[PATCH v2 10/28] powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation
Aneesh Kumar K.V
aneesh.kumar at linux.ibm.com
Sat May 2 21:22:11 AEST 2020
This patch updates kernel hash page table entries to use storage key 3
for its mapping. This implies all kernel access will now use key 3 to
control READ/WRITE. The patch also prevents the allocation of key 3 from
userspace and UAMOR value is updated such that userspace cannot modify key 3.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
---
.../powerpc/include/asm/book3s/64/hash-pkey.h | 24 ++++++++++++++-----
arch/powerpc/include/asm/book3s/64/hash.h | 3 ++-
arch/powerpc/include/asm/book3s/64/mmu-hash.h | 1 +
arch/powerpc/include/asm/mmu_context.h | 2 +-
arch/powerpc/mm/book3s64/hash_4k.c | 2 +-
arch/powerpc/mm/book3s64/hash_64k.c | 4 ++--
arch/powerpc/mm/book3s64/hash_hugepage.c | 2 +-
arch/powerpc/mm/book3s64/hash_hugetlbpage.c | 2 +-
arch/powerpc/mm/book3s64/hash_pgtable.c | 2 +-
arch/powerpc/mm/book3s64/hash_utils.c | 10 ++++----
arch/powerpc/mm/book3s64/pkeys.c | 4 ++++
11 files changed, 38 insertions(+), 18 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/hash-pkey.h b/arch/powerpc/include/asm/book3s/64/hash-pkey.h
index 795010897e5d..fc75b815c9ca 100644
--- a/arch/powerpc/include/asm/book3s/64/hash-pkey.h
+++ b/arch/powerpc/include/asm/book3s/64/hash-pkey.h
@@ -2,6 +2,9 @@
#ifndef _ASM_POWERPC_BOOK3S_64_HASH_PKEY_H
#define _ASM_POWERPC_BOOK3S_64_HASH_PKEY_H
+/* We use key 3 for KERNEL */
+#define HASH_DEFAULT_KERNEL_KEY (HPTE_R_KEY_BIT0 | HPTE_R_KEY_BIT1)
+
static inline u64 hash__vmflag_to_pte_pkey_bits(u64 vm_flags)
{
return (((vm_flags & VM_PKEY_BIT0) ? H_PTE_PKEY_BIT0 : 0x0UL) |
@@ -11,13 +14,22 @@ static inline u64 hash__vmflag_to_pte_pkey_bits(u64 vm_flags)
((vm_flags & VM_PKEY_BIT4) ? H_PTE_PKEY_BIT4 : 0x0UL));
}
-static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
+static inline u64 pte_to_hpte_pkey_bits(u64 pteflags, unsigned long flags)
{
- return (((pteflags & H_PTE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL) |
- ((pteflags & H_PTE_PKEY_BIT3) ? HPTE_R_KEY_BIT3 : 0x0UL) |
- ((pteflags & H_PTE_PKEY_BIT2) ? HPTE_R_KEY_BIT2 : 0x0UL) |
- ((pteflags & H_PTE_PKEY_BIT1) ? HPTE_R_KEY_BIT1 : 0x0UL) |
- ((pteflags & H_PTE_PKEY_BIT0) ? HPTE_R_KEY_BIT0 : 0x0UL));
+ unsigned long pte_pkey;
+
+ pte_pkey = (((pteflags & H_PTE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL) |
+ ((pteflags & H_PTE_PKEY_BIT3) ? HPTE_R_KEY_BIT3 : 0x0UL) |
+ ((pteflags & H_PTE_PKEY_BIT2) ? HPTE_R_KEY_BIT2 : 0x0UL) |
+ ((pteflags & H_PTE_PKEY_BIT1) ? HPTE_R_KEY_BIT1 : 0x0UL) |
+ ((pteflags & H_PTE_PKEY_BIT0) ? HPTE_R_KEY_BIT0 : 0x0UL));
+
+ if (mmu_has_feature(MMU_FTR_KUAP)) {
+ if ((pte_pkey == 0) && (flags & HPTE_USE_KERNEL_KEY))
+ return HASH_DEFAULT_KERNEL_KEY;
+ }
+
+ return pte_pkey;
}
static inline u16 hash__pte_to_pkey_bits(u64 pteflags)
diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h
index 6fc4520092c7..12b65d3d79aa 100644
--- a/arch/powerpc/include/asm/book3s/64/hash.h
+++ b/arch/powerpc/include/asm/book3s/64/hash.h
@@ -145,7 +145,8 @@ extern void hash__mark_initmem_nx(void);
extern void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
pte_t *ptep, unsigned long pte, int huge);
-extern unsigned long htab_convert_pte_flags(unsigned long pteflags);
