[RFC PATCH 13/14] sparc64 mm: add shared context support to mmap() and shmat() APIs
From: Mike Kravetz
Date: Fri Dec 16 2016 - 13:37:38 EST
Add new mmap(MAP_SHAREDCTX) and shm(SHM_SHAREDCTX) flags to specify
desire for shared context mappings. This only works on HUGETLB
mappings. In addition, the mappings must be SHARED and at a FIXED
address otherwize EINVAL will be returned.
Also, populate the sparc specific hooks to mmap and shmat that perform
shared context processing.
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
arch/sparc/include/asm/hugetlb.h | 4 +++
arch/sparc/include/asm/mman.h | 6 ++++
arch/sparc/include/asm/mmu_context_64.h | 62 ++++++++++++++++++++++++++++++++-
arch/sparc/include/uapi/asm/mman.h | 1 +
arch/sparc/kernel/sys_sparc_64.c | 17 +++++++++
arch/sparc/mm/init_64.c | 36 +++++++++++++++++++
include/uapi/linux/shm.h | 1 +
7 files changed, 126 insertions(+), 1 deletion(-)
diff --git a/arch/sparc/include/asm/hugetlb.h b/arch/sparc/include/asm/hugetlb.h
index dcbf985..13157b3 100644
--- a/arch/sparc/include/asm/hugetlb.h
+++ b/arch/sparc/include/asm/hugetlb.h
@@ -78,4 +78,8 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb, unsigned long addr,
unsigned long end, unsigned long floor,
unsigned long ceiling);
+#if defined(CONFIG_SHARED_MMU_CTX)
+void huge_get_shared_ctx(struct mm_struct *mm, unsigned long addr);
+#endif
+
#endif /* _ASM_SPARC64_HUGETLB_H */
diff --git a/arch/sparc/include/asm/mman.h b/arch/sparc/include/asm/mman.h
index 59bb593..cbe384e 100644
--- a/arch/sparc/include/asm/mman.h
+++ b/arch/sparc/include/asm/mman.h
@@ -6,5 +6,11 @@
#ifndef __ASSEMBLY__
#define arch_mmap_check(addr,len,flags) sparc_mmap_check(addr,len)
int sparc_mmap_check(unsigned long addr, unsigned long len);
+
+#if defined(CONFIG_SHARED_MMU_CTX)
+#define arch_shmat_check(file, shmflg, flags) \
+ sparc_shmat_check(file, shmflg, flags)
+int sparc_shmat_check(struct file *file, int shmflg, unsigned long *flags);
+#endif
#endif
#endif /* __SPARC_MMAN_H__ */
diff --git a/arch/sparc/include/asm/mmu_context_64.h b/arch/sparc/include/asm/mmu_context_64.h
index 46c2c7e..8ab05f2 100644
--- a/arch/sparc/include/asm/mmu_context_64.h
+++ b/arch/sparc/include/asm/mmu_context_64.h
@@ -7,7 +7,6 @@
#include <linux/spinlock.h>
#include <asm/spitfire.h>
-#include <asm-generic/mm_hooks.h>
static inline void enter_lazy_tlb(struct mm_struct *mm, struct task_struct *tsk)
{
@@ -24,6 +23,13 @@ void put_shared_context(struct mm_struct *mm);
void set_mm_shared_ctx(struct mm_struct *mm, struct shared_mmu_ctx *ctx);
void destroy_shared_context(struct mm_struct *mm);
void set_vma_shared_ctx(struct vm_area_struct *vma);
+void sparc64_exit_mmap(struct mm_struct *mm);
+void sparc64_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long start, unsigned long end);
+unsigned long sparc64_pre_mmap_flags(struct file *file, unsigned long flags,
+ vm_flags_t *vm_flags);
+void sparc64_post_mmap(struct mm_struct *mm, unsigned long addr,
+ vm_flags_t vm_flags);
#endif
#ifdef CONFIG_SMP
void smp_new_mmu_context_version(void);
@@ -208,6 +214,60 @@ static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm
spin_unlock_irqrestore(&mm->context.lock, flags);
}
+#if defined(CONFIG_SHARED_MMU_CTX)
+/*
+ * mm_hooks only needed for CONFIG_SHARED_MMU_CTX
+ */
+static inline unsigned long arch_pre_mmap_flags(struct file *file,
+ unsigned long flags,
+ vm_flags_t *vm_flags)
+{
+ return sparc64_pre_mmap_flags(file, flags, vm_flags);
+}
+
+static inline void arch_post_mmap(struct mm_struct *mm, unsigned long addr,
+ vm_flags_t vm_flags)
+{
+ sparc64_post_mmap(mm, addr, vm_flags);
+}
+
+static inline void arch_dup_mmap(struct mm_struct *oldmm,
+ struct mm_struct *mm)
+{
+}
+
+static inline void arch_exit_mmap(struct mm_struct *mm)
+{
