[tip:x86/boot] x86/mm: Separate variable for trampoline PGD

[tip-bot for Thomas Garnier]

Commit-ID:  b234e8a09003af108d3573f0369e25c080676b14
Gitweb: http://git.kernel.org/tip/b234e8a09003af108d3573f0369e25c080676b14
Author: Thomas Garnier 
AuthorDate: Tue, 21 Jun 2016 17:47:01 -0700
Committer:  Ingo Molnar 
CommitDate: Fri, 8 Jul 2016 17:33:46 +0200

x86/mm: Separate variable for trampoline PGD

Use a separate global variable to define the trampoline PGD used to
start other processors. This change will allow KALSR memory
randomization to change the trampoline PGD to be correctly aligned with
physical memory.

Signed-off-by: Thomas Garnier 
Signed-off-by: Kees Cook 
Cc: Alexander Kuleshov 
Cc: Alexander Popov 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Aneesh Kumar K.V 
Cc: Baoquan He 
Cc: Boris Ostrovsky 
Cc: Borislav Petkov 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Christian Borntraeger 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: Dave Young 
Cc: Denys Vlasenko 
Cc: Dmitry Vyukov 
Cc: H. Peter Anvin 
Cc: Jan Beulich 
Cc: Joerg Roedel 
Cc: Jonathan Corbet 
Cc: Josh Poimboeuf 
Cc: Juergen Gross 
Cc: Kirill A. Shutemov 
Cc: Linus Torvalds 
Cc: Lv Zheng 
Cc: Mark Salter 
Cc: Martin Schwidefsky 
Cc: Matt Fleming 
Cc: Peter Zijlstra 
Cc: Stephen Smalley 
Cc: Thomas Gleixner 
Cc: Toshi Kani 
Cc: Xiao Guangrong 
Cc: Yinghai Lu 
Cc: kernel-harden...@lists.openwall.com
Cc: linux-...@vger.kernel.org
Link: 
http://lkml.kernel.org/r/1466556426-32664-5-git-send-email-keesc...@chromium.org
Signed-off-by: Ingo Molnar 
---
 arch/x86/include/asm/pgtable.h | 12 
 arch/x86/mm/init.c |  3 +++
 arch/x86/realmode/init.c   |  5 -
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1a27396..d455bef 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -729,6 +729,18 @@ extern int direct_gbpages;
 void init_mem_mapping(void);
 void early_alloc_pgt_buf(void);
 
+#ifdef CONFIG_X86_64
+/* Realmode trampoline initialization. */
+extern pgd_t trampoline_pgd_entry;
+static inline void __meminit init_trampoline(void)
+{
+   /* Default trampoline pgd value */
+   trampoline_pgd_entry = init_level4_pgt[pgd_index(__PAGE_OFFSET)];
+}
+#else
+static inline void init_trampoline(void) { }
+#endif
+
 /* local pte updates need not use xchg for locking */
 static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
 {
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 372aad2..4252acd 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -590,6 +590,9 @@ void __init init_mem_mapping(void)
/* the ISA range is always mapped regardless of memory holes */
init_memory_mapping(0, ISA_END_ADDRESS);
 
+   /* Init the trampoline, possibly with KASLR memory offset */
+   init_trampoline();
+
/*
 * If the allocation is in bottom-up direction, we setup direct mapping
 * in bottom-up, otherwise we setup direct mapping in top-down.
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 0b7a63d..705e3ff 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -8,6 +8,9 @@
 struct real_mode_header *real_mode_header;
 u32 *trampoline_cr4_features;
 
+/* Hold the pgd entry used on booting additional CPUs */
+pgd_t trampoline_pgd_entry;
+
 void __init reserve_real_mode(void)
 {
phys_addr_t mem;
@@ -84,7 +87,7 @@ void __init setup_real_mode(void)
*trampoline_cr4_features = __read_cr4();
 
trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
-   trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd;
+   trampoline_pgd[0] = trampoline_pgd_entry.pgd;
trampoline_pgd[511] = init_level4_pgt[511].pgd;
 #endif
 }

[tip:x86/boot] x86/mm: Separate variable for trampoline PGD

[tip-bot for Thomas Garnier]

Commit-ID:  b234e8a09003af108d3573f0369e25c080676b14
Gitweb: http://git.kernel.org/tip/b234e8a09003af108d3573f0369e25c080676b14
Author: Thomas Garnier 
AuthorDate: Tue, 21 Jun 2016 17:47:01 -0700
Committer:  Ingo Molnar 
CommitDate: Fri, 8 Jul 2016 17:33:46 +0200

x86/mm: Separate variable for trampoline PGD

Use a separate global variable to define the trampoline PGD used to
start other processors. This change will allow KALSR memory
randomization to change the trampoline PGD to be correctly aligned with
physical memory.

