[PATCH v13 0/3] mm, x86, powerpc: Enhancements to Memory Protection Keys.

[PATCH v13 0/3] mm, x86, powerpc: Enhancements to Memory Protection Keys.

[Ram Pai]

This patch series provides arch-neutral enhancements to
enable memory-keys on new architecutes, and the corresponding
changes in x86 and powerpc specific code to support that.

a) Provides ability to support upto 32 keys.  PowerPC
	can handle 32 keys and hence needs this.

b) Arch-neutral code; and not the arch-specific code,
   determines the format of the string, that displays the key
   for each vma in smaps.

History:
-------
version v13:
	(1) fixed a git bisect error. :(

version v12:
	(1) fixed compilation errors seen with various x86
		configs.
version v11:
	(1) code that displays key in smaps is not any more
		defined under CONFIG_ARCH_HAS_PKEYS.
       	    - Comment by Eric W. Biederman and Michal Hocko
	(2) merged two patches that implemented (1).
		- comment by Michal Hocko

version prior to v11:
	(1) used one additional bit from VM_HIGH_ARCH_*
       		to support 32 keys.
	    - Suggestion by Dave Hansen.
	(2) powerpc specific changes to support memory keys.


Ram Pai (3):
  mm, powerpc, x86: define VM_PKEY_BITx bits if CONFIG_ARCH_HAS_PKEYS
    is enabled
  mm, powerpc, x86: introduce an additional vma bit for powerpc pkey
  mm, x86, powerpc: display pkey in smaps only if arch supports pkeys

 arch/powerpc/include/asm/mmu_context.h |    5 -----
 arch/powerpc/include/asm/pkeys.h       |    2 ++
 arch/x86/include/asm/mmu_context.h     |    5 -----
 arch/x86/include/asm/pkeys.h           |    1 +
 arch/x86/kernel/fpu/xstate.c           |    5 +++++
 arch/x86/kernel/setup.c                |    8 --------
 fs/proc/task_mmu.c                     |   15 ++++++++-------
 include/linux/mm.h                     |   12 +++++++-----
 include/linux/pkeys.h                  |    7 ++++++-
 9 files changed, 29 insertions(+), 31 deletions(-)

[PATCH v13 1/3] mm, powerpc, x86: define VM_PKEY_BITx bits if CONFIG_ARCH_HAS_PKEYS is enabled

[Ram Pai]

VM_PKEY_BITx are defined only if CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
is enabled. Powerpc also needs these bits. Hence lets define the
VM_PKEY_BITx bits for any architecture that enables
CONFIG_ARCH_HAS_PKEYS.

cc: Michael Ellermen <mpe@ellerman.id.au>
cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pkeys.h |    2 ++
 fs/proc/task_mmu.c               |    4 ++--
 include/linux/mm.h               |    9 +++++----
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
index 0d3c630..99344d7 100644
--- a/arch/powerpc/include/asm/pkeys.h
+++ b/arch/powerpc/include/asm/pkeys.h
@@ -26,6 +26,8 @@
 # define VM_PKEY_BIT2	VM_HIGH_ARCH_2
 # define VM_PKEY_BIT3	VM_HIGH_ARCH_3
 # define VM_PKEY_BIT4	VM_HIGH_ARCH_4
+#elif !defined(VM_PKEY_BIT4)
+# define VM_PKEY_BIT4	VM_HIGH_ARCH_4
 #endif
 
 #define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index ec6d298..6b996d0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -679,13 +679,13 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 		[ilog2(VM_MERGEABLE)]	= "mg",
 		[ilog2(VM_UFFD_MISSING)]= "um",
 		[ilog2(VM_UFFD_WP)]	= "uw",
-#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+#ifdef CONFIG_ARCH_HAS_PKEYS
 		/* These come out via ProtectionKey: */
 		[ilog2(VM_PKEY_BIT0)]	= "",
 		[ilog2(VM_PKEY_BIT1)]	= "",
 		[ilog2(VM_PKEY_BIT2)]	= "",
 		[ilog2(VM_PKEY_BIT3)]	= "",
-#endif
+#endif /* CONFIG_ARCH_HAS_PKEYS */
 	};
 	size_t i;
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ad06d42..ad207ad 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -228,15 +228,16 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
 #define VM_HIGH_ARCH_4	BIT(VM_HIGH_ARCH_BIT_4)
 #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
 
