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Groups > linux.kernel > #1375361
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 4.5 022/238] s390: fix floating pointer register corruption (again) |
| Date | 2016-04-10 23:00 +0200 |
| Message-ID | <rmuCF-2to-79@gated-at.bofh.it> (permalink) |
| References | <rmsr7-Nr-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Martin Schwidefsky <schwidefsky@de.ibm.com> commit e370e4769463a65dcf8806fa26d2874e0542ac41 upstream. There is a tricky interaction between the machine check handler and the critical sections of load_fpu_regs and save_fpu_regs functions. If the machine check interrupts one of the two functions the critical section cleanup will complete the function before the machine check handler s390_do_machine_check is called. Trouble is that the machine check handler needs to validate the floating point registers *before* and not *after* the completion of load_fpu_regs/save_fpu_regs. The simplest solution is to rewind the PSW to the start of the load_fpu_regs/save_fpu_regs and retry the function after the return from the machine check handler. Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/s390/kernel/entry.S | 106 ----------------------------------------------- 1 file changed, 2 insertions(+), 104 deletions(-) --- a/arch/s390/kernel/entry.S +++ b/arch/s390/kernel/entry.S @@ -1199,114 +1199,12 @@ cleanup_critical: .quad .Lpsw_idle_lpsw .Lcleanup_save_fpu_regs: - TSTMSK __LC_CPU_FLAGS,_CIF_FPU - bor %r14 - clg %r9,BASED(.Lcleanup_save_fpu_regs_done) - jhe 5f - clg %r9,BASED(.Lcleanup_save_fpu_regs_fp) - jhe 4f - clg %r9,BASED(.Lcleanup_save_fpu_regs_vx_high) - jhe 3f - clg %r9,BASED(.Lcleanup_save_fpu_regs_vx_low) - jhe 2f - clg %r9,BASED(.Lcleanup_save_fpu_fpc_end) - jhe 1f - lg %r2,__LC_CURRENT - aghi %r2,__TASK_thread -0: # Store floating-point controls - stfpc __THREAD_FPU_fpc(%r2) -1: # Load register save area and check if VX is active - lg %r3,__THREAD_FPU_regs(%r2) - TSTMSK __LC_MACHINE_FLAGS,MACHINE_FLAG_VX - jz 4f # no VX -> store FP regs -2: # Store vector registers (V0-V15) - VSTM %v0,%v15,0,%r3 # vstm 0,15,0(3) -3: # Store vector registers (V16-V31) - VSTM %v16,%v31,256,%r3 # vstm 16,31,256(3) - j 5f # -> done, set CIF_FPU flag -4: # Store floating-point registers - std 0,0(%r3) - std 1,8(%r3) - std 2,16(%r3) - std 3,24(%r3) - std 4,32(%r3) - std 5,40(%r3) - std 6,48(%r3) - std 7,56(%r3) - std 8,64(%r3) - std 9,72(%r3) - std 10,80(%r3) - std 11,88(%r3) - std 12,96(%r3) - std 13,104(%r3) - std 14,112(%r3) - std 15,120(%r3) -5: # Set CIF_FPU flag - oi __LC_CPU_FLAGS+7,_CIF_FPU - lg %r9,48(%r11) # return from save_fpu_regs + larl %r9,save_fpu_regs br %r14 -.Lcleanup_save_fpu_fpc_end: - .quad .Lsave_fpu_regs_fpc_end -.Lcleanup_save_fpu_regs_vx_low: - .quad .Lsave_fpu_regs_vx_low -.Lcleanup_save_fpu_regs_vx_high: - .quad .Lsave_fpu_regs_vx_high -.Lcleanup_save_fpu_regs_fp: - .quad .Lsave_fpu_regs_fp -.Lcleanup_save_fpu_regs_done: - .quad .Lsave_fpu_regs_done .Lcleanup_load_fpu_regs: - TSTMSK __LC_CPU_FLAGS,_CIF_FPU - bnor %r14 - clg %r9,BASED(.Lcleanup_load_fpu_regs_done) - jhe 1f - clg %r9,BASED(.Lcleanup_load_fpu_regs_fp) - jhe 2f - clg %r9,BASED(.Lcleanup_load_fpu_regs_vx_high) - jhe 3f - clg %r9,BASED(.Lcleanup_load_fpu_regs_vx) - jhe 4f - lg %r4,__LC_CURRENT - aghi %r4,__TASK_thread - lfpc __THREAD_FPU_fpc(%r4) - TSTMSK __LC_MACHINE_FLAGS,MACHINE_FLAG_VX - lg %r4,__THREAD_FPU_regs(%r4) # %r4 <- reg save area - jz 2f # -> no VX, load FP regs -4: # Load V0 ..V15 registers - VLM %v0,%v15,0,%r4 -3: # Load V16..V31 registers - VLM %v16,%v31,256,%r4 - j 1f -2: # Load floating-point registers - ld 0,0(%r4) - ld 1,8(%r4) - ld 2,16(%r4) - ld 3,24(%r4) - ld 4,32(%r4) - ld 5,40(%r4) - ld 6,48(%r4) - ld 7,56(%r4) - ld 8,64(%r4) - ld 9,72(%r4) - ld 10,80(%r4) - ld 11,88(%r4) - ld 12,96(%r4) - ld 13,104(%r4) - ld 14,112(%r4) - ld 15,120(%r4) -1: # Clear CIF_FPU bit - ni __LC_CPU_FLAGS+7,255-_CIF_FPU - lg %r9,48(%r11) # return from load_fpu_regs + larl %r9,load_fpu_regs br %r14 -.Lcleanup_load_fpu_regs_vx: - .quad .Lload_fpu_regs_vx -.Lcleanup_load_fpu_regs_vx_high: - .quad .Lload_fpu_regs_vx_high -.Lcleanup_load_fpu_regs_fp: - .quad .Lload_fpu_regs_fp -.Lcleanup_load_fpu_regs_done: - .quad .Lload_fpu_regs_done /* * Integer constants
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[PATCH 4.5 000/238] 4.5.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 027/238] PCI: ACPI: IA64: fix IO port generic range check Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 001/238] x86/microcode/intel: Make early loader look for builtin microcode too Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 010/238] KVM: VMX: avoid guest hang on invalid invvpid instruction Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 033/238] sg: fix dxferp in from_to case Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 023/238] s390/cpumf: add missing lpp magic initialization Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 024/238] s390/pci: enforce fmb page boundary rule Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 025/238] pinctrl-bcm2835: Fix cut-and-paste error in "pull" parsing Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 031/238] x86/iopl: Fix iopl capability check on Xen PV Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 026/238] PCI: Disable IO/MEM decoding for devices with non-compliant BARs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
Re: [PATCH 4.5 026/238] PCI: Disable IO/MEM decoding for devices with non-compliant BARs Ben Hutchings <ben@decadent.org.uk> - 2016-04-12 01:50 +0200
Re: [PATCH 4.5 026/238] PCI: Disable IO/MEM decoding for devices with non-compliant BARs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-12 16:40 +0200
[PATCH 4.5 022/238] s390: fix floating pointer register corruption (again) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 019/238] sched/preempt, sh: kmap_coherent relies on disabled preemption Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 029/238] x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
[PATCH 4.5 021/238] EDAC, amd64_edac: Shift wrapping issue in f1x_get_norm_dct_addr() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-10 23:00 +0200
Re: [PATCH 4.5 000/238] 4.5.1-stable review Guenter Roeck <linux@roeck-us.net> - 2016-04-11 08:50 +0200
Re: [PATCH 4.5 000/238] 4.5.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-12 16:40 +0200
Re: [PATCH 4.5 000/238] 4.5.1-stable review shuahkh <shuahkh@osg.sisa.samsung.com> - 2016-04-11 19:30 +0200
Re: [PATCH 4.5 000/238] 4.5.1-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-04-12 08:50 +0200
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