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x86/mm/fixmap: Generalize the GDT fixmap mechanism, introduce struct cpu_entry_area

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Currently, the GDT is an ad-hoc array of pages, one per CPU, in the
fixmap.  Generalize it to be an array of a new 'struct cpu_entry_area'
so that we can cleanly add new things to it.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.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: Rik van Riel <riel@redhat.com>
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
Link: https://lkml.kernel.org/r/20171204150605.563271721@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Andy Lutomirski
2017-12-04 15:07:15 +01:00
committed by Ingo Molnar
parent aaeed3aeb3
commit ef8813ab28
4 changed files with 44 additions and 18 deletions
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37
arch/x86/include/asm/fixmap.h
View File

@@ -44,6 +44,19 @@ extern unsigned long __FIXADDR_TOP;
PAGE_SIZE)
#endif
/*
* cpu_entry_area is a percpu region in the fixmap that contains things
* needed by the CPU and early entry/exit code. Real types aren't used
* for all fields here to avoid circular header dependencies.
*
* Every field is a virtual alias of some other allocated backing store.
* There is no direct allocation of a struct cpu_entry_area.
*/
struct cpu_entry_area {
char gdt[PAGE_SIZE];
};
#define CPU_ENTRY_AREA_PAGES (sizeof(struct cpu_entry_area) / PAGE_SIZE)
/*
* Here we define all the compile-time 'special' virtual
@@ -101,8 +114,8 @@ enum fixed_addresses {
FIX_LNW_VRTC,
#endif
/* Fixmap entries to remap the GDTs, one per processor. */
FIX_GDT_REMAP_BEGIN,
FIX_GDT_REMAP_END = FIX_GDT_REMAP_BEGIN + NR_CPUS - 1,
FIX_CPU_ENTRY_AREA_TOP,
FIX_CPU_ENTRY_AREA_BOTTOM = FIX_CPU_ENTRY_AREA_TOP + (CPU_ENTRY_AREA_PAGES * NR_CPUS) - 1,
#ifdef CONFIG_ACPI_APEI_GHES
/* Used for GHES mapping from assorted contexts */
@@ -191,5 +204,25 @@ void __init *early_memremap_decrypted_wp(resource_size_t phys_addr,
void __early_set_fixmap(enum fixed_addresses idx,
phys_addr_t phys, pgprot_t flags);
static inline unsigned int __get_cpu_entry_area_page_index(int cpu, int page)
{
BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0);
return FIX_CPU_ENTRY_AREA_BOTTOM - cpu*CPU_ENTRY_AREA_PAGES - page;
}
#define __get_cpu_entry_area_offset_index(cpu, offset) ({ \
BUILD_BUG_ON(offset % PAGE_SIZE != 0); \
__get_cpu_entry_area_page_index(cpu, offset / PAGE_SIZE); \
})
#define get_cpu_entry_area_index(cpu, field) \
__get_cpu_entry_area_offset_index((cpu), offsetof(struct cpu_entry_area, field))
static inline struct cpu_entry_area *get_cpu_entry_area(int cpu)
{
return (struct cpu_entry_area *)__fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0));
}
#endif /* !__ASSEMBLY__ */
#endif /* _ASM_X86_FIXMAP_H */