mm: remove vmalloc_sync_(un)mappings()

These functions are not needed anymore because the vmalloc and ioremap mappings are now synchronized when they are created or torn down. Remove all callers and function definitions. Signed-off-by: Joerg Roedel <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Tested-by: Steven Rostedt (VMware) <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra (Intel) <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Dave Hansen <[email protected]> Cc: "H . Peter Anvin" <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Matthew Wilcox (Oracle) <[email protected]> Cc: Michal Hocko <[email protected]> Cc: "Rafael J. Wysocki" <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Vlastimil Babka <[email protected]> Link: http:https://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]>
torvalds · Jun 2, 2020 · 73f693c · 73f693c
1 parent 86cf69f
commit 73f693c
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diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
@@ -214,26 +214,6 @@ void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
  }
 }
 
-static void vmalloc_sync(void)
-{
- unsigned long address;
-
- if (SHARED_KERNEL_PMD)
- return;
-
- arch_sync_kernel_mappings(VMALLOC_START, VMALLOC_END);
-}
-
-void vmalloc_sync_mappings(void)
-{
- vmalloc_sync();
-}
-
-void vmalloc_sync_unmappings(void)
-{
- vmalloc_sync();
-}
-
 /*
  * 32-bit:
  *
@@ -336,23 +316,6 @@ static void dump_pagetable(unsigned long address)
 
 #else /* CONFIG_X86_64: */
 
-void vmalloc_sync_mappings(void)
-{
- /*
- * 64-bit mappings might allocate new p4d/pud pages
- * that need to be propagated to all tasks' PGDs.
- */
- sync_global_pgds(VMALLOC_START & PGDIR_MASK, VMALLOC_END);
-}
-
-void vmalloc_sync_unmappings(void)
-{
- /*
- * Unmappings never allocate or free p4d/pud pages.
- * No work is required here.
- */
-}
-
 /*
  * 64-bit:
  *

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
@@ -167,12 +167,6 @@ int ghes_estatus_pool_init(int num_ghes)
  if (!addr)
  goto err_pool_alloc;
 
- /*
- * New allocation must be visible in all pgd before it can be found by
- * an NMI allocating from the pool.
- */
- vmalloc_sync_mappings();
-
  rc = gen_pool_add(ghes_estatus_pool, addr, PAGE_ALIGN(len), -1);
  if (rc)
  goto err_pool_add;

diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
@@ -130,8 +130,6 @@ extern int remap_vmalloc_range_partial(struct vm_area_struct *vma,
 
 extern int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
  unsigned long pgoff);
-void vmalloc_sync_mappings(void);
-void vmalloc_sync_unmappings(void);
 
 /*
  * Architectures can set this mask to a combination of PGTBL_P?D_MODIFIED values

diff --git a/kernel/notifier.c b/kernel/notifier.c
@@ -519,7 +519,6 @@ NOKPROBE_SYMBOL(notify_die);
 
 int register_die_notifier(struct notifier_block *nb)
 {
- vmalloc_sync_mappings();
  return atomic_notifier_chain_register(&die_chain, nb);
 }
 EXPORT_SYMBOL_GPL(register_die_notifier);

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
@@ -8527,18 +8527,6 @@ static int allocate_trace_buffers(struct trace_array *tr, int size)
  allocate_snapshot = false;
 #endif
 
- /*
- * Because of some magic with the way alloc_percpu() works on
- * x86_64, we need to synchronize the pgd of all the tables,
- * otherwise the trace events that happen in x86_64 page fault
- * handlers can't cope with accessing the chance that a
- * alloc_percpu()'d memory might be touched in the page fault trace
- * event. Oh, and we need to audit all other alloc_percpu() and vmalloc()
- * calls in tracing, because something might get triggered within a
- * page fault trace event!
- */
- vmalloc_sync_mappings();
-
  return 0;
 }
 

diff --git a/mm/nommu.c b/mm/nommu.c
@@ -371,18 +371,6 @@ void vm_unmap_aliases(void)
 }
 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
 
-/*
- * Implement a stub for vmalloc_sync_[un]mapping() if the architecture
- * chose not to have one.
- */
-void __weak vmalloc_sync_mappings(void)
-{
-}
-
-void __weak vmalloc_sync_unmappings(void)
-{
-}
-
 struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
 {
  BUG();

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
@@ -1353,12 +1353,6 @@ static bool __purge_vmap_area_lazy(unsigned long start, unsigned long end)
  if (unlikely(valist == NULL))
  return false;
 
- /*
- * First make sure the mappings are removed from all page-tables
- * before they are freed.
- */
- vmalloc_sync_unmappings();
-
  /*
  * TODO: to calculate a flush range without looping.
  * The list can be up to lazy_max_pages() elements.
@@ -3089,21 +3083,6 @@ int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
 }
 EXPORT_SYMBOL(remap_vmalloc_range);
 
-/*
- * Implement stubs for vmalloc_sync_[un]mappings () if the architecture chose
- * not to have one.
- *
- * The purpose of this function is to make sure the vmalloc area
- * mappings are identical in all page-tables in the system.
- */
-void __weak vmalloc_sync_mappings(void)
-{
-}
-
-void __weak vmalloc_sync_unmappings(void)
-{
-}
-
 static int f(pte_t *pte, unsigned long addr, void *data)
 {
  pte_t ***p = data;