From bcf084de5d429c0a321de6e2c508440148da1884 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Wed, 19 Oct 2016 14:33:20 +0100 Subject: MIPS: traps: Fix output of show_backtrace Since commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") the output from show_backtrace on MIPS has been pretty unreadable due to the lack of KERN_CONT markers. Use pr_cont to provide the appropriate markers & restore the expected output. Signed-off-by: Matt Redfearn Cc: Maciej W. Rozycki Cc: James Hogan Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14429/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/traps.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/mips/kernel/traps.c') diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 1f5fdee1dfc3..6ae5ea752d4c 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -156,7 +156,7 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs) print_ip_sym(pc); pc = unwind_stack(task, &sp, pc, &ra); } while (pc); - printk("\n"); + pr_cont("\n"); } /* -- cgit v1.2.3 From fe4e09e701213213cf2024e2979ea227c2e36c60 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Wed, 19 Oct 2016 14:33:21 +0100 Subject: MIPS: traps: Fix output of show_stacktrace Since commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") the output from show_stacktrace on MIPS has been pretty unreadable due to the lack of KERN_CONT markers. Use pr_cont to provide the appropriate markers & restore the expected output. Also start a new line with printk such that the presence of timing information does not interfere with output. Signed-off-by: Matt Redfearn Cc: Maciej W. Rozycki Cc: James Hogan Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14430/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/traps.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) (limited to 'arch/mips/kernel/traps.c') diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 6ae5ea752d4c..25ce866b2895 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -174,22 +174,24 @@ static void show_stacktrace(struct task_struct *task, printk("Stack :"); i = 0; while ((unsigned long) sp & (PAGE_SIZE - 1)) { - if (i && ((i % (64 / field)) == 0)) - printk("\n "); + if (i && ((i % (64 / field)) == 0)) { + pr_cont("\n"); + printk(" "); + } if (i > 39) { - printk(" ..."); + pr_cont(" ..."); break; } if (__get_user(stackdata, sp++)) { - printk(" (Bad stack address)"); + pr_cont(" (Bad stack address)"); break; } - printk(" %0*lx", field, stackdata); + pr_cont(" %0*lx", field, stackdata); i++; } - printk("\n"); + pr_cont("\n"); show_backtrace(task, regs); } -- cgit v1.2.3 From 41000c5819ee5aea8c5c3b388e4e21e679c1b95c Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Wed, 19 Oct 2016 14:33:22 +0100 Subject: MIPS: traps: Fix output of show_code Since commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") the output from show_code on MIPS has been pretty unreadable due to the lack of KERN_CONT markers. Use pr_cont to provide the appropriate markers & restore the expected output. Signed-off-by: Matt Redfearn Cc: Maciej W. Rozycki Cc: James Hogan Cc: Paul Burton Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14431/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/traps.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'arch/mips/kernel/traps.c') diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 25ce866b2895..273b4a419f76 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -231,18 +231,19 @@ static void show_code(unsigned int __user *pc) long i; unsigned short __user *pc16 = NULL; - printk("\nCode:"); + printk("Code:"); if ((unsigned long)pc & 1) pc16 = (unsigned short __user *)((unsigned long)pc & ~1); for(i = -3 ; i < 6 ; i++) { unsigned int insn; if (pc16 ? __get_user(insn, pc16 + i) : __get_user(insn, pc + i)) { - printk(" (Bad address in epc)\n"); + pr_cont(" (Bad address in epc)\n"); break; } - printk("%c%0*x%c", (i?' ':'<'), pc16 ? 