x86/xen: Drop 5-level paging support code from the XEN_PV code

It was decided 5-level paging is not going to be supported in XEN_PV.

Let's drop the dead code from the XEN_PV code.

Tested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170929140821.37654-6-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 60 insertions, 99 deletions

diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c
index 71495f1a86d7..2ccdaba31a07 100644
--- a/arch/x86/xen/mmu_pv.c
+++ b/arch/x86/xen/mmu_pv.c
@@ -449,7 +449,7 @@ __visible pmd_t xen_make_pmd(pmdval_t pmd)
 }
 PV_CALLEE_SAVE_REGS_THUNK(xen_make_pmd);
 
-#if CONFIG_PGTABLE_LEVELS == 4
+#ifdef CONFIG_X86_64
 __visible pudval_t xen_pud_val(pud_t pud)
 {
         return pte_mfn_to_pfn(pud.pud);
@@ -538,7 +538,7 @@ static void xen_set_p4d(p4d_t *ptr, p4d_t val)
 
         xen_mc_issue(PARAVIRT_LAZY_MMU);
 }
-#endif  /* CONFIG_PGTABLE_LEVELS == 4 */
+#endif  /* CONFIG_X86_64 */
 
 static int xen_pmd_walk(struct mm_struct *mm, pmd_t *pmd,
                 int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
@@ -580,21 +580,17 @@ static int xen_p4d_walk(struct mm_struct *mm, p4d_t *p4d,
                 int (*func)(struct mm_struct *mm, struct page *, enum pt_level),
                 bool last, unsigned long limit)
 {
-        int i, nr, flush = 0;
+        int flush = 0;
+        pud_t *pud;
 
-        nr = last ? p4d_index(limit) + 1 : PTRS_PER_P4D;
-        for (i = 0; i < nr; i++) {
-                pud_t *pud;
 
-                if (p4d_none(p4d[i]))
-                        continue;
+        if (p4d_none(*p4d))
+                return flush;
 
-                pud = pud_offset(&p4d[i], 0);
-                if (PTRS_PER_PUD > 1)
-                        flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
-                flush |= xen_pud_walk(mm, pud, func,
-                                last && i == nr - 1, limit);
-        }
+        pud = pud_offset(p4d, 0);
+        if (PTRS_PER_PUD > 1)
+                flush |= (*func)(mm, virt_to_page(pud), PT_PUD);
+        flush |= xen_pud_walk(mm, pud, func, last, limit);
         return flush;
 }
 
@@ -644,8 +640,6 @@ static int __xen_pgd_walk(struct mm_struct *mm, pgd_t *pgd,
                         continue;
 
                 p4d = p4d_offset(&pgd[i], 0);
-                if (PTRS_PER_P4D > 1)
-                        flush |= (*func)(mm, virt_to_page(p4d), PT_P4D);
                 flush |= xen_p4d_walk(mm, p4d, func, i == nr - 1, limit);
         }
 
@@ -1176,22 +1170,14 @@ static void __init xen_cleanmfnmap(unsigned long vaddr)
 {
         pgd_t *pgd;
         p4d_t *p4d;
-        unsigned int i;
         bool unpin;
 
         unpin = (vaddr == 2 * PGDIR_SIZE);
         vaddr &= PMD_MASK;
         pgd = pgd_offset_k(vaddr);
         p4d = p4d_offset(pgd, 0);
-        for (i = 0; i < PTRS_PER_P4D; i++) {
-                if (p4d_none(p4d[i]))
-                        continue;
-                xen_cleanmfnmap_p4d(p4d + i, unpin);
-        }
-        if (IS_ENABLED(CONFIG_X86_5LEVEL)) {
-                set_pgd(pgd, __pgd(0));
-                xen_cleanmfnmap_free_pgtbl(p4d, unpin);
-        }
+        if (!p4d_none(*p4d))
+                xen_cleanmfnmap_p4d(p4d, unpin);
 }
 
 static void __init xen_pagetable_p2m_free(void)
@@ -1692,7 +1678,7 @@ static void xen_release_pmd(unsigned long pfn)
         xen_release_ptpage(pfn, PT_PMD);
 }
 
