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authorMark Rutland <mark.rutland@arm.com>2020-12-02 16:15:57 +0300
committerCatalin Marinas <catalin.marinas@arm.com>2020-12-02 22:49:11 +0300
commit7cf283c7bd6260ae43a74cd213f5ec9d665a19b5 (patch)
tree5545af2e5ab25dfc021e79ab6ab140a7d7ad4b4f /arch/arm64/include
parentb5a5a01d8e9a44ecb18dc31d471233cad2f88291 (diff)
downloadlinux-7cf283c7bd6260ae43a74cd213f5ec9d665a19b5.tar.xz
arm64: uaccess: remove redundant PAN toggling
Some code (e.g. futex) needs to make privileged accesses to userspace memory, and uses uaccess_{enable,disable}_privileged() in order to permit this. All other uaccess primitives use LDTR/STTR, and never need to toggle PAN. Remove the redundant PAN toggling. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: James Morse <james.morse@arm.com> Cc: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20201202131558.39270-12-mark.rutland@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include')
-rw-r--r--arch/arm64/include/asm/cpucaps.h1
-rw-r--r--arch/arm64/include/asm/uaccess.h59
2 files changed, 19 insertions, 41 deletions
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index 64ea0bb9f420..ab3bec7a5a4d 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -17,7 +17,6 @@
#define ARM64_WORKAROUND_834220 7
#define ARM64_HAS_NO_HW_PREFETCH 8
#define ARM64_HAS_UAO 9
-#define ARM64_ALT_PAN_NOT_UAO 10
#define ARM64_HAS_VIRT_HOST_EXTN 11
#define ARM64_WORKAROUND_CAVIUM_27456 12
#define ARM64_HAS_32BIT_EL0 13
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index e639d8b2b38d..769cad7b4910 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -159,41 +159,20 @@ static inline void __uaccess_enable_hw_pan(void)
CONFIG_ARM64_PAN));
}
-#define __uaccess_disable(alt) \
-do { \
- if (!uaccess_ttbr0_disable()) \
- asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt, \
- CONFIG_ARM64_PAN)); \
-} while (0)
-
-#define __uaccess_enable(alt) \
-do { \
- if (!uaccess_ttbr0_enable()) \
- asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt, \
- CONFIG_ARM64_PAN)); \
-} while (0)
-
static inline void uaccess_disable_privileged(void)
{
- __uaccess_disable(ARM64_HAS_PAN);
-}
+ if (uaccess_ttbr0_disable())
+ return;
-static inline void uaccess_enable_privileged(void)
-{
- __uaccess_enable(ARM64_HAS_PAN);
+ __uaccess_enable_hw_pan();
}
-/*
- * These functions are no-ops when UAO is present.
- */
-static inline void uaccess_disable_not_uao(void)
+static inline void uaccess_enable_privileged(void)
{
- __uaccess_disable(ARM64_ALT_PAN_NOT_UAO);
-}
+ if (uaccess_ttbr0_enable())
+ return;
-static inline void uaccess_enable_not_uao(void)
-{
- __uaccess_enable(ARM64_ALT_PAN_NOT_UAO);
+ __uaccess_disable_hw_pan();
}
/*
@@ -265,9 +244,9 @@ do { \
#define __raw_get_user(x, ptr, err) \
do { \
__chk_user_ptr(ptr); \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__raw_get_mem("ldtr", x, ptr, err); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
} while (0)
#define __get_user_error(x, ptr, err) \
@@ -338,9 +317,9 @@ do { \
#define __raw_put_user(x, ptr, err) \
do { \
__chk_user_ptr(ptr); \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__raw_put_mem("sttr", x, ptr, err); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
} while (0)
#define __put_user_error(x, ptr, err) \
@@ -378,10 +357,10 @@ extern unsigned long __must_check __arch_copy_from_user(void *to, const void __u
#define raw_copy_from_user(to, from, n) \
({ \
unsigned long __acfu_ret; \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__acfu_ret = __arch_copy_from_user((to), \
__uaccess_mask_ptr(from), (n)); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
__acfu_ret; \
})
@@ -389,10 +368,10 @@ extern unsigned long __must_check __arch_copy_to_user(void __user *to, const voi
#define raw_copy_to_user(to, from, n) \
({ \
unsigned long __actu_ret; \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__actu_ret = __arch_copy_to_user(__uaccess_mask_ptr(to), \
(from), (n)); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
__actu_ret; \
})
@@ -400,10 +379,10 @@ extern unsigned long __must_check __arch_copy_in_user(void __user *to, const voi
#define raw_copy_in_user(to, from, n) \
({ \
unsigned long __aciu_ret; \
- uaccess_enable_not_uao(); \
+ uaccess_ttbr0_enable(); \
__aciu_ret = __arch_copy_in_user(__uaccess_mask_ptr(to), \
__uaccess_mask_ptr(from), (n)); \
- uaccess_disable_not_uao(); \
+ uaccess_ttbr0_disable(); \
__aciu_ret; \
})
@@ -414,9 +393,9 @@ extern unsigned long __must_check __arch_clear_user(void __user *to, unsigned lo
static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n)
{
if (access_ok(to, n)) {
- uaccess_enable_not_uao();
+ uaccess_ttbr0_enable();
n = __arch_clear_user(__uaccess_mask_ptr(to), n);
- uaccess_disable_not_uao();
+ uaccess_ttbr0_disable();
}
return n;
}