Revert "FROMLIST: arm64: Factor out PAN enabling/disabling into separate uaccess_* macros"

This reverts commit 23368b642deb01ac6ce668ec1dedfcc0cab25c71.

Bug: 31432001
Change-Id: Ia59e5fc75ef905b89d5f9194f1e762c1e5eff5bf
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>

7 files changed, 40 insertions, 95 deletions

diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h
index 71dfa3b42313..f2585cdd32c2 100644
--- a/arch/arm64/include/asm/futex.h
+++ b/arch/arm64/include/asm/futex.h
@@ -27,9 +27,9 @@
 #include <asm/sysreg.h>
 
 #define __futex_atomic_op(insn, ret, oldval, uaddr, tmp, oparg)		\
-do {									\
-	uaccess_enable();						\
 	asm volatile(							\
+	ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN,		\
+		    CONFIG_ARM64_PAN)					\
 "	prfm	pstl1strm, %2\n"					\
 "1:	ldxr	%w1, %2\n"						\
 	insn "\n"							\
@@ -44,11 +44,11 @@ do {									\
 "	.popsection\n"							\
 	_ASM_EXTABLE(1b, 4b)						\
 	_ASM_EXTABLE(2b, 4b)						\
+	ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN,		\
+		    CONFIG_ARM64_PAN)					\
 	: "=&r" (ret), "=&r" (oldval), "+Q" (*uaddr), "=&r" (tmp)	\
 	: "r" (oparg), "Ir" (-EFAULT)					\
-	: "memory");							\
-	uaccess_disable();						\
-} while (0)
+	: "memory")
 
 static inline int
 futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
@@ -118,8 +118,8 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
 		return -EFAULT;
 
-	uaccess_enable();
 	asm volatile("// futex_atomic_cmpxchg_inatomic\n"
+ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
 "	prfm	pstl1strm, %2\n"
 "1:	ldxr	%w1, %2\n"
 "	sub	%w3, %w1, %w4\n"
@@ -134,10 +134,10 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
 "	.popsection\n"
 	_ASM_EXTABLE(1b, 4b)
 	_ASM_EXTABLE(2b, 4b)
+ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, CONFIG_ARM64_PAN)
 	: "+r" (ret), "=&r" (val), "+Q" (*uaddr), "=&r" (tmp)
 	: "r" (oldval), "r" (newval), "Ir" (-EFAULT)
 	: "memory");
-	uaccess_disable();
 
 	*uval = val;
 	return ret;
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index c8ef22a9a83b..c3d445b42351 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -18,8 +18,6 @@
 #ifndef __ASM_UACCESS_H
 #define __ASM_UACCESS_H
 
-#ifndef __ASSEMBLY__
-
 /*
  * User space memory access functions
  */
@@ -126,44 +124,6 @@ static inline void set_fs(mm_segment_t fs)
 	"	.popsection\n"
 
 /*
- * User access enabling/disabling.
- */
-#define __uaccess_disable(alt)						\
-do {									\
-	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt,			\
-			CONFIG_ARM64_PAN));				\
-} while (0)
-
-#define __uaccess_enable(alt)						\
-do {									\
-	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt,			\
-			CONFIG_ARM64_PAN));				\
-} while (0)
-
-static inline void uaccess_disable(void)
-{
-	__uaccess_disable(ARM64_HAS_PAN);
-}
-
-static inline void uaccess_enable(void)
-{
-	__uaccess_enable(ARM64_HAS_PAN);
-}
-
-/*
- * These functions are no-ops when UAO is present.
- */
-static inline void uaccess_disable_not_uao(void)
-{
-	__uaccess_disable(ARM64_ALT_PAN_NOT_UAO);
-}
-
-static inline void uaccess_enable_not_uao(void)
-{
-	__uaccess_enable(ARM64_ALT_PAN_NOT_UAO);
-}
-
-/*
  * The "__xxx" versions of the user access functions do not verify the address
  * space - it must have been done previously with a separate "access_ok()"
  * call.
@@ -190,7 +150,8 @@ static inline void uaccess_enable_not_uao(void)
 do {									\
 	unsigned long __gu_val;						\
 	__chk_user_ptr(ptr);						\
-	uaccess_enable_not_uao();					\
+	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
+			CONFIG_ARM64_PAN));				\
 	switch (sizeof(*(ptr))) {					\
 	case 1:								\
 		__get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr),  \
@@ -211,8 +172,9 @@ do {									\
 	default:							\
 		BUILD_BUG();						\
 	}								\
-	uaccess_disable_not_uao();					\
 	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
+	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
+			CONFIG_ARM64_PAN));				\
 } while (0)
 