-#if CONFIG_PGTABLE_LEVELS >= 4
+#ifdef CONFIG_X86_64
 static void xen_alloc_pud(struct mm_struct *mm, unsigned long pfn)
 {
         xen_alloc_ptpage(mm, pfn, PT_PUD);
@@ -2029,13 +2015,12 @@ static phys_addr_t __init xen_early_virt_to_phys(unsigned long vaddr)
  */
 void __init xen_relocate_p2m(void)
 {
-        phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys, p4d_phys;
+        phys_addr_t size, new_area, pt_phys, pmd_phys, pud_phys;
         unsigned long p2m_pfn, p2m_pfn_end, n_frames, pfn, pfn_end;
-        int n_pte, n_pt, n_pmd, n_pud, n_p4d, idx_pte, idx_pt, idx_pmd, idx_pud, idx_p4d;
+        int n_pte, n_pt, n_pmd, n_pud, idx_pte, idx_pt, idx_pmd, idx_pud;
         pte_t *pt;
         pmd_t *pmd;
         pud_t *pud;
-        p4d_t *p4d = NULL;
         pgd_t *pgd;
         unsigned long *new_p2m;
         int save_pud;
@@ -2045,11 +2030,7 @@ void __init xen_relocate_p2m(void)
         n_pt = roundup(size, PMD_SIZE) >> PMD_SHIFT;
         n_pmd = roundup(size, PUD_SIZE) >> PUD_SHIFT;
         n_pud = roundup(size, P4D_SIZE) >> P4D_SHIFT;
-        if (PTRS_PER_P4D > 1)
-                n_p4d = roundup(size, PGDIR_SIZE) >> PGDIR_SHIFT;
-        else
-                n_p4d = 0;
-        n_frames = n_pte + n_pt + n_pmd + n_pud + n_p4d;
+        n_frames = n_pte + n_pt + n_pmd + n_pud;
 
         new_area = xen_find_free_area(PFN_PHYS(n_frames));
         if (!new_area) {
@@ -2065,76 +2046,56 @@ void __init xen_relocate_p2m(void)
          * To avoid any possible virtual address collision, just use
          * 2 * PUD_SIZE for the new area.
          */
-        p4d_phys = new_area;
-        pud_phys = p4d_phys + PFN_PHYS(n_p4d);
+        pud_phys = new_area;
         pmd_phys = pud_phys + PFN_PHYS(n_pud);
         pt_phys = pmd_phys + PFN_PHYS(n_pmd);
         p2m_pfn = PFN_DOWN(pt_phys) + n_pt;
 
         pgd = __va(read_cr3_pa());
         new_p2m = (unsigned long *)(2 * PGDIR_SIZE);
-        idx_p4d = 0;
         save_pud = n_pud;
-        do {
-                if (n_p4d > 0) {
-                        p4d = early_memremap(p4d_phys, PAGE_SIZE);
-                        clear_page(p4d);
-                        n_pud = min(save_pud, PTRS_PER_P4D);
-                }
-                for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
-                        pud = early_memremap(pud_phys, PAGE_SIZE);
-                        clear_page(pud);
-                        for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
-                                 idx_pmd++) {
-                                pmd = early_memremap(pmd_phys, PAGE_SIZE);
-                                clear_page(pmd);
-                                for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
-                                         idx_pt++) {
-                                        pt = early_memremap(pt_phys, PAGE_SIZE);
-                                        clear_page(pt);
-                                        for (idx_pte = 0;
-                                                 idx_pte < min(n_pte, PTRS_PER_PTE);
-                                                 idx_pte++) {
-                                                set_pte(pt + idx_pte,
-                                                                pfn_pte(p2m_pfn, PAGE_KERNEL));
-                                                p2m_pfn++;
-                                        }
-                                        n_pte -= PTRS_PER_PTE;
-                                        early_memunmap(pt, PAGE_SIZE);
-                                        make_lowmem_page_readonly(__va(pt_phys));
-                                        pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
-                                                        PFN_DOWN(pt_phys));
-                                        set_pmd(pmd + idx_pt,
-                                                        __pmd(_PAGE_TABLE | pt_phys));
-                                        pt_phys += PAGE_SIZE;
+        for (idx_pud = 0; idx_pud < n_pud; idx_pud++) {
+                pud = early_memremap(pud_phys, PAGE_SIZE);
+                clear_page(pud);
+                for (idx_pmd = 0; idx_pmd < min(n_pmd, PTRS_PER_PUD);
+                                idx_pmd++) {
+                        pmd = early_memremap(pmd_phys, PAGE_SIZE);
+                        clear_page(pmd);
+                        for (idx_pt = 0; idx_pt < min(n_pt, PTRS_PER_PMD);
+                                        idx_pt++) {
+                                pt = early_memremap(pt_phys, PAGE_SIZE);
+                                clear_page(pt);
+                                for (idx_pte = 0;
+                                                idx_pte < min(n_pte, PTRS_PER_PTE);
+                                                idx_pte++) {
+                                        set_pte(pt + idx_pte,
+                                                        pfn_pte(p2m_pfn, PAGE_KERNEL));
+                                        p2m_pfn++;
                                 }
-                                n_pt -= PTRS_PER_PMD;
-                                early_memunmap(pmd, PAGE_SIZE);
-                                make_lowmem_page_readonly(__va(pmd_phys));
-                                pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
-                                                PFN_DOWN(pmd_phys));
-                                set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys));
-                                pmd_phys += PAGE_SIZE;
+                                n_pte -= PTRS_PER_PTE;
+                                early_memunmap(pt, PAGE_SIZE);
+                                make_lowmem_page_readonly(__va(pt_phys));
+                                pin_pagetable_pfn(MMUEXT_PIN_L1_TABLE,
+                                                PFN_DOWN(pt_phys));
+                                set_pmd(pmd + idx_pt,
+                                                __pmd(_PAGE_TABLE | pt_phys));
+                                pt_phys += PAGE_SIZE;
                         }
-                        n_pmd -= PTRS_PER_PUD;
-                        early_memunmap(pud, PAGE_SIZE);
-                        make_lowmem_page_readonly(__va(pud_phys));
-                        pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
-                        if (n_p4d > 0)
-                                set_p4d(p4d + idx_pud, __p4d(_PAGE_TABLE | pud_phys));
-                        else
-                                set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
-                        pud_phys += PAGE_SIZE;
-                }
-                if (n_p4d > 0) {
-                        save_pud -= PTRS_PER_P4D;
-                        early_memunmap(p4d, PAGE_SIZE);
-                        make_lowmem_page_readonly(__va(p4d_phys));
-                        pin_pagetable_pfn(MMUEXT_PIN_L4_TABLE, PFN_DOWN(p4d_phys));
-                        set_pgd(pgd + 2 + idx_p4d, __pgd(_PAGE_TABLE | p4d_phys));
-                        p4d_phys += PAGE_SIZE;
+                        n_pt -= PTRS_PER_PMD;
+                        early_memunmap(pmd, PAGE_SIZE);
+                        make_lowmem_page_readonly(__va(pmd_phys));
+                        pin_pagetable_pfn(MMUEXT_PIN_L2_TABLE,
+                                        PFN_DOWN(pmd_phys));
+                        set_pud(pud + idx_pmd, __pud(_PAGE_TABLE | pmd_phys));
+                        pmd_phys += PAGE_SIZE;
                 }
-        } while (++idx_p4d < n_p4d);
+                n_pmd -= PTRS_PER_PUD;
+                early_memunmap(pud, PAGE_SIZE);
+                make_lowmem_page_readonly(__va(pud_phys));
+                pin_pagetable_pfn(MMUEXT_PIN_L3_TABLE, PFN_DOWN(pud_phys));
+                set_pgd(pgd + 2 + idx_pud, __pgd(_PAGE_TABLE | pud_phys));
+                pud_phys += PAGE_SIZE;
+        }
 
