Le 22/09/2023 à 09:33, Ryan Roberts a écrit :
On 22/09/2023 07:56, Christophe Leroy wrote:
Le 21/09/2023 à 18:20, Ryan Roberts a écrit :
In order to fix a bug, arm64 needs access to the vma inside it's implementation of set_huge_pte_at(). Provide for this by converting the mm parameter to be a vma. Any implementations that require the mm can access it via vma->vm_mm.
This commit makes the required powerpc modifications. Separate commits update the other arches and core code, before the actual bug is fixed in arm64.
No behavioral changes intended.
Signed-off-by: Ryan Roberts ryan.roberts@arm.com
arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h | 3 ++- arch/powerpc/mm/book3s64/hugetlbpage.c | 2 +- arch/powerpc/mm/book3s64/radix_hugetlbpage.c | 2 +- arch/powerpc/mm/nohash/8xx.c | 2 +- arch/powerpc/mm/pgtable.c | 7 ++++++- 5 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h index de092b04ee1a..fff8cd726bc7 100644 --- a/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/hugetlb-8xx.h @@ -46,7 +46,8 @@ static inline int check_and_get_huge_psize(int shift) } #define __HAVE_ARCH_HUGE_SET_HUGE_PTE_AT -void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte); +void set_huge_pte_at(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t pte); +void __set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte);
Don't add the burden of an additional function, see below
#define __HAVE_ARCH_HUGE_PTE_CLEAR static inline void huge_pte_clear(struct mm_struct *mm, unsigned long addr, diff --git a/arch/powerpc/mm/book3s64/hugetlbpage.c b/arch/powerpc/mm/book3s64/hugetlbpage.c index 3bc0eb21b2a0..ae7fd7c90eb8 100644 --- a/arch/powerpc/mm/book3s64/hugetlbpage.c +++ b/arch/powerpc/mm/book3s64/hugetlbpage.c @@ -147,7 +147,7 @@ void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long addr if (radix_enabled()) return radix__huge_ptep_modify_prot_commit(vma, addr, ptep, old_pte, pte);
- set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
- set_huge_pte_at(vma, addr, ptep, pte); } void __init hugetlbpage_init_defaultsize(void)
diff --git a/arch/powerpc/mm/book3s64/radix_hugetlbpage.c b/arch/powerpc/mm/book3s64/radix_hugetlbpage.c index 17075c78d4bc..7cd40a334c3a 100644 --- a/arch/powerpc/mm/book3s64/radix_hugetlbpage.c +++ b/arch/powerpc/mm/book3s64/radix_hugetlbpage.c @@ -58,5 +58,5 @@ void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma, atomic_read(&mm->context.copros) > 0) radix__flush_hugetlb_page(vma, addr);
- set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
- set_huge_pte_at(vma, addr, ptep, pte); }
diff --git a/arch/powerpc/mm/nohash/8xx.c b/arch/powerpc/mm/nohash/8xx.c index dbbfe897455d..650a7a8496b6 100644 --- a/arch/powerpc/mm/nohash/8xx.c +++ b/arch/powerpc/mm/nohash/8xx.c @@ -91,7 +91,7 @@ static int __ref __early_map_kernel_hugepage(unsigned long va, phys_addr_t pa, if (new && WARN_ON(pte_present(*ptep) && pgprot_val(prot))) return -EINVAL;
- set_huge_pte_at(&init_mm, va, ptep, pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot)));
- __set_huge_pte_at(&init_mm, va, ptep, pte_mkhuge(pfn_pte(pa >> PAGE_SHIFT, prot)));
Call set_huge_pte_at() with a NULL vma instead.
I'm happy to take your proposed approach if that's your preference. Another option is to use a dummy VMA, as I have done in the core code, for the one call site that calls set_huge_pte_at() with init_mm:
struct vm_area_struct vma = TLB_FLUSH_VMA(&init_mm, 0);
This is an existing macro that creates a dummy vma with vma->vm_mm filled in. Then I pass &vma to the function.
I don't like that, I prefer the solution I proposed. We already have a couple places where powerpc do things based on whether vma is NULL or not.
Or yet another option would be to keep the mm param as is in set_huge_pte_at(), and add a size param to the function. But then all call sites have the burden of figuring out the size of the huge pte (although I think most know already).
Indeed.
arch_make_huge_pte() used to take a vma until commit 79c1c594f49a ("mm/hugetlb: change parameters of arch_make_huge_pte()").
Should we try and have the same approach ? Or is it irrelevant ?
Christophe
Thanks, Ryan
return 0; } diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c index 3f86fd217690..9cbcb561a4d8 100644 --- a/arch/powerpc/mm/pgtable.c +++ b/arch/powerpc/mm/pgtable.c @@ -288,7 +288,7 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma, } #if defined(CONFIG_PPC_8xx) -void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte) +void __set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte)
Keep it as set_huge_pte_at() with vma argument.
{ pmd_t *pmd = pmd_off(mm, addr);
Change to:
pmd_t *pmd = vma ? pmd_off(vma->vm_mm, addr) : pmd_off_k(addr);
pte_basic_t val;@@ -310,6 +310,11 @@ void set_huge_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_ for (i = 0; i < num; i++, entry++, val += SZ_4K) *entry = val; }
+void set_huge_pte_at(struct vm_area_struct *vma, unsigned long addr, pte_t *ptep, pte_t pte) +{
- __set_huge_pte_at(vma->vm_mm, addr, ptep, pte);
+}
Remove this burden.
#endif #endif /* CONFIG_HUGETLB_PAGE */
Christophe