Building a VDSO32 on a 64 bits kernel is problematic when some
system headers are included. See commit 8c59ab839f52 ("lib/vdso:
Enable common headers") for more details.
Minimise the amount of headers by moving needed items into
dedicated common headers.
For PAGE_SIZE and PAGE_MASK, redefine them from CONFIG_PAGE_SHIFT
in the same way as commit cffaefd15a8f ("vdso: Use CONFIG_PAGE_SHIFT
in vdso/datapage.h")
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/x86/include/asm/pvclock.h | 1 +
include/vdso/helpers.h | 1 +
lib/vdso/getrandom.c | 15 ++++++++-------
3 files changed, 10 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
index 0c92db84469d..6e4f8fae3ce9 100644
--- a/arch/x86/include/asm/pvclock.h
+++ b/arch/x86/include/asm/pvclock.h
@@ -5,6 +5,7 @@
#include <asm/clocksource.h>
#include <asm/pvclock-abi.h>
+struct timespec64;
/* some helper functions for xen and kvm pv clock sources */
u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
u64 pvclock_clocksource_read_nowd(struct pvclock_vcpu_time_info *src);
diff --git a/include/vdso/helpers.h b/include/vdso/helpers.h
index 73501149439d..3ddb03bb05cb 100644
--- a/include/vdso/helpers.h
+++ b/include/vdso/helpers.h
@@ -4,6 +4,7 @@
#ifndef __ASSEMBLY__
+#include <asm/barrier.h>
#include <vdso/datapage.h>
static __always_inline u32 vdso_read_begin(const struct vdso_data *vd)
diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c
index b230f0b10832..cab153c5f9be 100644
--- a/lib/vdso/getrandom.c
+++ b/lib/vdso/getrandom.c
@@ -3,15 +3,13 @@
* Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
-#include <linux/cache.h>
-#include <linux/kernel.h>
-#include <linux/time64.h>
+#include <linux/minmax.h>
#include <vdso/datapage.h>
#include <vdso/getrandom.h>
+#include <vdso/unaligned.h>
#include <asm/vdso/getrandom.h>
-#include <asm/vdso/vsyscall.h>
-#include <asm/unaligned.h>
#include <uapi/linux/mman.h>
+#include <uapi/linux/random.h>
#define MEMCPY_AND_ZERO_SRC(type, dst, src, len) do { \
while (len >= sizeof(type)) { \
@@ -23,6 +21,9 @@
} \
} while (0)
+#define _PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
+#define _PAGE_MASK (~(_PAGE_SIZE - 1))
+
static void memcpy_and_zero_src(void *dst, void *src, size_t len)
{
if (IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)) {
@@ -64,7 +65,7 @@ static __always_inline ssize_t
__cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_t len,
unsigned int flags, void *opaque_state, size_t opaque_len)
{
- ssize_t ret = min_t(size_t, INT_MAX & PAGE_MASK /* = MAX_RW_COUNT */, len);
+ ssize_t ret = min_t(size_t, INT_MAX & _PAGE_MASK /* = MAX_RW_COUNT */, len);
struct vgetrandom_state *state = opaque_state;
size_t batch_len, nblocks, orig_len = len;
bool in_use, have_retried = false;
@@ -82,7 +83,7 @@ __cvdso_getrandom_data(const struct vdso_rng_data *rng_info, void *buffer, size_
}
/* The state must not straddle a page, since pages can be zeroed at any time. */
- if (unlikely(((unsigned long)opaque_state & ~PAGE_MASK) + sizeof(*state) > PAGE_SIZE))
+ if (unlikely(((unsigned long)opaque_state & ~_PAGE_MASK) + sizeof(*state) > _PAGE_SIZE))
return -EFAULT;
/* If the caller passes the wrong size, which might happen due to CRIU, fallback. */
--
2.44.0On Thu, Aug 22, 2024 at 09:13:10AM +0200, Christophe Leroy wrote:
> diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
> index 0c92db84469d..6e4f8fae3ce9 100644
> --- a/arch/x86/include/asm/pvclock.h
> +++ b/arch/x86/include/asm/pvclock.h
> @@ -5,6 +5,7 @@
> #include <asm/clocksource.h>
> #include <asm/pvclock-abi.h>
>
> +struct timespec64;
> /* some helper functions for xen and kvm pv clock sources */
> u64 pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
> u64 pvclock_clocksource_read_nowd(struct pvclock_vcpu_time_info *src);
This change isn't mentioned in the commit message and could probably
benefit from doing so.
> diff --git a/lib/vdso/getrandom.c b/lib/vdso/getrandom.c
> index b230f0b10832..cab153c5f9be 100644
> --- a/lib/vdso/getrandom.c
> +++ b/lib/vdso/getrandom.c
> @@ -3,15 +3,13 @@
> * Copyright (C) 2022-2024 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
> */
>
> -#include <linux/cache.h>
> -#include <linux/kernel.h>
> -#include <linux/time64.h>
> +#include <linux/minmax.h>
> #include <vdso/datapage.h>
> #include <vdso/getrandom.h>
> +#include <vdso/unaligned.h>
Ah, that's where you do it. Ignore my comment on the previous commit,
then.