4 : 8, insn, (i?' ':'>')); + pr_cont("%c%0*x%c", (i?' ':'<'), pc16 ? 4 : 8, insn, (i?' ':'>')); } + pr_cont("\n"); } static void __show_regs(const struct pt_regs *regs) -- cgit v1.2.3 From 752f5499823edb0c13c594f739363527178f714d Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Wed, 19 Oct 2016 14:33:23 +0100 Subject: MIPS: Fix __show_regs() output Since commit 4bcc595ccd80 ("printk: reinstate KERN_CONT for printing continuation lines") the output from __show_regs() on MIPS has been pretty unreadable due to the lack of KERN_CONT markers. Use pr_cont to provide the appropriate markers & restore the expected register output. Signed-off-by: Paul Burton Signed-off-by: Matt Redfearn Cc: Maciej W. Rozycki Cc: James Hogan Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14432/ Signed-off-by: Ralf Baechle --- arch/mips/kernel/traps.c | 42 +++++++++++++++++++++--------------------- 1 file changed, 21 insertions(+), 21 deletions(-) (limited to 'arch/mips/kernel/traps.c') diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 273b4a419f76..b9a910b208f9 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -262,15 +262,15 @@ static void __show_regs(const struct pt_regs *regs) if ((i % 4) == 0) printk("$%2d :", i); if (i == 0) - printk(" %0*lx", field, 0UL); + pr_cont(" %0*lx", field, 0UL); else if (i == 26 || i == 27) - printk(" %*s", field, ""); + pr_cont(" %*s", field, ""); else - printk(" %0*lx", field, regs->regs[i]); + pr_cont(" %0*lx", field, regs->regs[i]); i++; if ((i % 4) == 0) - printk("\n"); + pr_cont("\n"); } #ifdef CONFIG_CPU_HAS_SMARTMIPS @@ -291,46 +291,46 @@ static void __show_regs(const struct pt_regs *regs) if (cpu_has_3kex) { if (regs->cp0_status & ST0_KUO) - printk("KUo "); + pr_cont("KUo "); if (regs->cp0_status & ST0_IEO) - printk("IEo "); + pr_cont("IEo "); if (regs->cp0_status & ST0_KUP) - printk("KUp "); + pr_cont("KUp "); if (regs->cp0_status & ST0_IEP) - printk("IEp "); + pr_cont("IEp "); if (regs->cp0_status & ST0_KUC) - printk("KUc "); + pr_cont("KUc "); if (regs->cp0_status & ST0_IEC) - printk("IEc "); + pr_cont("IEc "); } else if (cpu_has_4kex) { if (regs->cp0_status & ST0_KX) - printk("KX "); + pr_cont("KX "); if (regs->cp0_status & ST0_SX) - printk("SX "); + pr_cont("SX "); if (regs->cp0_status & ST0_UX) - printk("UX "); + pr_cont("UX "); switch (regs->cp0_status & ST0_KSU) { case KSU_USER: - printk("USER "); + pr_cont("USER "); break; case KSU_SUPERVISOR: - printk("SUPERVISOR "); + pr_cont("SUPERVISOR "); break; case KSU_KERNEL: - printk("KERNEL "); + pr_cont("KERNEL "); break; default: - printk("BAD_MODE "); + pr_cont("BAD_MODE "); break; } if (regs->cp0_status & ST0_ERL) - printk("ERL "); + pr_cont("ERL "); if (regs->cp0_status & ST0_EXL) - printk("EXL "); + pr_cont("EXL "); if (regs->cp0_status & ST0_IE) - printk("IE "); + pr_cont("IE "); } - printk("\n"); + pr_cont("\n"); exccode = (cause & CAUSEF_EXCCODE) >> CAUSEB_EXCCODE; printk("Cause : %08x (ExcCode %02x)\n", cause, exccode); -- cgit v1.2.3 From 5a1aca4469fdccd5b74ba0b4e490173b2b447895 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Fri, 28 Oct 2016 08:21:03 +0100 Subject: MIPS: Fix FCSR Cause bit handling for correct SIGFPE issue Sanitize FCSR Cause bit handling, following a trail of past attempts: * commit 4249548454f7 ("MIPS: ptrace: Fix FP context restoration FCSR regression"), * commit 443c44032a54 ("MIPS: Always clear FCSR cause bits after emulation"), * commit 64bedffe4968 ("MIPS: Clear [MSA]FPE CSR.Cause after notify_die()"), * commit b1442d39fac2 ("MIPS: Prevent user from setting FCSR cause bits"), * commit b54d2901517d ("Properly handle branch delay slots in connection with signals."). Specifically do not mask these bits out in ptrace(2) processing and send a SIGFPE signal instead whenever a