Rémi Bernon (@rbernon) commented about dlls/ntdll/unix/signal_arm64.c:
"sub x29, x1, #0xc0\n\t"
__ASM_CFI(".cfi_def_cfa_register 29\n\t")
__ASM_CFI(".cfi_rel_offset 29,0x00\n\t")
__ASM_CFI(".cfi_rel_offset 30,0x08\n\t")
__ASM_CFI(".cfi_rel_offset 19,0x10\n\t")
__ASM_CFI(".cfi_rel_offset 20,0x18\n\t")
__ASM_CFI(".cfi_rel_offset 21,0x20\n\t")
__ASM_CFI(".cfi_rel_offset 22,0x28\n\t")
__ASM_CFI(".cfi_rel_offset 23,0x30\n\t")
__ASM_CFI(".cfi_rel_offset 24,0x38\n\t")
__ASM_CFI(".cfi_rel_offset 25,0x40\n\t")
__ASM_CFI(".cfi_rel_offset 26,0x48\n\t")
__ASM_CFI(".cfi_rel_offset 27,0x50\n\t")
__ASM_CFI(".cfi_rel_offset 28,0x58\n\t")
/* switch to kernel stack */
"mov sp, x29\n\t"
And here.