> #include <asm/vdso/getrandom.h>
> -#include <asm/vdso/vsyscall.h>
> -#include <asm/unaligned.h>
> #include <uapi/linux/mman.h>
> +#include <uapi/linux/random.h>
>
> #define MEMCPY_AND_ZERO_SRC(type, dst, src, len) do { \
> while (len >= sizeof(type)) { \
> @@ -23,6 +21,9 @@
> } \
> } while (0)
>
> +#define _PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
> +#define _PAGE_MASK (~(_PAGE_SIZE - 1))
If PAGE_SIZE isn't defined at this point, why not just call it PAGE_SIZE
instead of _PAGE_SIZE? But if that's the case, why not put the vdso
definition of PAGE_SIZE into some vdso header included by this file?
Le 26/08/2024 à 10:07, Jason A. Donenfeld a écrit :
> On Thu, Aug 22, 2024 at 09:13:10AM +0200, Christophe Leroy wrote:
>>
>> +#define _PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
>> +#define _PAGE_MASK (~(_PAGE_SIZE - 1))
>
> If PAGE_SIZE isn't defined at this point, why not just call it PAGE_SIZE
> instead of _PAGE_SIZE? But if that's the case, why not put the vdso
> definition of PAGE_SIZE into some vdso header included by this file?
It was working ok on powerpc but on x86 I got:
CC arch/x86/entry/vdso/vgetrandom.o
In file included from arch/x86/entry/vdso/vgetrandom.c:7:
arch/x86/entry/vdso/../../../../lib/vdso/getrandom.c:24: error:
"PAGE_SIZE" redefined [-Werror]
24 | #define PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
|
In file included from ./arch/x86/include/asm/page.h:9,
from ./arch/x86/include/asm/thread_info.h:12,
from ./include/linux/thread_info.h:60,
from ./include/linux/smp.h:118,
from ./include/linux/alloc_tag.h:14,
from ./include/linux/percpu.h:5,
from ./arch/x86/include/asm/msr.h:15,
from ./arch/x86/include/asm/vdso/gettimeofday.h:19,
from ./include/vdso/datapage.h:164,
from
arch/x86/entry/vdso/../../../../lib/vdso/getrandom.c:7,
from arch/x86/entry/vdso/vgetrandom.c:7:
./arch/x86/include/asm/page_types.h:11: note: this is the location of
the previous definition
11 | #define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT)
|
In file included from arch/x86/entry/vdso/vgetrandom.c:7:
arch/x86/entry/vdso/../../../../lib/vdso/getrandom.c:25: error:
"PAGE_MASK" redefined [-Werror]
25 | #define PAGE_MASK (~(PAGE_SIZE - 1))
|
In file included from ./arch/x86/include/asm/page.h:9,
from ./arch/x86/include/asm/thread_info.h:12,
from ./include/linux/thread_info.h:60,
from ./include/linux/smp.h:118,
from ./include/linux/alloc_tag.h:14,
from ./include/linux/percpu.h:5,
from ./arch/x86/include/asm/msr.h:15,
from ./arch/x86/include/asm/vdso/gettimeofday.h:19,
from ./include/vdso/datapage.h:164,
from
arch/x86/entry/vdso/../../../../lib/vdso/getrandom.c:7,
from arch/x86/entry/vdso/vgetrandom.c:7:
./arch/x86/include/asm/page_types.h:12: note: this is the location of
the previous definition
12 | #define PAGE_MASK (~(PAGE_SIZE-1))
|
cc1: all warnings being treated as errors
Christophe
On Mon, Aug 26, 2024 at 10:37:49AM +0200, Christophe Leroy wrote: > > > Le 26/08/2024 à 10:07, Jason A. Donenfeld a écrit : > > On Thu, Aug 22, 2024 at 09:13:10AM +0200, Christophe Leroy wrote: > >> > >> +#define _PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT) > >> +#define _PAGE_MASK (~(_PAGE_SIZE - 1)) > > > > If PAGE_SIZE isn't defined at this point, why not just call it PAGE_SIZE > > instead of _PAGE_SIZE? But if that's the case, why not put the vdso > > definition of PAGE_SIZE into some vdso header included by this file? > > It was working ok on powerpc but on x86 I got: Seems like there might be some more fiddling to do, then? Or did you conclude it's impossible?
Le 26/08/2024 à 10:58, Jason A. Donenfeld a écrit :
> On Mon, Aug 26, 2024 at 10:37:49AM +0200, Christophe Leroy wrote:
>>
>>
>> Le 26/08/2024 à 10:07, Jason A. Donenfeld a écrit :
>>> On Thu, Aug 22, 2024 at 09:13:10AM +0200, Christophe Leroy wrote:
>>>>
>>>> +#define _PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
>>>> +#define _PAGE_MASK (~(_PAGE_SIZE - 1))
>>>
>>> If PAGE_SIZE isn't defined at this point, why not just call it PAGE_SIZE
>>> instead of _PAGE_SIZE? But if that's the case, why not put the vdso
>>> definition of PAGE_SIZE into some vdso header included by this file?
