Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Will Deacon:
 "Nothing particularly interesting here, but all important fixes
  nonetheless:

   - Add missing PAN toggling in the futex code

   - Fix missing #include that briefly caused issues in -next

   - Allow changing of vmalloc permissions with set_memory_* (used by
     bpf)"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: asm: Explicitly include linux/personality.h in asm/page.h
  arm64: futex.h: Add missing PAN toggling
  arm64: allow vmalloc regions to be set with set_memory_*

3 files changed, 22 insertions, 4 deletions

diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h
index 007a69f..5f3ab8c 100644
--- a/arch/arm64/include/asm/futex.h
+++ b/arch/arm64/include/asm/futex.h
@@ -121,6 +121,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 		return -EFAULT;
 
 	asm volatile("// futex_atomic_cmpxchg_inatomic\n"
+ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
 "	prfm	pstl1strm, %2\n"
 "1:	ldxr	%w1, %2\n"
 "	sub	%w3, %w1, %w4\n"
@@ -137,6 +138,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 "	.align	3\n"
 "	.quad	1b, 4b, 2b, 4b\n"
 "	.popsection\n"
+ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
 	: "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp)
 	: "r" (oldval), "r" (newval), "Ir" (-EFAULT)
 	: "memory");
diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h
index 9b2f5a9..ae615b9 100644
--- a/arch/arm64/include/asm/page.h
+++ b/arch/arm64/include/asm/page.h
@@ -39,6 +39,7 @@
 
 #ifndef __ASSEMBLY__
 
+#include <linux/personality.h> /* for READ_IMPLIES_EXEC */
 #include <asm/pgtable-types.h>
 
 extern void __cpu_clear_user_page(void *p, unsigned long user);
diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index cf62407..0795c3a 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -14,6 +14,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/sched.h>
+#include <linux/vmalloc.h>
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -44,6 +45,7 @@ static int change_memory_common(unsigned long addr, int numpages,
 	unsigned long end = start + size;
 	int ret;
 	struct page_change_data data;
+	struct vm_struct *area;
 
 	if (!PAGE_ALIGNED(addr)) {
 		start &= PAGE_MASK;
@@ -51,10 +53,23 @@ static int change_memory_common(unsigned long addr, int numpages,
 		WARN_ON_ONCE(1);
 	}
 
-	if (start < MODULES_VADDR || start >= MODULES_END)
-		return -EINVAL;
-
-	if (end < MODULES_VADDR || end >= MODULES_END)
+	/*
+	 * Kernel VA mappings are always live, and splitting live section
+	 * mappings into page mappings may cause TLB conflicts. This means
+	 * we have to ensure that changing the permission bits of the range
+	 * we are operating on does not result in such splitting.
+	 *
+	 * Let's restrict ourselves to mappings created by vmalloc (or vmap).
+	 * Those are guaranteed to consist entirely of page mappings, and
+	 * splitting is never needed.
+	 *
+	 * So check whether the [addr, addr + size) interval is entirely
+	 * covered by precisely one VM area that has the VM_ALLOC flag set.
+	 */
+	area = find_vm_area((void *)addr);
+	if (!area ||
+	    end > (unsigned long)area->addr + area->size ||
+	    !(area->flags & VM_ALLOC))
 		return -EINVAL;
 
 	if (!numpages)