linux-kernel - [PATCH] riscv: fix __user annotation in traps

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Date:   Thu, 23 Nov 2023 14:16:17 +0000
From:   Ben Dooks <ben.dooks@...ethink.co.uk>
To:     linux-riscv@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, paul.walmsley@...ive.com,
        palmer@...belt.com, aou@...s.berkeley.edu,
        Ben Dooks <ben.dooks@...ethink.co.uk>
Subject: [PATCH] riscv: fix __user annotation in traps_misaligned.c

The instruction reading code can read from either user or kernel addresses
and thus the use of __user on pointers to instructions depends on which
context. Fix a few sparse warnings by using __user for user-accesses and
remove it when not.

Fixes:

arch/riscv/kernel/traps_misaligned.c:361:21: warning: dereference of noderef expression
arch/riscv/kernel/traps_misaligned.c:373:21: warning: dereference of noderef expression
arch/riscv/kernel/traps_misaligned.c:381:21: warning: dereference of noderef expression
arch/riscv/kernel/traps_misaligned.c:322:24: warning: incorrect type in initializer (different address spaces)
arch/riscv/kernel/traps_misaligned.c:322:24:    expected unsigned char const [noderef] __user *__gu_ptr
arch/riscv/kernel/traps_misaligned.c:322:24:    got unsigned char const [usertype] *addr
arch/riscv/kernel/traps_misaligned.c:361:21: warning: dereference of noderef expression
arch/riscv/kernel/traps_misaligned.c:373:21: warning: dereference of noderef expression
arch/riscv/kernel/traps_misaligned.c:381:21: warning: dereference of noderef expression
arch/riscv/kernel/traps_misaligned.c:332:24: warning: incorrect type in initializer (different address spaces)
arch/riscv/kernel/traps_misaligned.c:332:24:    expected unsigned char [noderef] __user *__gu_ptr
arch/riscv/kernel/traps_misaligned.c:332:24:    got unsigned char [usertype] *addr

Fixes: 7c83232161f60 ("riscv: add support for misaligned trap handling in S-mode")
Signed-off-by: Ben Dooks <ben.dooks@...ethink.co.uk>
---
 arch/riscv/kernel/traps_misaligned.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c
index 5eba37147caa..446e3d4eeea9 100644
--- a/arch/riscv/kernel/traps_misaligned.c
+++ b/arch/riscv/kernel/traps_misaligned.c
@@ -319,7 +319,7 @@ static inline int get_insn(struct pt_regs *regs, ulong mepc, ulong *r_insn)
 static inline int load_u8(struct pt_regs *regs, const u8 *addr, u8 *r_val)
 {
 	if (user_mode(regs)) {
-		return __get_user(*r_val, addr);
+		return __get_user(*r_val, (u8 __user *)addr);
 	} else {
 		*r_val = *addr;
 		return 0;
@@ -329,7 +329,7 @@ static inline int load_u8(struct pt_regs *regs, const u8 *addr, u8 *r_val)
 static inline int store_u8(struct pt_regs *regs, u8 *addr, u8 val)
 {
 	if (user_mode(regs)) {
-		return __put_user(val, addr);
+		return __put_user(val, (u8 __user *)addr);
 	} else {
 		*addr = val;
 		return 0;
@@ -343,7 +343,7 @@ static inline int store_u8(struct pt_regs *regs, u8 *addr, u8 val)
 	if (user_mode(regs)) {				\
 		__ret = __get_user(insn, insn_addr);	\
 	} else {					\
-		insn = *insn_addr;			\
+		insn = *(__force u16 *)insn_addr;	\
 		__ret = 0;				\
 	}						\
 							\
-- 
2.37.2.352.g3c44437643