         /* Now copy the old p2m info to the new area. */
         memcpy(new_p2m, xen_p2m_addr, size);
@@ -2361,7 +2322,7 @@ static void __init xen_post_allocator_init(void)
         pv_mmu_ops.set_pte = xen_set_pte;
         pv_mmu_ops.set_pmd = xen_set_pmd;
         pv_mmu_ops.set_pud = xen_set_pud;
-#if CONFIG_PGTABLE_LEVELS >= 4
+#ifdef CONFIG_X86_64
         pv_mmu_ops.set_p4d = xen_set_p4d;
 #endif
 
@@ -2371,7 +2332,7 @@ static void __init xen_post_allocator_init(void)
         pv_mmu_ops.alloc_pmd = xen_alloc_pmd;
         pv_mmu_ops.release_pte = xen_release_pte;
         pv_mmu_ops.release_pmd = xen_release_pmd;
-#if CONFIG_PGTABLE_LEVELS >= 4
+#ifdef CONFIG_X86_64
         pv_mmu_ops.alloc_pud = xen_alloc_pud;
         pv_mmu_ops.release_pud = xen_release_pud;
 #endif
@@ -2435,14 +2396,14 @@ static const struct pv_mmu_ops xen_mmu_ops __initconst = {
         .make_pmd = PV_CALLEE_SAVE(xen_make_pmd),
         .pmd_val = PV_CALLEE_SAVE(xen_pmd_val),
 
-#if CONFIG_PGTABLE_LEVELS >= 4
+#ifdef CONFIG_X86_64
         .pud_val = PV_CALLEE_SAVE(xen_pud_val),
         .make_pud = PV_CALLEE_SAVE(xen_make_pud),
         .set_p4d = xen_set_p4d_hyper,
 
         .alloc_pud = xen_alloc_pmd_init,
         .release_pud = xen_release_pmd_init,
-#endif  /* CONFIG_PGTABLE_LEVELS == 4 */
+#endif  /* CONFIG_X86_64 */
 
         .activate_mm = xen_activate_mm,
         .dup_mmap = xen_dup_mmap,