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-rw-r--r--arch/arm64/include/asm/ptrace.h22
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index ec60174c8c18..b2de32939ada 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -305,6 +305,28 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
return regs->regs[0];
}
+/**
+ * regs_get_kernel_argument() - get Nth function argument in kernel
+ * @regs: pt_regs of that context
+ * @n: function argument number (start from 0)
+ *
+ * regs_get_argument() returns @n th argument of the function call.
+ *
+ * Note that this chooses the most likely register mapping. In very rare
+ * cases this may not return correct data, for example, if one of the
+ * function parameters is 16 bytes or bigger. In such cases, we cannot
+ * get access the parameter correctly and the register assignment of
+ * subsequent parameters will be shifted.
+ */
+static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs,
+ unsigned int n)
+{
+#define NR_REG_ARGUMENTS 8
+ if (n < NR_REG_ARGUMENTS)
+ return pt_regs_read_reg(regs, n);
+ return 0;
+}
+
/* We must avoid circular header include via sched.h */
struct task_struct;
int valid_user_regs(struct user_pt_regs *regs, struct task_struct *task);