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arm64: uaccess: Remove uaccess_*_not_uao asm macros 

It is safer and simpler to drop the uaccess assembly macros in favour of
inline C functions. Although this bloats the Image size slightly, it
aligns our user copy routines with '{get,put}_user()' and generally
makes the code a lot easier to reason about.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
[will: tweaked commit message and changed temporary variable names]
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Pavel Tatashin 2019-11-20 12:07:40 -05:00 committed by Will Deacon
parent 94bb804e1e
commit e50be648aa
7 changed files with 27 additions and 35 deletions
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17
arch/arm64/include/asm/asm-uaccess.h
View File

@ -58,23 +58,6 @@ alternative_else_nop_endif
.endm
#endif
/*
* These macros are no-ops when UAO is present.
*/
.macro uaccess_disable_not_uao, tmp1, tmp2
uaccess_ttbr0_disable \tmp1, \tmp2
alternative_if ARM64_ALT_PAN_NOT_UAO
SET_PSTATE_PAN(1)
alternative_else_nop_endif
.endm
.macro uaccess_enable_not_uao, tmp1, tmp2, tmp3
uaccess_ttbr0_enable \tmp1, \tmp2, \tmp3
alternative_if ARM64_ALT_PAN_NOT_UAO
SET_PSTATE_PAN(0)
alternative_else_nop_endif
.endm
/*
* Remove the address tag from a virtual address, if present.
*/

25
arch/arm64/include/asm/uaccess.h
View File

@ -378,20 +378,34 @@ do { \
extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
#define raw_copy_from_user(to, from, n) \
({ \
__arch_copy_from_user((to), __uaccess_mask_ptr(from), (n)); \
unsigned long __acfu_ret; \
uaccess_enable_not_uao(); \
__acfu_ret = __arch_copy_from_user((to), \
__uaccess_mask_ptr(from), (n)); \
uaccess_disable_not_uao(); \
__acfu_ret; \
})
extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n);
#define raw_copy_to_user(to, from, n) \
({ \
__arch_copy_to_user(__uaccess_mask_ptr(to), (from), (n)); \
unsigned long __actu_ret; \
uaccess_enable_not_uao(); \
__actu_ret = __arch_copy_to_user(__uaccess_mask_ptr(to), \
(from), (n)); \
uaccess_disable_not_uao(); \
__actu_ret; \
})
extern unsigned long __must_check __arch_copy_in_user(void __user *to, const void __user *from, unsigned long n);
#define raw_copy_in_user(to, from, n) \
({ \
__arch_copy_in_user(__uaccess_mask_ptr(to), \
unsigned long __aciu_ret; \
uaccess_enable_not_uao(); \
__aciu_ret = __arch_copy_in_user(__uaccess_mask_ptr(to), \
__uaccess_mask_ptr(from), (n)); \
uaccess_disable_not_uao(); \
__aciu_ret; \
})
#define INLINE_COPY_TO_USER
@ -400,8 +414,11 @@ extern unsigned long __must_check __arch_copy_in_user(void __user *to, const voi
extern unsigned long __must_check __arch_clear_user(void __user *to, unsigned long n);
static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n)
{
if (access_ok(to, n))
if (access_ok(to, n)) {
uaccess_enable_not_uao();
n = __arch_clear_user(__uaccess_mask_ptr(to), n);
uaccess_disable_not_uao();
}
return n;
}
#define clear_user __clear_user

3
arch/arm64/lib/clear_user.S
View File

@ -20,7 +20,6 @@
* Alignment fixed up by hardware.
*/
ENTRY(__arch_clear_user)
uaccess_enable_not_uao x2, x3, x4
mov x2, x1 // save the size for fixup return
subs x1, x1, #8
b.mi 2f
@ -40,7 +39,6 @@ uao_user_alternative 9f, strh, sttrh, wzr, x0, 2
b.mi 5f
uao_user_alternative 9f, strb, sttrb, wzr, x0, 0
5: mov x0, #0
uaccess_disable_not_uao x2, x3
ret
ENDPROC(__arch_clear_user)
EXPORT_SYMBOL(__arch_clear_user)
@ -48,6 +46,5 @@ EXPORT_SYMBOL(__arch_clear_user)
.section .fixup,"ax"
.align 2
9: mov x0, x2 // return the original size
uaccess_disable_not_uao x2, x3
ret
.previous

3
arch/arm64/lib/copy_from_user.S
View File

@ -54,10 +54,8 @@
end .req x5
ENTRY(__arch_copy_from_user)
uaccess_enable_not_uao x3, x4, x5
add end, x0, x2
#include "copy_template.S"
uaccess_disable_not_uao x3, x4
mov x0, #0 // Nothing to copy
ret
ENDPROC(__arch_copy_from_user)
@ -66,6 +64,5 @@ EXPORT_SYMBOL(__arch_copy_from_user)
.section .fixup,"ax"
.align 2
9998: sub x0, end, dst // bytes not copied
uaccess_disable_not_uao x3, x4
ret
.previous

3
arch/arm64/lib/copy_in_user.S
View File

@ -56,10 +56,8 @@
end .req x5
ENTRY(__arch_copy_in_user)
uaccess_enable_not_uao x3, x4, x5
add end, x0, x2
#include "copy_template.S"
uaccess_disable_not_uao x3, x4
mov x0, #0
ret
ENDPROC(__arch_copy_in_user)
@ -68,6 +66,5 @@ EXPORT_SYMBOL(__arch_copy_in_user)
.section .fixup,"ax"
.align 2
9998: sub x0, end, dst // bytes not copied
uaccess_disable_not_uao x3, x4
ret
.previous

3
arch/arm64/lib/copy_to_user.S
View File

@ -53,10 +53,8 @@
end .req x5
ENTRY(__arch_copy_to_user)
uaccess_enable_not_uao x3, x4, x5
add end, x0, x2
#include "copy_template.S"
uaccess_disable_not_uao x3, x4
mov x0, #0
ret
ENDPROC(__arch_copy_to_user)
@ -65,6 +63,5 @@ EXPORT_SYMBOL(__arch_copy_to_user)
.section .fixup,"ax"
.align 2
9998: sub x0, end, dst // bytes not copied
uaccess_disable_not_uao x3, x4
ret
.previous

6
arch/arm64/lib/uaccess_flushcache.c
View File

@ -28,7 +28,11 @@ void memcpy_page_flushcache(char *to, struct page *page, size_t offset,
unsigned long __copy_user_flushcache(void *to, const void __user *from,
unsigned long n)
{
unsigned long rc = __arch_copy_from_user(to, from, n);
unsigned long rc;
uaccess_enable_not_uao();
rc = __arch_copy_from_user(to, from, n);
uaccess_disable_not_uao();
/* See above */
__clean_dcache_area_pop(to, n - rc);