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Date: Wed, 20 Nov 2019 12:07:40 -0500
From: Pavel Tatashin <pasha.tatashin@...een.com>
To: pasha.tatashin@...een.com, jmorris@...ei.org, sashal@...nel.org,
linux-kernel@...r.kernel.org, catalin.marinas@....com,
will@...nel.org, steve.capper@....com,
linux-arm-kernel@...ts.infradead.org, marc.zyngier@....com,
james.morse@....com, vladimir.murzin@....com, mark.rutland@....com,
tglx@...utronix.de, gregkh@...uxfoundation.org,
allison@...utok.net, info@...ux.net, alexios.zavras@...el.com
Subject: [PATCH] arm64: kernel: remove uaccess_*_not_uao asm macros
It is safer, and less code to maintain to keep uaccess_*
as inline C functions instead of ASM macros.
There is no performance overhead from this change because
the generated code is almost identical.
Signed-off-by: Pavel Tatashin <pasha.tatashin@...een.com>
---
arch/arm64/include/asm/asm-uaccess.h | 17 -----------------
arch/arm64/include/asm/uaccess.h | 27 ++++++++++++++++++++++-----
arch/arm64/lib/clear_user.S | 3 ---
arch/arm64/lib/copy_from_user.S | 3 ---
arch/arm64/lib/copy_in_user.S | 3 ---
arch/arm64/lib/copy_to_user.S | 3 ---
arch/arm64/lib/uaccess_flushcache.c | 6 +++++-
7 files changed, 27 insertions(+), 35 deletions(-)
diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h
index 5bf963830b17..c764cc8fb3b6 100644
--- a/arch/arm64/include/asm/asm-uaccess.h
+++ b/arch/arm64/include/asm/asm-uaccess.h
@@ -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.
*/
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index 097d6bfac0b7..f9c75d623d0f 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -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 __cpy; \
+ uaccess_enable_not_uao(); \
+ __cpy = __arch_copy_from_user((to), \
+ __uaccess_mask_ptr(from), (n)); \
+ uaccess_disable_not_uao(); \
+ __cpy; \
})
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 __cpy; \
+ uaccess_enable_not_uao(); \
+ __cpy = __arch_copy_to_user(__uaccess_mask_ptr(to), \
+ (from), (n)); \
+ uaccess_disable_not_uao(); \
+ __cpy; \
})
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), \
- __uaccess_mask_ptr(from), (n)); \
+ unsigned long __cpy; \
+ uaccess_enable_not_uao(); \
+ __cpy = __arch_copy_in_user(__uaccess_mask_ptr(to), \
+ __uaccess_mask_ptr(from), (n)); \
+ uaccess_disable_not_uao(); \
+ __cpy; \
})
#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
diff --git a/arch/arm64/lib/clear_user.S b/arch/arm64/lib/clear_user.S
index 322b55664cca..aeafc03e961a 100644
--- a/arch/arm64/lib/clear_user.S
+++ b/arch/arm64/lib/clear_user.S
@@ -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
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S
index 8472dc7798b3..ebb3c06cbb5d 100644
--- a/arch/arm64/lib/copy_from_user.S
+++ b/arch/arm64/lib/copy_from_user.S
@@ -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
diff --git a/arch/arm64/lib/copy_in_user.S b/arch/arm64/lib/copy_in_user.S
index 8e0355c1e318..3d8153a1ebce 100644
--- a/arch/arm64/lib/copy_in_user.S
+++ b/arch/arm64/lib/copy_in_user.S
@@ -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
diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S
index 6085214654dc..357eae2c18eb 100644
--- a/arch/arm64/lib/copy_to_user.S
+++ b/arch/arm64/lib/copy_to_user.S
@@ -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
diff --git a/arch/arm64/lib/uaccess_flushcache.c b/arch/arm64/lib/uaccess_flushcache.c
index cbfcbe6470a5..bfa30b75b2b8 100644
--- a/arch/arm64/lib/uaccess_flushcache.c
+++ b/arch/arm64/lib/uaccess_flushcache.c
@@ -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);
--
2.24.0
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