[ 0.000000] ... [ 0.000000] Call Trace: [ 0.000000] [] init_idle+0x130/0x270 [ 0.000000] [] sched_init+0x5c8/0x6c0 [ 0.000000] [] start_kernel+0x27c/0x7a8 This bug has been reported to LLVM[2] and affects version from (at least) 18 to 21. Let's work around this by using inline assembly to assign $gp before a fix is widely available. Cc: stable@vger.kernel.org Link: https://gcc.gnu.org/onlinedocs/gcc-15.2.0/gcc/Global-Register-Variables.html # [1] Link: https://github.com/llvm/llvm-project/issues/176546 # [2] Signed-off-by: Yao Zi Acked-by: Nathan Chancellor Signed-off-by: Thomas Bogendoerfer Signed-off-by: Greg Kroah-Hartman --- arch/mips/kernel/relocate.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) --- a/arch/mips/kernel/relocate.c +++ b/arch/mips/kernel/relocate.c @@ -420,7 +420,20 @@ void *__init relocate_kernel(void) goto out; /* The current thread is now within the relocated image */ +#ifndef CONFIG_CC_IS_CLANG __current_thread_info = RELOCATED(&init_thread_union); +#else + /* + * LLVM may wrongly restore $gp ($28) in epilog even if it's + * intentionally modified. Work around this by using inline + * assembly to assign $gp. $gp couldn't be listed as output or + * clobber, or LLVM will still restore its original value. + * See also LLVM upstream issue + * https://github.com/llvm/llvm-project/issues/176546 + */ + asm volatile("move $28, %0" : : + "r" (RELOCATED(&init_thread_union))); +#endif /* Return the new kernel's entry point */ kernel_entry = RELOCATED(start_kernel);[PATCH 6.19 752/781] MIPS: Work around LLVM bug when gp is used as global register variableGreg Kroah-Hartman undefinedstable@vger.kernel.org undefined undefined undefined undefined undefined‘D†–