[tip: x86/boot] x86/boot: Introduce setup_indirect
From: tip-bot2 for Daniel Kiper
Date: Tue Nov 12 2019 - 12:54:28 EST
The following commit has been merged into the x86/boot branch of tip:
Commit-ID: b3c72fc9a78e74161f9d05ef7191706060628f8c
Gitweb: https://git.kernel.org/tip/b3c72fc9a78e74161f9d05ef7191706060628f8c
Author: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
AuthorDate: Tue, 12 Nov 2019 14:46:40 +01:00
Committer: Borislav Petkov <bp@xxxxxxx>
CommitterDate: Tue, 12 Nov 2019 16:21:15 +01:00
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) <hpa@xxxxxxxxx>
Signed-off-by: Daniel Kiper <daniel.kiper@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Reviewed-by: Ross Philipson <ross.philipson@xxxxxxxxxx>
Reviewed-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: ard.biesheuvel@xxxxxxxxxx
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Cc: dave.hansen@xxxxxxxxxxxxxxx
Cc: eric.snowberg@xxxxxxxxxx
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: kanth.ghatraju@xxxxxxxxxx
Cc: linux-doc@xxxxxxxxxxxxxxx
Cc: linux-efi <linux-efi@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: rdunlap@xxxxxxxxxxxxx
Cc: ross.philipson@xxxxxxxxxx
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: x86-ml <x86@xxxxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20191112134640.16035-4-daniel.kiper@xxxxxxxxxx
---
Documentation/x86/boot.rst | 43 ++++++++++++++++++++++++-
arch/x86/boot/compressed/kaslr.c | 12 +++++++-
arch/x86/boot/compressed/kernel_info.S | 2 +-
arch/x86/boot/header.S | 2 +-
arch/x86/include/uapi/asm/bootparam.h | 16 +++++++--
arch/x86/kernel/e820.c | 11 ++++++-
arch/x86/kernel/kdebugfs.c | 21 +++++++++---
arch/x86/kernel/ksysfs.c | 31 +++++++++++++-----
arch/x86/kernel/setup.c | 6 +++-
arch/x86/mm/ioremap.c | 11 ++++++-
10 files changed, 138 insertions(+), 17 deletions(-)
diff --git a/Documentation/x86/boot.rst b/Documentation/x86/boot.rst
index 6cdd767..90bb8f5 100644
--- a/Documentation/x86/boot.rst
+++ b/Documentation/x86/boot.rst
@@ -827,6 +827,47 @@ Protocol: 2.09+
sure to consider the case where the linked list already contains
entries.
+ 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 setup_indirect struct and SETUP_INDIRECT type were introduced in
+ protocol 2.15.
+
+ struct setup_indirect {
+ __u32 type;
+ __u32 reserved; /* Reserved, must be set to zero. */
+ __u64 len;
+ __u64 addr;
+ };
+
+ The type member is a SETUP_INDIRECT | SETUP_* type. However, it cannot be
+ SETUP_INDIRECT itself since making the setup_indirect a tree structure
+ could require a lot of stack space in something that needs to parse it
+ and stack space can be limited in boot contexts.
+
+ Let's give an example how to point to SETUP_E820_EXT data using setup_indirect.
+ In this case setup_data and setup_indirect will look like this:
+
+ struct setup_data {
+ __u64 next = 0 or <addr_of_next_setup_data_struct>;
+ __u32 type = SETUP_INDIRECT;
+ __u32 len = sizeof(setup_data);
+ __u8 data[sizeof(setup_indirect)] = struct setup_indirect {
+ __u32 type = SETUP_INDIRECT | SETUP_E820_EXT;
+ __u32 reserved = 0;
+ __u64 len = <len_of_SETUP_E820_EXT_data>;
+ __u64 addr = <addr_of_SETUP_E820_EXT_data>;
+ }
+ }
+
+.. note::
+ SETUP_INDIRECT | SETUP_NONE objects cannot be properly distinguished
+ from SETUP_INDIRECT itself. So, this kind of objects cannot be provided
+ by the bootloaders.
+
============ ============
Field name: pref_address
Type: read (reloc)
@@ -986,7 +1027,7 @@ Field name: setup_type_max
Offset/size: 0x000c/4
============ ==============
- This field contains maximal allowed type for setup_data.
+ This field contains maximal allowed type for setup_data and setup_indirect structs.
