From 10043e02db7f8a4161f76434931051e7d797a5f6 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Mon, 4 Dec 2017 15:07:49 +0100 Subject: 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 Cc: Andy Lutomirski Cc: Boris Ostrovsky Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: David Laight Cc: Denys Vlasenko Cc: Eduardo Valentin Cc: Greg KH Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Will Deacon Cc: aliguori@amazon.com Cc: daniel.gruss@iaik.tugraz.at Cc: hughd@google.com Cc: keescook@google.com Signed-off-by: Ingo Molnar --- arch/x86/include/asm/intel_ds.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100644 arch/x86/include/asm/intel_ds.h (limited to 'arch/x86/include/asm/intel_ds.h') diff --git a/arch/x86/include/asm/intel_ds.h b/arch/x86/include/asm/intel_ds.h new file mode 100644 index 000000000000..62a9f4966b42 --- /dev/null +++ b/arch/x86/include/asm/intel_ds.h @@ -0,0 +1,36 @@ +#ifndef _ASM_INTEL_DS_H +#define _ASM_INTEL_DS_H + +#include + +#define BTS_BUFFER_SIZE (PAGE_SIZE << 4) +#define PEBS_BUFFER_SIZE (PAGE_SIZE << 4) + +/* The maximal number of PEBS events: */ +#define MAX_PEBS_EVENTS 8 + +/* + * A debug store configuration. + * + * We only support architectures that use 64bit fields. + */ +struct debug_store { + u64 bts_buffer_base; + u64 bts_index; + u64 bts_absolute_maximum; + u64 bts_interrupt_threshold; + u64 pebs_buffer_base; + u64 pebs_index; + u64 pebs_absolute_maximum; + u64 pebs_interrupt_threshold; + u64 pebs_event_reset[MAX_PEBS_EVENTS]; +} __aligned(PAGE_SIZE); + +DECLARE_PER_CPU_PAGE_ALIGNED(struct debug_store, cpu_debug_store); + +struct debug_store_buffers { + char bts_buffer[BTS_BUFFER_SIZE]; + char pebs_buffer[PEBS_BUFFER_SIZE]; +}; + +#endif -- cgit v1.2.3