Merge branch 'akpm' (patches from Andrew)

Merge even more updates from Andrew Morton:

 - a kernel-wide sweep of show_stack()

 - pagetable cleanups

 - abstract out accesses to mmap_sem - prep for mmap_sem scalability work

 - hch's user acess work

Subsystems affected by this patch series: debug, mm/pagemap, mm/maccess,
mm/documentation.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (93 commits)
  include/linux/cache.h: expand documentation over __read_mostly
  maccess: return -ERANGE when probe_kernel_read() fails
  x86: use non-set_fs based maccess routines
  maccess: allow architectures to provide kernel probing directly
  maccess: move user access routines together
  maccess: always use strict semantics for probe_kernel_read
  maccess: remove strncpy_from_unsafe
  tracing/kprobes: handle mixed kernel/userspace probes better
  bpf: rework the compat kernel probe handling
  bpf:bpf_seq_printf(): handle potentially unsafe format string better
  bpf: handle the compat string in bpf_trace_copy_string better
  bpf: factor out a bpf_trace_copy_string helper
  maccess: unify the probe kernel arch hooks
  maccess: remove probe_read_common and probe_write_common
  maccess: rename strnlen_unsafe_user to strnlen_user_nofault
  maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault
  maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault
  maccess: update the top of file comment
  maccess: clarify kerneldoc comments
  maccess: remove duplicate kerneldoc comments
  ...

9 files changed, 24 insertions, 45 deletions

diff --git a/arch/um/kernel/maccess.c b/arch/um/kernel/maccess.c
index 67b2e0fa92bb..e929c0966696 100644
--- a/arch/um/kernel/maccess.c
+++ b/arch/um/kernel/maccess.c
@@ -7,15 +7,13 @@
 #include <linux/kernel.h>
 #include <os.h>
 
-long probe_kernel_read(void *dst, const void *src, size_t size)
+bool probe_kernel_read_allowed(const void *src, size_t size)
 {
 	void *psrc = (void *)rounddown((unsigned long)src, PAGE_SIZE);
 
 	if ((unsigned long)src < PAGE_SIZE || size <= 0)
-		return -EFAULT;
-
+		return false;
 	if (os_mincore(psrc, size + src - psrc) <= 0)
-		return -EFAULT;
-
-	return __probe_kernel_read(dst, src, size);
+		return false;
+	return true;
 }
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index 401b22f14743..c2ff76c8981e 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -125,10 +125,6 @@ static void __init fixaddr_user_init( void)
 {
 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
 	long size = FIXADDR_USER_END - FIXADDR_USER_START;
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
-	pmd_t *pmd;
 	pte_t *pte;
 	phys_t p;
 	unsigned long v, vaddr = FIXADDR_USER_START;
@@ -146,11 +142,7 @@ static void __init fixaddr_user_init( void)
 	p = __pa(v);
 	for ( ; size > 0; size -= PAGE_SIZE, vaddr += PAGE_SIZE,
 		      p += PAGE_SIZE) {
-		pgd = swapper_pg_dir + pgd_index(vaddr);
-		p4d = p4d_offset(pgd, vaddr);
-		pud = pud_offset(p4d, vaddr);
-		pmd = pmd_offset(pud, vaddr);
-		pte = pte_offset_kernel(pmd, vaddr);
+		pte = virt_to_kpte(vaddr);
 		pte_set_val(*pte, p, PAGE_READONLY);
 	}
 #endif
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index cbe33af2a880..e3a2cf92a373 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -25,7 +25,6 @@
 #include <linux/threads.h>
 #include <linux/tracehook.h>
 #include <asm/current.h>
-#include <asm/pgtable.h>
 #include <asm/mmu_context.h>
 #include <linux/uaccess.h>
 #include <as-layout.h>
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 3f0d9a573fd6..d9961163da66 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -9,7 +9,6 @@
 #include <linux/slab.h>
 
 #include <asm/pgalloc.h>
-#include <asm/pgtable.h>
 #include <asm/sections.h>
 #include <as-layout.h>
 #include <os.h>
@@ -115,7 +114,7 @@ void uml_setup_stubs(struct mm_struct *mm)
 	mm->context.stub_pages[0] = virt_to_page(__syscall_stub_start);
 	mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
 
