ioremap: Update pgtable free interfaces with addr

commit 785a19f9d1dd8a4ab2d0633be4656653bd3de1fc upstream.

The following kernel panic was observed on ARM64 platform due to a stale
TLB entry.

 1. ioremap with 4K size, a valid pte page table is set.
 2. iounmap it, its pte entry is set to 0.
 3. ioremap the same address with 2M size, update its pmd entry with
    a new value.
 4. CPU may hit an exception because the old pmd entry is still in TLB,
    which leads to a kernel panic.

Commit b6bdb7517c3d ("mm/vmalloc: add interfaces to free unmapped page
table") has addressed this panic by falling to pte mappings in the above
case on ARM64.

To support pmd mappings in all cases, TLB purge needs to be performed
in this case on ARM64.

Add a new arg, 'addr', to pud_free_pmd_page() and pmd_free_pte_page()
so that TLB purge can be added later in seprate patches.

[toshi.kani@hpe.com: merge changes, rewrite patch description]
Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces")
Signed-off-by: Chintan Pandya <cpandya@codeaurora.org>
Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: mhocko@suse.com
Cc: akpm@linux-foundation.org
Cc: hpa@zytor.com
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will.deacon@arm.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: stable@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20180627141348.21777-3-toshi.kani@hpe.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 4cd4862845cda973831350a5d117b1c17254e867..0a56898f8410c9b9b7b0e48604f31d69d9aab8d2 100644 (file)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -804,12 +804,12 @@ int pmd_clear_huge(pmd_t *pmd)
        return 1;
 }
 
-int pud_free_pmd_page(pud_t *pud)
+int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 {
        return pud_none(*pud);
 }
 
-int pmd_free_pte_page(pmd_t *pmd)
+int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 {
        return pmd_none(*pmd);
 }

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 36d0b81933f8cce601f5fcefde326d6ef6f9de45..37786b101b511a5068a93492860b6b41c648c9f3 100644 (file)
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -657,11 +657,12 @@ int pmd_clear_huge(pmd_t *pmd)
 /**
  * pud_free_pmd_page - Clear pud entry and free pmd page.
  * @pud: Pointer to a PUD.
+ * @addr: Virtual address associated with pud.
  *
  * Context: The pud range has been unmaped and TLB purged.
  * Return: 1 if clearing the entry succeeded. 0 otherwise.
  */
-int pud_free_pmd_page(pud_t *pud)
+int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 {
        pmd_t *pmd;
        int i;
@@ -672,7 +673,7 @@ int pud_free_pmd_page(pud_t *pud)
        pmd = (pmd_t *)pud_page_vaddr(*pud);
 
        for (i = 0; i < PTRS_PER_PMD; i++)
-               if (!pmd_free_pte_page(&pmd[i]))
+               if (!pmd_free_pte_page(&pmd[i], addr + (i * PMD_SIZE)))
                        return 0;
 
        pud_clear(pud);
@@ -684,11 +685,12 @@ int pud_free_pmd_page(pud_t *pud)
 /**
  * pmd_free_pte_page - Clear pmd entry and free pte page.
  * @pmd: Pointer to a PMD.
+ * @addr: Virtual address associated with pmd.
  *
  * Context: The pmd range has been unmaped and TLB purged.
  * Return: 1 if clearing the entry succeeded. 0 otherwise.
  */
-int pmd_free_pte_page(pmd_t *pmd)
+int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 {
        pte_t *pte;
 
@@ -704,7 +706,7 @@ int pmd_free_pte_page(pmd_t *pmd)
 
 #else /* !CONFIG_X86_64 */
 
-int pud_free_pmd_page(pud_t *pud)
+int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 {
        return pud_none(*pud);
 }
@@ -713,7 +715,7 @@ int pud_free_pmd_page(pud_t *pud)
  * Disable free page handling on x86-PAE. This assures that ioremap()
  * does not update sync'd pmd entries. See vmalloc_sync_one().
  */
-int pmd_free_pte_page(pmd_t *pmd)
+int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 {
        return pmd_none(*pmd);
 }

diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index a88ea9e37a25be85372eac276940c5c445061a0e..0a4c2d4d9f8d5bfea50a61fc2b3bd5280503d1fb 100644 (file)
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -779,8 +779,8 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot);
 int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot);
 int pud_clear_huge(pud_t *pud);
 int pmd_clear_huge(pmd_t *pmd);
-int pud_free_pmd_page(pud_t *pud);
-int pmd_free_pte_page(pmd_t *pmd);
+int pud_free_pmd_page(pud_t *pud, unsigned long addr);
+int pmd_free_pte_page(pmd_t *pmd, unsigned long addr);
 #else  /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
 static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
 {
@@ -798,11 +798,11 @@ static inline int pmd_clear_huge(pmd_t *pmd)
 {
        return 0;
 }
-static inline int pud_free_pmd_page(pud_t *pud)
+static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr)
 {
        return 0;
 }
-static inline int pmd_free_pte_page(pmd_t *pmd)
+static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
 {
        return 0;
 }

diff --git a/lib/ioremap.c b/lib/ioremap.c
index 5323b59ca3936d653fa9fbf91ef3c05284de299e..b9462037868d0decd562163a776e31da98290b31 100644 (file)
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -84,7 +84,7 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr,
                if (ioremap_pmd_enabled() &&
                    ((next - addr) == PMD_SIZE) &&
                    IS_ALIGNED(phys_addr + addr, PMD_SIZE) &&
-                   pmd_free_pte_page(pmd)) {
+                   pmd_free_pte_page(pmd, addr)) {
                        if (pmd_set_huge(pmd, phys_addr + addr, prot))
                                continue;
                }
@@ -111,7 +111,7 @@ static inline int ioremap_pud_range(pgd_t *pgd, unsigned long addr,
                if (ioremap_pud_enabled() &&
                    ((next - addr) == PUD_SIZE) &&
                    IS_ALIGNED(phys_addr + addr, PUD_SIZE) &&
-                   pud_free_pmd_page(pud)) {
+                   pud_free_pmd_page(pud, addr)) {
                        if (pud_set_huge(pud, phys_addr + addr, prot))
                                continue;
                }