On Wed, Jun 16, 2021 at 08:25:35PM +0000, Al Viro wrote: > On Wed, Jun 16, 2021 at 01:32:50PM -0500, Eric W. Biederman wrote: > > > -.macro fork_like name > > +.macro allregs name > > .align 4 > > .globl alpha_\name > > .ent alpha_\name > > + .cfi_startproc > > alpha_\name: > > .prologue 0 > > - bsr $1, do_switch_stack > > + SAVE_SWITCH_STACK > > jsr $26, sys_\name > > - ldq $26, 56($sp) > > - lda $sp, SWITCH_STACK_SIZE($sp) > > + RESTORE_SWITCH_STACK > > No. You've just added one hell of an overhead to fork(2), > for no reason whatsoever. sys_fork() et.al. does *NOT* modify the > callee-saved registers; it's plain C. So this change is complete > BS. > > > +allregs exit > > +allregs exit_group > > Details, please - what exactly makes exit(2) different from > e.g. open(2)? Ah... PTRACE_EVENT_EXIT garbage, fortunately having no counterparts in case of open(2)... Still, WTF would you want to restore callee-saved registers for in case of exit(2)?
