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// 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;
}
static bool ex_handler_zeropad(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_data = FIELD_GET(EX_DATA_REG_ERR, ex->data);
unsigned long data, addr, offset;
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;
}
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);
case EX_TYPE_ZEROPAD:
return ex_handler_zeropad(ex, regs);
}
panic("invalid exception table entry");
}
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