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 get the same function as if we used the weak generic
function.
---
b/arch/x86/kernel/setup.c | 9 +++++++++
b/fs/proc/task_mmu.c | 5 +++++
2 files changed, 14 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 2015-09-16 10:48:18.838309381
-0700
+++ b/arch/x86/kernel/setup.c 2015-09-16 10:48:18.844309653 -0700
@@ -111,6 +111,7 @@
#include <asm/mce.h>
#include <asm/alternative.h>
#include <asm/prom.h>
+#include <asm/special_insns.h>
/*
* max_low_pfn_mapped: highest direct mapped pfn under 4GB
@@ -1264,3 +1265,11 @@ 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 2015-09-16 10:48:18.840309472 -0700
+++ b/fs/proc/task_mmu.c 2015-09-16 10:48:18.844309653 -0700
@@ -625,6 +625,10 @@ static void show_smap_vma_flags(struct s
seq_putc(m, '\n');
}
+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;
@@ -674,6 +678,7 @@ 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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