forked from mirrors/linux
11a3799dbe
Fix a regression introduced with commitfb6883e580("MIPS: microMIPS: Support handling of delay slots.") and defer to `__compute_return_epc' if the ISA bit is set in EPC with non-MIPS16, non-microMIPS hardware, which will then arrange for a SIGBUS due to an unaligned instruction reference. Returning EPC here is never correct as the API defines this function's result to be either a negative error code on failure or one of 0 and BRANCH_LIKELY_TAKEN on success. Fixes:fb6883e580("MIPS: microMIPS: Support handling of delay slots.") Signed-off-by: Maciej W. Rozycki <macro@imgtec.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # 3.9+ Patchwork: https://patchwork.linux-mips.org/patch/16395/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1996, 1997, 1998, 2001 by Ralf Baechle
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*/
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#ifndef _ASM_BRANCH_H
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#define _ASM_BRANCH_H
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#include <asm/cpu-features.h>
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#include <asm/mipsregs.h>
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#include <asm/ptrace.h>
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#include <asm/inst.h>
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extern int __isa_exception_epc(struct pt_regs *regs);
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extern int __compute_return_epc(struct pt_regs *regs);
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extern int __compute_return_epc_for_insn(struct pt_regs *regs,
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union mips_instruction insn);
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extern int __microMIPS_compute_return_epc(struct pt_regs *regs);
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extern int __MIPS16e_compute_return_epc(struct pt_regs *regs);
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/*
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* microMIPS bitfields
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*/
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#define MM_POOL32A_MINOR_MASK 0x3f
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#define MM_POOL32A_MINOR_SHIFT 0x6
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#define MM_MIPS32_COND_FC 0x30
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extern int __mm_isBranchInstr(struct pt_regs *regs,
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struct mm_decoded_insn dec_insn, unsigned long *contpc);
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static inline int mm_isBranchInstr(struct pt_regs *regs,
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struct mm_decoded_insn dec_insn, unsigned long *contpc)
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{
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if (!cpu_has_mmips)
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return 0;
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return __mm_isBranchInstr(regs, dec_insn, contpc);
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}
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static inline int delay_slot(struct pt_regs *regs)
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{
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return regs->cp0_cause & CAUSEF_BD;
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}
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static inline void clear_delay_slot(struct pt_regs *regs)
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{
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regs->cp0_cause &= ~CAUSEF_BD;
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}
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static inline void set_delay_slot(struct pt_regs *regs)
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{
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regs->cp0_cause |= CAUSEF_BD;
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}
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static inline unsigned long exception_epc(struct pt_regs *regs)
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{
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if (likely(!delay_slot(regs)))
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return regs->cp0_epc;
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if (get_isa16_mode(regs->cp0_epc))
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return __isa_exception_epc(regs);
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return regs->cp0_epc + 4;
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}
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#define BRANCH_LIKELY_TAKEN 0x0001
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static inline int compute_return_epc(struct pt_regs *regs)
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{
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if (get_isa16_mode(regs->cp0_epc)) {
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if (cpu_has_mmips)
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return __microMIPS_compute_return_epc(regs);
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if (cpu_has_mips16)
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return __MIPS16e_compute_return_epc(regs);
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} else if (!delay_slot(regs)) {
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regs->cp0_epc += 4;
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return 0;
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}
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return __compute_return_epc(regs);
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}
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static inline int MIPS16e_compute_return_epc(struct pt_regs *regs,
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union mips16e_instruction *inst)
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{
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if (likely(!delay_slot(regs))) {
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if (inst->ri.opcode == MIPS16e_extend_op) {
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regs->cp0_epc += 4;
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return 0;
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}
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regs->cp0_epc += 2;
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return 0;
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}
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return __MIPS16e_compute_return_epc(regs);
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}
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#endif /* _ASM_BRANCH_H */
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