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| author |   Thomas Gleixner <tglx@linutronix.de> | 2017-12-04 15:07:49 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2017-12-23 21:13:00 +0100 |
| commit | 10043e02db7f8a4161f76434931051e7d797a5f6 (patch) | |
| tree | 02cfe50fc9c3ea40989a78394c81e88095abf725 /arch/x86/events/intel/ds.c | |
| parent | x86/mm/pti: Map ESPFIX into user space (diff) | |
| download | linux-dev-10043e02db7f8a4161f76434931051e7d797a5f6.tar.xz linux-dev-10043e02db7f8a4161f76434931051e7d797a5f6.zip | |
x86/cpu_entry_area: Add debugstore entries to cpu_entry_area
The Intel PEBS/BTS debug store is a design trainwreck as it expects virtual
addresses which must be visible in any execution context.
So it is required to make these mappings visible to user space when kernel
page table isolation is active.
Provide enough room for the buffer mappings in the cpu_entry_area so the
buffers are available in the user space visible page tables.
At the point where the kernel side entry area is populated there is no
buffer available yet, but the kernel PMD must be populated. To achieve this
set the entries for these buffers to non present.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/events/intel/ds.c')
| -rw-r--r-- | arch/x86/events/intel/ds.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/events/intel/ds.c b/arch/x86/events/intel/ds.c index 3674a4b6f8bd..6522f0279cb8 100644 --- a/arch/x86/events/intel/ds.c +++ b/arch/x86/events/intel/ds.c @@ -8,11 +8,12 @@ #include "../perf_event.h" +/* Waste a full page so it can be mapped into the cpu_entry_area */ +DEFINE_PER_CPU_PAGE_ALIGNED(struct debug_store, cpu_debug_store); + /* The size of a BTS record in bytes: */ #define BTS_RECORD_SIZE 24 -#define BTS_BUFFER_SIZE (PAGE_SIZE << 4) -#define PEBS_BUFFER_SIZE (PAGE_SIZE << 4) #define PEBS_FIXUP_SIZE PAGE_SIZE /* |