+ sparc64_exit_mmap(mm);
+}
+
+static inline void arch_unmap(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ sparc64_unmap(mm, vma, start, end);
+}
+
+static inline void arch_bprm_mm_init(struct mm_struct *mm,
+ struct vm_area_struct *vma)
+{
+}
+
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool execute, bool foreign)
+{
+ /* by default, allow everything */
+ return true;
+}
+
+static inline bool arch_pte_access_permitted(pte_t pte, bool write)
+{
+ /* by default, allow everything */
+ return true;
+}
+#else
+#include <asm-generic/mm_hooks.h>
+#endif
#endif /* !(__ASSEMBLY__) */
#endif /* !(__SPARC64_MMU_CONTEXT_H) */
diff --git a/arch/sparc/include/uapi/asm/mman.h b/arch/sparc/include/uapi/asm/mman.h
index 9765896..a52c6fe 100644
--- a/arch/sparc/include/uapi/asm/mman.h
+++ b/arch/sparc/include/uapi/asm/mman.h
@@ -23,6 +23,7 @@
#define MAP_NONBLOCK 0x10000 /* do not block on IO */
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x40000 /* create a huge page mapping */
+#define MAP_SHAREDCTX 0x80000 /* request shared cxt mapping */
#endif /* _UAPI__SPARC_MMAN_H__ */
diff --git a/arch/sparc/kernel/sys_sparc_64.c b/arch/sparc/kernel/sys_sparc_64.c
index fe8b8ee..23fa538 100644
--- a/arch/sparc/kernel/sys_sparc_64.c
+++ b/arch/sparc/kernel/sys_sparc_64.c
@@ -25,6 +25,7 @@
#include <linux/random.h>
#include <linux/export.h>
#include <linux/context_tracking.h>
+#include <linux/hugetlb.h>
#include <asm/uaccess.h>
#include <asm/utrap.h>
@@ -444,6 +445,22 @@ int sparc_mmap_check(unsigned long addr, unsigned long len)
return 0;
}
+int sparc_shmat_check(struct file *file, int shmflg, unsigned long *flags)
+{
+ if (shmflg & SHM_SHAREDCTX) {
+ if ((*flags & (MAP_SHARED | MAP_FIXED)) !=
+ (unsigned long)(MAP_SHARED | MAP_FIXED))
+ return -EINVAL;
+
+ if (!is_file_hugepages(file))
+ return -EINVAL;
+
+ *flags |= MAP_SHAREDCTX;
+ }
+
+ return 0;
+}
+
/* Linux version of mmap */
SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags, unsigned long, fd,
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 25ad5bd..0637762 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -27,6 +27,7 @@
#include <linux/memblock.h>
#include <linux/mmzone.h>
#include <linux/gfp.h>
+#include <linux/mman.h>
#include <asm/head.h>
#include <asm/page.h>
@@ -832,6 +833,41 @@ void set_vma_shared_ctx(struct vm_area_struct *vma)
atomic_inc(&mm->context.shared_ctx->refcount);
vma->vm_shared_mmu_ctx.ctx = mm->context.shared_ctx;
}
+
+unsigned long sparc64_pre_mmap_flags(struct file *file, unsigned long flags,
+ vm_flags_t *vm_flags)
+{
+ if (flags & MAP_SHAREDCTX) {
+ /* Must be a shared huge page mapping */
+ if (!(flags & (MAP_SHARED | MAP_FIXED)))
+ return -EINVAL;
+ if (!(flags & MAP_HUGETLB) &&
+ !(file && is_file_hugepages(file)))
+ return -EINVAL;
+
+ *vm_flags |= VM_SHARED_CTX;
+ }
+
+ return 0;
+}
+
+void sparc64_post_mmap(struct mm_struct *mm, unsigned long addr,
+ vm_flags_t vm_flags)
+{
+ if (vm_flags & VM_SHARED_CTX)
+ huge_get_shared_ctx(mm, addr);
+}
+
+void sparc64_exit_mmap(struct mm_struct *mm)
+{
+ put_shared_context(mm);
+}
+
+void sparc64_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
+ unsigned long start, unsigned long end)
+{
+ put_shared_context(mm);
+}
#endif
static int numa_enabled = 1;
diff --git a/include/uapi/linux/shm.h b/include/uapi/linux/shm.h
index 1fbf24e..3373567 100644
--- a/include/uapi/linux/shm.h
+++ b/include/uapi/linux/shm.h
@@ -49,6 +49,7 @@ struct shmid_ds {
#define SHM_RND 020000 /* round attach address to SHMLBA boundary */
#define SHM_REMAP 040000 /* take-over region on attach */
#define SHM_EXEC 0100000 /* execution access */
+#define SHM_SHAREDCTX 0200000 /* share context (TLB entries) if possible */
/* super user shmctl commands */
#define SHM_LOCK 11
--
2.7.4