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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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f39a8c4a22
Add new exception table type which is able to handle register pairs. If an exception is recognized on such an instruction the specified register pair will be zeroed, and the specified error register will be modified so it contains -EFAULT, similar to the existing EX_TABLE_UA_LOAD_REG() macro. Link: https://lore.kernel.org/r/Y2J8RSW2khWLgpPo@osiris Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
86 lines
2.3 KiB
C
86 lines
2.3 KiB
C
// 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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