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s390x: fix makecontext(3) implementation for passing arguments via stack

master
Ariadne Conill 2020-03-30 01:04:16 -05:00
parent f708c95659
commit ef42ad682a
1 changed files with 12 additions and 23 deletions
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35
arch/s390x/makecontext.c
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@ -28,41 +28,30 @@ extern int __setcontext(const ucontext_t *ucp);
void
__makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
{
greg_t *sp, *argp;
greg_t *sp;
va_list va;
int i;
unsigned int stack_args;
stack_args = argc > 5 ? argc - 5 : 0;
sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
sp -= stack_args; // maybe +1
sp = (greg_t *) (((uintptr_t) sp & -16L));
sp = (greg_t *) (((uintptr_t) sp & -8L));
ucp->uc_mcontext.gregs[7] = (uintptr_t) func;
ucp->uc_mcontext.gregs[8] = (uintptr_t) ucp->uc_link;
ucp->uc_mcontext.gregs[9] = (uintptr_t) &__setcontext;
ucp->uc_mcontext.gregs[14] = (uintptr_t) &__start_context;
argp = sp;
va_start(va, argc);
for (i = 0; i < argc; i++)
switch (i)
{
case 0:
case 1:
case 2:
case 3:
case 4:
case 5:
ucp->uc_mcontext.gregs[i + 2] = va_arg (va, greg_t);
break;
default:
*argp++ = va_arg (va, greg_t);
break;
}
for (i = 0; i < argc && i < 5; i++)
ucp->uc_mcontext.gregs[i + 2] = va_arg (va, greg_t);
if (argc > 5)
{
sp -= argc - 5;
for (i = 5; i < argc; i++)
sp[i - 5] = va_arg (va, greg_t);
}
va_end(va);