-#if defined(CONFIG_X86)
-# define VM_PAT		VM_ARCH_1	/* PAT reserves whole VMA at once (x86) */
-#if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS)
+#ifdef CONFIG_ARCH_HAS_PKEYS
 # define VM_PKEY_SHIFT	VM_HIGH_ARCH_BIT_0
 # define VM_PKEY_BIT0	VM_HIGH_ARCH_0	/* A protection key is a 4-bit value */
 # define VM_PKEY_BIT1	VM_HIGH_ARCH_1
 # define VM_PKEY_BIT2	VM_HIGH_ARCH_2
 # define VM_PKEY_BIT3	VM_HIGH_ARCH_3
-#endif
+#endif /* CONFIG_ARCH_HAS_PKEYS */
+
+#if defined(CONFIG_X86)
+# define VM_PAT		VM_ARCH_1	/* PAT reserves whole VMA at once (x86) */
 #elif defined(CONFIG_PPC)
 # define VM_SAO		VM_ARCH_1	/* Strong Access Ordering (powerpc) */
 #elif defined(CONFIG_PARISC)
-- 
1.7.1

[PATCH v13 2/3] mm, powerpc, x86: introduce an additional vma bit for powerpc pkey

[Ram Pai]

Currently only 4bits are allocated in the vma flags to hold 16
keys. This is sufficient for x86. PowerPC  supports  32  keys,
which needs 5bits. This patch allocates an  additional bit.

cc: Dave Hansen <dave.hansen@intel.com>
cc: Michael Ellermen <mpe@ellerman.id.au>
cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
 fs/proc/task_mmu.c |    1 +
 include/linux/mm.h |    3 ++-
 2 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6b996d0..6d83bb7 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -685,6 +685,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 		[ilog2(VM_PKEY_BIT1)]	= "",
 		[ilog2(VM_PKEY_BIT2)]	= "",
 		[ilog2(VM_PKEY_BIT3)]	= "",
+		[ilog2(VM_PKEY_BIT4)]	= "",
 #endif /* CONFIG_ARCH_HAS_PKEYS */
 	};
 	size_t i;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ad207ad..d534f46 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -231,9 +231,10 @@ extern int overcommit_kbytes_handler(struct ctl_table *, int, void __user *,
 #ifdef CONFIG_ARCH_HAS_PKEYS
 # define VM_PKEY_SHIFT	VM_HIGH_ARCH_BIT_0
 # define VM_PKEY_BIT0	VM_HIGH_ARCH_0	/* A protection key is a 4-bit value */
-# define VM_PKEY_BIT1	VM_HIGH_ARCH_1
+# define VM_PKEY_BIT1	VM_HIGH_ARCH_1	/* on x86 and 5-bit value on ppc64   */
 # define VM_PKEY_BIT2	VM_HIGH_ARCH_2
 # define VM_PKEY_BIT3	VM_HIGH_ARCH_3
+# define VM_PKEY_BIT4	VM_HIGH_ARCH_4
 #endif /* CONFIG_ARCH_HAS_PKEYS */
 
 #if defined(CONFIG_X86)
-- 
1.7.1

[PATCH v13 3/3] mm, x86, powerpc: display pkey in smaps only if arch supports pkeys

[Ram Pai]

Currently the  architecture  specific code is expected to
display  the  protection  keys  in  smap  for a given vma.
This can lead to redundant code and possibly to divergent
formats in which the key gets displayed.

This  patch  changes  the implementation. It displays the
pkey only if the architecture support pkeys, i.e
arch_pkeys_enabled() returns true.  This patch
provides x86 implementation for arch_pkeys_enabled().

x86 arch_show_smap() function is not needed anymore.
Deleting it.

cc: Michael Ellermen <mpe@ellerman.id.au>
cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
cc: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>
(fixed compilation errors for x86 configs)
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ram Pai <linuxram@us.ibm.com>
---
 arch/powerpc/include/asm/mmu_context.h |    5 -----
 arch/x86/include/asm/mmu_context.h     |    5 -----
 arch/x86/include/asm/pkeys.h           |    1 +
 arch/x86/kernel/fpu/xstate.c           |    5 +++++
 arch/x86/kernel/setup.c                |    8 --------
 fs/proc/task_mmu.c                     |   10 +++++-----
 include/linux/pkeys.h                  |    7 ++++++-
 7 files changed, 17 insertions(+), 24 deletions(-)

diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 051b3d6..566b3c2 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -203,11 +203,6 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
 #define thread_pkey_regs_restore(new_thread, old_thread)
 #define thread_pkey_regs_init(thread)
 
