x86/boot: Introduce setup_indirect

The setup_data is a bit awkward to use for extremely large data objects,
both because the setup_data header has to be adjacent to the data object
and because it has a 32-bit length field. However, it is important that
intermediate stages of the boot process have a way to identify which
chunks of memory are occupied by kernel data. Thus introduce an uniform
way to specify such indirect data as setup_indirect struct and
SETUP_INDIRECT type.

And finally bump setup_header version in arch/x86/boot/header.S.

Suggested-by: H. Peter Anvin (Intel) <[email protected]>
Signed-off-by: Daniel Kiper <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Ross Philipson <[email protected]>
Reviewed-by: H. Peter Anvin (Intel) <[email protected]>
Acked-by: Konrad Rzeszutek Wilk <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: [email protected]
Cc: Boris Ostrovsky <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Ingo Molnar <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: linux-efi <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: Thomas Gleixner <[email protected]>
Cc: x86-ml <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]

1 files changed, 24 insertions, 7 deletions

diff --git a/arch/x86/kernel/ksysfs.c b/arch/x86/kernel/ksysfs.c
index 7969da939213..d0a19121c6a4 100644
--- a/arch/x86/kernel/ksysfs.c
+++ b/arch/x86/kernel/ksysfs.c
@@ -100,7 +100,12 @@ static int __init get_setup_data_size(int nr, size_t *size)
 		if (!data)
 			return -ENOMEM;
 		if (nr == i) {
-			*size = data->len;
+			if (data->type == SETUP_INDIRECT &&
+			    ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT)
+				*size = ((struct setup_indirect *)data->data)->len;
+			else
+				*size = data->len;
+
 			memunmap(data);
 			return 0;
 		}
@@ -130,7 +135,10 @@ static ssize_t type_show(struct kobject *kobj,
 	if (!data)
 		return -ENOMEM;
 
-	ret = sprintf(buf, "0x%x\n", data->type);
+	if (data->type == SETUP_INDIRECT)
+		ret = sprintf(buf, "0x%x\n", ((struct setup_indirect *)data->data)->type);
+	else
+		ret = sprintf(buf, "0x%x\n", data->type);
 	memunmap(data);
 	return ret;
 }
@@ -142,7 +150,7 @@ static ssize_t setup_data_data_read(struct file *fp,
 				    loff_t off, size_t count)
 {
 	int nr, ret = 0;
-	u64 paddr;
+	u64 paddr, len;
 	struct setup_data *data;
 	void *p;
 
@@ -157,19 +165,28 @@ static ssize_t setup_data_data_read(struct file *fp,
 	if (!data)
 		return -ENOMEM;
 
-	if (off > data->len) {
+	if (data->type == SETUP_INDIRECT &&
+	    ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
+		paddr = ((struct setup_indirect *)data->data)->addr;
+		len = ((struct setup_indirect *)data->data)->len;
+	} else {
+		paddr += sizeof(*data);
+		len = data->len;
+	}
+
+	if (off > len) {
 		ret = -EINVAL;
 		goto out;
 	}
 
-	if (count > data->len - off)
-		count = data->len - off;
+	if (count > len - off)
+		count = len - off;
 
 	if (!count)
 		goto out;
 
 	ret = count;
-	p = memremap(paddr + sizeof(*data), data->len, MEMREMAP_WB);
+	p = memremap(paddr, len, MEMREMAP_WB);
 	if (!p) {
 		ret = -ENOMEM;
 		goto out;