Messages in this thread Patch in this message | | | Date | Wed, 23 Nov 2005 15:09:14 GMT | From | David Howells <> | Subject | [PATCH 3/3] FRV: Make futex code compilable on nommu |
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The attached patch makes the futex code compilable on nommu by making the attempt to handle page faults conditional on CONFIG_MMU. If this is not enabled, then we can assume that EFAULT returned from futex_atomic_op_inuser() is not recoverable, and that the address lies outside of valid memory.
Signed-Off-By: David Howells <dhowells@redhat.com> --- warthog>diffstat -p1 frv-futex-2615rc2.diff include/linux/mm.h | 3 +++ kernel/futex.c | 18 +++++++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-)
diff -uNrp /warthog/kernels/linux-2.6.15-rc2/include/linux/mm.h linux-2.6.15-rc2-frv/include/linux/mm.h --- /warthog/kernels/linux-2.6.15-rc2/include/linux/mm.h 2005-11-23 12:09:22.000000000 +0000 +++ linux-2.6.15-rc2-frv/include/linux/mm.h 2005-11-23 13:29:08.000000000 +0000 @@ -708,12 +708,15 @@ static inline void unmap_shared_mapping_ extern int vmtruncate(struct inode * inode, loff_t offset); extern int install_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, struct page *page, pgprot_t prot); extern int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, unsigned long pgoff, pgprot_t prot); + +#ifdef CONFIG_MMU extern int __handle_mm_fault(struct mm_struct *mm,struct vm_area_struct *vma, unsigned long address, int write_access); static inline int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, int write_access) { return __handle_mm_fault(mm, vma, address, write_access) & (~VM_FAULT_WRITE); } +#endif extern int make_pages_present(unsigned long addr, unsigned long end); extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write); diff -uNrp /warthog/kernels/linux-2.6.15-rc2/kernel/futex.c linux-2.6.15-rc2-frv/kernel/futex.c --- /warthog/kernels/linux-2.6.15-rc2/kernel/futex.c 2005-11-23 12:09:23.000000000 +0000 +++ linux-2.6.15-rc2-frv/kernel/futex.c 2005-11-23 13:41:33.000000000 +0000 @@ -335,9 +335,14 @@ static int futex_wake_op(unsigned long u struct futex_hash_bucket *bh1, *bh2; struct list_head *head; struct futex_q *this, *next; - int ret, op_ret, attempt = 0; + int ret, op_ret; +#ifdef CONFIG_MMU + int attempt = 0; +#endif +#ifdef CONFIG_MMU retryfull: +#endif down_read(¤t->mm->mmap_sem); ret = get_futex_key(uaddr1, &key1); @@ -350,7 +355,9 @@ retryfull: bh1 = hash_futex(&key1); bh2 = hash_futex(&key2); +#ifdef CONFIG_MMU retry: +#endif if (bh1 < bh2) spin_lock(&bh1->lock); spin_lock(&bh2->lock); @@ -359,12 +366,15 @@ retry: op_ret = futex_atomic_op_inuser(op, (int __user *)uaddr2); if (unlikely(op_ret < 0)) { +#ifdef CONFIG_MMU int dummy; +#endif spin_unlock(&bh1->lock); if (bh1 != bh2) spin_unlock(&bh2->lock); +#ifdef CONFIG_MMU if (unlikely(op_ret != -EFAULT)) { ret = op_ret; goto out; @@ -408,6 +418,12 @@ retry: return ret; goto retryfull; + +#else + /* we don't get EFAULT from MMU faults if we don't have an MMU, + * but we might get them from range checking */ + goto out; +#endif } head = &bh1->chain; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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