From 44a12806d010944a5727f1dc99123121e3e2c8c6 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Mon, 7 Aug 2017 21:25:01 +1000 Subject: Revert "powerpc/64: Avoid restore_math call if possible in syscall exit" This reverts commit bc4f65e4cf9d6cc43e0e9ba0b8648cf9201cd55f. As reported by Andreas, this commit is causing unrecoverable SLB misses in the system call exit path: Unrecoverable exception 4100 at c00000000000a1ec Oops: Unrecoverable exception, sig: 6 [#1] SMP NR_CPUS=2 PowerMac ... CPU: 0 PID: 18626 Comm: rm Not tainted 4.13.0-rc3 #1 task: c00000018335e080 task.stack: c000000139e50000 NIP: c00000000000a1ec LR: c00000000000a118 CTR: 0000000000000000 REGS: c000000139e53bb0 TRAP: 4100 Not tainted (4.13.0-rc3) MSR: 9000000000001030 CR: 24000044 XER: 20000000 SOFTE: 1 GPR00: 0000000000000000 c000000139e53e30 c000000000abb500 fffffffffffffffe GPR04: c0000001eb866298 0000000000000000 0000000000000000 c00000018335e080 GPR08: 900000000000d032 0000000000000000 0000000000000002 fffffffffffff001 GPR12: c000000139e50000 c00000000ffff000 00003fffa8c0dca0 00003fffa8c0dc88 GPR16: 0000000010000000 0000000000000001 00003fffa8c0eaa0 0000000000000000 GPR20: 00003fffa8c27528 00003fffa8c27b00 0000000000000000 0000000000000000 GPR24: 00003fffa8c0d918 00003ffff1b3efa0 00003fffa8c26d68 0000000000000000 GPR28: 00003fffa8c249e8 00003fffa8c263d0 00003fffa8c27550 00003ffff1b3ef10 NIP [c00000000000a1ec] system_call_exit+0xc0/0x21c LR [c00000000000a118] system_call+0x58/0x6c Call Trace: [c000000139e53e30] [c00000000000a118] system_call+0x58/0x6c (unreliable) Instruction dump: 64a51000 7c6300d0 f8a101a0 4bffff9c 3c000000 60000006 780007c6 64000000 60000000 7c004039 4082001c e8ed0170 <88070b78> 88c70b79 7c003214 2c200000 This is caused by us trying to load THREAD_LOAD_FP with MSR_RI=0, and taking an SLB miss on the thread struct. Reported-by: Andreas Schwab Diagnosed-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 9f3e2c932dcc..ec480966f9bf 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -511,10 +511,6 @@ void restore_math(struct pt_regs *regs) { unsigned long msr; - /* - * Syscall exit makes a similar initial check before branching - * to restore_math. Keep them in synch. - */ if (!msr_tm_active(regs->msr) && !current->thread.load_fp && !loadvec(current->thread)) return; -- cgit v1.2.3 From 5a69aec945d27e78abac9fd032533d3aaebf7c1e Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 16 Aug 2017 16:01:14 +1000 Subject: powerpc: Fix VSX enabling/flushing to also test MSR_FP and MSR_VEC VSX uses a combination of the old vector registers, the old FP registers and new "second halves" of the FP registers. Thus when we need to see the VSX state in the thread struct (flush_vsx_to_thread()) or when we'll use the VSX in the kernel (enable_kernel_vsx()) we need to ensure they are all flushed into the thread struct if either of them is individually enabled. Unfortunately we only tested if the whole VSX was enabled, not if they were individually enabled. Fixes: 72cd7b44bc99 ("powerpc: Uncomment and make enable_kernel_vsx() routine available") Cc: stable@vger.kernel.org # v4.3+ Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index ec480966f9bf..1f0fd361e09b 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -362,7 +362,8 @@ void enable_kernel_vsx(void) cpumsr = msr_check_and_set(MSR_FP|MSR_VEC|MSR_VSX); - if (current->thread.regs && (current->thread.regs->msr & MSR_VSX)) { + if (current->thread.regs && + (current->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP))) { check_if_tm_restore_required(current); /* * If a thread has already been reclaimed then the @@ -386,7 +387,7 @@ void flush_vsx_to_thread(struct task_struct *tsk) { if (tsk->thread.regs) { preempt_disable(); - if (tsk->thread.regs->msr & MSR_VSX) { + if (tsk->thread.regs->msr & (MSR_VSX|MSR_VEC|MSR_FP)) { BUG_ON(tsk != current); giveup_vsx(tsk); } -- cgit v1.2.3 From 6a303833b5e3acbb4c97cc11cc688650d070da19 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 16 Aug 2017 16:01:15 +1000 Subject: powerpc: Fix missing newline before { Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 9f3e2c932dcc..cd476e338768 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -230,7 +230,8 @@ void enable_kernel_fp(void) } EXPORT_SYMBOL(enable_kernel_fp); -static int restore_fp(struct task_struct *tsk) { +static int restore_fp(struct task_struct *tsk) +{ if (tsk->thread.load_fp || msr_tm_active(tsk->thread.regs->msr)) { load_fp_state(¤t->thread.fp_state); current->thread.load_fp++; -- cgit v1.2.3 From 746874d31cd1173f2dd234c1a5f692939afe0b71 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 16 Aug 2017 16:01:16 +1000 Subject: powerpc: Remove redundant FP/Altivec giveup code __giveup_vsx() already calls those two functions. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 4 ---- 1 file changed, 4 deletions(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index cd476e338768..32b58648052f 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -374,10 +374,6 @@ void enable_kernel_vsx(void) */ if(!msr_tm_active(cpumsr) && msr_tm_active(current->thread.regs->msr)) return; - if (current->thread.regs->msr & MSR_FP) - __giveup_fpu(current); - if (current->thread.regs->msr & MSR_VEC) - __giveup_altivec(current); __giveup_vsx(current); } } -- cgit v1.2.3 From dc801081f2eae57a389bc9230ff4fb0d91487990 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 16 Aug 2017 16:01:17 +1000 Subject: powerpc: Remove redundant clear of MSR_VSX in __giveup_vsx() __giveup_fpu() already does it and we cannot have MSR_VSX set without having MSR_FP also set. This also adds a warning to check we indeed do Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 32b58648052f..ff522bf75d53 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -331,11 +331,19 @@ static inline int restore_altivec(struct task_struct *tsk) { return 0; } #ifdef CONFIG_VSX static void __giveup_vsx(struct task_struct *tsk) { - if (tsk->thread.regs->msr & MSR_FP) + unsigned long msr = tsk->thread.regs->msr; + + /* + * We should never be ssetting MSR_VSX without also setting + * MSR_FP and MSR_VEC + */ + WARN_ON((msr & MSR_VSX) && !((msr & MSR_FP) && (msr & MSR_VEC))); + + /* __giveup_fpu will clear MSR_VSX */ + if (msr & MSR_FP) __giveup_fpu(tsk); - if (tsk->thread.regs->msr & MSR_VEC) + if (msr & MSR_VEC) __giveup_altivec(tsk); - tsk->thread.regs->msr &= ~MSR_VSX; } static void giveup_vsx(struct task_struct *tsk) -- cgit v1.2.3 From 96c79b6bd74039e8a799e4aa2d331cbd478ab5a1 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Wed, 16 Aug 2017 16:01:18 +1000 Subject: powerpc: Remove more redundant VSX save/tests __giveup_vsx/save_vsx are completely equivalent to testing MSR_FP and MSR_VEC and calling the corresponding giveup/save function so just remove the spurious VSX cases. Also add WARN_ONs checking that we never have VSX enabled without the two other. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 33 ++++++++------------------------- 1 file changed, 8 insertions(+), 25 deletions(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index ff522bf75d53..cc5bae4bba7b 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -355,14 +355,6 @@ static void giveup_vsx(struct task_struct *tsk) msr_check_and_clear(MSR_FP|MSR_VEC|MSR_VSX); } -static void save_vsx(struct task_struct *tsk) -{ - if (tsk->thread.regs->msr & MSR_FP) - save_fpu(tsk); - if (tsk->thread.regs->msr & MSR_VEC) - save_altivec(tsk); -} - void enable_kernel_vsx(void) { unsigned long cpumsr; @@ -411,7 +403,6 @@ static int restore_vsx(struct task_struct *tsk) } #else static inline int restore_vsx(struct task_struct *tsk) { return 0; } -static inline void save_vsx(struct task_struct *tsk) { } #endif /* CONFIG_VSX */ #ifdef CONFIG_SPE @@ -491,6 +482,8 @@ void giveup_all(struct task_struct *tsk) msr_check_and_set(msr_all_available); check_if_tm_restore_required(tsk); + WARN_ON((usermsr & MSR_VSX) && !((usermsr & MSR_FP) && (usermsr & MSR_VEC))); + #ifdef CONFIG_PPC_FPU if (usermsr & MSR_FP) __giveup_fpu(tsk); @@ -499,10 +492,6 @@ void giveup_all(struct task_struct *tsk) if (usermsr & MSR_VEC) __giveup_altivec(tsk); #endif -#ifdef CONFIG_VSX - if (usermsr & MSR_VSX) - __giveup_vsx(tsk); -#endif #ifdef CONFIG_SPE if (usermsr & MSR_SPE) __giveup_spe(tsk); @@ -561,19 +550,13 @@ void save_all(struct task_struct *tsk) msr_check_and_set(msr_all_available); - /* - * Saving the way the register space is in hardware, save_vsx boils - * down to a save_fpu() and save_altivec() - */ - if (usermsr & MSR_VSX) { - save_vsx(tsk); - } else { - if (usermsr & MSR_FP) - save_fpu(tsk); + WARN_ON((usermsr & MSR_VSX) && !((usermsr & MSR_FP) && (usermsr & MSR_VEC))); - if (usermsr & MSR_VEC) - save_altivec(tsk); - } + if (usermsr & MSR_FP) + save_fpu(tsk); + + if (usermsr & MSR_VEC) + save_altivec(tsk); if (usermsr & MSR_SPE) __giveup_spe(tsk); -- cgit v1.2.3 From d1d0d5ffb3006eaf9b5f41c89fe801e032cbbfe4 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Sat, 12 Aug 2017 02:39:07 +1000 Subject: powerpc/64: Optimise set/clear of CTRL[RUN] (runlatch) On modern CPUs the CTRL register is read-only except bit 63 which is the run latch control. This means it can be updated with a mtspr rather than mfspr/mtspr. To accomodate older CPUs (Cell at least), where there are other bits in the register, we still do a read/modify/write on pre 2.06 CPUs. Signed-off-by: Nicholas Piggin [mpe: Update change log to mention 2.06 workaround] Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 34bd94b090e2..0a00d59df537 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1979,11 +1979,25 @@ void show_stack(struct task_struct *tsk, unsigned long *stack) void notrace __ppc64_runlatch_on(void) { struct thread_info *ti = current_thread_info(); - unsigned long ctrl; - ctrl = mfspr(SPRN_CTRLF); - ctrl |= CTRL_RUNLATCH; - mtspr(SPRN_CTRLT, ctrl); + if (cpu_has_feature(CPU_FTR_ARCH_206)) { + /* + * Least significant bit (RUN) is the only writable bit of + * the CTRL register, so we can avoid mfspr. 