From 5e91bf5ce9b8740076f5283f1ec3a5b023950920 Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Tue, 14 May 2019 15:55:31 -0700 Subject: [PATCH] ARC: mm: do_page_fault refactor #7: fold the various error handling - single up_read() call vs. 4 - so much easier on eyes Technically it seems like @bad_area label moved up, but even in old regime, it was a special case of delivering SIGSEGV unconditionally which we now do as well, although with checks. Also note that @fault needs to be initialized since we can land in @bad_area (which reads it) without setting it up with return value of handle_mm_fault() - failing to do so did bite us although as a side effect of different patch: see [1] [1]: http://lists.infradead.org/pipermail/linux-snps-arc/2019-May/005803.html Signed-off-by: Vineet Gupta --- arch/arc/mm/fault.c | 48 +++++++++++++-------------------------------- 1 file changed, 14 insertions(+), 34 deletions(-) diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c index 2672ce24d741..6a78a2d776a9 100644 --- a/arch/arc/mm/fault.c +++ b/arch/arc/mm/fault.c @@ -63,9 +63,9 @@ void do_page_fault(unsigned long address, struct pt_regs *regs) struct vm_area_struct *vma = NULL; struct task_struct *tsk = current; struct mm_struct *mm = tsk->mm; - int si_code = SEGV_MAPERR; + int sig, si_code = SEGV_MAPERR; unsigned int write = 0, exec = 0, mask; - vm_fault_t fault; /* handle_mm_fault() output */ + vm_fault_t fault = VM_FAULT_SIGSEGV; /* handle_mm_fault() output */ unsigned int flags; /* handle_mm_fault() input */ /* @@ -174,47 +174,27 @@ retry: return; } - if (fault & VM_FAULT_OOM) - goto out_of_memory; - else if (fault & VM_FAULT_SIGSEGV) - goto bad_area; - else if (fault & VM_FAULT_SIGBUS) - goto do_sigbus; - - /* no man's land */ - BUG(); - - /* - * Something tried to access memory that isn't in our memory map.. - * Fix it, but check if it's kernel or user first.. - */ bad_area: up_read(&mm->mmap_sem); if (!user_mode(regs)) goto no_context; - tsk->thread.fault_address = address; - force_sig_fault(SIGSEGV, si_code, (void __user *)address, tsk); - return; - -out_of_memory: - up_read(&mm->mmap_sem); - - if (!user_mode(regs)) - goto no_context; - - pagefault_out_of_memory(); - return; - -do_sigbus: - up_read(&mm->mmap_sem); + if (fault & VM_FAULT_OOM) { + pagefault_out_of_memory(); + return; + } - if (!user_mode(regs)) - goto no_context; + if (fault & VM_FAULT_SIGBUS) { + sig = SIGBUS; + si_code = BUS_ADRERR; + } + else { + sig = SIGSEGV; + } tsk->thread.fault_address = address; - force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, tsk); + force_sig_fault(sig, si_code, (void __user *)address, tsk); return; no_context: -- 2.30.2