>>
>> It was working ok on powerpc but on x86 I got:
>
> Seems like there might be some more fiddling to do, then? Or did you
> conclude it's impossible?
Maybe someone who knows x86 in details could helps but after a first
look I gave up because it looks very x86 specific, indeed that's
x86/asm/vdso/gettimeofday.h that pulls several x86/asm/ headers , and
the same type of issue might arise for any new architecture coming in.
For me it looked cleaner to just do as commit cffaefd15a8f ("vdso: Use
CONFIG_PAGE_SHIFT in vdso/datapage.h") and not use PAGE_SIZE at all. But
I didn't want to directly use (1UL << CONFIG_PAGE_SHIFT) and (~(1UL <<
(CONFIG_PAGE_SHIFT - 1))) in the code directly hence the new macros with
a leading underscore to avoid any conflict with existing macros.
Christophe
On Mon, Aug 26 2024 at 12:45, Christophe Leroy wrote:
> Le 26/08/2024 à 10:58, Jason A. Donenfeld a écrit :
>> On Mon, Aug 26, 2024 at 10:37:49AM +0200, Christophe Leroy wrote:
>>>
>>>
>>> Le 26/08/2024 à 10:07, Jason A. Donenfeld a écrit :
>>>> On Thu, Aug 22, 2024 at 09:13:10AM +0200, Christophe Leroy wrote:
>>>>>
>>>>> +#define _PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
>>>>> +#define _PAGE_MASK (~(_PAGE_SIZE - 1))
>>>>
>>>> If PAGE_SIZE isn't defined at this point, why not just call it PAGE_SIZE
>>>> instead of _PAGE_SIZE? But if that's the case, why not put the vdso
>>>> definition of PAGE_SIZE into some vdso header included by this file?
>>>
>>> It was working ok on powerpc but on x86 I got:
>>
>> Seems like there might be some more fiddling to do, then? Or did you
>> conclude it's impossible?
>
> Maybe someone who knows x86 in details could helps but after a first
> look I gave up because it looks very x86 specific, indeed that's
> x86/asm/vdso/gettimeofday.h that pulls several x86/asm/ headers , and
> the same type of issue might arise for any new architecture coming in.
Of course :)
> For me it looked cleaner to just do as commit cffaefd15a8f ("vdso: Use
> CONFIG_PAGE_SHIFT in vdso/datapage.h") and not use PAGE_SIZE at all. But
> I didn't want to directly use (1UL << CONFIG_PAGE_SHIFT) and (~(1UL <<
> (CONFIG_PAGE_SHIFT - 1))) in the code directly hence the new macros with
> a leading underscore to avoid any conflict with existing macros.
#ifndef PAGE_SIZE
# define
#endif
Perhaps?
Thanks,
tglx
On Mon, Aug 26, 2024 at 12:45:40PM +0200, Christophe Leroy wrote:
>
>
> Le 26/08/2024 à 10:58, Jason A. Donenfeld a écrit :
> > On Mon, Aug 26, 2024 at 10:37:49AM +0200, Christophe Leroy wrote:
> >>
> >>
> >> Le 26/08/2024 à 10:07, Jason A. Donenfeld a écrit :
> >>> On Thu, Aug 22, 2024 at 09:13:10AM +0200, Christophe Leroy wrote:
> >>>>
> >>>> +#define _PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
> >>>> +#define _PAGE_MASK (~(_PAGE_SIZE - 1))
> >>>
> >>> If PAGE_SIZE isn't defined at this point, why not just call it PAGE_SIZE
> >>> instead of _PAGE_SIZE? But if that's the case, why not put the vdso
> >>> definition of PAGE_SIZE into some vdso header included by this file?
> >>
> >> It was working ok on powerpc but on x86 I got:
> >
> > Seems like there might be some more fiddling to do, then? Or did you
> > conclude it's impossible?
>
> Maybe someone who knows x86 in details could helps but after a first
> look I gave up because it looks very x86 specific, indeed that's
> x86/asm/vdso/gettimeofday.h that pulls several x86/asm/ headers , and
> the same type of issue might arise for any new architecture coming in.
>
> For me it looked cleaner to just do as commit cffaefd15a8f ("vdso: Use
> CONFIG_PAGE_SHIFT in vdso/datapage.h") and not use PAGE_SIZE at all. But
> I didn't want to directly use (1UL << CONFIG_PAGE_SHIFT) and (~(1UL <<
> (CONFIG_PAGE_SHIFT - 1))) in the code directly hence the new macros with
> a leading underscore to avoid any conflict with existing macros.
If that's the case and you can't sort it out or it's impossible, then it
seems like adding #ifndef PAGE_SIZE, #define... inside of some vdso header
(not inside getrandom.c) would make sense.
Jason
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