[PATCH v3 10/24] powerpc/mm: add pte helpers to query and change pte flags

Christophe Leroy
2018-10-09T13:51:59Z

In order to avoid using generic _PAGE_XXX flags in powerpc
core functions, define helpers for all needed flags:
- pte_mkuser() and pte_mkprivileged() to set/unset and/or
unset/set _PAGE_USER and/or _PAGE_PRIVILEGED
- pte_hashpte() to check if _PAGE_HASHPTE is set.
- pte_ci() check if cache is inhibited (already existing on book3s/64)
- pte_exprotect() to protect against execution
- pte_exec() and pte_mkexec() to query and set page execution
- pte_mkpte() to set _PAGE_PTE flag.
- pte_hw_valid() to check _PAGE_PRESENT since pte_present does
something different on book3s/64.

On book3s/32 there is no exec protection, so pte_mkexec() and
pte_exprotect() are nops and pte_exec() returns always true.

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/include/asm/book3s/32/pgtable.h | 41 ++++++++++++++++++++++++++++
arch/powerpc/include/asm/book3s/64/pgtable.h | 35 ++++++++++++++++++++++++
arch/powerpc/include/asm/nohash/32/pgtable.h | 5 ++++
arch/powerpc/include/asm/nohash/64/pgtable.h | 5 ++++
arch/powerpc/include/asm/nohash/pgtable.h | 28 +++++++++++++++++++
5 files changed, 114 insertions(+)

diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h
index 3127cc529aa1..a6ca799e0eb5 100644
--- a/arch/powerpc/include/asm/book3s/32/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/32/pgtable.h
@@ -301,6 +301,7 @@ static inline int pte_dirty(pte_t pte) { return !!(pte_val(pte) & _PAGE_DIRTY);
static inline int pte_young(pte_t pte) { return !!(pte_val(pte) & _PAGE_ACCESSED); }
static inline int pte_special(pte_t pte) { return !!(pte_val(pte) & _PAGE_SPECIAL); }
static inline int pte_none(pte_t pte) { return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
+static inline bool pte_exec(pte_t pte) { return true; }
static inline pgprot_t pte_pgprot(pte_t pte) { return __pgprot(pte_val(pte) & PAGE_PROT_BITS); }

static inline int pte_present(pte_t pte)
@@ -308,6 +309,21 @@ static inline int pte_present(pte_t pte)
return pte_val(pte) & _PAGE_PRESENT;
}

+static inline bool pte_hw_valid(pte_t pte)
+{
+ return pte_val(pte) & _PAGE_PRESENT;
+}
+
+static inline bool pte_hashpte(pte_t pte)
+{
+ return !!(pte_val(pte) & _PAGE_HASHPTE);
+}
+
+static inline bool pte_ci(pte_t pte)
+{
+ return !!(pte_val(pte) & _PAGE_NO_CACHE);
+}
+
/*
* We only find page table entry in the last level
* Hence no need for other accessors
@@ -354,6 +370,11 @@ static inline pte_t pte_wrprotect(pte_t pte)
return __pte(pte_val(pte) & ~_PAGE_RW);
}

+static inline pte_t pte_exprotect(pte_t pte)
+{
+ return pte;
+}
+
static inline pte_t pte_mkclean(pte_t pte)
{
return __pte(pte_val(pte) & ~_PAGE_DIRTY);
@@ -364,6 +385,16 @@ static inline pte_t pte_mkold(pte_t pte)
return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
}

+static inline pte_t pte_mkexec(pte_t pte)
+{
+ return pte;
+}
+
+static inline pte_t pte_mkpte(pte_t pte)
+{
+ return pte;
+}
+
static inline pte_t pte_mkwrite(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_RW);
@@ -389,6 +420,16 @@ static inline pte_t pte_mkhuge(pte_t pte)
return pte;
}

+static inline pte_t pte_mkprivileged(pte_t pte)
+{
+ return __pte(pte_val(pte) & ~_PAGE_USER);
+}
+
+static inline pte_t pte_mkuser(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_USER);
+}
+
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index d4327f494371..c8564762b6f0 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -519,6 +519,11 @@ static inline int pte_special(pte_t pte)
return !!(pte_raw(pte) & cpu_to_be64(_PAGE_SPECIAL));
}

+static inline bool pte_exec(pte_t pte)
+{
+ return !!(pte_raw(pte) & cpu_to_be64(_PAGE_EXEC));
+}
+
static inline pgprot_t pte_pgprot(pte_t pte) { return __pgprot(pte_val(pte) & PAGE_PROT_BITS); }

#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
@@ -587,6 +592,11 @@ static inline int pte_present(pte_t pte)
return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_INVALID));
}

+static inline bool pte_hw_valid(pte_t pte)
+{
+ return !!(pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT));
+}
+
#ifdef CONFIG_PPC_MEM_KEYS
extern bool arch_pte_access_permitted(u64 pte, bool write, bool execute);
#else
@@ -646,6 +656,11 @@ static inline pte_t pte_wrprotect(pte_t pte)
return __pte(pte_val(pte) & ~_PAGE_WRITE);
}