 #define __get_user(x, ptr)						\
@@ -257,7 +219,8 @@ do {									\
 do {									\
 	__typeof__(*(ptr)) __pu_val = (x);				\
 	__chk_user_ptr(ptr);						\
-	uaccess_enable_not_uao();					\
+	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
+			CONFIG_ARM64_PAN));				\
 	switch (sizeof(*(ptr))) {					\
 	case 1:								\
 		__put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr),	\
@@ -278,7 +241,8 @@ do {									\
 	default:							\
 		BUILD_BUG();						\
 	}								\
-	uaccess_disable_not_uao();					\
+	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
+			CONFIG_ARM64_PAN));				\
 } while (0)
 
 #define __put_user(x, ptr)						\
@@ -363,31 +327,4 @@ extern long strncpy_from_user(char *dest, const char __user *src, long count);
 extern __must_check long strlen_user(const char __user *str);
 extern __must_check long strnlen_user(const char __user *str, long n);
 
-#else	/* __ASSEMBLY__ */
-
-#include <asm/alternative.h>
-#include <asm/assembler.h>
-
-/*
- * User access enabling/disabling macros. These are no-ops when UAO is
- * present.
- */
-	.macro	uaccess_disable_not_uao, tmp1
-alternative_if_not ARM64_ALT_PAN_NOT_UAO
-	nop
-alternative_else
-	SET_PSTATE_PAN(1)
-alternative_endif
-	.endm
-
-	.macro	uaccess_enable_not_uao, tmp1, tmp2
-alternative_if_not ARM64_ALT_PAN_NOT_UAO
-	nop
-alternative_else
-	SET_PSTATE_PAN(0)
-alternative_endif
-	.endm
-
-#endif	/* __ASSEMBLY__ */
-
 #endif /* __ASM_UACCESS_H */
diff --git a/arch/arm64/kernel/armv8_deprecated.c b/arch/arm64/kernel/armv8_deprecated.c
index 562f7ddb158b..c37202c0c838 100644
--- a/arch/arm64/kernel/armv8_deprecated.c
+++ b/arch/arm64/kernel/armv8_deprecated.c
@@ -281,9 +281,9 @@ static void __init register_insn_emulation_sysctl(struct ctl_table *table)
  * Error-checking SWP macros implemented using ldxr{b}/stxr{b}
  */
 #define __user_swpX_asm(data, addr, res, temp, B)		\
-do {								\
-	uaccess_enable();					\
 	__asm__ __volatile__(					\
+	ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN,	\
+		    CONFIG_ARM64_PAN)				\
 	"0:	ldxr"B"		%w2, [%3]\n"			\
 	"1:	stxr"B"		%w0, %w1, [%3]\n"		\
 	"	cbz		%w0, 2f\n"			\
@@ -299,11 +299,11 @@ do {								\
 	"	.popsection"					\
 	_ASM_EXTABLE(0b, 4b)					\
 	_ASM_EXTABLE(1b, 4b)					\
+	ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN,	\
+		CONFIG_ARM64_PAN)				\
 	: "=&r" (res), "+r" (data), "=&r" (temp)		\
 	: "r" (addr), "i" (-EAGAIN), "i" (-EFAULT)		\
-	: "memory");						\
-	uaccess_disable();					\
-} while (0)
+	: "memory")
 
 #define __user_swp_asm(data, addr, res, temp) \
 	__user_swpX_asm(data, addr, res, temp, "")
diff --git a/arch/arm64/lib/clear_user.S b/arch/arm64/lib/clear_user.S
index 08b5f18ba604..5d1cad3ce6d6 100644
--- a/arch/arm64/lib/clear_user.S
+++ b/arch/arm64/lib/clear_user.S
@@ -17,10 +17,10 @@
  */
 #include <linux/linkage.h>
 
+#include <asm/alternative.h>
 #include <asm/assembler.h>
 #include <asm/cpufeature.h>
 #include <asm/sysreg.h>
-#include <asm/uaccess.h>
 
