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>

1 files changed, 12 insertions, 8 deletions

diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
index 6a0a9b132d7a..4ae68579031d 100644
--- 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)