Signed-off-by: Thomas Garnier 
Signed-off-by: Kees Cook 
Cc: Alexander Kuleshov 
Cc: Alexander Popov 
Cc: Andrew Morton 
Cc: Andy Lutomirski 
Cc: Aneesh Kumar K.V 
Cc: Baoquan He 
Cc: Boris Ostrovsky 
Cc: Borislav Petkov 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Christian Borntraeger 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: Dave Young 
Cc: Denys Vlasenko 
Cc: Dmitry Vyukov 
Cc: H. Peter Anvin 
Cc: Jan Beulich 
Cc: Joerg Roedel 
Cc: Jonathan Corbet 
Cc: Josh Poimboeuf 
Cc: Juergen Gross 
Cc: Kirill A. Shutemov 
Cc: Linus Torvalds 
Cc: Lv Zheng 
Cc: Mark Salter 
Cc: Martin Schwidefsky 
Cc: Matt Fleming 
Cc: Peter Zijlstra 
Cc: Stephen Smalley 
Cc: Thomas Gleixner 
Cc: Toshi Kani 
Cc: Xiao Guangrong 
Cc: Yinghai Lu 
Cc: kernel-harden...@lists.openwall.com
Cc: linux-...@vger.kernel.org
Link: 
http://lkml.kernel.org/r/1466556426-32664-5-git-send-email-keesc...@chromium.org
Signed-off-by: Ingo Molnar 
---
 arch/x86/include/asm/pgtable.h | 12 
 arch/x86/mm/init.c |  3 +++
 arch/x86/realmode/init.c   |  5 -
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index 1a27396..d455bef 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -729,6 +729,18 @@ extern int direct_gbpages;
 void init_mem_mapping(void);
 void early_alloc_pgt_buf(void);
 
+#ifdef CONFIG_X86_64
+/* Realmode trampoline initialization. */
+extern pgd_t trampoline_pgd_entry;
+static inline void __meminit init_trampoline(void)
+{
+   /* Default trampoline pgd value */
+   trampoline_pgd_entry = init_level4_pgt[pgd_index(__PAGE_OFFSET)];
+}
+#else
+static inline void init_trampoline(void) { }
+#endif
+
 /* local pte updates need not use xchg for locking */
 static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
 {
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 372aad2..4252acd 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -590,6 +590,9 @@ void __init init_mem_mapping(void)
/* the ISA range is always mapped regardless of memory holes */
init_memory_mapping(0, ISA_END_ADDRESS);
 
+   /* Init the trampoline, possibly with KASLR memory offset */
+   init_trampoline();
+
/*
 * If the allocation is in bottom-up direction, we setup direct mapping
 * in bottom-up, otherwise we setup direct mapping in top-down.
diff --git a/arch/x86/realmode/init.c b/arch/x86/realmode/init.c
index 0b7a63d..705e3ff 100644
--- a/arch/x86/realmode/init.c
+++ b/arch/x86/realmode/init.c
@@ -8,6 +8,9 @@
 struct real_mode_header *real_mode_header;
 u32 *trampoline_cr4_features;
 
+/* Hold the pgd entry used on booting additional CPUs */
+pgd_t trampoline_pgd_entry;
+
 void __init reserve_real_mode(void)
 {
phys_addr_t mem;
@@ -84,7 +87,7 @@ void __init setup_real_mode(void)
*trampoline_cr4_features = __read_cr4();
 
trampoline_pgd = (u64 *) __va(real_mode_header->trampoline_pgd);
-   trampoline_pgd[0] = init_level4_pgt[pgd_index(__PAGE_OFFSET)].pgd;
+   trampoline_pgd[0] = trampoline_pgd_entry.pgd;
trampoline_pgd[511] = init_level4_pgt[511].pgd;
 #endif
 }