGLE
+	REG_L t0, a0, 0*SZREG
+	PTR_DEMANGLE (ra, t0, t1, t2)
+	REG_L t0, a0, 1*SZREG
+	PTR_DEMANGLE2 (sp, t0, t1)
+#else
 	REG_L ra, a0, 0*SZREG
 	REG_L sp, a0, 1*SZREG
+#endif
 	REG_L x,  a0, 2*SZREG
 	REG_L fp, a0, 3*SZREG
 	REG_L s0, a0, 4*SZREG
diff --git a/sysdeps/loongarch/setjmp.S b/sysdeps/loongarch/setjmp.S
index 3afb9f3948..ec4ddc72da 100644
--- a/sysdeps/loongarch/setjmp.S
+++ b/sysdeps/loongarch/setjmp.S
@@ -29,8 +29,15 @@ ENTRY (setjmp)
 END (setjmp)
 
 ENTRY (__sigsetjmp)
+#ifdef PTR_MANGLE
+	PTR_MANGLE (t0, ra, t1, t2)
+	REG_S t0, a0, 0*SZREG
+	PTR_MANGLE2 (t0, sp, t1)
+	REG_S t0, a0, 1*SZREG
+#else
 	REG_S ra, a0, 0*SZREG
 	REG_S sp, a0, 1*SZREG
+#endif
 	REG_S x,  a0, 2*SZREG
 	REG_S fp, a0, 3*SZREG
 	REG_S s0, a0, 4*SZREG
diff --git a/sysdeps/unix/sysv/linux/loongarch/sysdep.h b/sysdeps/unix/sysv/linux/loongarch/sysdep.h
index 8a398adb70..157cbd6c6b 100644
--- a/sysdeps/unix/sysv/linux/loongarch/sysdep.h
+++ b/sysdeps/unix/sysv/linux/loongarch/sysdep.h
@@ -314,8 +314,65 @@ extern long int __syscall_error (long int neg_errno);
 
 #endif /* ! __ASSEMBLER__ */
 
-/* Pointer mangling is not supported.  */
-#define PTR_MANGLE(var) (void) (var)
-#define PTR_DEMANGLE(var) (void) (var)
+/* Pointer mangling is supported for LoongArch.  */
+
+/* Load or store to/from a got-relative EXPR into/from G, using T.
+   Note G and T are register names.  */
+#define LDST_GLOBAL(OP, G, T,  EXPR) \
+  pcalau12i T, %got_pc_hi20(EXPR); \
+  OP	    T, T, %got_pc_lo12(EXPR); \
+  OP	    G, T, 0;
+
+/* Load or store to/from a pc-relative EXPR into/from G, using T.
+   Note G and T are register names.  */
+#define LDST_PCREL(OP, G, T,  EXPR) \
+  pcalau12i T, %pc_hi20(EXPR); \
+  OP	    G, T, %pc_lo12(EXPR);
+
+#if (IS_IN (rtld) \
+     || (!defined SHARED && (IS_IN (libc) \
+     || IS_IN (libpthread))))
+
+#ifdef __ASSEMBLER__
+#define PTR_MANGLE(dst, src, guard, tmp) \
+  LDST_PCREL (REG_L, guard, tmp, __pointer_chk_guard_local); \
+  PTR_MANGLE2 (dst, src, guard);
+#define PTR_DEMANGLE(dst, src, guard, tmp) \
+  LDST_PCREL (REG_L, guard, tmp, __pointer_chk_guard_local); \
+  PTR_DEMANGLE2 (dst, src, guard);
+/* Use PTR_MANGLE2 for efficiency if guard is already loaded.  */
+#define PTR_MANGLE2(dst, src, guard) \
+  xor  dst, src, guard;
+#define PTR_DEMANGLE2(dst, src, guard) \
+  PTR_MANGLE2 (dst, src, guard);
+#else
+extern uintptr_t __pointer_chk_guard_local attribute_relro attribute_hidden;
+#define PTR_MANGLE(var) \
+  (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard_local)
+#define PTR_DEMANGLE(var) PTR_MANGLE (var)
+#endif
+
+#else
+
+#ifdef __ASSEMBLER__
+#define PTR_MANGLE(dst, src, guard, tmp) \
+  LDST_GLOBAL (REG_L, guard, tmp, __pointer_chk_guard); \
+  PTR_MANGLE2 (dst, src, guard);
+#define PTR_DEMANGLE(dst, src, guard, tmp) \
+  LDST_GLOBAL (REG_L, guard, tmp, __pointer_chk_guard); \
+  PTR_DEMANGLE2 (dst, src, guard);
+/* Use PTR_MANGLE2 for efficiency if guard is already loaded.  */
+#define PTR_MANGLE2(dst, src, guard) \
+  xor dst, src, guard;
+#define PTR_DEMANGLE2(dst, src, guard) \
+  PTR_MANGLE2 (dst, src, guard);
+#else
+extern uintptr_t __pointer_chk_guard attribute_relro;
+#define PTR_MANGLE(var) \
+  (var) = (__typeof (var)) ((uintptr_t) (var) ^ __pointer_chk_guard)
+#define PTR_DEMANGLE(var) PTR_MANGLE (var)
+#endif
+
+#endif
 
 #endif /* linux/loongarch/sysdep.h */
-- 
2.31.1