-	/* dup_mmap already holds mmap_sem */
+	/* dup_mmap already holds mmap_lock */
 	err = install_special_mapping(mm, STUB_START, STUB_END - STUB_START,
 				      VM_READ | VM_MAYREAD | VM_EXEC |
 				      VM_MAYEXEC | VM_DONTCOPY | VM_PFNMAP,
diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
index d617f8dc9c19..2dec915abe6f 100644
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -10,7 +10,6 @@
 #include <linux/sched.h>
 #include <asm/current.h>
 #include <asm/page.h>
-#include <asm/pgtable.h>
 #include <kern_util.h>
 #include <os.h>
 
diff --git a/arch/um/kernel/sysrq.c b/arch/um/kernel/sysrq.c
index c71b5ef7ea8c..acbc879d2773 100644
--- a/arch/um/kernel/sysrq.c
+++ b/arch/um/kernel/sysrq.c
@@ -17,7 +17,9 @@
 
 static void _print_addr(void *data, unsigned long address, int reliable)
 {
-	pr_info(" [<%08lx>] %s%pS\n", address, reliable ? "" : "? ",
+	const char *loglvl = data;
+
+	printk("%s [<%08lx>] %s%pS\n", loglvl, address, reliable ? "" : "? ",
 		(void *)address);
 }
 
@@ -25,9 +27,9 @@ static const struct stacktrace_ops stackops = {
 	.address = _print_addr
 };
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
-	unsigned long *sp = stack;
 	struct pt_regs *segv_regs = current->thread.segv_regs;
 	int i;
 
@@ -38,20 +40,19 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	}
 
 	if (!stack)
-		sp = get_stack_pointer(task, segv_regs);
+		stack = get_stack_pointer(task, segv_regs);
 
-	pr_info("Stack:\n");
-	stack = sp;
+	printk("%sStack:\n", loglvl);
 	for (i = 0; i < 3 * STACKSLOTS_PER_LINE; i++) {
 		if (kstack_end(stack))
 			break;
 		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			pr_cont("\n");
+			printk("%s\n", loglvl);
 		pr_cont(" %08lx", *stack++);
 	}
-	pr_cont("\n");
+	printk("%s\n", loglvl);
 
-	pr_info("Call Trace:\n");
-	dump_trace(current, &stackops, NULL);
-	pr_info("\n");
+	printk("%sCall Trace:\n", loglvl);
+	dump_trace(current, &stackops, (void *)loglvl);
+	printk("%s\n", loglvl);
 }
diff --git a/arch/um/kernel/tlb.c b/arch/um/kernel/tlb.c
index 80a358c6d652..61776790cd67 100644
--- a/arch/um/kernel/tlb.c
+++ b/arch/um/kernel/tlb.c
@@ -7,7 +7,6 @@
 #include <linux/module.h>
 #include <linux/sched/signal.h>
 
-#include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <as-layout.h>
 #include <mem_user.h>
@@ -349,8 +348,8 @@ void fix_range_common(struct mm_struct *mm, unsigned long start_addr,
 	if (ret) {
 		printk(KERN_ERR "fix_range_common: failed, killing current "
 		       "process: %d\n", task_tgid_vnr(current));
-		/* We are under mmap_sem, release it such that current can terminate */
-		up_write(&current->mm->mmap_sem);
+		/* We are under mmap_lock, release it such that current can terminate */
+		mmap_write_unlock(current->mm);
 		force_sig(SIGKILL);
 		do_signal(&current->thread.regs);
 	}
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 8f18cf56b3dd..2b3afa354a90 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -10,7 +10,6 @@
 #include <linux/uaccess.h>
 #include <linux/sched/debug.h>
 #include <asm/current.h>
-#include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <arch.h>
 #include <as-layout.h>
@@ -27,9 +26,6 @@ int handle_page_fault(unsigned long address, unsigned long ip,
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 	int err = -EFAULT;
@@ -47,7 +43,7 @@ int handle_page_fault(unsigned long address, unsigned long ip,
 	if (is_user)
 		flags |= FAULT_FLAG_USER;
 retry:
-	down_read(&mm->mmap_sem);
+	mmap_read_lock(mm);
 	vma = find_vma(mm, address);
 	if (!vma)
 		goto out;
@@ -103,10 +99,7 @@ good_area:
 			}
 		}
 
-		pgd = pgd_offset(mm, address);
-		p4d = p4d_offset(pgd, address);
-		pud = pud_offset(p4d, address);
-		pmd = pmd_offset(pud, address);
+		pmd = pmd_off(mm, address);
 		pte = pte_offset_kernel(pmd, address);
 	} while (!pte_present(*pte));
 	err = 0;
@@ -123,7 +116,7 @@ good_area:
 #endif
 	flush_tlb_page(vma, address);
 out:
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 out_nosemaphore:
 	return err;
 
@@ -132,7 +125,7 @@ out_of_memory:
 	 * We ran out of memory, call the OOM killer, and return the userspace
 	 * (which will retry the fault, or kill us if we got oom-killed).
 	 */
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 	if (!is_user)
 		goto out_nosemaphore;
 	pagefault_out_of_memory();
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 375ab720e4aa..00141e70de56 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -14,7 +14,6 @@
 #include <linux/sched/task.h>
 #include <linux/kmsg_dump.h>
 
-#include <asm/pgtable.h>
 #include <asm/processor.h>
 #include <asm/sections.h>
 #include <asm/setup.h>