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4801e961be
commitae02615b7fupstream. The fixup section was added again by mistake when test_fp_ctl() was removed. The reason for the removal of the fixup section is described in commit484a8ed8b7("s390/extable: add dedicated uaccess handler"). Remove it again for the same reason. Add an exception handler which handles exceptions when the floating point control register is attempted to be set to invalid values. The exception handler sets the floating point control register to zero and continues execution at the specified address. The new sfpc inline assembly is open-coded to make back porting a bit easier. Fixes:702644249d("s390/fpu: get rid of test_fp_ctl()") Cc: stable@vger.kernel.org Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
114 lines
3.1 KiB
C
114 lines
3.1 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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static bool ex_handler_zeropad(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_data = FIELD_GET(EX_DATA_REG_ERR, ex->data);
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unsigned long data, addr, offset;
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addr = regs->gprs[reg_addr];
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offset = addr & (sizeof(unsigned long) - 1);
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addr &= ~(sizeof(unsigned long) - 1);
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data = *(unsigned long *)addr;
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data <<= BITS_PER_BYTE * offset;
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regs->gprs[reg_data] = data;
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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_fpc(const struct exception_table_entry *ex, struct pt_regs *regs)
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{
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asm volatile("sfpc %[val]\n" : : [val] "d" (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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case EX_TYPE_ZEROPAD:
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return ex_handler_zeropad(ex, regs);
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case EX_TYPE_FPC:
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return ex_handler_fpc(ex, regs);
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}
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panic("invalid exception table entry");
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}
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