From 304acb717e5b67cf56f05bc5b21123758e1f7ea0 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 3 Apr 2015 23:27:15 +0100 Subject: [PATCH] MIPS: Set `si_code' for SIGFPE signals sent from emulation too Rework `process_fpemu_return' and move IEEE 754 exception interpretation there, from `do_fpe'. Record the cause bits set in FCSR before they are cleared and pass them through to `process_fpemu_return' so as to set `si_code' correctly too for SIGFPE signals sent from emulation rather than those issued by hardware with the FPE processor exception only. For simplicity `mipsr2_decoder' assumes `*fcr31' has been preinitialised and only sets it to anything if an FPU instruction has been emulated, which in turn is the only case SIGFPE can be issued for here. Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9705/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/fpu_emulator.h | 3 +- arch/mips/include/asm/mips-r2-to-r6-emul.h | 9 +- arch/mips/kernel/mips-r2-to-r6-emul.c | 4 +- arch/mips/kernel/traps.c | 150 ++++++++++++--------- arch/mips/kernel/unaligned.c | 4 +- 5 files changed, 97 insertions(+), 73 deletions(-) diff --git a/arch/mips/include/asm/fpu_emulator.h b/arch/mips/include/asm/fpu_emulator.h index 6370c82eb5e1..bfcc5c64b7b0 100644 --- a/arch/mips/include/asm/fpu_emulator.h +++ b/arch/mips/include/asm/fpu_emulator.h @@ -66,7 +66,8 @@ extern int do_dsemulret(struct pt_regs *xcp); extern int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx, int has_fpu, void *__user *fault_addr); -int process_fpemu_return(int sig, void __user *fault_addr); +int process_fpemu_return(int sig, void __user *fault_addr, + unsigned long fcr31); int mm_isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn, unsigned long *contpc); diff --git a/arch/mips/include/asm/mips-r2-to-r6-emul.h b/arch/mips/include/asm/mips-r2-to-r6-emul.h index dd6f1de5b621..4b89f28047f7 100644 --- a/arch/mips/include/asm/mips-r2-to-r6-emul.h +++ b/arch/mips/include/asm/mips-r2-to-r6-emul.h @@ -84,11 +84,16 @@ extern void do_trap_or_bp(struct pt_regs *regs, unsigned int code, #ifndef CONFIG_MIPSR2_TO_R6_EMULATOR static int mipsr2_emulation; -static inline int mipsr2_decoder(struct pt_regs *regs, u32 inst) { return 0; }; +static inline int mipsr2_decoder(struct pt_regs *regs, u32 inst, + unsigned long *fcr31) +{ + return 0; +}; #else /* MIPS R2 Emulator ON/OFF */ extern int mipsr2_emulation; -extern int mipsr2_decoder(struct pt_regs *regs, u32 inst); +extern int mipsr2_decoder(struct pt_regs *regs, u32 inst, + unsigned long *fcr31); #endif /* CONFIG_MIPSR2_TO_R6_EMULATOR */ #define NO_R6EMU (cpu_has_mips_r6 && !mipsr2_emulation) diff --git a/arch/mips/kernel/mips-r2-to-r6-emul.c b/arch/mips/kernel/mips-r2-to-r6-emul.c index 6633fa97d431..f2977f00911b 100644 --- a/arch/mips/kernel/mips-r2-to-r6-emul.c +++ b/arch/mips/kernel/mips-r2-to-r6-emul.c @@ -898,8 +898,9 @@ static inline int mipsr2_find_op_func(struct pt_regs *regs, u32 inst, * mipsr2_decoder: Decode and emulate a MIPS R2 instruction * @regs: Process register set * @inst: Instruction to decode and emulate + * @fcr31: Floating Point Control and Status Register returned */ -int mipsr2_decoder(struct pt_regs *regs, u32 inst) +int mipsr2_decoder(struct pt_regs *regs, u32 inst, unsigned long *fcr31) { int err = 0; unsigned long vaddr; @@ -1168,6 +1169,7 @@ fpu_emul: err = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 0, &fault_addr); + *fcr31 = current->thread.fpu.fcr31; /* * We can't allow the emulated instruction to leave any of diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 4a0552dbcf4a..7d5532adc890 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -700,29 +700,60 @@ asmlinkage