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Subject[patch 38/60] x86/fixmap: Move cpu entry area into a separate PMD
From: Andy Lutomirski <luto@kernel.org>

This allows the cpu entry area PMDs to be shared between the kernel and
user space page tables.

[ tglx: Fixed bottom of by one and added guards so other fixmaps can be
added later ]

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
arch/x86/include/asm/fixmap.h | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)

--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -134,16 +134,22 @@ enum fixed_addresses {
#ifdef CONFIG_PARAVIRT
FIX_PARAVIRT_BOOTMAP,
#endif
- FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
- FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
#ifdef CONFIG_X86_INTEL_MID
FIX_LNW_VRTC,
#endif
- /* Fixmap entries to remap the GDTs, one per processor. */
+ FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
+ FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
+
+ /*
+ * Fixmap entries to remap the IDT, and the per cpu entry areas.
+ * Aligend to a PMD boundary.
+ */
+ FIX_USR_SHARED_TOP = round_up(FIX_TEXT_POKE0 + 1, PTRS_PER_PMD),
FIX_CPU_ENTRY_AREA_TOP,
FIX_CPU_ENTRY_AREA_BOTTOM = FIX_CPU_ENTRY_AREA_TOP + (CPU_ENTRY_AREA_PAGES * NR_CPUS) - 1,
+ FIX_USR_SHARED_BOTTOM = round_up(FIX_CPU_ENTRY_AREA_BOTTOM + 2, PTRS_PER_PMD) - 1,

- __end_of_permanent_fixed_addresses,
+ __end_of_permanent_fixed_addresses = FIX_USR_SHARED_BOTTOM,

/*
* 512 temporary boot-time mappings, used by early_ioremap(),

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