On Wed, 7 Jun 2017 22:47:56 +0200
Heiko Carstens <heiko.carstens@xxxxxxxxxx> wrote:
> On Wed, Jun 07, 2017 at 02:34:40PM +0200, Martin Schwidefsky wrote:
> > +#define arch_elf_pt_proc(ehdr, phdr, elf, interp, state) \
> > +({ \
> > + struct elf64_hdr *_ehdr = (void *) ehdr; \
> > + struct elf64_phdr *_phdr = (void *) phdr; \
> > + int _rc = 0; \
> > + if (_ehdr->e_ident[EI_CLASS] == ELFCLASS64 && \
> > + _phdr->p_type == PT_S390_REQUEST_PGSTE && \
> > + !page_table_allocate_pgste && \
> > + !test_thread_flag(TIF_REQUEST_PGSTE)) { \
> > + set_thread_flag(TIF_REQUEST_PGSTE); \
> > + set_pt_regs_flag(task_pt_regs(current), \
> > + PIF_SYSCALL_RESTART); \
> > + _rc = -EAGAIN; \
> > + } \
> > + _rc; \
> > +})
>
> I'm wondering if this should simply fail, if a PT_S390_REQUEST_PGSTE type
> segment exists, but it is not ELFCLASS64?
> It will fail later anyway on s390_enable_sie(), but...
Does it matter if it fails for a 32-bit ELF file? Just makes the code more
complex without benefit, no?
> > diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
> > index c119d564d8f2..1201b18e817d 100644
> > --- a/arch/s390/include/asm/mmu_context.h
> > +++ b/arch/s390/include/asm/mmu_context.h
> > @@ -25,7 +25,8 @@ static inline int init_new_context(struct task_struct *tsk,
> > mm->context.gmap_asce = 0;
> > mm->context.flush_mm = 0;
> > #ifdef CONFIG_PGSTE
> > - mm->context.alloc_pgste = page_table_allocate_pgste;
> > + mm->context.alloc_pgste = page_table_allocate_pgste ||
> > + test_thread_flag(TIF_REQUEST_PGSTE);
>
> I think the alloc_pgste flag should be inherited on fork, no?
Yes, that makes it more consistent. I'll add it.
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