void do_ov(struct pt_regs *regs) exception_exit(prev_state); } -int process_fpemu_return(int sig, void __user *fault_addr) +int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31) { - if (sig == SIGSEGV || sig == SIGBUS) { - struct siginfo si = {0}; + struct siginfo si = { 0 }; + + switch (sig) { + case 0: + return 0; + + case SIGFPE: si.si_addr = fault_addr; si.si_signo = sig; - if (sig == SIGSEGV) { - down_read(¤t->mm->mmap_sem); - if (find_vma(current->mm, (unsigned long)fault_addr)) - si.si_code = SEGV_ACCERR; - else - si.si_code = SEGV_MAPERR; - up_read(¤t->mm->mmap_sem); - } else { - si.si_code = BUS_ADRERR; - } + /* + * Inexact can happen together with Overflow or Underflow. + * Respect the mask to deliver the correct exception. + */ + fcr31 &= (fcr31 & FPU_CSR_ALL_E) << + (ffs(FPU_CSR_ALL_X) - ffs(FPU_CSR_ALL_E)); + if (fcr31 & FPU_CSR_INV_X) + si.si_code = FPE_FLTINV; + else if (fcr31 & FPU_CSR_DIV_X) + si.si_code = FPE_FLTDIV; + else if (fcr31 & FPU_CSR_OVF_X) + si.si_code = FPE_FLTOVF; + else if (fcr31 & FPU_CSR_UDF_X) + si.si_code = FPE_FLTUND; + else if (fcr31 & FPU_CSR_INE_X) + si.si_code = FPE_FLTRES; + else + si.si_code = __SI_FAULT; force_sig_info(sig, &si, current); return 1; - } else if (sig) { + + case SIGBUS: + si.si_addr = fault_addr; + si.si_signo = sig; + si.si_code = BUS_ADRERR; + force_sig_info(sig, &si, current); + return 1; + + case SIGSEGV: + si.si_addr = fault_addr; + si.si_signo = sig; + down_read(¤t->mm->mmap_sem); + if (find_vma(current->mm, (unsigned long)fault_addr)) + si.si_code = SEGV_ACCERR; + else + si.si_code = SEGV_MAPERR; + up_read(¤t->mm->mmap_sem); + force_sig_info(sig, &si, current); + return 1; + + default: force_sig(sig, current); return 1; - } else { - return 0; } } @@ -730,7 +761,8 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode, unsigned long old_epc, unsigned long old_ra) { union mips_instruction inst = { .word = opcode }; - void __user *fault_addr = NULL; + void __user *fault_addr; + unsigned long fcr31; int sig; /* If it's obviously not an FP instruction, skip it */ @@ -760,6 +792,7 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode, /* Run the emulator */ sig = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 1, &fault_addr); + fcr31 = current->thread.fpu.fcr31; /* * We can't allow the emulated instruction to leave any of @@ -767,12 +800,12 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode, */ current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X; - /* If something went wrong, signal */ - process_fpemu_return(sig, fault_addr); - /* Restore the hardware register state */ own_fpu(1); + /* Send a signal if required. */ + process_fpemu_return(sig, fault_addr, fcr31); + return 0; } @@ -782,7 +815,8 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode, asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31) { enum ctx_state prev_state; - siginfo_t info = {0}; + void __user *fault_addr; + int sig; prev_state = exception_enter(); if (notify_die(DIE_FP, "FP exception", regs, 0, regs_to_trapnr(regs), @@ -791,9 +825,6 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31) die_if_kernel("FP exception in kernel code", regs); if (fcr31 & FPU_CSR_UNI_X) { - int sig; - void __user *fault_addr = NULL; - /* * Unimplemented operation exception. If we've got the full * software emulator on-board, let's use it... @@ -810,6 +841,7 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31) /* Run the emulator */ sig = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 1, &fault_addr); + fcr31 = current->thread.fpu.fcr31; /* * We can't allow the emulated instruction to leave any of @@ -819,35 +851,13 