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x86/cpu_entry_area: Prepare for IST guard pages

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To allow guard pages between the IST stacks each stack needs to be
mapped individually.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190414160144.592691557@linutronix.de
This commit is contained in:
Thomas Gleixner 2019-04-14 17:59:48 +02:00 committed by Borislav Petkov
parent 019b17b3ff
commit a4af767ae5
1 changed files with 30 additions and 7 deletions
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37
arch/x86/mm/cpu_entry_area.c
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@ -77,6 +77,34 @@ static void __init percpu_setup_debug_store(unsigned int cpu)
#endif
}
#ifdef CONFIG_X86_64
#define cea_map_stack(name) do { \
npages = sizeof(estacks->name## _stack) / PAGE_SIZE; \
cea_map_percpu_pages(cea->estacks.name## _stack, \
estacks->name## _stack, npages, PAGE_KERNEL); \
} while (0)
static void __init percpu_setup_exception_stacks(unsigned int cpu)
{
struct exception_stacks *estacks = per_cpu_ptr(&exception_stacks, cpu);
struct cpu_entry_area *cea = get_cpu_entry_area(cpu);
unsigned int npages;
BUILD_BUG_ON(sizeof(exception_stacks) % PAGE_SIZE != 0);
/*
* The exceptions stack mappings in the per cpu area are protected
* by guard pages so each stack must be mapped separately.
*/
cea_map_stack(DF);
cea_map_stack(NMI);
cea_map_stack(DB);
cea_map_stack(MCE);
}
#else
static inline void percpu_setup_exception_stacks(unsigned int cpu) {}
#endif
/* Setup the fixmap mappings only once per-processor */
static void __init setup_cpu_entry_area(unsigned int cpu)
{
@ -134,13 +162,8 @@ static void __init setup_cpu_entry_area(unsigned int cpu)
per_cpu(cpu_entry_area, cpu) = cea;
#endif
#ifdef CONFIG_X86_64
BUILD_BUG_ON(sizeof(exception_stacks) % PAGE_SIZE != 0);
BUILD_BUG_ON(sizeof(exception_stacks) !=
sizeof(((struct cpu_entry_area *)0)->estacks));
cea_map_percpu_pages(&cea->estacks, &per_cpu(exception_stacks, cpu),
sizeof(exception_stacks) / PAGE_SIZE, PAGE_KERNEL);
#endif
percpu_setup_exception_stacks(cpu);
percpu_setup_debug_store(cpu);
}