1 files changed, 81 insertions, 15 deletions

diff --git a/arch/s390/mm/extable.c b/arch/s390/mm/extable.c
index 1e4d2187541a..7498e858c401 100644
--- a/arch/s390/mm/extable.c
+++ b/arch/s390/mm/extable.c
@@ -7,6 +7,7 @@
 #include <linux/panic.h>
 #include <asm/asm-extable.h>
 #include <asm/extable.h>
+#include <asm/fpu.h>
 
 const struct exception_table_entry *s390_search_extables(unsigned long addr)
 {
@@ -26,7 +27,7 @@ static bool ex_handler_fixup(const struct exception_table_entry *ex, struct pt_r
 	return true;
 }
 
-static bool ex_handler_ua_store(const struct exception_table_entry *ex, struct pt_regs *regs)
+static bool ex_handler_ua_fault(const struct exception_table_entry *ex, struct pt_regs *regs)
 {
 	unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
 
@@ -35,26 +36,83 @@ static bool ex_handler_ua_store(const struct exception_table_entry *ex, struct p
 	return true;
 }
 
-static bool ex_handler_ua_load_mem(const struct exception_table_entry *ex, struct pt_regs *regs)
+static bool ex_handler_ua_load_reg(const struct exception_table_entry *ex,
+				   bool pair, struct pt_regs *regs)
 {
-	unsigned int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
+	unsigned int reg_zero = 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->gprs[reg_zero] = 0;
+	if (pair)
+		regs->gprs[reg_zero + 1] = 0;
 	regs->psw.addr = extable_fixup(ex);
 	return true;
 }
 
-static bool ex_handler_ua_load_reg(const struct exception_table_entry *ex, struct pt_regs *regs)
+static bool ex_handler_zeropad(const struct exception_table_entry *ex, 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);
+	unsigned int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
+	unsigned int reg_data = FIELD_GET(EX_DATA_REG_ERR, ex->data);
+	unsigned long data, addr, offset;
 
-	regs->gprs[reg_err] = -EFAULT;
-	regs->gprs[reg_zero] = 0;
+	addr = regs->gprs[reg_addr];
+	offset = addr & (sizeof(unsigned long) - 1);
+	addr &= ~(sizeof(unsigned long) - 1);
+	data = *(unsigned long *)addr;
+	data <<= BITS_PER_BYTE * offset;
+	regs->gprs[reg_data] = data;
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
+static bool ex_handler_fpc(const struct exception_table_entry *ex, struct pt_regs *regs)
+{
+	fpu_sfpc(0);
+	regs->psw.addr = extable_fixup(ex);
+	return true;
+}
+
+struct insn_ssf {
+	u64	opc1 : 8;
+	u64	r3   : 4;
+	u64	opc2 : 4;
+	u64	b1   : 4;
+	u64	d1   : 12;
+	u64	b2   : 4;
+	u64	d2   : 12;
+} __packed;
+
+static bool ex_handler_ua_mvcos(const struct exception_table_entry *ex,
+				bool from, struct pt_regs *regs)
+{
+	unsigned long uaddr, remainder;
+	struct insn_ssf *insn;
+
+	/*
+	 * If the faulting user space access crossed a page boundary retry by
+	 * limiting the access to the first page (adjust length accordingly).
+	 * Then the mvcos instruction will either complete with condition code
+	 * zero, or generate another fault where the user space access did not
+	 * cross a page boundary.
+	 * If the faulting user space access did not cross a page boundary set
+	 * length to zero and retry. In this case no user space access will
+	 * happen, and the mvcos instruction will complete with condition code
+	 * zero.
+	 * In both cases the instruction will complete with condition code
+	 * zero (copying finished), and the register which contains the
+	 * length, indicates the number of bytes copied.
+	 */
 	regs->psw.addr = extable_fixup(ex);
+	insn = (struct insn_ssf *)regs->psw.addr;
+	if (from)
+		uaddr = regs->gprs[insn->b2] + insn->d2;
+	else
+		uaddr = regs->gprs[insn->b1] + insn->d1;
+	remainder = PAGE_SIZE - (uaddr & (PAGE_SIZE - 1));
+	if (regs->gprs[insn->r3] <= remainder)
+		remainder = 0;
+	regs->gprs[insn->r3] = remainder;
 	return true;
 }
 
@@ -70,12 +128,20 @@ bool fixup_exception(struct pt_regs *regs)
 		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_FAULT:
+		return ex_handler_ua_fault(ex, regs);
 	case EX_TYPE_UA_LOAD_REG:
-		return ex_handler_ua_load_reg(ex, regs);
+		return ex_handler_ua_load_reg(ex, false, regs);
+	case EX_TYPE_UA_LOAD_REGPAIR:
+		return ex_handler_ua_load_reg(ex, true, regs);
+	case EX_TYPE_ZEROPAD:
+		return ex_handler_zeropad(ex, regs);
+	case EX_TYPE_FPC:
+		return ex_handler_fpc(ex, regs);
+	case EX_TYPE_UA_MVCOS_TO:
+		return ex_handler_ua_mvcos(ex, false, regs);
+	case EX_TYPE_UA_MVCOS_FROM:
+		return ex_handler_ua_mvcos(ex, true, regs);
 	}
 	panic("invalid exception table entry");
 }