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-rw-r--r--arch/s390/mm/extable.c86
1 files changed, 86 insertions, 0 deletions
diff --git a/arch/s390/mm/extable.c b/arch/s390/mm/extable.c
new file mode 100644
index 0000000000..fe87291df9
--- /dev/null
+++ b/arch/s390/mm/extable.c
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bitfield.h>
+#include <linux/extable.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/panic.h>
+#include <asm/asm-extable.h>
+#include <asm/extable.h>
+
+const struct exception_table_entry *s390_search_extables(unsigned long addr)
+{
+ const struct exception_table_entry *fixup;
+ size_t num;
+
+ fixup = search_exception_tables(addr);
+ if (fixup)
+ return fixup;
+ num = __stop_amode31_ex_table - __start_amode31_ex_table;
+ return search_extable(__start_amode31_ex_table, num, addr);
+}
+
+static bool ex_handler_fixup(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+ regs->psw.addr = extable_fixup(ex);
+ return true;
+}
+
+static bool ex_handler_ua_store(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+ unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+
+ regs->gprs[reg_err] = -EFAULT;
+ regs->psw.addr = extable_fixup(ex);
+ return true;
+}
+
+static bool ex_handler_ua_load_mem(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+ unsigned int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
+ unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+ size_t len = FIELD_GET(EX_DATA_LEN, ex->data);
+
+ regs->gprs[reg_err] = -EFAULT;
+ memset((void *)regs->gprs[reg_addr], 0, len);
+ regs->psw.addr = extable_fixup(ex);
+ return true;
+}
+
+static bool ex_handler_ua_load_reg(const struct exception_table_entry *ex,
+ bool pair, struct pt_regs *regs)
+{
+ unsigned int reg_zero = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
+ unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+
+ regs->gprs[reg_err] = -EFAULT;
+ regs->gprs[reg_zero] = 0;
+ if (pair)
+ regs->gprs[reg_zero + 1] = 0;
+ regs->psw.addr = extable_fixup(ex);
+ return true;
+}
+
+bool fixup_exception(struct pt_regs *regs)
+{
+ const struct exception_table_entry *ex;
+
+ ex = s390_search_extables(instruction_pointer(regs));
+ 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_UA_STORE:
+ return ex_handler_ua_store(ex, regs);
+ case EX_TYPE_UA_LOAD_MEM:
+ return ex_handler_ua_load_mem(ex, regs);
+ case EX_TYPE_UA_LOAD_REG:
+ return ex_handler_ua_load_reg(ex, false, regs);
+ case EX_TYPE_UA_LOAD_REGPAIR:
+ return ex_handler_ua_load_reg(ex, true, regs);
+ }
+ panic("invalid exception table entry");
+}