2 files changed, 36 insertions, 0 deletions

diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 8a4ae8e73213..f576781d8d3b 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -551,6 +551,32 @@ static int tls_set(struct task_struct *target, const struct user_regset *regset,
         return ret;
 }
 
+static int system_call_get(struct task_struct *target,
+                           const struct user_regset *regset,
+                           unsigned int pos, unsigned int count,
+                           void *kbuf, void __user *ubuf)
+{
+        int syscallno = task_pt_regs(target)->syscallno;
+
+        return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
+                                   &syscallno, 0, -1);
+}
+
+static int system_call_set(struct task_struct *target,
+                           const struct user_regset *regset,
+                           unsigned int pos, unsigned int count,
+                           const void *kbuf, const void __user *ubuf)
+{
+        int syscallno, ret;
+
+        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &syscallno, 0, -1);
+        if (ret)
+                return ret;
+
+        task_pt_regs(target)->syscallno = syscallno;
+        return ret;
+}
+
 enum aarch64_regset {
         REGSET_GPR,
         REGSET_FPR,
@@ -559,6 +585,7 @@ enum aarch64_regset {
         REGSET_HW_BREAK,
         REGSET_HW_WATCH,
 #endif
+        REGSET_SYSTEM_CALL,
 };
 
 static const struct user_regset aarch64_regsets[] = {
@@ -608,6 +635,14 @@ static const struct user_regset aarch64_regsets[] = {
                 .set = hw_break_set,
         },
 #endif
+        [REGSET_SYSTEM_CALL] = {
+                .core_note_type = NT_ARM_SYSTEM_CALL,
+                .n = 1,
+                .size = sizeof(int),
+                .align = sizeof(int),
+                .get = system_call_get,
+                .set = system_call_set,
+        },
 };
 
 static const struct user_regset_view user_aarch64_view = {
diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
index ea9bf2561b9e..71e1d0ed92f7 100644
--- a/include/uapi/linux/elf.h
+++ b/include/uapi/linux/elf.h
@@ -397,6 +397,7 @@ typedef struct elf64_shdr {
 #define NT_ARM_TLS      0x401           /* ARM TLS register */
 #define NT_ARM_HW_BREAK 0x402           /* ARM hardware breakpoint registers */
 #define NT_ARM_HW_WATCH 0x403           /* ARM hardware watchpoint registers */
+#define NT_ARM_SYSTEM_CALL      0x404   /* ARM system call number */
 #define NT_METAG_CBUF   0x500           /* Metag catch buffer registers */
 #define NT_METAG_RPIPE  0x501           /* Metag read pipeline state */
 #define NT_METAG_TLS    0x502           /* Metag TLS pointer */