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authorIra Weiny <ira.weiny@intel.com>2022-10-06 07:05:55 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-10-13 04:51:51 +0300
commitef6e06b2ef87077104d1145a0fd452ff8dbbc4b7 (patch)
tree57c08d46dad37f9879db3cedc124799973d36f38 /mm/highmem.c
parent15cd90049d595e592d8860ee15a3f23491d54d17 (diff)
downloadlinux-ef6e06b2ef87077104d1145a0fd452ff8dbbc4b7.tar.xz
highmem: fix kmap_to_page() for kmap_local_page() addresses
kmap_to_page() is used to get the page for a virtual address which may be kmap'ed. Unfortunately, kmap_local_page() stores mappings in a thread local array separate from kmap(). These mappings were not checked by the call. Check the kmap_local_page() mappings and return the page if found. Because it is intended to remove kmap_to_page() add a warn on once to the kmap checks to flag potential issues early. NOTE Due to 32bit x86 use of kmap local in iomap atmoic, KMAP_LOCAL does not require HIGHMEM to be set. Therefore the support calls required a new KMAP_LOCAL section to fix 0day build errors. [akpm@linux-foundation.org: fix warning] Link: https://lkml.kernel.org/r/20221006040555.1502679-1-ira.weiny@intel.com Signed-off-by: Ira Weiny <ira.weiny@intel.com> Reported-by: Al Viro <viro@zeniv.linux.org.uk> Reported-by: kernel test robot <lkp@intel.com> Cc: "Fabio M. De Francesco" <fmdefrancesco@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/highmem.c')
-rw-r--r--mm/highmem.c43
1 files changed, 31 insertions, 12 deletions
diff --git a/mm/highmem.c b/mm/highmem.c
index c707d7202d5f..db251e77f98f 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -30,6 +30,17 @@
#include <asm/tlbflush.h>
#include <linux/vmalloc.h>
+#ifdef CONFIG_KMAP_LOCAL
+static inline int kmap_local_calc_idx(int idx)
+{
+ return idx + KM_MAX_IDX * smp_processor_id();
+}
+
+#ifndef arch_kmap_local_map_idx
+#define arch_kmap_local_map_idx(idx, pfn) kmap_local_calc_idx(idx)
+#endif
+#endif /* CONFIG_KMAP_LOCAL */
+
/*
* Virtual_count is not a pure "count".
* 0 means that it is not mapped, and has not been mapped
@@ -142,12 +153,29 @@ pte_t *pkmap_page_table;
struct page *__kmap_to_page(void *vaddr)
{
+ unsigned long base = (unsigned long) vaddr & PAGE_MASK;
+ struct kmap_ctrl *kctrl = &current->kmap_ctrl;
unsigned long addr = (unsigned long)vaddr;
+ int i;
+
+ /* kmap() mappings */
+ if (WARN_ON_ONCE(addr >= PKMAP_ADDR(0) &&
+ addr < PKMAP_ADDR(LAST_PKMAP)))
+ return pte_page(pkmap_page_table[PKMAP_NR(addr)]);
- if (addr >= PKMAP_ADDR(0) && addr < PKMAP_ADDR(LAST_PKMAP)) {
- int i = PKMAP_NR(addr);
+ /* kmap_local_page() mappings */
+ if (WARN_ON_ONCE(base >= __fix_to_virt(FIX_KMAP_END) &&
+ base < __fix_to_virt(FIX_KMAP_BEGIN))) {
+ for (i = 0; i < kctrl->idx; i++) {
+ unsigned long base_addr;
+ int idx;
- return pte_page(pkmap_page_table[i]);
+ idx = arch_kmap_local_map_idx(i, pte_pfn(pteval));
+ base_addr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
+
+ if (base_addr == base)
+ return pte_page(kctrl->pteval[i]);
+ }
}
return virt_to_page(vaddr);
@@ -462,10 +490,6 @@ static inline void kmap_local_idx_pop(void)
# define arch_kmap_local_post_unmap(vaddr) do { } while (0)
#endif
-#ifndef arch_kmap_local_map_idx
-#define arch_kmap_local_map_idx(idx, pfn) kmap_local_calc_idx(idx)
-#endif
-
#ifndef arch_kmap_local_unmap_idx
#define arch_kmap_local_unmap_idx(idx, vaddr) kmap_local_calc_idx(idx)
#endif
@@ -494,11 +518,6 @@ static inline bool kmap_high_unmap_local(unsigned long vaddr)
return false;
}
-static inline int kmap_local_calc_idx(int idx)
-{
- return idx + KM_MAX_IDX * smp_processor_id();
-}
-
static pte_t *__kmap_pte;
static pte_t *kmap_get_pte(unsigned long vaddr, int idx)