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Groups > linux.kernel > #1321985

[PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps

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From: Dave Hansen <dave.hansen@linux.intel.com>

The protection key can now be just as important as read/write
permissions on a VMA.  We need some debug mechanism to help
figure out if it is in play.  smaps seems like a logical
place to expose it.

arch/x86/kernel/setup.c is a bit of a weirdo place to put
this code, but it already had seq_file.h and there was not
a much better existing place to put it.

We also use no #ifdef.  If protection keys is .config'd out we
will effectively get the same function as if we used the weak
generic function.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: vbabka@suse.cz
---

 b/arch/x86/kernel/setup.c |    9 +++++++++
 b/fs/proc/task_mmu.c      |   14 ++++++++++++++
 2 files changed, 23 insertions(+)

diff -puN arch/x86/kernel/setup.c~pkeys-40-smaps arch/x86/kernel/setup.c
--- a/arch/x86/kernel/setup.c~pkeys-40-smaps	2016-01-28 15:52:26.386680200 -0800
+++ b/arch/x86/kernel/setup.c	2016-01-28 15:52:26.391680429 -0800
@@ -112,6 +112,7 @@
 #include <asm/alternative.h>
 #include <asm/prom.h>
 #include <asm/microcode.h>
+#include <asm/mmu_context.h>
 
 /*
  * max_low_pfn_mapped: highest direct mapped pfn under 4GB
@@ -1282,3 +1283,11 @@ static int __init register_kernel_offset
 	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 -puN fs/proc/task_mmu.c~pkeys-40-smaps fs/proc/task_mmu.c
--- a/fs/proc/task_mmu.c~pkeys-40-smaps	2016-01-28 15:52:26.387680246 -0800
+++ b/fs/proc/task_mmu.c	2016-01-28 15:52:26.391680429 -0800
@@ -668,11 +668,20 @@ static void show_smap_vma_flags(struct s
 		[ilog2(VM_MERGEABLE)]	= "mg",
 		[ilog2(VM_UFFD_MISSING)]= "um",
 		[ilog2(VM_UFFD_WP)]	= "uw",
+#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
+		/* These come out via ProtectionKey: */
+		[ilog2(VM_PKEY_BIT0)]	= "",
+		[ilog2(VM_PKEY_BIT1)]	= "",
+		[ilog2(VM_PKEY_BIT2)]	= "",
+		[ilog2(VM_PKEY_BIT3)]	= "",
+#endif
 	};
 	size_t i;
 
 	seq_puts(m, "VmFlags: ");
 	for (i = 0; i < BITS_PER_LONG; i++) {
+		if (!mnemonics[i][0])
+			continue;
 		if (vma->vm_flags & (1UL << i)) {
 			seq_printf(m, "%c%c ",
 				   mnemonics[i][0], mnemonics[i][1]);
@@ -710,6 +719,10 @@ static int smaps_hugetlb_range(pte_t *pt
 }
 #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 vm_area_struct *vma = v;
@@ -791,6 +804,7 @@ static int show_smap(struct seq_file *m,
 		   (vma->vm_flags & VM_LOCKED) ?
 			(unsigned long)(mss.pss >> (10 + PSS_SHIFT)) : 0);
 
+	arch_show_smap(m, vma);
 	show_smap_vma_flags(m, vma);
 	m_cache_vma(m, vma);
 	return 0;
_

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[PATCH 00/31] x86: Memory Protection Keys (v9) Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 21/31] x86, pkeys: dump PKRU with other kernel registers Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 26/31] x86, pkeys: add arch_validate_pkey() Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 29/31] x86, pkeys: allow kernel to modify user pkey rights register Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 03/31] x86, pkeys: Add Kconfig option Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 09/31] x86, pkeys: store protection in high VMA flags Dave Hansen <dave@sr71.net> - 2016-01-29 19:20 +0100
  [PATCH 05/31] x86, pkeys: define new CR4 bit Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 23/31] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 12/31] signals, pkeys: notify userspace about protection key faults Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 24/31] x86, pkeys: actually enable Memory Protection Keys in CPU Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 15/31] mm: factor out VMA fault permission checking Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 20/31] x86, pkeys: differentiate instruction fetches Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 18/31] mm: do not enforce PKEY permissions on "foreign" mm access Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 08/31] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 14/31] x86, pkeys: add functions to fetch PKRU Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 04/31] x86, pkeys: cpuid bit definition Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 10/31] x86, pkeys: arch-specific protection bits Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 13/31] x86, pkeys: fill in pkey field in siginfo Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 25/31] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 17/31] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 07/31] x86, pkeys: PTE bits for storing protection key Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 02/31] x86, fpu: add placeholder for Processor Trace XSAVE state Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 16/31] x86, mm: simplify get_user_pages() PTE bit handling Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 11/31] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
  [PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100
    Re: [PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Vlastimil Babka <vbabka@suse.cz> - 2016-02-02 17:20 +0100
      Re: [PATCH 22/31] x86, pkeys: dump pkey from VMA in /proc/pid/smaps Dave Hansen <dave@sr71.net> - 2016-02-02 20:10 +0100
  [PATCH 06/31] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen <dave@sr71.net> - 2016-01-29 19:30 +0100

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