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ppc32/64: don't store uc_link on the stack 

This was previously stored either in the CR (ppc64) or LR (ppc32) save
area of the stack, or to one of the parameter save slots.

In either case, the saved value was unused.  This value is also passed
to __start_context via r31, so there's no need to pass it on the stack.
pull/11/head
Bobby Bingham 2019-04-05 13:38:36 -05:00
parent b9bd4045fb
commit b500b054c7
2 changed files with 4 additions and 8 deletions
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6
arch/ppc/makecontext.c
View File

@ -30,13 +30,12 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
greg_t *sp, *argp; greg_t *sp, *argp;
va_list va; va_list va;
int i; int i;
unsigned int uc_link, stack_args; unsigned int stack_args;
stack_args = argc > 8 ? argc - 8 : 0; stack_args = argc > 8 ? argc - 8 : 0;
uc_link = stack_args + 1;
sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
sp -= (uc_link + 1); sp -= stack_args + 2;
sp = (greg_t *) ((uintptr_t) sp & -16L); sp = (greg_t *) ((uintptr_t) sp & -16L);
ucp->uc_mcontext.gregs[REG_NIP] = (uintptr_t) func; ucp->uc_mcontext.gregs[REG_NIP] = (uintptr_t) func;
@ -45,7 +44,6 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
ucp->uc_mcontext.gregs[REG_SP] = (uintptr_t) sp; ucp->uc_mcontext.gregs[REG_SP] = (uintptr_t) sp;
sp[0] = 0; sp[0] = 0;
sp[uc_link] = (uintptr_t) ucp->uc_link;
argp = &sp[2]; argp = &sp[2];
va_start(va, argc); va_start(va, argc);

6
arch/ppc64/makecontext.c
View File

@ -30,13 +30,12 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
greg_t *sp, *argp; greg_t *sp, *argp;
va_list va; va_list va;
int i; int i;
unsigned int uc_link, stack_args; unsigned int stack_args;
stack_args = argc > 8 ? argc - 8 : 0; stack_args = argc > 8 ? argc - 8 : 0;
uc_link = stack_args + 1;
sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size); sp = (greg_t *) ((uintptr_t) ucp->uc_stack.ss_sp + ucp->uc_stack.ss_size);
sp -= (uc_link + 1); sp -= stack_args + 2;
sp = (greg_t *) (((uintptr_t) sp & -16L)); sp = (greg_t *) (((uintptr_t) sp & -16L));
ucp->uc_mcontext.gp_regs[REG_NIP] = (uintptr_t) func; ucp->uc_mcontext.gp_regs[REG_NIP] = (uintptr_t) func;
@ -46,7 +45,6 @@ __makecontext(ucontext_t *ucp, void (*func)(void), int argc, ...)
ucp->uc_mcontext.gp_regs[REG_R31] = (uintptr_t) ucp->uc_link; ucp->uc_mcontext.gp_regs[REG_R31] = (uintptr_t) ucp->uc_link;
sp[0] = 0; sp[0] = 0;
sp[uc_link] = (uintptr_t) ucp->uc_link;
argp = &sp[2]; argp = &sp[2];
va_start(va, argc); va_start(va, argc);