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31) /* Restore the hardware register state */ own_fpu(1); /* Using the FPU again. */ - - /* If something went wrong, signal */ - process_fpemu_return(sig, fault_addr); - - goto out; + } else { + sig = SIGFPE; + fault_addr = (void __user *) regs->cp0_epc; } - /* - * Inexact can happen together with Overflow or Underflow. - * Respect the mask to deliver the correct exception. - */ - fcr31 &= (fcr31 & FPU_CSR_ALL_E) << - (ffs(FPU_CSR_ALL_X) - ffs(FPU_CSR_ALL_E)); - if (fcr31 & FPU_CSR_INV_X) - info.si_code = FPE_FLTINV; - else if (fcr31 & FPU_CSR_DIV_X) - info.si_code = FPE_FLTDIV; - else if (fcr31 & FPU_CSR_OVF_X) - info.si_code = FPE_FLTOVF; - else if (fcr31 & FPU_CSR_UDF_X) - info.si_code = FPE_FLTUND; - else if (fcr31 & FPU_CSR_INE_X) - info.si_code = FPE_FLTRES; - else - info.si_code = __SI_FAULT; - info.si_signo = SIGFPE; - info.si_errno = 0; - info.si_addr = (void __user *) regs->cp0_epc; - force_sig_info(SIGFPE, &info, current); + /* Send a signal if required. */ + process_fpemu_return(sig, fault_addr, fcr31); out: exception_exit(prev_state); @@ -1050,7 +1060,9 @@ asmlinkage void do_ri(struct pt_regs *regs) if (mipsr2_emulation && cpu_has_mips_r6 && likely(user_mode(regs)) && likely(get_user(opcode, epc) >= 0)) { - status = mipsr2_decoder(regs, opcode); + unsigned long fcr31 = 0; + + status = mipsr2_decoder(regs, opcode, &fcr31); switch (status) { case 0: case SIGEMT: @@ -1060,7 +1072,8 @@ asmlinkage void do_ri(struct pt_regs *regs) goto no_r2_instr; default: process_fpemu_return(status, - ¤t->thread.cp0_baduaddr); + ¤t->thread.cp0_baduaddr, + fcr31); task_thread_info(current)->r2_emul_return = 1; return; } @@ -1307,10 +1320,13 @@ asmlinkage void do_cpu(struct pt_regs *regs) enum ctx_state prev_state; unsigned int __user *epc; unsigned long old_epc, old31; + void __user *fault_addr; unsigned int opcode; + unsigned long fcr31; unsigned int cpid; int status, err; unsigned long __maybe_unused flags; + int sig; prev_state = exception_enter(); cpid = (regs->cp0_cause >> CAUSEB_CE) & 3; @@ -1384,22 +1400,22 @@ asmlinkage void do_cpu(struct pt_regs *regs) case 1: err = enable_restore_fp_context(0); - if (!raw_cpu_has_fpu || err) { - int sig; - void __user *fault_addr = NULL; - sig = fpu_emulator_cop1Handler(regs, - ¤t->thread.fpu, - 0, &fault_addr); + if (raw_cpu_has_fpu && !err) + break; - /* - * We can't allow the emulated instruction to leave - * any of the cause bits set in $fcr31. - */ - current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X; + sig = fpu_emulator_cop1Handler(regs, ¤t->thread.fpu, 0, + &fault_addr); + fcr31 = current->thread.fpu.fcr31; - if (!process_fpemu_return(sig, fault_addr) && !err) - mt_ase_fp_affinity(); - } + /* + * We can't allow the emulated instruction to leave + * any of the cause bits set in $fcr31. + */ + current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X; + + /* Send a signal if required. */ + if (!process_fpemu_return(sig, fault_addr, fcr31) && !err) + mt_ase_fp_affinity(); break; diff --git a/arch/mips/kernel/unaligned.c b/arch/mips/kernel/unaligned.c index bbb69695a0a1..cf51ad36f213 100644 --- a/arch/mips/kernel/unaligned.c +++ b/arch/mips/kernel/unaligned.c @@ -1076,7 +1076,7 @@ static void emulate_load_store_insn(struct pt_regs *regs, own_fpu(1); /* Restore FPU state. */ /* Signal if something went wrong. */ - process_fpemu_return(res, fault_addr); + process_fpemu_return(res, fault_addr, 0); if (res == 0) break; @@ -1511,7 +1511,7 @@ fpu_emul: own_fpu(1); /* restore FPU state */ /* If something went wrong, signal */ - process_fpemu_return(res, fault_addr); + process_fpemu_return(res, fault_addr, 0); if (res == 0) goto success; -- 2.20.1