The Image Checksum
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 2e53c05..bb9bfef 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -459,6 +459,18 @@ static bool mem_avoid_overlap(struct mem_vector *img,
is_overlapping = true;
}
+ if (ptr->type == SETUP_INDIRECT &&
+ ((struct setup_indirect *)ptr->data)->type != SETUP_INDIRECT) {
+ avoid.start = ((struct setup_indirect *)ptr->data)->addr;
+ avoid.size = ((struct setup_indirect *)ptr->data)->len;
+
+ if (mem_overlaps(img, &avoid) && (avoid.start < earliest)) {
+ *overlap = avoid;
+ earliest = overlap->start;
+ is_overlapping = true;
+ }
+ }
+
ptr = (struct setup_data *)(unsigned long)ptr->next;
}
diff --git a/arch/x86/boot/compressed/kernel_info.S b/arch/x86/boot/compressed/kernel_info.S
index 018dacb..f818ee8 100644
--- a/arch/x86/boot/compressed/kernel_info.S
+++ b/arch/x86/boot/compressed/kernel_info.S
@@ -14,7 +14,7 @@ kernel_info:
/* Size total. */
.long kernel_info_end - kernel_info
- /* Maximal allowed type for setup_data. */
+ /* Maximal allowed type for setup_data and setup_indirect structs. */
.long SETUP_TYPE_MAX
kernel_info_var_len_data:
diff --git a/arch/x86/boot/header.S b/arch/x86/boot/header.S
index 22dceca..97d9b6d 100644
--- a/arch/x86/boot/header.S
+++ b/arch/x86/boot/header.S
@@ -300,7 +300,7 @@ _start:
# Part 2 of the header, from the old setup.S
.ascii "HdrS" # header signature
- .word 0x020d # header version number (>= 0x0105)
+ .word 0x020f # header version number (>= 0x0105)
# or else old loadlin-1.5 will fail)
.globl realmode_swtch
realmode_swtch: .word 0, 0 # default_switch, SETUPSEG
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index dbb4112..949066b 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -2,7 +2,7 @@
#ifndef _ASM_X86_BOOTPARAM_H
#define _ASM_X86_BOOTPARAM_H
-/* setup_data types */
+/* setup_data/setup_indirect types */
#define SETUP_NONE 0
#define SETUP_E820_EXT 1
#define SETUP_DTB 2
@@ -11,8 +11,10 @@
#define SETUP_APPLE_PROPERTIES 5
#define SETUP_JAILHOUSE 6
-/* max(SETUP_*) */
-#define SETUP_TYPE_MAX SETUP_JAILHOUSE
+#define SETUP_INDIRECT (1<<31)
+
+/* SETUP_INDIRECT | max(SETUP_*) */
+#define SETUP_TYPE_MAX (SETUP_INDIRECT | SETUP_JAILHOUSE)
/* ram_size flags */
#define RAMDISK_IMAGE_START_MASK 0x07FF
@@ -52,6 +54,14 @@ struct setup_data {
__u8 data[0];
};
+/* extensible setup indirect data node */
+struct setup_indirect {
+ __u32 type;
+ __u32 reserved; /* Reserved, must be set to zero. */
+ __u64 len;
+ __u64 addr;
+};
+
struct setup_header {
__u8 setup_sects;
__u16 root_flags;
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 7da2bcd..0bfe9a6 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -999,6 +999,17 @@ void __init e820__reserve_setup_data(void)
data = early_memremap(pa_data, sizeof(*data));
e820__range_update(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
e820__range_update_kexec(pa_data, sizeof(*data)+data->len, E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
+
+ if (data->type == SETUP_INDIRECT &&
+ ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
+ e820__range_update(((struct setup_indirect *)data->data)->addr,
+ ((struct setup_indirect *)data->data)->len,
+ E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
+ e820__range_update_kexec(((struct setup_indirect *)data->data)->addr,
+ ((struct setup_indirect *)data->data)->len,
+ E820_TYPE_RAM, E820_TYPE_RESERVED_KERN);
+ }
+
pa_data = data->next;
early_memunmap(data, sizeof(*data));
}
diff --git a/arch/x86/kernel/kdebugfs.c b/arch/x86/kernel/kdebugfs.c
index edaa30b..64b6da9 100644
--- a/arch/x86/kernel/kdebugfs.c
+++ b/arch/x86/kernel/kdebugfs.c
@@ -44,7 +44,12 @@ static ssize_t setup_data_read(struct file *file, char __user *user_buf,
if (count > node->len - pos)
count = node->len - pos;
- pa = node->paddr + sizeof(struct setup_data) + pos;
+ pa = node->paddr + pos;
+
+ /* Is it direct data or invalid indirect one? */
+ if (!(node->type & SETUP_INDIRECT) || node->type == SETUP_INDIRECT)
+ pa += sizeof(struct setup_data);
+
p = memremap(pa, count, MEMREMAP_WB);
if (!p)
return -ENOMEM;
@@ -108,9 +113,17 @@ static int __init create_setup_data_nodes(struct dentry *parent)
goto err_dir;
}
- node->paddr = pa_data;
- node->type = data->type;
- node->len = data->len;
+ if (data->type == SETUP_INDIRECT &&
+ ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT) {
+ node->paddr = ((struct setup_indirect *)data->data)->addr;
+ node->type = ((struct setup_indirect *)data->data)->type;
+ node->len = ((struct setup_indirect *)data->data)->len;
+ } else {
+ node->paddr = pa_data;
+ node->type = data->type;
+ node->len = data->len;
+ }
+
create_setup_data_node(d, no, node);
pa_data = data->next;
diff --git a/arch/x86/kernel/ksysfs.c b/arch/x86/kernel/ksysfs.c
index 7969da9..d0a1912 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;
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 77ea96b..8f48bb8 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -438,6 +438,12 @@ static void __init memblock_x86_reserve_range_setup_data(void)
while (pa_data) {
data = early_memremap(pa_data, sizeof(*data));
memblock_reserve(pa_data, sizeof(*data) + data->len);
+
+ if (data->type == SETUP_INDIRECT &&
+ ((struct setup_indirect *)data->data)->type != SETUP_INDIRECT)
+ memblock_reserve(((struct setup_indirect *)data->data)->addr,
+ ((struct setup_indirect *)data->data)->len);
+
pa_data = data->next;
early_memunmap(data, sizeof(*data));
}
diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index a39dcdb..1ff9c20 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -626,6 +626,17 @@ static bool memremap_is_setup_data(resource_size_t phys_addr,
paddr_next = data->next;
len = data->len;
+ if ((phys_addr > paddr) && (phys_addr < (paddr + len))) {
+ memunmap(data);
+ return true;
+ }
+
+ 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;
+ }
+
memunmap(data);
if ((phys_addr > paddr) && (phys_addr < (paddr + len)))