Commit 923e1e7d authored by Mark Rutland's avatar Mark Rutland Committed by Catalin Marinas
Browse files

arm64: uaccess: rename privileged uaccess routines 



We currently have many uaccess_*{enable,disable}*() variants, which
subsequent patches will cut down as part of removing set_fs() and
friends. Once this simplification is made, most uaccess routines will
only need to ensure that the user page tables are mapped in TTBR0, as is
currently dealt with by uaccess_ttbr0_{enable,disable}().

The existing uaccess_{enable,disable}() routines ensure that user page
tables are mapped in TTBR0, and also disable PAN protections, which is
necessary to be able to use atomics on user memory, but also permit
unrelated privileged accesses to access user memory.

As preparatory step, let's rename uaccess_{enable,disable}() to
uaccess_{enable,disable}_privileged(), highlighting this caveat and
discouraging wider misuse. Subsequent patches can reuse the
uaccess_{enable,disable}() naming for the common case of ensuring the
user page tables are mapped in TTBR0.

There should be no functional change as a result of this patch.

Signed-off-by: default avatarMark 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/20201202131558.39270-5-mark.rutland@arm.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 2376e75c

arch/arm64/include/asm/futex.h

+4 −4
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ 
do {									\

	unsigned int loops = FUTEX_MAX_LOOPS;				\

									\

	uaccess_enable();						\

	uaccess_enable_privileged();					\

	asm volatile(							\

"	prfm	pstl1strm, %2\n"					\

"1:	ldxr	%w1, %2\n"						\
@@ -39,7 +39,7 @@ do { \ 
	  "+r" (loops)							\

	: "r" (oparg), "Ir" (-EFAULT), "Ir" (-EAGAIN)			\

	: "memory");							\

	uaccess_disable();						\

	uaccess_disable_privileged();					\

} while (0)



static inline int
@@ -95,7 +95,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr, 
		return -EFAULT;



	uaddr = __uaccess_mask_ptr(_uaddr);

	uaccess_enable();

	uaccess_enable_privileged();

	asm volatile("// futex_atomic_cmpxchg_inatomic\n"

"	prfm	pstl1strm, %2\n"

"1:	ldxr	%w1, %2\n"
@@ -118,7 +118,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr, 
	: "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp), "+r" (loops)

	: "r" (oldval), "r" (newval), "Ir" (-EFAULT), "Ir" (-EAGAIN)

	: "memory");

	uaccess_disable();

	uaccess_disable_privileged();



	if (!ret)

		*uval = val;

arch/arm64/include/asm/uaccess.h

+2 −2
Original line number Diff line number Diff line
@@ -200,12 +200,12 @@ do { \ 
				CONFIG_ARM64_PAN));			\

} while (0)



static inline void uaccess_disable(void)

static inline void uaccess_disable_privileged(void)

{

	__uaccess_disable(ARM64_HAS_PAN);

}



static inline void uaccess_enable(void)

static inline void uaccess_enable_privileged(void)

{

	__uaccess_enable(ARM64_HAS_PAN);

}

arch/arm64/kernel/armv8_deprecated.c

+2 −2
Original line number Diff line number Diff line
@@ -277,7 +277,7 @@ static void __init register_insn_emulation_sysctl(void) 


#define __user_swpX_asm(data, addr, res, temp, temp2, B)	\

do {								\

	uaccess_enable();					\

	uaccess_enable_privileged();				\

	__asm__ __volatile__(					\

	"	mov		%w3, %w7\n"			\

	"0:	ldxr"B"		%w2, [%4]\n"			\
@@ -302,7 +302,7 @@ do { \ 
	  "i" (-EFAULT),					\

	  "i" (__SWP_LL_SC_LOOPS)				\

	: "memory");						\

	uaccess_disable();					\

	uaccess_disable_privileged();				\

} while (0)



#define __user_swp_asm(data, addr, res, temp, temp2) \