FAILED: patch "[PATCH] s390/mm: make the pxd_offset functions more robust" failed to apply to 4.19-stable tree
Subsystems (3)
[email protected]
maintainerThe patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From d1874a0c2805fcfa9162c972d6b7541e57adb542 Mon Sep 17 00:00:00 2001
From: Martin Schwidefsky <[email protected]>
Date: Tue, 23 Apr 2019 10:51:12 +0200
Subject: [PATCH] s390/mm: make the pxd_offset functions more robust
Change the way how pgd_offset, p4d_offset, pud_offset and pmd_offset walk the page tables. pgd_offset now always calculates the index for the top-level page table and adds it to the pgd, this is either a segment table offset for a 2-level setup, a region-3 offset for 3-levels, region-2 offset for 4-levels, or a region-1 offset for a 5-level setup. The other three functions p4d_offset, pud_offset and pmd_offset will only add the respective offset if they dereference the passed pointer.
With the new way of walking the page tables a sequence like this from mm/gup.c now works:
pgdp = pgd_offset(current->mm, addr);
pgd = READ_ONCE(*pgdp);
p4dp = p4d_offset(&pgd, addr);
p4d = READ_ONCE(*p4dp);
pudp = pud_offset(&p4d, addr);
pud = READ_ONCE(*pudp);
pmdp = pmd_offset(&pud, addr);
pmd = READ_ONCE(*pmdp);Signed-off-by Martin Schwidefsky <[email protected]>
arch/s390/include/asm/pgtable.h +43 -24
@@ -1204,42 +1204,67 @@ static inline pte_t mk_pte(struct page *page, pgprot_t pgprot)#define pmd_index (address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))#define pte_index (address) (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE-1)) -#define pgd_offset (mm, address) ((mm)->pgd + pgd_index(address)) -#define pgd_offset_k (address) pgd_offset(&init_mm, address) -#define pgd_offset_raw (pgd, addr) ((pgd) + pgd_index(addr)) -#define pmd_deref (pmd) (pmd_val(pmd) & _SEGMENT_ENTRY_ORIGIN)#define pud_deref (pud) (pud_val(pud) & _REGION_ENTRY_ORIGIN)#define p4d_deref (pud) (p4d_val(pud) & _REGION_ENTRY_ORIGIN)#define pgd_deref (pgd) (pgd_val(pgd) & _REGION_ENTRY_ORIGIN) -static inline p4d_t *p4d_offset (pgd_t *pgd,unsigned long address) +/* +* The pgd_offset function *always* adds the index for the top-level +* region/segment table. This is done to get a sequence like the +* following to work: +* pgdp = pgd_offset(current->mm, addr); +* pgd = READ_ONCE(*pgdp); +* p4dp = p4d_offset(&pgd, addr); +* ... +* The subsequent p4d_offset, pud_offset and pmd_offset functions +* only add an index if they dereferenced the pointer. +*/ +static inline pgd_t *pgd_offset_raw (pgd_t *pgd,unsigned long address) { -p4d_t *p4d = (p4d_t *) pgd; +unsigned long rste; +unsigned int shift; -if ((pgd_val (*pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R1) - p4d = (p4d_t *)pgd_deref (*pgd); -return p4d +p4d_index (address); +/* Get the first entry of the top level table */ + rste =pgd_val (*pgd); +/* Pick up the shift from the table type of the first entry */ + shift = ((rste & _REGION_ENTRY_TYPE_MASK) >>2 ) *11 +20 ; +return pgd + ((address >> shift) & (PTRS_PER_PGD -1 )); } -static inline pud_t *pud_offset (p4d_t *p4d,unsigned long address) +#define pgd_offset (mm, address) pgd_offset_raw(READ_ONCE((mm)->pgd), address) +#define pgd_offset_k (address) pgd_offset(&init_mm, address) + +static inline p4d_t *p4d_offset (pgd_t *pgd,unsigned long address) { -pud_t *pud = (pud_t *) p4d; +if ((pgd_val (*pgd) & _REGION_ENTRY_TYPE_MASK) >= _REGION_ENTRY_TYPE_R1) +return (p4d_t *)pgd_deref (*pgd) +p4d_index (address); +return (p4d_t *) pgd; +} -if ((p4d_val (*p4d) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2) - pud = (pud_t *)p4d_deref (*p4d); -return pud +pud_index (address); +static inline pud_t *pud_offset (p4d_t *p4d,unsigned long address) +{ +if ((p4d_val (*p4d) & _REGION_ENTRY_TYPE_MASK) >= _REGION_ENTRY_TYPE_R2) +return (pud_t *)p4d_deref (*p4d) +pud_index (address); +return (pud_t *) p4d; }static inline pmd_t *pmd_offset (pud_t *pud,unsigned long address) { -pmd_t *pmd = (pmd_t *) pud; +if ((pud_val (*pud) & _REGION_ENTRY_TYPE_MASK) >= _REGION_ENTRY_TYPE_R3) +return (pmd_t *)pud_deref (*pud) +pmd_index (address); +return (pmd_t *) pud; +} -if ((pud_val (*pud) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) - pmd = (pmd_t *)pud_deref (*pud); -return pmd +pmd_index (address); +static inline pte_t *pte_offset (pmd_t *pmd,unsigned long address) +{ +return (pte_t *)pmd_deref (*pmd) +pte_index (address); } +#define pte_offset_kernel (pmd, address) pte_offset(pmd, address) +#define pte_offset_map (pmd, address) pte_offset_kernel(pmd, address) +#define pte_unmap (pte) do { } while (0) +#define pfn_pte (pfn,pgprot) mk_pte_phys(__pa((pfn) << PAGE_SHIFT),(pgprot))#define pte_pfn (x) (pte_val(x) >> PAGE_SHIFT)#define pte_page (x) pfn_to_page(pte_pfn(x))
