On Mon, Mar 02, 2015 at 10:58:23AM -0800, Yinghai Lu wrote:
> On Mon, Mar 2, 2015 at 6:53 AM, Borislav Petkov <bp@xxxxxxx> wrote:
> > Well, it seems to work here but it still doesn't look reliable enough to
> > me. And this addon_zo thing of arbitrary 256K is strange.
>
> Thanks for check that out.
>
> That is not arbitrary number. Need to make that bigger than _end - _rodata
>
> > objdump -t arch/x86/boot/compressed/vmlinux | grep \ _end
> 0000000000996000 g .pgtable 0000000000000000 _end
> > objdump -t arch/x86/boot/compressed/vmlinux | grep \ _rodata
> 0000000000981780 g .rodata 0000000000000000 _rodata
>
> We only get that size after arch/x86/boot/compressed/vmlinux
>
> but need number during building kernel vmlinux.
>
> other way would be just increase init_size in arch/x86/boot/header.S
> instead of put it BRK area.
Ok, I'll take a look at this more tomorrow, on a clear head, but why
can't we make a special, explicit section which is not touched by
the early decompression and relocation code and which we can use for
setup_data only?
IOW, something like that although that doesn't work yet:
---
diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index 7083c16cccba..01d5ddf1d22f 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -14,12 +14,12 @@
static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@"
LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION;
-struct kaslr_setup_data {
- __u64 next;
- __u32 type;
- __u32 len;
- __u8 data[1];
-} kaslr_setup_data;
+extern char _setup_data[];
+struct setup_data __attribute__((section (".setup_data"))) ksd = {
+ .type = SETUP_KASLR,
+ .len = 1,
+ .next = 0,
+};
#define I8254_PORT_CONTROL 0x43
#define I8254_PORT_COUNTER0 0x40
@@ -306,10 +306,7 @@ static void add_kaslr_setup_data(struct boot_params *params, __u8 enabled)
{
struct setup_data *data;
- kaslr_setup_data.type = SETUP_KASLR;
- kaslr_setup_data.len = 1;
- kaslr_setup_data.next = 0;
- kaslr_setup_data.data[0] = enabled;
+ ksd.data[0] = enabled;
data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
@@ -317,10 +314,9 @@ static void add_kaslr_setup_data(struct boot_params *params, __u8 enabled)
data = (struct setup_data *)(unsigned long)data->next;
if (data)
- data->next = (unsigned long)&kaslr_setup_data;
+ data->next = (unsigned long)&ksd;
else
- params->hdr.setup_data = (unsigned long)&kaslr_setup_data;
-
+ params->hdr.setup_data = (unsigned long)&ksd;
}
unsigned char *choose_kernel_location(struct boot_params *params,
diff --git a/arch/x86/boot/compressed/vmlinux.lds.S b/arch/x86/boot/compressed/vmlinux.lds.S
index 34d047c98284..26d62f4b27b9 100644
--- a/arch/x86/boot/compressed/vmlinux.lds.S
+++ b/arch/x86/boot/compressed/vmlinux.lds.S
@@ -29,6 +29,10 @@ SECTIONS
.rodata..compressed : {
*(.rodata..compressed)
}
+ .setup_data : {
+ _setup_data = . ;
+ *(.setup_data)
+ }
.text : {
_text = .; /* Text */
*(.text)
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 98dc9317286e..0978c61f84bd 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -429,7 +429,11 @@ static void __init reserve_initrd(void)
static void __init parse_kaslr_setup(u64 pa_data, u32 data_len)
{
- kaslr_enabled = (bool)(pa_data + sizeof(struct setup_data));
+ struct setup_data *kdata;
+
+ kdata = early_memremap(pa_data, data_len);
+ kaslr_enabled = kdata->data[0];
+ early_iounmap(kdata, data_len);
}
static void __init parse_setup_data(void)
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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