87 lines
2.3 KiB
C
87 lines
2.3 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/bitfield.h>
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#include <linux/extable.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/panic.h>
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#include <asm/asm-extable.h>
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#include <asm/extable.h>
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const struct exception_table_entry *s390_search_extables(unsigned long addr)
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{
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const struct exception_table_entry *fixup;
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size_t num;
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fixup = search_exception_tables(addr);
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if (fixup)
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return fixup;
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num = __stop_amode31_ex_table - __start_amode31_ex_table;
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return search_extable(__start_amode31_ex_table, num, addr);
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}
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static bool ex_handler_fixup(const struct exception_table_entry *ex, struct pt_regs *regs)
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{
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regs->psw.addr = extable_fixup(ex);
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return true;
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}
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static bool ex_handler_ua_store(const struct exception_table_entry *ex, struct pt_regs *regs)
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{
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unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
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regs->gprs[reg_err] = -EFAULT;
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regs->psw.addr = extable_fixup(ex);
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return true;
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}
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static bool ex_handler_ua_load_mem(const struct exception_table_entry *ex, struct pt_regs *regs)
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{
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unsigned int reg_addr = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
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unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
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size_t len = FIELD_GET(EX_DATA_LEN, ex->data);
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regs->gprs[reg_err] = -EFAULT;
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memset((void *)regs->gprs[reg_addr], 0, len);
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regs->psw.addr = extable_fixup(ex);
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return true;
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}
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static bool ex_handler_ua_load_reg(const struct exception_table_entry *ex,
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bool pair, struct pt_regs *regs)
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{
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unsigned int reg_zero = FIELD_GET(EX_DATA_REG_ADDR, ex->data);
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unsigned int reg_err = FIELD_GET(EX_DATA_REG_ERR, ex->data);
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regs->gprs[reg_err] = -EFAULT;
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regs->gprs[reg_zero] = 0;
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if (pair)
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regs->gprs[reg_zero + 1] = 0;
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regs->psw.addr = extable_fixup(ex);
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return true;
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}
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bool fixup_exception(struct pt_regs *regs)
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{
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const struct exception_table_entry *ex;
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ex = s390_search_extables(instruction_pointer(regs));
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if (!ex)
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return false;
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switch (ex->type) {
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case EX_TYPE_FIXUP:
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return ex_handler_fixup(ex, regs);
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case EX_TYPE_BPF:
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return ex_handler_bpf(ex, regs);
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case EX_TYPE_UA_STORE:
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return ex_handler_ua_store(ex, regs);
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case EX_TYPE_UA_LOAD_MEM:
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return ex_handler_ua_load_mem(ex, regs);
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case EX_TYPE_UA_LOAD_REG:
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return ex_handler_ua_load_reg(ex, false, regs);
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case EX_TYPE_UA_LOAD_REGPAIR:
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return ex_handler_ua_load_reg(ex, true, regs);
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}
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panic("invalid exception table entry");
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}
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