1 files changed, 31 insertions, 0 deletions

diff --git a/arch/arm64/kernel/syscall.c b/arch/arm64/kernel/syscall.c
index 5610ac01c1ec..871c739f060a 100644
--- a/arch/arm64/kernel/syscall.c
+++ b/arch/arm64/kernel/syscall.c
@@ -8,6 +8,7 @@
 #include <linux/syscalls.h>
 
 #include <asm/daifflags.h>
+#include <asm/debug-monitors.h>
 #include <asm/fpsimd.h>
 #include <asm/syscall.h>
 #include <asm/thread_info.h>
@@ -60,6 +61,35 @@ static inline bool has_syscall_work(unsigned long flags)
 int syscall_trace_enter(struct pt_regs *regs);
 void syscall_trace_exit(struct pt_regs *regs);
 
+#ifdef CONFIG_ARM64_ERRATUM_1463225
+DECLARE_PER_CPU(int, __in_cortex_a76_erratum_1463225_wa);
+
+static void cortex_a76_erratum_1463225_svc_handler(void)
+{
+        u32 reg, val;
+
+        if (!unlikely(test_thread_flag(TIF_SINGLESTEP)))
+                return;
+
+        if (!unlikely(this_cpu_has_cap(ARM64_WORKAROUND_1463225)))
+                return;
+
+        __this_cpu_write(__in_cortex_a76_erratum_1463225_wa, 1);
+        reg = read_sysreg(mdscr_el1);
+        val = reg | DBG_MDSCR_SS | DBG_MDSCR_KDE;
+        write_sysreg(val, mdscr_el1);
+        asm volatile("msr daifclr, #8");
+        isb();
+
+        /* We will have taken a single-step exception by this point */
+
+        write_sysreg(reg, mdscr_el1);
+        __this_cpu_write(__in_cortex_a76_erratum_1463225_wa, 0);
+}
+#else
+static void cortex_a76_erratum_1463225_svc_handler(void) { }
+#endif /* CONFIG_ARM64_ERRATUM_1463225 */
+
 static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
                            const syscall_fn_t syscall_table[])
 {
@@ -68,6 +98,7 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
         regs->orig_x0 = regs->regs[0];
         regs->syscallno = scno;
 
+        cortex_a76_erratum_1463225_svc_handler();
         local_daif_restore(DAIF_PROCCTX);
         user_exit();