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 f6b877d2726dfe16cbee6ab29e0346c8f1dded12..6ac0d32d60a527f590199a65d453e769e738acd5 100644 (file)
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -938,12 +938,12 @@ 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 debb7b7650b27f45ecea987222c62573622d7a76..31286ff041417bb8ba6040bf8ed78939423542b3 100644 (file)
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -716,11 +716,12 @@ 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;
@@ -731,7 +732,7 @@ 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);
@@ -743,11 +744,12 @@ 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;
 
@@ -763,7 +765,7 @@ 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);
 }
@@ -772,7 +774,7 @@ 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 46a2f5d9aa251d9f3037f5d3382e4139a61bd0a6..f00421dfacbd06bf6dba7f9f7d7783f0518135dd 100644 (file)
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -991,8 +991,8 @@ 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 p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot)
 {
@@ -1018,11 +1018,11 @@ 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 54e5bbaa3200317534926e65982dcd3cbab71492..517f5853ffed1726a462543f902450ddb7f9a9b4 100644 (file)
--- a/lib/ioremap.c
+++ b/lib/ioremap.c
@@ -92,7 +92,7 @@ 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;
                }
@@ -119,7 +119,7 @@ static inline int ioremap_pud_range(p4d_t *p4d, 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;
                }