matching pair of an FCSR Cause and Enable bit is seen as execution of an affected context is about to resume. Only then clear Cause bits, and even then do not clear any bits that are set but masked with the respective Enable bits. Adjust Cause bit clearing throughout code likewise, except within the FPU emulator proper where they are set according to IEEE 754 exceptions raised as the operation emulated executed. Do so so that any IEEE 754 exceptions subject to their default handling are recorded like with operations executed by FPU hardware. Signed-off-by: Maciej W. Rozycki Cc: Paul Burton Cc: James Hogan Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/14460/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/fpu_emulator.h | 13 +++++++ arch/mips/include/asm/switch_to.h | 18 +++++++++ arch/mips/kernel/mips-r2-to-r6-emul.c | 10 ++--- arch/mips/kernel/ptrace.c | 7 ++-- arch/mips/kernel/traps.c | 72 +++++++++++++++++++---------------- 5 files changed, 78 insertions(+), 42 deletions(-) (limited to 'arch/mips/kernel/traps.c') diff --git a/arch/mips/include/asm/fpu_emulator.h b/arch/mips/include/asm/fpu_emulator.h index 355dc25172e7..c05369e0b8d6 100644 --- a/arch/mips/include/asm/fpu_emulator.h +++ b/arch/mips/include/asm/fpu_emulator.h @@ -63,6 +63,8 @@ do { \ extern int fpu_emulator_cop1Handler(struct pt_regs *xcp, struct mips_fpu_struct *ctx, int has_fpu, void *__user *fault_addr); +void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr, + struct task_struct *tsk); int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31); int isBranchInstr(struct pt_regs *regs, struct mm_decoded_insn dec_insn, @@ -81,4 +83,15 @@ static inline void fpu_emulator_init_fpu(void) set_fpr64(&t->thread.fpu.fpr[i], 0, SIGNALLING_NAN); } +/* + * Mask the FCSR Cause bits according to the Enable bits, observing + * that Unimplemented is always enabled. + */ +static inline unsigned long mask_fcr31_x(unsigned long fcr31) +{ + return fcr31 & (FPU_CSR_UNI_X | + ((fcr31 & FPU_CSR_ALL_E) << + (ffs(FPU_CSR_ALL_X) - ffs(FPU_CSR_ALL_E)))); +} + #endif /* _ASM_FPU_EMULATOR_H */ diff --git a/arch/mips/include/asm/switch_to.h b/arch/mips/include/asm/switch_to.h index ebb5c0f2f90d..c0ae27971e31 100644 --- a/arch/mips/include/asm/switch_to.h +++ b/arch/mips/include/asm/switch_to.h @@ -75,6 +75,22 @@ do { if (cpu_has_rw_llb) { \ } \ } while (0) +/* + * Check FCSR for any unmasked exceptions pending set with `ptrace', + * clear them and send a signal. + */ +#define __sanitize_fcr31(next) \ +do { \ + unsigned long fcr31 = mask_fcr31_x(next->thread.fpu.fcr31); \ + void __user *pc; \ + \ + if (unlikely(fcr31)) { \ + pc = (void __user *)task_pt_regs(next)->cp0_epc; \ + next->thread.fpu.fcr31 &= ~fcr31; \ + force_fcr31_sig(fcr31, pc, next); \ + } \ +} while (0) + /* * For newly created kernel threads switch_to() will return to * ret_from_kernel_thread, newly created user threads to ret_from_fork. @@ -85,6 +101,8 @@ do { if (cpu_has_rw_llb) { \ do { \ __mips_mt_fpaff_switch_to(prev); \ lose_fpu_inatomic(1, prev); \ + if (tsk_used_math(next)) \ + __sanitize_fcr31(next); \ if (cpu_has_dsp) { \ __save_dsp(prev); \ __restore_dsp(next); \ diff --git a/arch/mips/kernel/mips-r2-to-r6-emul.c b/arch/mips/kernel/mips-r2-to-r6-emul.c index 22dedd62818a..bd09853aecdf 100644 --- a/arch/mips/kernel/mips-r2-to-r6-emul.c +++ b/arch/mips/kernel/mips-r2-to-r6-emul.c @@ -899,7 +899,7 @@ 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 + * @fcr31: Floating Point Control and Status Register Cause bits returned */ int mipsr2_decoder(struct pt_regs *regs, u32 inst, unsigned long *fcr31) { @@ -1172,13 +1172,13 @@ 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 - * the cause bits set in $fcr31. + * We can't allow the emulated instruction to leave any + * enabled Cause bits set in $fcr31. */ - current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X; + *fcr31 = res = mask_fcr31_x(current->thread.fpu.fcr31); + current->thread.fpu.fcr31 &= ~res; /* * this is a tricky issue - lose_fpu() uses LL/SC atomics diff --git a/arch/mips/kernel/ptrace.c b/arch/mips/kernel/ptrace.c index fd3a9580661a..a92994d60e91 100644 --- a/arch/mips/kernel/ptrace.c +++ b/arch/mips/kernel/ptrace.c @@ -79,16 +79,15 @@ void ptrace_disable(struct task_struct *child) } /* - * Poke at FCSR according to its mask. Don't set the cause bits as - * this is currently not handled correctly in FP context restoration - * and will cause an oops if a corresponding enable bit is set. + * Poke at FCSR according to its mask. Set the Cause bits even + * if a corresponding Enable bit is set. This will be noticed at + * the time the thread is switched to and SIGFPE thrown accordingly. */ static void ptrace_setfcr31(struct task_struct *child, u32 value) { u32 fcr31; u32 mask; - value &= ~FPU_CSR_ALL_X; fcr31 = child->thread.fpu.fcr31; mask = boot_cpu_data.fpu_msk31; child->thread.fpu.fcr31 = (value & ~mask) | (fcr31 & mask); diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index b9a910b208f9..3905003dfe2b 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -708,6 +708,32 @@ asmlinkage void do_ov(struct pt_regs *regs) exception_exit(prev_state); } +/* + * Send SIGFPE according to FCSR Cause bits, which must have already + * been masked against Enable bits. This is impotant as Inexact can + * happen together with Overflow or Underflow, and `ptrace' can set + * any bits. + */ +void force_fcr31_sig(unsigned long fcr31, void __user *fault_addr, + struct task_struct *tsk) +{ + struct siginfo si = { .si_addr = fault_addr, .si_signo = SIGFPE }; + + 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(SIGFPE, &si, tsk); +} + int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31) { struct siginfo si = { 0 }; @@ -718,27 +744,7 @@ int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31) return 0; case SIGFPE: - si.si_addr = fault_addr; - si.si_signo = sig; - /* - * 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); + force_fcr31_sig(fcr31, fault_addr, current); return 1; case SIGBUS: @@ -802,13 +808,13 @@ 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 - * the cause bits set in $fcr31. + * We can't allow the emulated instruction to leave any + * enabled Cause bits set in $fcr31. */ - current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X; + fcr31 = mask_fcr31_x(current->thread.fpu.fcr31); + current->thread.fpu.fcr31 &= ~fcr31; /* Restore the hardware register state */ own_fpu(1); @@ -834,7 +840,7 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31) goto out; /* Clear FCSR.Cause before enabling interrupts */ - write_32bit_cp1_register(CP1_STATUS, fcr31 & ~FPU_CSR_ALL_X); + write_32bit_cp1_register(CP1_STATUS, fcr31 & ~mask_fcr31_x(fcr31)); local_irq_enable(); die_if_kernel("FP exception in kernel code", regs); @@ -856,13 +862,13 @@ 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 - * the cause bits set in $fcr31. + * We can't allow the emulated instruction to leave any + * enabled Cause bits set in $fcr31. */ - current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X; + fcr31 = mask_fcr31_x(current->thread.fpu.fcr31); + current->thread.fpu.fcr31 &= ~fcr31; /* Restore the hardware register state */ own_fpu(1); /* Using the FPU again. */ @@ -1427,13 +1433,13 @@ asmlinkage void do_cpu(struct pt_regs *regs) sig = 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 the cause bits set in $fcr31. + * any enabled Cause bits set in $fcr31. */ - current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X; + fcr31 = mask_fcr31_x(current->thread.fpu.fcr31); + current->thread.fpu.fcr31 &= ~fcr31; /* Send a signal if required. */ if (!process_fpemu_return(sig, fault_addr, fcr31) && !err) -- cgit v1.2.3