The MIPS calling convention requires the address of the current function
to be available in $t9.
This was not done so far.

For GCC this seems to have worked, but when compiled with clang the
executable segfault instantly.
Properly load the address of _start_c() into $t9 before calling it.

Signed-off-by: Thomas Weißschuh <li...@weissschuh.net>
---
 tools/include/nolibc/arch-mips.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/include/nolibc/arch-mips.h b/tools/include/nolibc/arch-mips.h
index 62cc50ef3288..a2ee77ed2fbb 100644
--- a/tools/include/nolibc/arch-mips.h
+++ b/tools/include/nolibc/arch-mips.h
@@ -194,7 +194,9 @@ void __attribute__((weak, noreturn, optimize("Os", 
"omit-frame-pointer"))) __no_
                "li    $t0, -8\n"
                "and   $sp, $sp, $t0\n"  /* $sp must be 8-byte aligned          
           */
                "addiu $sp, $sp, -16\n"  /* the callee expects to save a0..a3 
there        */
-               "jal   _start_c\n"       /* transfer to c runtime               
           */
+               "lui $t9, %hi(_start_c)\n" /* ABI requires current function 
address in $t9 */
+               "ori $t9, %lo(_start_c)\n"
+               "jalr $t9\n"             /* transfer to c runtime               
           */
                " nop\n"                 /* delayed slot                        
           */
                ".set pop\n"
        );

-- 
2.46.0


Reply via email to