From 65ea11ec6a82b1d44aba62b59e9eb20247e57c6e Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Mon, 8 Aug 2016 20:35:29 +0300 Subject: [PATCH] x86/hweight: Don't clobber %rdi MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit The caller expects %rdi to remain intact, push+pop it make that happen. Fixes the following kind of explosions on my core2duo machine when trying to reboot or shut down: general protection fault: 0000 [#1] PREEMPT SMP Modules linked in: i915 i2c_algo_bit drm_kms_helper cfbfillrect syscopyarea cfbimgblt sysfillrect sysimgblt fb_sys_fops cfbcopyarea drm netconsole configfs binfmt_misc iTCO_wdt psmouse pcspkr snd_hda_codec_idt e100 coretemp hwmon snd_hda_codec_generic i2c_i801 mii i2c_smbus lpc_ich mfd_core snd_hda_intel uhci_hcd snd_hda_codec snd_hwdep snd_hda_core ehci_pci 8250 ehci_hcd snd_pcm 8250_base usbcore evdev serial_core usb_common parport_pc parport snd_timer snd soundcore CPU: 0 PID: 3070 Comm: reboot Not tainted 4.8.0-rc1-perf-dirty #69 Hardware name: /D946GZIS, BIOS TS94610J.86A.0087.2007.1107.1049 11/07/2007 task: ffff88012a0b4080 task.stack: ffff880123850000 RIP: 0010:[] [] x86_perf_event_update+0x52/0xc0 RSP: 0018:ffff880123853b60 EFLAGS: 00010087 RAX: 0000000000000001 RBX: ffff88012fc0a3c0 RCX: 000000000000001e RDX: 0000000000000000 RSI: 0000000040000000 RDI: ffff88012b014800 RBP: ffff880123853b88 R08: ffffffffffffffff R09: 0000000000000000 R10: ffffea0004a012c0 R11: ffffea0004acedc0 R12: ffffffff80000001 R13: ffff88012b0149c0 R14: ffff88012b014800 R15: 0000000000000018 FS: 00007f8b155cd700(0000) GS:ffff88012fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f8b155f5000 CR3: 000000012a2d7000 CR4: 00000000000006f0 Stack: ffff88012fc0a3c0 ffff88012b014800 0000000000000004 0000000000000001 ffff88012fc1b750 ffff880123853bb0 ffffffff81003d59 ffff88012b014800 ffff88012fc0a3c0 ffff88012b014800 ffff880123853bd8 ffffffff81003e13 Call Trace: [] x86_pmu_stop+0x59/0xd0 [] x86_pmu_del+0x43/0x140 [] event_sched_out.isra.105+0xbd/0x260 [] __perf_remove_from_context+0x2d/0xb0 [] __perf_event_exit_context+0x4d/0x70 [] generic_exec_single+0xb6/0x140 [] ? __perf_remove_from_context+0xb0/0xb0 [] ? __perf_remove_from_context+0xb0/0xb0 [] smp_call_function_single+0xdf/0x140 [] perf_event_exit_cpu_context+0x87/0xc0 [] perf_reboot+0x13/0x40 [] notifier_call_chain+0x4a/0x70 [] __blocking_notifier_call_chain+0x47/0x60 [] blocking_notifier_call_chain+0x16/0x20 [] kernel_restart_prepare+0x1d/0x40 [] kernel_restart+0x12/0x60 [] SYSC_reboot+0xf6/0x1b0 [] ? mntput_no_expire+0x2c/0x1b0 [] ? mntput+0x24/0x40 [] ? __fput+0x16c/0x1e0 [] ? ____fput+0xe/0x10 [] ? task_work_run+0x83/0xa0 [] ? exit_to_usermode_loop+0x53/0xc0 [] ? trace_hardirqs_on_thunk+0x1a/0x1c [] SyS_reboot+0xe/0x10 [] entry_SYSCALL_64_fastpath+0x18/0xa3 Code: 7c 4c 8d af c0 01 00 00 49 89 fe eb 10 48 09 c2 4c 89 e0 49 0f b1 55 00 4c 39 e0 74 35 4d 8b a6 c0 01 00 00 41 8b 8e 60 01 00 00 <0f> 33 8b 35 6e 02 8c 00 48 c1 e2 20 85 f6 7e d2 48 89 d3 89 cf RIP [] x86_perf_event_update+0x52/0xc0 RSP ---[ end trace 7ec95181faf211be ]--- note: reboot[3070] exited with preempt_count 2 Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Andy Lutomirski Cc: Brian Gerst Cc: Denys Vlasenko Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Fixes: f5967101e9de ("x86/hweight: Get rid of the special calling convention") Signed-off-by: Ville Syrjälä Signed-off-by: Linus Torvalds --- arch/x86/lib/hweight.S | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/lib/hweight.S b/arch/x86/lib/hweight.S index 02de3d74d2c5b..8a602a1e404a2 100644 --- a/arch/x86/lib/hweight.S +++ b/arch/x86/lib/hweight.S @@ -35,6 +35,7 @@ ENDPROC(__sw_hweight32) ENTRY(__sw_hweight64) #ifdef CONFIG_X86_64 + pushq %rdi pushq %rdx movq %rdi, %rdx # w -> t @@ -60,6 +61,7 @@ ENTRY(__sw_hweight64) shrq $56, %rax # w = w_tmp >> 56 popq %rdx + popq %rdi ret #else /* CONFIG_X86_32 */ /* We're getting an u64 arg in (%eax,%edx): unsigned long hweight64(__u64 w) */ -- 2.39.5