linux-kernel - [PATCH 26/29] csky: kprobe: fix code in simulate without 'long'

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Date:   Thu, 21 Jan 2021 14:53:46 +0800
From:   guoren@...nel.org
To:     guoren@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-csky@...r.kernel.org,
        Guo Ren <guoren@...ux.alibaba.com>,
        Menglong Dong <dong.menglong@....com.cn>
Subject: [PATCH 26/29] csky: kprobe: fix code in simulate without 'long'

From: Guo Ren <guoren@...ux.alibaba.com>

The type of 'val' is 'unsigned long' in simulate_blz32, so 'val < 0'
can't be true.

Cast 'val' to 'long' here to determine branch token or not,

Fixup instructions: bnezad32, bhsz32, bhz32, blsz32, blz32

Link: https://lore.kernel.org/linux-csky/CAJF2gTQjKXR9gpo06WAWG1aquiT87mATiMGorXs6ChxOxoe90Q@mail.gmail.com/T/#t
Signed-off-by: Guo Ren <guoren@...ux.alibaba.com>
Co-developed-by: Menglong Dong <dong.menglong@....com.cn>
Signed-off-by: Menglong Dong <dong.menglong@....com.cn>
---
 arch/csky/kernel/probes/simulate-insn.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/arch/csky/kernel/probes/simulate-insn.c b/arch/csky/kernel/probes/simulate-insn.c
index 4e464fed52ec..d6e8d092c9b7 100644
--- a/arch/csky/kernel/probes/simulate-insn.c
+++ b/arch/csky/kernel/probes/simulate-insn.c
@@ -274,9 +274,9 @@ void __kprobes
 simulate_bnezad32(u32 opcode, long addr, struct pt_regs *regs)
 {
 	unsigned long tmp = opcode & 0x1f;
-	unsigned long val;
+	long val;
 
-	csky_insn_reg_get_val(regs, tmp, &val);
+	csky_insn_reg_get_val(regs, tmp, (unsigned long *)&val);
 
 	val -= 1;
 
@@ -286,7 +286,7 @@ simulate_bnezad32(u32 opcode, long addr, struct pt_regs *regs)
 	} else
 		instruction_pointer_set(regs, addr + 4);
 
-	csky_insn_reg_set_val(regs, tmp, val);
+	csky_insn_reg_set_val(regs, tmp, (unsigned long)val);
 }
 
 void __kprobes
@@ -297,13 +297,11 @@ simulate_bhsz32(u32 opcode, long addr, struct pt_regs *regs)
 
 	csky_insn_reg_get_val(regs, tmp, &val);
 
-	if (val >= 0) {
+	if ((long) val >= 0) {
 		instruction_pointer_set(regs,
 			addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
 	} else
 		instruction_pointer_set(regs, addr + 4);
-
-	csky_insn_reg_set_val(regs, tmp, val);
 }
 
 void __kprobes
@@ -314,13 +312,11 @@ simulate_bhz32(u32 opcode, long addr, struct pt_regs *regs)
 
 	csky_insn_reg_get_val(regs, tmp, &val);
 
-	if (val > 0) {
+	if ((long) val > 0) {
 		instruction_pointer_set(regs,
 			addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
 	} else
 		instruction_pointer_set(regs, addr + 4);
-
-	csky_insn_reg_set_val(regs, tmp, val);
 }
 
 void __kprobes
@@ -331,13 +327,11 @@ simulate_blsz32(u32 opcode, long addr, struct pt_regs *regs)
 
 	csky_insn_reg_get_val(regs, tmp, &val);
 
-	if (val <= 0) {
+	if ((long) val <= 0) {
 		instruction_pointer_set(regs,
 			addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
 	} else
 		instruction_pointer_set(regs, addr + 4);
-
-	csky_insn_reg_set_val(regs, tmp, val);
 }
 
 void __kprobes
@@ -348,13 +342,11 @@ simulate_blz32(u32 opcode, long addr, struct pt_regs *regs)
 
 	csky_insn_reg_get_val(regs, tmp, &val);
 
-	if (val < 0) {
+	if ((long) val < 0) {
 		instruction_pointer_set(regs,
 			addr + sign_extend32((opcode & 0xffff0000) >> 15, 15));
 	} else
 		instruction_pointer_set(regs, addr + 4);
-
-	csky_insn_reg_set_val(regs, tmp, val);
 }
 
 void __kprobes
-- 
2.17.1