Add VMA callbacks for ptrace() that can be used with debug enclaves.
With debug enclaves data can be read and write the memory word at a time
by using ENCLS(EDBGRD) and ENCLS(EDBGWR) leaf instructions.
Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
---
arch/x86/kernel/cpu/sgx/encl.c | 97 ++++++++++++++++++++++++++++++++++
1 file changed, 97 insertions(+)
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c
index 1b8874699dd3..5b5fc933ee19 100644
--- a/arch/x86/kernel/cpu/sgx/encl.c
+++ b/arch/x86/kernel/cpu/sgx/encl.c
@@ -256,10 +256,107 @@ static unsigned int sgx_vma_fault(struct vm_fault *vmf)
return ret;
}
+static int sgx_edbgrd(struct sgx_encl *encl, struct sgx_encl_page *page,
+ unsigned long addr, void *data)
+{
+ unsigned long offset;
+ int ret;
+
+ offset = addr & ~PAGE_MASK;
+
+ if ((page->desc & SGX_ENCL_PAGE_TCS) &&
+ offset > offsetof(struct sgx_tcs, gs_limit))
+ return -ECANCELED;
+
+ ret = __edbgrd(sgx_epc_addr(page->epc_page) + offset, data);
+ if (ret)
+ return -EIO;
+
+ return 0;
+}
+
+static int sgx_edbgwr(struct sgx_encl *encl, struct sgx_encl_page *page,
+ unsigned long addr, void *data)
+{
+ unsigned long offset;
+ int ret;
+
+ offset = addr & ~PAGE_MASK;
+
+ /* Writing anything else than flags will cause #GP */
+ if ((page->desc & SGX_ENCL_PAGE_TCS) &&
+ offset != offsetof(struct sgx_tcs, flags))
+ return -ECANCELED;
+
+ ret = __edbgwr(sgx_epc_addr(page->epc_page) + offset, data);
+ if (ret)
+ return -EIO;
+
+ return 0;
+}
+
+static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr,
+ void *buf, int len, int write)
+{
+ struct sgx_encl *encl = vma->vm_private_data;
+ struct sgx_encl_page *entry = NULL;
+ unsigned long align;
+ char data[sizeof(unsigned long)];
+ int offset;
+ int cnt;
+ int ret = 0;
+ int i;
+
+ /* If process was forked, VMA is still there but vm_private_data is set
+ * to NULL.
+ */
+ if (!encl)
+ return -EFAULT;
+
+ if (!(encl->flags & SGX_ENCL_DEBUG) ||
+ !(encl->flags & SGX_ENCL_INITIALIZED) ||
+ (encl->flags & SGX_ENCL_DEAD))
+ return -EFAULT;
+
+ for (i = 0; i < len; i += cnt) {
+ entry = sgx_encl_reserve_page(encl, (addr + i) & PAGE_MASK);
+ if (IS_ERR(entry)) {
+ ret = PTR_ERR(entry);
+ break;
+ }
+
+ align = ALIGN_DOWN(addr + i, sizeof(unsigned long));
+ offset = (addr + i) & (sizeof(unsigned long) - 1);
+ cnt = sizeof(unsigned long) - offset;
+ cnt = min(cnt, len - i);
+
+ ret = sgx_edbgrd(encl, entry, align, data);
+ if (ret)
+ goto out;
+
+ if (write) {
+ memcpy(data + offset, buf + i, cnt);
+ ret = sgx_edbgwr(encl, entry, align, data);
+ if (ret)
+ goto out;
+ } else
+ memcpy(buf + i, data + offset, cnt);
+
+out:
+ mutex_unlock(&encl->lock);
+
+ if (ret)
+ break;
+ }
+
+ return ret < 0 ? ret : i;
+}
+
const struct vm_operations_struct sgx_vm_ops = {
.close = sgx_vma_close,
.open = sgx_vma_open,
.fault = sgx_vma_fault,
+ .access = sgx_vma_access,
};
EXPORT_SYMBOL_GPL(sgx_vm_ops);
--
2.19.1
