Linux-libre 4.2-gnu

1 files changed, 4 insertions, 108 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 626899af4..9dc909841 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -13,7 +13,7 @@
 #include <linux/hugetlb.h>		/* hstate_index_to_shift	*/
 #include <linux/prefetch.h>		/* prefetchw			*/
 #include <linux/context_tracking.h>	/* exception_enter(), ...	*/
-#include <linux/tuxonice.h>             /* incremental image support    */
+#include <linux/uaccess.h>		/* faulthandler_disabled()	*/
 
 #include <asm/traps.h>			/* dotraplinkage, ...		*/
 #include <asm/pgalloc.h>		/* pgd_*(), ...			*/
@@ -652,10 +652,6 @@ no_context(struct pt_regs *regs, unsigned long error_code,
 	unsigned long flags;
 	int sig;
 
-        if (toi_make_writable(init_mm.pgd, address)) {
-            return;
-        }
-
 	/* Are we prepared to handle this kernel fault? */
 	if (fixup_exception(regs)) {
 		/*
@@ -910,101 +906,10 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
 	}
 }
 
-#ifdef CONFIG_TOI_INCREMENTAL
-/**
- * _toi_do_cbw - Do a copy-before-write before letting the faulting process continue
- */
-static void toi_do_cbw(struct page *page)
-{
-    struct toi_cbw_state *state = this_cpu_ptr(&toi_cbw_states);
-
-    state->active = 1;
-    wmb();
-
-    if (state->enabled && state->next && PageTOI_CBW(page)) {
-        struct toi_cbw *this = state->next;
-        memcpy(this->virt, page_address(page), PAGE_SIZE);
-        this->pfn = page_to_pfn(page);
-        state->next = this->next;
-    }
-
-    state->active = 0;
-}
-
-/**
- * _toi_make_writable - Defuse TOI's write protection
- */
-int _toi_make_writable(pte_t *pte)
-{
-    struct page *page = pte_page(*pte);
-    if (PageTOI_RO(page)) {
-        pgd_t *pgd = __va(read_cr3());
-        /*
-         * If this is a TuxOnIce caused fault, we may not have permission to
-         * write to a page needed to reset the permissions of the original
-         * page. Use swapper_pg_dir to get around this.
-         */
-        load_cr3(swapper_pg_dir);
-
-        set_pte_atomic(pte, pte_mkwrite(*pte));
-        SetPageTOI_Dirty(page);
-        ClearPageTOI_RO(page);
-
-        toi_do_cbw(page);
-
-        load_cr3(pgd);
-        return 1;
-    }
-    return 0;
-}
-
-/**
- * toi_make_writable - Handle a (potential) fault caused by TOI's write protection
- *
- * Make a page writable that was protected. Might be because of a fault, or
- * because we're allocating it and want it to be untracked.
- *
- * Note that in the fault handling case, we don't care about the error code. If
- * called from the double fault handler, we won't have one. We just check to
- * see if the page was made RO by TOI, and mark it dirty/release the protection
- * if it was.
- */
-int toi_make_writable(pgd_t *pgd, unsigned long address)
-{
-    pud_t *pud;
-    pmd_t *pmd;
-    pte_t *pte;
-
-    pgd = pgd + pgd_index(address);
-    if (!pgd_present(*pgd))
-        return 0;
-
-    pud = pud_offset(pgd, address);
-    if (!pud_present(*pud))
-        return 0;
-
-    if (pud_large(*pud))
-        return _toi_make_writable((pte_t *) pud);
-
-    pmd = pmd_offset(pud, address);
-    if (!pmd_present(*pmd))
-        return 0;
-
-    if (pmd_large(*pmd))
-        return _toi_make_writable((pte_t *) pmd);
-
-    pte = pte_offset_kernel(pmd, address);
-    if (!pte_present(*pte))
-        return 0;
-
-    return _toi_make_writable(pte);
-}
-#endif
-
 static int spurious_fault_check(unsigned long error_code, pte_t *pte)
 {
 	if ((error_code & PF_WRITE) && !pte_write(*pte))
-                return 0;
+		return 0;
 
 	if ((error_code & PF_INSTR) && !pte_exec(*pte))
 		return 0;
@@ -1167,15 +1072,6 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
 		kmemcheck_hide(regs);
 	prefetchw(&mm->mmap_sem);
 
-        /*
-         * Detect and handle page faults due to TuxOnIce making pages read-only
-         * so that it can create incremental images.
-         *
-         * Do it early to avoid double faults.
-         */
-        if (unlikely(toi_make_writable(init_mm.pgd, address)))
-            return;
-
 	if (unlikely(kmmio_fault(regs, address)))
 		return;
 
@@ -1231,9 +1127,9 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
 
 	/*
 	 * If we're in an interrupt, have no user context or are running
-	 * in an atomic region then we must not take the fault:
+	 * in a region with pagefaults disabled then we must not take the fault
 	 */
-	if (unlikely(in_atomic() || !mm)) {
+	if (unlikely(faulthandler_disabled() || !mm)) {
 		bad_area_nosemaphore(regs, error_code, address);
 		return;
 	}