2.06 is not the + * earliest ISA where this is the case, but it's convenient. + */ + mtspr(SPRN_CTRLT, CTRL_RUNLATCH); + } else { + unsigned long ctrl; + + /* + * Some architectures (e.g., Cell) have writable fields other + * than RUN, so do the read-modify-write. + */ + ctrl = mfspr(SPRN_CTRLF); + ctrl |= CTRL_RUNLATCH; + mtspr(SPRN_CTRLT, ctrl); + } ti->local_flags |= _TLF_RUNLATCH; } @@ -1992,13 +2006,18 @@ void notrace __ppc64_runlatch_on(void) void notrace __ppc64_runlatch_off(void) { struct thread_info *ti = current_thread_info(); - unsigned long ctrl; ti->local_flags &= ~_TLF_RUNLATCH; - ctrl = mfspr(SPRN_CTRLF); - ctrl &= ~CTRL_RUNLATCH; - mtspr(SPRN_CTRLT, ctrl); + if (cpu_has_feature(CPU_FTR_ARCH_206)) { + mtspr(SPRN_CTRLT, 0); + } else { + unsigned long ctrl; + + ctrl = mfspr(SPRN_CTRLF); + ctrl &= ~CTRL_RUNLATCH; + mtspr(SPRN_CTRLT, ctrl); + } } #endif /* CONFIG_PPC64 */ -- cgit v1.2.3 From f6fc73fb965f6c1fd7ad75aabfdee6b1af0f7093 Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 23 Aug 2017 23:56:23 +1000 Subject: powerpc/oops: Print CR/XER on same line as MSR Somehow we missed this when the pr_cont() changes went in. Fix CR/XER to go on the same line as MSR, as they have historically, eg: MSR: 8000000000009032 CR: 4804408a XER: 20000000 Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 0a00d59df537..1e24d6f1be90 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1386,7 +1386,7 @@ void show_regs(struct pt_regs * regs) regs, regs->trap, print_tainted(), init_utsname()->release); printk("MSR: "REG" ", regs->msr); print_msr_bits(regs->msr); - printk(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer); + pr_cont(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer); trap = TRAP(regs); if ((regs->trap != 0xc00) && cpu_has_feature(CPU_FTR_CFAR)) pr_cont("CFAR: "REG" ", regs->orig_gpr3); -- cgit v1.2.3 From a6036100edd1d8e024beb4b97c1f15c114660c6c Mon Sep 17 00:00:00 2001 From: Michael Ellerman Date: Wed, 23 Aug 2017 23:56:24 +1000 Subject: powerpc/oops: Line up NIP & MSR with other rows This is purely cosmetic, but does look nicer IMHO: Before: task: c000000001453400 task.stack: c000000001c6c000 NIP: c000000000a0fbfc LR: c000000000a0fbf4 CTR: c000000000ba6220 REGS: c0000001fffef820 TRAP: 0300 Not tainted (4.13.0-rc6-gcc-6.3.1-00234-g423af27f7d81) MSR: 8000000000009033 CR: 88088242 XER: 00000000 CFAR: c0000000000b3488 DAR: 0000000000000000 DSISR: 42000000 SOFTE: 0 After: task: c000000001453400 task.stack: c000000001c6c000 NIP: c000000000a0fbfc LR: c000000000a0fbf4 CTR: c000000000ba6220 REGS: c0000001fffef820 TRAP: 0300 Not tainted (4.13.0-rc6-gcc-6.3.1-00234-g423af27f7d81-dirty) MSR: 8000000000009033 CR: 88088242 XER: 00000000 CFAR: c0000000000b34a4 DAR: 0000000000000000 DSISR: 42000000 SOFTE: 0 Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/process.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/kernel/process.c') diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 1e24d6f1be90..a0c74bbf3454 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1380,11 +1380,11 @@ void show_regs(struct pt_regs * regs) show_regs_print_info(KERN_DEFAULT); - printk("NIP: "REG" LR: "REG" CTR: "REG"\n", + printk("NIP: "REG" LR: "REG" CTR: "REG"\n", regs->nip, regs->link, regs->ctr); printk("REGS: %p TRAP: %04lx %s (%s)\n", regs, regs->trap, print_tainted(), init_utsname()->release); - printk("MSR: "REG" ", regs->msr); + printk("MSR: "REG" ", regs->msr); print_msr_bits(regs->msr); pr_cont(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer); trap = TRAP(regs); -- cgit v1.2.3