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
  ...

1 files changed, 7 insertions, 21 deletions

diff --git a/arch/x86/mm/maccess.c b/arch/x86/mm/maccess.c
index f5b85bdc0535..e1d7d7477c22 100644
--- a/arch/x86/mm/maccess.c
+++ b/arch/x86/mm/maccess.c
@@ -9,35 +9,21 @@ static __always_inline u64 canonical_address(u64 vaddr, u8 vaddr_bits)
 	return ((s64)vaddr << (64 - vaddr_bits)) >> (64 - vaddr_bits);
 }
 
-static __always_inline bool invalid_probe_range(u64 vaddr)
+bool probe_kernel_read_allowed(const void *unsafe_src, size_t size)
 {
+	unsigned long vaddr = (unsigned long)unsafe_src;
+
 	/*
 	 * Range covering the highest possible canonical userspace address
 	 * as well as non-canonical address range. For the canonical range
 	 * we also need to include the userspace guard page.
 	 */
-	return vaddr < TASK_SIZE_MAX + PAGE_SIZE ||
-	       canonical_address(vaddr, boot_cpu_data.x86_virt_bits) != vaddr;
+	return vaddr >= TASK_SIZE_MAX + PAGE_SIZE &&
+	       canonical_address(vaddr, boot_cpu_data.x86_virt_bits) == vaddr;
 }
 #else
-static __always_inline bool invalid_probe_range(u64 vaddr)
+bool probe_kernel_read_allowed(const void *unsafe_src, size_t size)
 {
-	return vaddr < TASK_SIZE_MAX;
+	return (unsigned long)unsafe_src >= TASK_SIZE_MAX;
 }
 #endif
-
-long probe_kernel_read_strict(void *dst, const void *src, size_t size)
-{
-	if (unlikely(invalid_probe_range((unsigned long)src)))
-		return -EFAULT;
-
-	return __probe_kernel_read(dst, src, size);
-}
-
-long strncpy_from_unsafe_strict(char *dst, const void *unsafe_addr, long count)
-{
-	if (unlikely(invalid_probe_range((unsigned long)unsafe_addr)))
-		return -EFAULT;
-
-	return __strncpy_from_unsafe(dst, unsafe_addr, count);
-}