+extern unsigned long htab_convert_pte_flags(unsigned long pteflags,
+ unsigned long flags);
/* Atomic PTE updates */
static inline unsigned long hash__pte_update(struct mm_struct *mm,
unsigned long addr,
diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index 58fcc959f9d5..eb9950043b78 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -452,6 +452,7 @@ static inline unsigned long hpt_hash(unsigned long vpn,
#define HPTE_LOCAL_UPDATE 0x1
#define HPTE_NOHPTE_UPDATE 0x2
+#define HPTE_USE_KERNEL_KEY 0x4
extern int __hash_page_4K(unsigned long ea, unsigned long access,
unsigned long vsid, pte_t *ptep, unsigned long trap,
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index 1a474f6b1992..2d85e0ea5f1c 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -286,7 +286,7 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
#define thread_pkey_regs_init(thread)
#define arch_dup_pkeys(oldmm, mm)
-static inline u64 pte_to_hpte_pkey_bits(u64 pteflags)
+static inline u64 pte_to_hpte_pkey_bits(u64 pteflags, unsigned long flags)
{
return 0x0UL;
}
diff --git a/arch/powerpc/mm/book3s64/hash_4k.c b/arch/powerpc/mm/book3s64/hash_4k.c
index 22e787123cdf..7de1a8a0c62a 100644
--- a/arch/powerpc/mm/book3s64/hash_4k.c
+++ b/arch/powerpc/mm/book3s64/hash_4k.c
@@ -54,7 +54,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
* PP bits. _PAGE_USER is already PP bit 0x2, so we only
* need to add in 0x1 if it's a read-only user page
*/
- rflags = htab_convert_pte_flags(new_pte);
+ rflags = htab_convert_pte_flags(new_pte, flags);
rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE);
if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
diff --git a/arch/powerpc/mm/book3s64/hash_64k.c b/arch/powerpc/mm/book3s64/hash_64k.c
index 7084ce2951e6..998c6817ed47 100644
--- a/arch/powerpc/mm/book3s64/hash_64k.c
+++ b/arch/powerpc/mm/book3s64/hash_64k.c
@@ -72,7 +72,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid,
* Handle the subpage protection bits
*/
subpg_pte = new_pte & ~subpg_prot;
- rflags = htab_convert_pte_flags(subpg_pte);
+ rflags = htab_convert_pte_flags(subpg_pte, flags);
if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
@@ -260,7 +260,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access,
new_pte |= _PAGE_DIRTY;
} while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte)));
- rflags = htab_convert_pte_flags(new_pte);
+ rflags = htab_convert_pte_flags(new_pte, flags);
rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE);
if (cpu_has_feature(CPU_FTR_NOEXECUTE) &&
diff --git a/arch/powerpc/mm/book3s64/hash_hugepage.c b/arch/powerpc/mm/book3s64/hash_hugepage.c
index 440823797de7..c0fabe6c5a12 100644
--- a/arch/powerpc/mm/book3s64/hash_hugepage.c
+++ b/arch/powerpc/mm/book3s64/hash_hugepage.c
@@ -57,7 +57,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid,
if (!(old_pmd & (H_PAGE_THP_HUGE | _PAGE_DEVMAP)))
return 0;
- rflags = htab_convert_pte_flags(new_pmd);
+ rflags = htab_convert_pte_flags(new_pmd, flags);
#if 0
if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
diff --git a/arch/powerpc/mm/book3s64/hash_hugetlbpage.c b/arch/powerpc/mm/book3s64/hash_hugetlbpage.c
index eefa89c6117b..8ce8fc327af4 100644
--- a/arch/powerpc/mm/book3s64/hash_hugetlbpage.c
+++ b/arch/powerpc/mm/book3s64/hash_hugetlbpage.c
@@ -72,7 +72,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid,
