[RFC PATCH 1/4] x86/sgx: Export sgx_encl_eaug_page

[Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>]

Change return type so it can be reused later for fops->fadvise

Signed-off-by: Haitao Huang <haitao.huang@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/cpu/sgx/encl.c | 46 ++++++++++++++++++++++------------
 arch/x86/kernel/cpu/sgx/encl.h |  3 ++-
 2 files changed, 32 insertions(+), 17 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 8bdeae2fc309..c57e60d5a0aa 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -305,11 +305,11 @@ struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
  * on a SGX2 system then the EPC can be added dynamically via the SGX2
  * ENCLS[EAUG] instruction.
  *
- * Returns: Appropriate vm_fault_t: VM_FAULT_NOPAGE when PTE was installed
- * successfully, VM_FAULT_SIGBUS or VM_FAULT_OOM as error otherwise.
+ * Returns: 0 when PTE was installed successfully, -EBUSY for waiting on
+ * reclaimer to free EPC, -ENOMEM for out of RAM, -EFAULT as error otherwise.
  */
-static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
-				     struct sgx_encl *encl, unsigned long addr)
+int sgx_encl_eaug_page(struct vm_area_struct *vma,
+		       struct sgx_encl *encl, unsigned long addr)
 {
 	vm_fault_t vmret = VM_FAULT_SIGBUS;
 	struct sgx_pageinfo pginfo = {0};
@@ -318,10 +318,10 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
 	struct sgx_va_page *va_page;
 	unsigned long phys_addr;
 	u64 secinfo_flags;
-	int ret;
+	int ret = -EFAULT;
 
 	if (!test_bit(SGX_ENCL_INITIALIZED, &encl->flags))
-		return VM_FAULT_SIGBUS;
+		return -EFAULT;
 
 	/*
 	 * Ignore internal permission checking for dynamically added pages.
@@ -332,21 +332,21 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
 	secinfo_flags = SGX_SECINFO_R | SGX_SECINFO_W | SGX_SECINFO_X;
 	encl_page = sgx_encl_page_alloc(encl, addr - encl->base, secinfo_flags);
 	if (IS_ERR(encl_page))
-		return VM_FAULT_OOM;
+		return -ENOMEM;
 
 	mutex_lock(&encl->lock);
 
 	epc_page = sgx_alloc_epc_page(encl_page, false);
 	if (IS_ERR(epc_page)) {
 		if (PTR_ERR(epc_page) == -EBUSY)
-			vmret =  VM_FAULT_NOPAGE;
+			ret =  -EBUSY;
 		goto err_out_unlock;
 	}
 
 	va_page = sgx_encl_grow(encl, false);
 	if (IS_ERR(va_page)) {
 		if (PTR_ERR(va_page) == -EBUSY)
-			vmret = VM_FAULT_NOPAGE;
+			ret = -EBUSY;
 		goto err_out_epc;
 	}
 
@@ -359,16 +359,20 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
 	 * If ret == -EBUSY then page was created in another flow while
 	 * running without encl->lock
 	 */
-	if (ret)
+	if (ret) {
+		ret = -EFAULT;
 		goto err_out_shrink;
+	}
 
 	pginfo.secs = (unsigned long)sgx_get_epc_virt_addr(encl->secs.epc_page);
 	pginfo.addr = encl_page->desc & PAGE_MASK;
 	pginfo.metadata = 0;
 
 	ret = __eaug(&pginfo, sgx_get_epc_virt_addr(epc_page));
-	if (ret)
+	if (ret) {
+		ret = -EFAULT;
 		goto err_out;
+	}
 
 	encl_page->encl = encl;
 	encl_page->epc_page = epc_page;
@@ -385,10 +389,10 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
 	vmret = vmf_insert_pfn(vma, addr, PFN_DOWN(phys_addr));
 	if (vmret != VM_FAULT_NOPAGE) {
 		mutex_unlock(&encl->lock);
-		return VM_FAULT_SIGBUS;
+		return -EFAULT;
 	}
 	mutex_unlock(&encl->lock);
-	return VM_FAULT_NOPAGE;
+	return 0;
 
 err_out:
 	xa_erase(&encl->page_array, PFN_DOWN(encl_page->desc));
@@ -401,7 +405,7 @@ static vm_fault_t sgx_encl_eaug_page(struct vm_area_struct *vma,
 	mutex_unlock(&encl->lock);
 	kfree(encl_page);
 
-	return vmret;
+	return ret;
 }
 
 static vm_fault_t sgx_vma_fault(struct vm_fault *vmf)
@@ -431,8 +435,18 @@ static vm_fault_t sgx_vma_fault(struct vm_fault *vmf)
 	 * enclave that will be checked for right away.
 	 */
 	if (cpu_feature_enabled(X86_FEATURE_SGX2) &&
-	    (!xa_load(&encl->page_array, PFN_DOWN(addr))))
-		return sgx_encl_eaug_page(vma, encl, addr);
+	    (!xa_load(&encl->page_array, PFN_DOWN(addr)))) {
+		switch (sgx_encl_eaug_page(vma, encl, addr)) {
+		case 0:
+		case -EBUSY:
+			return VM_FAULT_NOPAGE;
+		case -ENOMEM:
+			return VM_FAULT_OOM;
+		case -EFAULT:
+		default:
+			return VM_FAULT_SIGBUS;
+		}
+	}
 
 	mutex_lock(&encl->lock);
 
diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h
index a65a952116fd..36059d35e1bc 100644
--- a/arch/x86/kernel/cpu/sgx/encl.h
+++ b/arch/x86/kernel/cpu/sgx/encl.h
@@ -127,5 +127,6 @@ struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl,
 					 unsigned long addr);
 struct sgx_va_page *sgx_encl_grow(struct sgx_encl *encl, bool reclaim);
 void sgx_encl_shrink(struct sgx_encl *encl, struct sgx_va_page *va_page);
-
+int sgx_encl_eaug_page(struct vm_area_struct *vma,
+		       struct sgx_encl *encl, unsigned long addr);
 #endif /* _X86_ENCL_H */
-- 
2.25.1