From: Linus Torvalds torvalds@linux-foundation.org
commit ae870a68b5d13d67cf4f18d47bb01ee3fee40acb upstream.
This converts arm64 to use the new page fault helper. It was very straightforward, but still needed a fix for the "obvious" conversion I initially did. Thanks to Suren for the fix and testing.
Fixed-and-tested-by: Suren Baghdasaryan surenb@google.com Unnecessary-code-removal-by: Liam R. Howlett Liam.Howlett@oracle.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/arm64/Kconfig | 1 + arch/arm64/mm/fault.c | 44 +++++++------------------------------------- 2 files changed, 8 insertions(+), 37 deletions(-)
--- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -219,6 +219,7 @@ config ARM64 select IRQ_DOMAIN select IRQ_FORCED_THREADING select KASAN_VMALLOC if KASAN + select LOCK_MM_AND_FIND_VMA select MODULES_USE_ELF_RELA select NEED_DMA_MAP_STATE select NEED_SG_DMA_LENGTH --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -483,27 +483,14 @@ static void do_bad_area(unsigned long fa #define VM_FAULT_BADMAP ((__force vm_fault_t)0x010000) #define VM_FAULT_BADACCESS ((__force vm_fault_t)0x020000)
-static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, +static vm_fault_t __do_page_fault(struct mm_struct *mm, + struct vm_area_struct *vma, unsigned long addr, unsigned int mm_flags, unsigned long vm_flags, struct pt_regs *regs) { - struct vm_area_struct *vma = find_vma(mm, addr); - - if (unlikely(!vma)) - return VM_FAULT_BADMAP; - /* * Ok, we have a good vm_area for this memory access, so we can handle * it. - */ - if (unlikely(vma->vm_start > addr)) { - if (!(vma->vm_flags & VM_GROWSDOWN)) - return VM_FAULT_BADMAP; - if (expand_stack(vma, addr)) - return VM_FAULT_BADMAP; - } - - /* * Check that the permissions on the VMA allow for the fault which * occurred. */ @@ -585,31 +572,14 @@ static int __kprobes do_page_fault(unsig
perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, addr);
- /* - * As per x86, we may deadlock here. However, since the kernel only - * validly references user space from well defined areas of the code, - * we can bug out early if this is from code which shouldn't. - */ - if (!mmap_read_trylock(mm)) { - if (!user_mode(regs) && !search_exception_tables(regs->pc)) - goto no_context; retry: - mmap_read_lock(mm); - } else { - /* - * The above mmap_read_trylock() might have succeeded in which - * case, we'll have missed the might_sleep() from down_read(). - */ - might_sleep(); -#ifdef CONFIG_DEBUG_VM - if (!user_mode(regs) && !search_exception_tables(regs->pc)) { - mmap_read_unlock(mm); - goto no_context; - } -#endif + vma = lock_mm_and_find_vma(mm, addr, regs); + if (unlikely(!vma)) { + fault = VM_FAULT_BADMAP; + goto done; }
- fault = __do_page_fault(mm, addr, mm_flags, vm_flags, regs); + fault = __do_page_fault(mm, vma, addr, mm_flags, vm_flags, regs);
/* Quick path to respond to signals */ if (fault_signal_pending(fault, regs)) {