arm64: debug: make aarch32 bkpt checking endian clean

The current breakpoint instruction checking code for A32 is not endian
clean. Fix this with appropriate byte-swapping when retrieving
instructions.

Signed-off-by: Matthew Leach <matthew.leach@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 6a0a9b1..4ae6857 100644 (file)
--- a/arch/arm64/kernel/debug-monitors.c
+++ b/arch/arm64/kernel/debug-monitors.c
@@ -248,7 +248,8 @@ static int brk_handler(unsigned long addr, unsigned int esr,
 int aarch32_break_handler(struct pt_regs *regs)
 {
        siginfo_t info;
-       unsigned int instr;
+       u32 arm_instr;
+       u16 thumb_instr;
        bool bp = false;
        void __user *pc = (void __user *)instruction_pointer(regs);
 
@@ -257,18 +258,21 @@ int aarch32_break_handler(struct pt_regs *regs)
 
        if (compat_thumb_mode(regs)) {
                /* get 16-bit Thumb instruction */
-               get_user(instr, (u16 __user *)pc);
-               if (instr == AARCH32_BREAK_THUMB2_LO) {
+               get_user(thumb_instr, (u16 __user *)pc);
+               thumb_instr = le16_to_cpu(thumb_instr);
+               if (thumb_instr == AARCH32_BREAK_THUMB2_LO) {
                        /* get second half of 32-bit Thumb-2 instruction */
-                       get_user(instr, (u16 __user *)(pc + 2));
-                       bp = instr == AARCH32_BREAK_THUMB2_HI;
+                       get_user(thumb_instr, (u16 __user *)(pc + 2));
+                       thumb_instr = le16_to_cpu(thumb_instr);
+                       bp = thumb_instr == AARCH32_BREAK_THUMB2_HI;
                } else {
-                       bp = instr == AARCH32_BREAK_THUMB;
+                       bp = thumb_instr == AARCH32_BREAK_THUMB;
                }
        } else {
                /* 32-bit ARM instruction */
-               get_user(instr, (u32 __user *)pc);
-               bp = (instr & ~0xf0000000) == AARCH32_BREAK_ARM;
+               get_user(arm_instr, (u32 __user *)pc);
+               arm_instr = le32_to_cpu(arm_instr);
+               bp = (arm_instr & ~0xf0000000) == AARCH32_BREAK_ARM;
        }
 
        if (!bp)