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10043e02db
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>
36 lines
793 B
C
36 lines
793 B
C
#ifndef _ASM_INTEL_DS_H
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#define _ASM_INTEL_DS_H
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#include <linux/percpu-defs.h>
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#define BTS_BUFFER_SIZE (PAGE_SIZE << 4)
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#define PEBS_BUFFER_SIZE (PAGE_SIZE << 4)
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/* The maximal number of PEBS events: */
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#define MAX_PEBS_EVENTS 8
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/*
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* A debug store configuration.
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*
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* We only support architectures that use 64bit fields.
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*/
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struct debug_store {
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u64 bts_buffer_base;
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u64 bts_index;
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u64 bts_absolute_maximum;
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u64 bts_interrupt_threshold;
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u64 pebs_buffer_base;
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u64 pebs_index;
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u64 pebs_absolute_maximum;
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u64 pebs_interrupt_threshold;
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u64 pebs_event_reset[MAX_PEBS_EVENTS];
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} __aligned(PAGE_SIZE);
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DECLARE_PER_CPU_PAGE_ALIGNED(struct debug_store, cpu_debug_store);
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struct debug_store_buffers {
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char bts_buffer[BTS_BUFFER_SIZE];
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char pebs_buffer[PEBS_BUFFER_SIZE];
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};
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#endif
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