From: Michael Ellerman mpe@ellerman.id.au
commit e6fe228c4ffafdfc970cf6d46883a1f481baf7ea upstream.
Signed-off-by: Michael Ellerman mpe@ellerman.id.au Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/Kconfig | 1 + arch/powerpc/mm/fault.c | 41 ++++------------------------------------- 2 files changed, 5 insertions(+), 37 deletions(-)
--- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -278,6 +278,7 @@ config PPC select IRQ_DOMAIN select IRQ_FORCED_THREADING select KASAN_VMALLOC if KASAN && MODULES + select LOCK_MM_AND_FIND_VMA select MMU_GATHER_PAGE_SIZE select MMU_GATHER_RCU_TABLE_FREE select MMU_GATHER_MERGE_VMAS --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -84,11 +84,6 @@ static int __bad_area(struct pt_regs *re return __bad_area_nosemaphore(regs, address, si_code); }
-static noinline int bad_area(struct pt_regs *regs, unsigned long address) -{ - return __bad_area(regs, address, SEGV_MAPERR); -} - static noinline int bad_access_pkey(struct pt_regs *regs, unsigned long address, struct vm_area_struct *vma) { @@ -515,40 +510,12 @@ lock_mmap: * we will deadlock attempting to validate the fault against the * address space. Luckily the kernel only validly references user * space from well defined areas of code, which are listed in the - * exceptions table. - * - * As the vast majority of faults will be valid we will only perform - * the source reference check when there is a possibility of a deadlock. - * Attempt to lock the address space, if we cannot we then validate the - * source. If this is invalid we can skip the address space check, - * thus avoiding the deadlock. - */ - if (unlikely(!mmap_read_trylock(mm))) { - if (!is_user && !search_exception_tables(regs->nip)) - return bad_area_nosemaphore(regs, address); - + * exceptions table. lock_mm_and_find_vma() handles that logic. + */ retry: - mmap_read_lock(mm); - } else { - /* - * The above down_read_trylock() might have succeeded in - * which case we'll have missed the might_sleep() from - * down_read(): - */ - might_sleep(); - } - - vma = find_vma(mm, address); + vma = lock_mm_and_find_vma(mm, address, regs); if (unlikely(!vma)) - return bad_area(regs, address); - - if (unlikely(vma->vm_start > address)) { - if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) - return bad_area(regs, address); - - if (unlikely(expand_stack(vma, address))) - return bad_area(regs, address); - } + return bad_area_nosemaphore(regs, address);
if (unlikely(access_pkey_error(is_write, is_exec, (error_code & DSISR_KEYFAULT), vma)))