The unwinder reports idle tasks' stack on XEN PV as unreliable which complicates things for at least live patching. The two patches in the series try to amend that by using similar approach as non-XEN x86 does. v1->v2: - call instruction used instead of push+jmp - initial_stack used directly There is a thing which makes me slightly uncomfortable. s/jmp/call/ means that, theoretically, the called function could return. GCC then generates not so nice code and there is asm_cpu_bringup_and_idle+0x5/0x1000 symbol last on the stack due to alignment in asm/x86/xen/xen-head.S which could be confusing. Practically it is all fine, because neither xen_start_kernel(), nor cpu_bringup_and_idle() return (there is unbounded loop in cpu_startup_entry() around do_idle()). __noreturn annotation of these functions did not help. So I don't think it is really a problem, but one may wonder. Miroslav Benes (2): x86/xen: Make the boot CPU idle task reliable x86/xen: Make the secondary CPU idle tasks reliable arch/x86/xen/smp_pv.c | 3 ++- arch/x86/xen/xen-head.S | 16 ++++++++++++++-- 2 files changed, 16 insertions(+), 3 deletions(-) -- 2.25.1