+static inline pte_t pte_exprotect(pte_t pte)
+{
+ return __pte(pte_val(pte) & ~_PAGE_EXEC);
+}
+
static inline pte_t pte_mkclean(pte_t pte)
{
return __pte(pte_val(pte) & ~_PAGE_DIRTY);
@@ -656,6 +671,16 @@ static inline pte_t pte_mkold(pte_t pte)
return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
}

+static inline pte_t pte_mkexec(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_EXEC);
+}
+
+static inline pte_t pte_mkpte(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_PTE);
+}
+
static inline pte_t pte_mkwrite(pte_t pte)
{
/*
@@ -689,6 +714,16 @@ static inline pte_t pte_mkdevmap(pte_t pte)
return __pte(pte_val(pte) | _PAGE_SPECIAL|_PAGE_DEVMAP);
}

+static inline pte_t pte_mkprivileged(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_PRIVILEGED);
+}
+
+static inline pte_t pte_mkuser(pte_t pte)
+{
+ return __pte(pte_val(pte) & ~_PAGE_PRIVILEGED);
+}
+
/*
* This is potentially called with a pmd as the argument, in which case it's not
* safe to check _PAGE_DEVMAP unless we also confirm that _PAGE_PTE is set.
diff --git a/arch/powerpc/include/asm/nohash/32/pgtable.h b/arch/powerpc/include/asm/nohash/32/pgtable.h
index 4373f8c44b6d..6fecfd7854f5 100644
--- a/arch/powerpc/include/asm/nohash/32/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/32/pgtable.h
@@ -164,6 +164,11 @@ static inline pte_t pte_wrprotect(pte_t pte)
return __pte(ptev);
}

+static inline pte_t pte_mkexec(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_EXEC);
+}
+
#define pmd_none(pmd) (!pmd_val(pmd))
#define pmd_bad(pmd) (pmd_val(pmd) & _PMD_BAD)
#define pmd_present(pmd) (pmd_val(pmd) & _PMD_PRESENT_MASK)
diff --git a/arch/powerpc/include/asm/nohash/64/pgtable.h b/arch/powerpc/include/asm/nohash/64/pgtable.h
index 72dac522aa66..b7d65d4b61be 100644
--- a/arch/powerpc/include/asm/nohash/64/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/64/pgtable.h
@@ -114,6 +114,11 @@ static inline pte_t pte_wrprotect(pte_t pte)
return __pte(pte_val(pte) & ~_PAGE_RW);
}

+static inline pte_t pte_mkexec(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_EXEC);
+}
+
#define PMD_BAD_BITS (PTE_TABLE_SIZE-1)
#define PUD_BAD_BITS (PMD_TABLE_SIZE-1)

diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index c746e9e784cd..b256e38a047c 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -19,6 +19,9 @@ static inline int pte_read(pte_t pte) { return 1; }
static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
static inline int pte_special(pte_t pte) { return pte_val(pte) & _PAGE_SPECIAL; }
static inline int pte_none(pte_t pte) { return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
+static inline bool pte_hashpte(pte_t pte) { return false; }
+static inline bool pte_ci(pte_t pte) { return pte_val(pte) & _PAGE_NO_CACHE; }
+static inline bool pte_exec(pte_t pte) { return pte_val(pte) & _PAGE_EXEC; }
static inline pgprot_t pte_pgprot(pte_t pte) { return __pgprot(pte_val(pte) & PAGE_PROT_BITS); }

#ifdef CONFIG_NUMA_BALANCING
@@ -44,6 +47,11 @@ static inline int pte_present(pte_t pte)
return pte_val(pte) & _PAGE_PRESENT;
}

+static inline bool pte_hw_valid(pte_t pte)
+{
+ return pte_val(pte) & _PAGE_PRESENT;
+}
+
/*
* We only find page table entry in the last level
* Hence no need for other accessors
@@ -77,6 +85,11 @@ static inline unsigned long pte_pfn(pte_t pte) {
return pte_val(pte) >> PTE_RPN_SHIFT; }

/* Generic modifiers for PTE bits */
+static inline pte_t pte_exprotect(pte_t pte)
+{
+ return __pte(pte_val(pte) & ~_PAGE_EXEC);
+}
+
static inline pte_t pte_mkclean(pte_t pte)
{
return __pte(pte_val(pte) & ~(_PAGE_DIRTY | _PAGE_HWWRITE));
@@ -87,6 +100,11 @@ static inline pte_t pte_mkold(pte_t pte)
return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
}

+static inline pte_t pte_mkpte(pte_t pte)
+{
+ return pte;
+}
+
static inline pte_t pte_mkspecial(pte_t pte)
{
return __pte(pte_val(pte) | _PAGE_SPECIAL);
@@ -97,6 +115,16 @@ static inline pte_t pte_mkhuge(pte_t pte)
return __pte(pte_val(pte) | _PAGE_HUGE);
}

+static inline pte_t pte_mkprivileged(pte_t pte)
+{
+ return __pte((pte_val(pte) & ~_PAGE_USER) | _PAGE_PRIVILEGED);
+}
+
+static inline pte_t pte_mkuser(pte_t pte)
+{
+ return __pte((pte_val(pte) & ~_PAGE_PRIVILEGED) | _PAGE_USER);
+}
+
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
--
2.13.3