 	.text
 
@@ -33,7 +33,8 @@
  * Alignment fixed up by hardware.
  */
 ENTRY(__clear_user)
-	uaccess_enable_not_uao x2, x3
+ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \
+	    CONFIG_ARM64_PAN)
 	mov	x2, x1			// save the size for fixup return
 	subs	x1, x1, #8
 	b.mi	2f
@@ -53,7 +54,8 @@ 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
+ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \
+	    CONFIG_ARM64_PAN)
 	ret
 ENDPROC(__clear_user)
 
diff --git a/arch/arm64/lib/copy_from_user.S b/arch/arm64/lib/copy_from_user.S
index 6505ec81f1da..0b90497d4424 100644
--- a/arch/arm64/lib/copy_from_user.S
+++ b/arch/arm64/lib/copy_from_user.S
@@ -16,11 +16,11 @@
 
 #include <linux/linkage.h>
 
+#include <asm/alternative.h>
 #include <asm/assembler.h>
 #include <asm/cache.h>
 #include <asm/cpufeature.h>
 #include <asm/sysreg.h>
-#include <asm/uaccess.h>
 
 /*
  * Copy from user space to a kernel buffer (alignment handled by the hardware)
@@ -67,10 +67,12 @@
 
 end	.req	x5
 ENTRY(__arch_copy_from_user)
-	uaccess_enable_not_uao x3, x4
+ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \
+	    CONFIG_ARM64_PAN)
 	add	end, x0, x2
 #include "copy_template.S"
-	uaccess_disable_not_uao x3
+ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \
+	    CONFIG_ARM64_PAN)
 	mov	x0, #0				// Nothing to copy
 	ret
 ENDPROC(__arch_copy_from_user)
diff --git a/arch/arm64/lib/copy_in_user.S b/arch/arm64/lib/copy_in_user.S
index 9b04ff3ab610..f7292dd08c84 100644
--- a/arch/arm64/lib/copy_in_user.S
+++ b/arch/arm64/lib/copy_in_user.S
@@ -18,11 +18,11 @@
 
 #include <linux/linkage.h>
 
+#include <asm/alternative.h>
 #include <asm/assembler.h>
 #include <asm/cache.h>
 #include <asm/cpufeature.h>
 #include <asm/sysreg.h>
-#include <asm/uaccess.h>
 
 /*
  * Copy from user space to user space (alignment handled by the hardware)
@@ -68,10 +68,12 @@
 
 end	.req	x5
 ENTRY(__copy_in_user)
-	uaccess_enable_not_uao x3, x4
+ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \
+	    CONFIG_ARM64_PAN)
 	add	end, x0, x2
 #include "copy_template.S"
-	uaccess_disable_not_uao x3
+ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \
+	    CONFIG_ARM64_PAN)
 	mov	x0, #0
 	ret
 ENDPROC(__copy_in_user)
diff --git a/arch/arm64/lib/copy_to_user.S b/arch/arm64/lib/copy_to_user.S
index 8077e4f34d56..7a7efe255034 100644
--- a/arch/arm64/lib/copy_to_user.S
+++ b/arch/arm64/lib/copy_to_user.S
@@ -16,11 +16,11 @@
 
 #include <linux/linkage.h>
 
+#include <asm/alternative.h>
 #include <asm/assembler.h>
 #include <asm/cache.h>
 #include <asm/cpufeature.h>
 #include <asm/sysreg.h>
-#include <asm/uaccess.h>
 
 /*
  * Copy to user space from a kernel buffer (alignment handled by the hardware)
@@ -66,10 +66,12 @@
 
 end	.req	x5
 ENTRY(__arch_copy_to_user)
-	uaccess_enable_not_uao x3, x4
+ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(0)), ARM64_ALT_PAN_NOT_UAO, \
+	    CONFIG_ARM64_PAN)
 	add	end, x0, x2
 #include "copy_template.S"
-	uaccess_disable_not_uao x3
+ALTERNATIVE("nop", __stringify(SET_PSTATE_PAN(1)), ARM64_ALT_PAN_NOT_UAO, \
+	    CONFIG_ARM64_PAN)
 	mov	x0, #0
 	ret
 ENDPROC(__arch_copy_to_user)