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authorAndy Lutomirski <luto@kernel.org>2017-12-04 17:07:15 +0300
committerIngo Molnar <mingo@kernel.org>2017-12-17 15:59:54 +0300
commitef8813ab280507972bb57e4b1b502811ad4411e9 (patch)
tree25a1769ec57aaedbf0e4453de51b0edf84ef845d /arch/x86/include/asm/fixmap.h
parentaaeed3aeb39c1ba69f0a49baec8cb728121d0a91 (diff)
downloadlinux-ef8813ab280507972bb57e4b1b502811ad4411e9.tar.xz
x86/mm/fixmap: Generalize the GDT fixmap mechanism, introduce struct cpu_entry_area
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>
Diffstat (limited to 'arch/x86/include/asm/fixmap.h')
-rw-r--r--arch/x86/include/asm/fixmap.h37
1 files changed, 35 insertions, 2 deletions
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index b0c505fe9a95..b61f0242f9d0 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -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 */