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author	Bram Moolenaar <Bram@vim.org>	2020-03-24 21:42:01 +0100
committer	Bram Moolenaar <Bram@vim.org>	2020-03-24 21:42:01 +0100
commit	45fffdf10b7cb6e59794e76e9b8a2930fcb4b192 (patch)
tree	9615bfdb0787577637e8d25b4049a31de10e52cd /src/Make_vms.mms
parent	71658f74ae64c366b2d35b82c0a2eadb1317f028 (diff)

patch 8.2.0443: clipboard code is spread outv8.2.0443

Problem: Clipboard code is spread out. Solution: Move clipboard code to its own file. (Yegappan Lakshmanan, closes #5827)

Diffstat (limited to 'src/Make_vms.mms')

-rw-r--r--

src/Make_vms.mms

1 files changed, 6 insertions, 0 deletions

/*P:700 * The pagetable code, on the other hand, still shows the scars of * previous encounters. It's functional, and as neat as it can be in the * circumstances, but be wary, for these things are subtle and break easily. * The Guest provides a virtual to physical mapping, but we can neither trust * it nor use it: we verify and convert it here then point the CPU to the * converted Guest pages when running the Guest. :*/ /* Copyright (C) Rusty Russell IBM Corporation 2013. * GPL v2 and any later version */ #include <linux/mm.h> #include <linux/gfp.h> #include <linux/types.h> #include <linux/spinlock.h> #include <linux/random.h> #include <linux/percpu.h> #include <asm/tlbflush.h> #include <asm/uaccess.h> #include "lg.h" /*M:008 * We hold reference to pages, which prevents them from being swapped. * It'd be nice to have a callback in the "struct mm_struct" when Linux wants * to swap out. If we had this, and a shrinker callback to trim PTE pages, we * could probably consider launching Guests as non-root. :*/ /*H:300 * The Page Table Code * * We use two-level page tables for the Guest, or three-level with PAE. If * you're not entirely comfortable with virtual addresses, physical addresses * and page tables then I recommend you review arch/x86/lguest/boot.c's "Page * Table Handling" (with diagrams!). * * The Guest keeps page tables, but we maintain the actual ones here: these are * called "shadow" page tables. Which is a very Guest-centric name: these are * the real page tables the CPU uses, although we keep them up to date to * reflect the Guest's. (See what I mean about weird naming? Since when do * shadows reflect anything?) * * Anyway, this is the most complicated part of the Host code. There are seven * parts to this: * (i) Looking up a page table entry when the Guest faults, * (ii) Making sure the Guest stack is mapped, * (iii) Setting up a page table entry when the Guest tells us one has changed, * (iv) Switching page tables, * (v) Flushing (throwing away) page tables, * (vi) Mapping the Switcher when the Guest is about to run, * (vii) Setting up the page tables initially. :*/ /* * The Switcher uses the complete top PTE page. That's 1024 PTE entries (4MB) * or 512 PTE entries with PAE (2MB). */ #define SWITCHER_PGD_INDEX (PTRS_PER_PGD - 1) /* * For PAE we need the PMD index as well. We use the last 2MB, so we * will need the last pmd entry of the last pmd page. */ #ifdef CONFIG_X86_PAE #define CHECK_GPGD_MASK _PAGE_PRESENT #else #define CHECK_GPGD_MASK _PAGE_TABLE #endif /*H:320 * The page table code is curly enough to need helper functions to keep it * clear and clean. The kernel itself provides many of them; one advantage * of insisting that the Guest and Host use the same CONFIG_X86_PAE setting. * * There are two functions which return pointers to the shadow (aka "real") * page tables. * * spgd_addr() takes the virtual address and returns a pointer to the top-level * page directory entry (PGD) for that address. Since we keep track of several * page tables, the "i" argument tells us which one we're interested in (it's * usually the current one). */ static pgd_t *spgd_addr(struct lg_cpu *cpu, u32 i, unsigned long vaddr) { unsigned int index = pgd_index(vaddr); /* Return a pointer index'th pgd entry for the i'th page table. */ return &cpu->lg->pgdirs[i].pgdir[index]; } #ifdef CONFIG_X86_PAE /* * This routine then takes the PGD entry given above, which contains the * address of the PMD page. It then returns a pointer to the PMD entry for the * given address. */ static pmd_t *spmd_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr) { unsigned int index = pmd_index(vaddr); pmd_t *page; /* You should never call this if the PGD entry wasn't valid */ BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT)); page = __va(pgd_pfn(spgd) << PAGE_SHIFT); return &page[index]; } #endif /* * This routine then takes the page directory entry returned above, which * contains the address of the page table entry (PTE) page. It then returns a * pointer to the PTE entry for the given address. */ static pte_t *spte_addr(struct lg_cpu *cpu, pgd_t spgd, unsigned long vaddr) { #ifdef CONFIG_X86_PAE pmd_t *pmd = spmd_addr(cpu, spgd, vaddr); pte_t *page = __va(pmd_pfn(*pmd) << PAGE_SHIFT); /* You should never call this if the PMD entry wasn't valid */ BUG_ON(!(pmd_flags(*pmd) & _PAGE_PRESENT)); #else pte_t *page = __va(pgd_pfn(spgd) << PAGE_SHIFT); /* You should never call this if the PGD entry wasn't valid */ BUG_ON(!(pgd_flags(spgd) & _PAGE_PRESENT)); #endif return &page[pte_index(vaddr)]; } /* * These functions are just like the above, except they access the Guest * page tables. Hence they return a Guest address. */ static unsigned long


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