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s390/maccess: rework absolute lowcore accessors

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Macro mem_assign_absolute() is able to access the whole memory, but
is only used and makes sense when updating the absolute lowcore.
Instead, introduce get_abs_lowcore() and put_abs_lowcore() macros
that limit access to absolute lowcore addresses only.

Suggested-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Alexander Gordeev
2022-03-17 15:03:03 +01:00
committed by Vasily Gorbik
parent 9097fc793f
commit ed0192bc64
6 changed files with 32 additions and 24 deletions
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17
arch/s390/include/asm/processor.h
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@@ -319,11 +319,18 @@ extern void (*s390_base_pgm_handler_fn)(struct pt_regs *regs);
extern int memcpy_real(void *, unsigned long, size_t);
extern void memcpy_absolute(void *, void *, size_t);
#define mem_assign_absolute(dest, val) do { \
__typeof__(dest) __tmp = (val); \
\
BUILD_BUG_ON(sizeof(__tmp) != sizeof(val)); \
memcpy_absolute(&(dest), &__tmp, sizeof(__tmp)); \
#define put_abs_lowcore(member, x) do { \
unsigned long __abs_address = offsetof(struct lowcore, member); \
__typeof__(((struct lowcore *)0)->member) __tmp = (x); \
\
memcpy_absolute(__va(__abs_address), &__tmp, sizeof(__tmp)); \
} while (0)
#define get_abs_lowcore(x, member) do { \
unsigned long __abs_address = offsetof(struct lowcore, member); \
__typeof__(((struct lowcore *)0)->member) *__ptr = &(x); \
\
memcpy_absolute(__ptr, __va(__abs_address), sizeof(*__ptr)); \
} while (0)
extern int s390_isolate_bp(void);