@@ -1249,12 +1274,6 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address)#define p4d_page (p4d) pfn_to_page(p4d_pfn(p4d))#define pgd_page (pgd) pfn_to_page(pgd_pfn(pgd)) -/* Find an entry in the lowest level page table.. */ -#define pte_offset (pmd, addr) ((pte_t *) pmd_deref(*(pmd)) + pte_index(addr)) -#define pte_offset_kernel (pmd, address) pte_offset(pmd,address) -#define pte_offset_map (pmd, address) pte_offset_kernel(pmd, address) -#define pte_unmap (pte) do { } while (0) -static inline pmd_t pmd_wrprotect (pmd_t pmd) {pmd_val (pmd) &= ~_SEGMENT_ENTRY_WRITE;
arch/s390/mm/gup.c +12 -21
@@ -18,7 +18,7 @@* inlines everything into a single function which results in too much * register pressure. */ -static inline int gup_pte_range (pmd_t *pmdp,pmd_t pmd,unsigned long addr, +static inline int gup_pte_range (pmd_t pmd,unsigned long addr,unsigned long end,int write,struct page **pages,int *nr) {struct page *head, *page;
@@ -27,7 +27,7 @@ static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr, mask = (write ? _PAGE_PROTECT :0 ) | _PAGE_INVALID | _PAGE_SPECIAL; - ptep = ((pte_t *)pmd_deref (pmd)) +pte_index (addr); + ptep =pte_offset_map (&pmd, addr); do { pte = *ptep; barrier();
@@ -93,16 +93,13 @@ static inline int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr, } -static inline int gup_pmd_range (pud_t *pudp,pud_t pud,unsigned long addr, +static inline int gup_pmd_range (pud_t pud,unsigned long addr,unsigned long end,int write,struct page **pages,int *nr) {unsigned long next;pmd_t *pmdp, pmd; - pmdp = (pmd_t *) pudp; -if ((pud_val (pud) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) - pmdp = (pmd_t *)pud_deref (pud); - pmdp +=pmd_index (addr); + pmdp =pmd_offset (&pud, addr); do { pmd = *pmdp; barrier();
@@ -120,7 +117,7 @@ static inline int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr,if (!gup_huge_pmd (pmdp, pmd, addr, next, write, pages, nr))return 0 ; - }else if (!gup_pte_range (pmdp, pmd, addr, next, + }else if (!gup_pte_range (pmd, addr, next, write, pages, nr))return 0 ; }while (pmdp++, addr = next, addr != end);
@@ -166,16 +163,13 @@ static int gup_huge_pud(pud_t *pudp, pud_t pud, unsigned long addr,return 1 ; } -static inline int gup_pud_range (p4d_t *p4dp,p4d_t p4d,unsigned long addr, +static inline int gup_pud_range (p4d_t p4d,unsigned long addr,unsigned long end,int write,struct page **pages,int *nr) {unsigned long next;pud_t *pudp, pud; - pudp = (pud_t *) p4dp; -if ((p4d_val (p4d) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2) - pudp = (pud_t *)p4d_deref (p4d); - pudp +=pud_index (addr); + pudp =pud_offset (&p4d, addr); do { pud = *pudp; barrier();
@@ -186,7 +180,7 @@ static inline int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr,if (!gup_huge_pud (pudp, pud, addr, next, write, pages, nr))return 0 ; - }else if (!gup_pmd_range (pudp, pud, addr, next, write, pages, + }else if (!gup_pmd_range (pud, addr, next, write, pages, nr))return 0 ; }while (pudp++, addr = next, addr != end);
@@ -194,23 +188,20 @@ static inline int gup_pud_range(p4d_t *p4dp, p4d_t p4d, unsigned long addr,return 1 ; } -static inline int gup_p4d_range (pgd_t *pgdp,pgd_t pgd,unsigned long addr, +static inline int gup_p4d_range (pgd_t pgd,unsigned long addr,unsigned long end,int write,struct page **pages,int *nr) {unsigned long next;p4d_t *p4dp, p4d; - p4dp = (p4d_t *) pgdp; -if ((pgd_val (pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R1) - p4dp = (p4d_t *)pgd_deref (pgd); - p4dp +=p4d_index (addr); + p4dp =p4d_offset (&pgd, addr);do { p4d = *p4dp;barrier (); next =p4d_addr_end (addr, end);if (p4d_none (p4d))return 0 ; -if (!gup_pud_range (p4dp, p4d, addr, next, write, pages, nr)) +if (!gup_pud_range (p4d, addr, next, write, pages, nr))return 0 ; }while (p4dp++, addr = next, addr != end);
@@ -253,7 +244,7 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, next =pgd_addr_end (addr, end);if (pgd_none (pgd))break ; -if (!gup_p4d_range (pgdp, pgd, addr, next, write, pages, &nr)) +if (!gup_p4d_range (pgd, addr, next, write, pages, &nr))break ; }while (pgdp++, addr = next, addr != end);local_irq_restore (flags);