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random: vDSO: minimize and simplify header includes

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Depending on the architecture, building a 32-bit vDSO on a 64-bit kernel
is problematic when some system headers are included.

Minimise the amount of headers by moving needed items, such as
__{get,put}_unaligned_t, into dedicated common headers and in general
use more specific headers, similar to what was done in commit
8165b57bca ("linux/const.h: Extract common header for vDSO") and
commit 8c59ab839f ("lib/vdso: Enable common headers").

On some architectures this results in missing PAGE_SIZE, as was
described by commit 8b3843ae36 ("vdso/datapage: Quick fix - use
asm/page-def.h for ARM64"), so define this if necessary, in the same way
as done prior by commit cffaefd15a ("vdso: Use CONFIG_PAGE_SHIFT in
vdso/datapage.h").

Removing linux/time64.h leads to missing 'struct timespec64' in
x86's asm/pvclock.h. Add a forward declaration of that struct in
that file.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
This commit is contained in:
Christophe Leroy 2024-08-27 09:31:47 +02:00 committed by Jason A. Donenfeld
parent b7bad082e1
commit 7f053812da
5 changed files with 26 additions and 15 deletions
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1
arch/x86/include/asm/pvclock.h
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@ -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);

11
include/asm-generic/unaligned.h
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@ -8,16 +8,7 @@
*/
#include <linux/unaligned/packed_struct.h>
#include <asm/byteorder.h>
#define __get_unaligned_t(type, ptr) ({ \
const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \
__pptr->x; \
})
#define __put_unaligned_t(type, val, ptr) do { \
struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \
__pptr->x = (val); \
} while (0)
#include <vdso/unaligned.h>
#define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr))
#define put_unaligned(val, ptr) __put_unaligned_t(typeof(*(ptr)), (val), (ptr))

1
include/vdso/helpers.h
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@ -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)

15
include/vdso/unaligned.h Normal file
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@ -0,0 +1,15 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __VDSO_UNALIGNED_H
#define __VDSO_UNALIGNED_H
#define __get_unaligned_t(type, ptr) ({ \
const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \
__pptr->x; \
})
#define __put_unaligned_t(type, val, ptr) do { \
struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \
__pptr->x = (val); \
} while (0)
#endif /* __VDSO_UNALIGNED_H */

13
lib/vdso/getrandom.c
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@ -4,15 +4,18 @@
*/
#include <linux/array_size.h>
#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>
#undef PAGE_SIZE
#undef PAGE_MASK
#define PAGE_SIZE (1UL << CONFIG_PAGE_SHIFT)
#define PAGE_MASK (~(PAGE_SIZE - 1))
#define MEMCPY_AND_ZERO_SRC(type, dst, src, len) do { \
while (len >= sizeof(type)) { \