From 5932c9fd19e6e5ac84756c5c32fe5155d9a6b458 Mon Sep 17 00:00:00 2001
From: Nadav Amit <namit@vmware.com>
Date: Thu, 25 Apr 2019 17:11:42 -0700
Subject: mm/tlb: Provide default nmi_uaccess_okay()

x86 has an nmi_uaccess_okay(), but other architectures do not.
Arch-independent code might need to know whether access to user
addresses is ok in an NMI context or in other code whose execution
context is unknown.  Specifically, this function is needed for
bpf_probe_write_user().

Add a default implementation of nmi_uaccess_okay() for architectures
that do not have such a function.

Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <akpm@linux-foundation.org>
Cc: <ard.biesheuvel@linaro.org>
Cc: <deneen.t.dock@intel.com>
Cc: <kernel-hardening@lists.openwall.com>
Cc: <kristen@linux.intel.com>
Cc: <linux_dti@icloud.com>
Cc: <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190426001143.4983-23-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 include/asm-generic/tlb.h | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'include/asm-generic')

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index 6be86c1c5c58..075b353cae86 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -20,6 +20,15 @@
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
 
+/*
+ * Blindly accessing user memory from NMI context can be dangerous
+ * if we're in the middle of switching the current user task or switching
+ * the loaded mm.
+ */
+#ifndef nmi_uaccess_okay
+# define nmi_uaccess_okay() true
+#endif
+
 #ifdef CONFIG_MMU
 
 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
-- 
cgit v1.2.3


From caa841360134f863987f2d4f77b8dc2fbb7596f8 Mon Sep 17 00:00:00 2001
From: Nadav Amit <nadav.amit@gmail.com>
Date: Sat, 4 May 2019 18:11:24 -0700
Subject: x86/mm: Initialize PGD cache during mm initialization

Poking-mm initialization might require to duplicate the PGD in early
stage. Initialize the PGD cache earlier to prevent boot failures.

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 4fc19708b165 ("x86/alternatives: Initialize temporary mm for patching")
Link: http://lkml.kernel.org/r/20190505011124.39692-1-namit@vmware.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 include/asm-generic/pgtable.h | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'include/asm-generic')

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index fa782fba51ee..75d9d68a6de7 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1126,6 +1126,8 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 static inline void init_espfix_bsp(void) { }
 #endif
 
+extern void __init pgd_cache_init(void);
+
 #ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED
 static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot)
 {
-- 
cgit v1.2.3