-static inline int vma_pkey(struct vm_area_struct *vma)
-{
-	return 0;
-}
-
 static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
 {
 	return 0x0UL;
diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h
index 1de72ce..e597d09 100644
--- a/arch/x86/include/asm/mmu_context.h
+++ b/arch/x86/include/asm/mmu_context.h
@@ -295,11 +295,6 @@ static inline int vma_pkey(struct vm_area_struct *vma)
 
 	return (vma->vm_flags & vma_pkey_mask) >> VM_PKEY_SHIFT;
 }
-#else
-static inline int vma_pkey(struct vm_area_struct *vma)
-{
-	return 0;
-}
 #endif
 
 /*
diff --git a/arch/x86/include/asm/pkeys.h b/arch/x86/include/asm/pkeys.h
index a0ba1ff..f6c287b 100644
--- a/arch/x86/include/asm/pkeys.h
+++ b/arch/x86/include/asm/pkeys.h
@@ -6,6 +6,7 @@
 
 extern int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 		unsigned long init_val);
+extern bool arch_pkeys_enabled(void);
 
 /*
  * Try to dedicate one of the protection keys to be used as an
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 87a57b7..4f566e9 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -945,6 +945,11 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 
 	return 0;
 }
+
+bool arch_pkeys_enabled(void)
+{
+	return boot_cpu_has(X86_FEATURE_OSPKE);
+}
 #endif /* ! CONFIG_ARCH_HAS_PKEYS */
 
 /*
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 4c616be..117ed01 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1307,11 +1307,3 @@ static int __init register_kernel_offset_dumper(void)
 	return 0;
 }
 __initcall(register_kernel_offset_dumper);
-
-void arch_show_smap(struct seq_file *m, struct vm_area_struct *vma)
-{
-	if (!boot_cpu_has(X86_FEATURE_OSPKE))
-		return;
-
-	seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
-}
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6d83bb7..70aa912 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -18,10 +18,12 @@
 #include <linux/page_idle.h>
 #include <linux/shmem_fs.h>
 #include <linux/uaccess.h>
+#include <linux/pkeys.h>
 
 #include <asm/elf.h>
 #include <asm/tlb.h>
 #include <asm/tlbflush.h>
+#include <asm/mmu_context.h>
 #include "internal.h"
 
 void task_mem(struct seq_file *m, struct mm_struct *mm)
@@ -733,10 +735,6 @@ static int smaps_hugetlb_range(pte_t *pte, unsigned long hmask,
 }
 #endif /* HUGETLB_PAGE */
 
-void __weak arch_show_smap(struct seq_file *m, struct vm_area_struct *vma)
-{
-}
-
 static int show_smap(struct seq_file *m, void *v, int is_pid)
 {
 	struct proc_maps_private *priv = m->private;
@@ -856,9 +854,11 @@ static int show_smap(struct seq_file *m, void *v, int is_pid)
 			   (unsigned long)(mss->pss >> (10 + PSS_SHIFT)));
 
 	if (!rollup_mode) {
-		arch_show_smap(m, vma);
+		if (arch_pkeys_enabled())
+			seq_printf(m, "ProtectionKey:  %8u\n", vma_pkey(vma));
 		show_smap_vma_flags(m, vma);
 	}
+
 	m_cache_vma(m, vma);
 	return ret;
 }
diff --git a/include/linux/pkeys.h b/include/linux/pkeys.h
index 0794ca7..49dff15 100644
--- a/include/linux/pkeys.h
+++ b/include/linux/pkeys.h
@@ -3,7 +3,6 @@
 #define _LINUX_PKEYS_H
 
 #include <linux/mm_types.h>
-#include <asm/mmu_context.h>
 
 #ifdef CONFIG_ARCH_HAS_PKEYS
 #include <asm/pkeys.h>
@@ -13,6 +12,7 @@
 #define arch_override_mprotect_pkey(vma, prot, pkey) (0)
 #define PKEY_DEDICATED_EXECUTE_ONLY 0
 #define ARCH_VM_PKEY_FLAGS 0
+#define vma_pkey(vma) 0
 
 static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
 {
@@ -35,6 +35,11 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
 	return 0;
 }
 
+static inline bool arch_pkeys_enabled(void)
+{
+	return false;
+}
+
 static inline void copy_init_pkru_to_fpregs(void)
 {
 }
-- 
1.7.1