summaryrefslogtreecommitdiffstats
path: root/arch/riscv/mm/extable.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/riscv/mm/extable.c')
-rw-r--r--arch/riscv/mm/extable.c71
1 files changed, 71 insertions, 0 deletions
diff --git a/arch/riscv/mm/extable.c b/arch/riscv/mm/extable.c
new file mode 100644
index 0000000000..35484d830f
--- /dev/null
+++ b/arch/riscv/mm/extable.c
@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2009 Sunplus Core Technology Co., Ltd.
+ * Lennox Wu <lennox.wu@sunplusct.com>
+ * Chen Liqin <liqin.chen@sunplusct.com>
+ * Copyright (C) 2013 Regents of the University of California
+ */
+
+
+#include <linux/bitfield.h>
+#include <linux/extable.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <asm/asm-extable.h>
+#include <asm/ptrace.h>
+
+static inline unsigned long
+get_ex_fixup(const struct exception_table_entry *ex)
+{
+ return ((unsigned long)&ex->fixup + ex->fixup);
+}
+
+static bool ex_handler_fixup(const struct exception_table_entry *ex,
+ struct pt_regs *regs)
+{
+ regs->epc = get_ex_fixup(ex);
+ return true;
+}
+
+static inline void regs_set_gpr(struct pt_regs *regs, unsigned int offset,
+ unsigned long val)
+{
+ if (unlikely(offset > MAX_REG_OFFSET))
+ return;
+
+ if (offset)
+ *(unsigned long *)((unsigned long)regs + offset) = val;
+}
+
+static bool ex_handler_uaccess_err_zero(const struct exception_table_entry *ex,
+ struct pt_regs *regs)
+{
+ int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+ int reg_zero = FIELD_GET(EX_DATA_REG_ZERO, ex->data);
+
+ regs_set_gpr(regs, reg_err * sizeof(unsigned long), -EFAULT);
+ regs_set_gpr(regs, reg_zero * sizeof(unsigned long), 0);
+
+ regs->epc = get_ex_fixup(ex);
+ return true;
+}
+
+bool fixup_exception(struct pt_regs *regs)
+{
+ const struct exception_table_entry *ex;
+
+ ex = search_exception_tables(regs->epc);
+ if (!ex)
+ return false;
+
+ switch (ex->type) {
+ case EX_TYPE_FIXUP:
+ return ex_handler_fixup(ex, regs);
+ case EX_TYPE_BPF:
+ return ex_handler_bpf(ex, regs);
+ case EX_TYPE_UACCESS_ERR_ZERO:
+ return ex_handler_uaccess_err_zero(ex, regs);
+ }
+
+ BUG();
+}