if (old_pte & (H_PAGE_THP_HUGE | _PAGE_DEVMAP))
return 0;
- rflags = htab_convert_pte_flags(new_pte);
+ rflags = htab_convert_pte_flags(new_pte, flags);
if (unlikely(mmu_psize == MMU_PAGE_16G))
offset = PTRS_PER_PUD;
else
diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c b/arch/powerpc/mm/book3s64/hash_pgtable.c
index 64733b9cb20a..6c43aaf1c713 100644
--- a/arch/powerpc/mm/book3s64/hash_pgtable.c
+++ b/arch/powerpc/mm/book3s64/hash_pgtable.c
@@ -454,7 +454,7 @@ void hash__mark_initmem_nx(void)
start = (unsigned long)__init_begin;
end = (unsigned long)__init_end;
- pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL));
+ pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL), HPTE_USE_KERNEL_KEY);
WARN_ON(!hash__change_memory_range(start, end, pp));
}
diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c
index 8ed2411c3f39..bdd4f1792c76 100644
--- a/arch/powerpc/mm/book3s64/hash_utils.c
+++ b/arch/powerpc/mm/book3s64/hash_utils.c
@@ -183,7 +183,7 @@ static struct mmu_psize_def mmu_psize_defaults_gp[] = {
* - We make sure R is always set and never lost
* - C is _PAGE_DIRTY, and *should* always be set for a writeable mapping
*/
-unsigned long htab_convert_pte_flags(unsigned long pteflags)
+unsigned long htab_convert_pte_flags(unsigned long pteflags, unsigned long flags)
{
unsigned long rflags = 0;
@@ -237,7 +237,7 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags)
*/
rflags |= HPTE_R_M;
- rflags |= pte_to_hpte_pkey_bits(pteflags);
+ rflags |= pte_to_hpte_pkey_bits(pteflags, flags);
return rflags;
}
@@ -252,7 +252,7 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend,
shift = mmu_psize_defs[psize].shift;
step = 1 << shift;
- prot = htab_convert_pte_flags(prot);
+ prot = htab_convert_pte_flags(prot, HPTE_USE_KERNEL_KEY);
DBG("htab_bolt_mapping(%lx..%lx -> %lx (%lx,%d,%d)\n",
vstart, vend, pstart, prot, psize, ssize);
@@ -1295,12 +1295,14 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
psize = mmu_vmalloc_psize;
ssize = mmu_kernel_ssize;
+ flags |= HPTE_USE_KERNEL_KEY;
break;
case IO_REGION_ID:
vsid = get_kernel_vsid(ea, mmu_kernel_ssize);
psize = mmu_io_psize;
ssize = mmu_kernel_ssize;
+ flags |= HPTE_USE_KERNEL_KEY;
break;
default:
/*
@@ -1894,7 +1896,7 @@ static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi)
unsigned long hash;
unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize);
unsigned long vpn = hpt_vpn(vaddr, vsid, mmu_kernel_ssize);
- unsigned long mode = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL));
+ unsigned long mode = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL), HPTE_USE_KERNEL_KEY);
long ret;
hash = hpt_hash(vpn, PAGE_SHIFT, mmu_kernel_ssize);
diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c
index 12a9ac169f5d..976f65f27324 100644
--- a/arch/powerpc/mm/book3s64/pkeys.c
+++ b/arch/powerpc/mm/book3s64/pkeys.c
@@ -189,6 +189,10 @@ void __init pkey_early_init_devtree(void)
reserved_allocation_mask |= (0x1 << 1);
default_uamor &= ~(0x3ul << pkeyshift(1));
+ /* handle key 3 which is used by kernel for KAUP */
+ reserved_allocation_mask |= (0x1 << 3);
+ default_uamor &= ~(0x3ul << pkeyshift(3));
+
/*
* Prevent the usage of OS reserved keys. Update UAMOR
* for those keys. Also mark the rest of the bits in the
--
2.26.2
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