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author | Thomas Gleixner <tglx@linutronix.de> | 2014-02-19 13:52:29 +0200 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2014-02-19 17:12:24 +0100 |
commit | 5f0e030930d715920be4de638084aaf8653867e8 (patch) | |
tree | 18d86d39a9cd4c61b1f4d548c97d64c88a73510c /arch/x86/kernel/tsc_msr.c | |
parent | 805937cf45f9a9933e6b8e5c6660406e977a9a23 (diff) | |
download | linux-stable-5f0e030930d715920be4de638084aaf8653867e8.tar.gz linux-stable-5f0e030930d715920be4de638084aaf8653867e8.tar.bz2 linux-stable-5f0e030930d715920be4de638084aaf8653867e8.zip |
x86, tsc: Fallback to normal calibration if fast MSR calibration fails
If we cannot calibrate TSC via MSR based calibration
try_msr_calibrate_tsc() stores zero to fast_calibrate and returns that
to the caller. This value gets then propagated further to clockevents
code resulting division by zero oops like the one below:
divide error: 0000 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 3.13.0+ #47
task: ffff880075508000 ti: ffff880075506000 task.ti: ffff880075506000
RIP: 0010:[<ffffffff810aec14>] [<ffffffff810aec14>] clockevents_config.part.3+0x24/0xa0
RSP: 0000:ffff880075507e58 EFLAGS: 00010246
RAX: ffffffffffffffff RBX: ffff880079c0cd80 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffffffffffff
RBP: ffff880075507e70 R08: 0000000000000001 R09: 00000000000000be
R10: 00000000000000bd R11: 0000000000000003 R12: 000000000000b008
R13: 0000000000000008 R14: 000000000000b010 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff880079c00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: ffff880079fff000 CR3: 0000000001c0b000 CR4: 00000000001006f0
Stack:
ffff880079c0cd80 000000000000b008 0000000000000008 ffff880075507e88
ffffffff810aecb0 ffff880079c0cd80 ffff880075507e98 ffffffff81030168
ffff880075507ed8 ffffffff81d1104f 00000000000000c3 0000000000000000
Call Trace:
[<ffffffff810aecb0>] clockevents_config_and_register+0x20/0x30
[<ffffffff81030168>] setup_APIC_timer+0xc8/0xd0
[<ffffffff81d1104f>] setup_boot_APIC_clock+0x4cc/0x4d8
[<ffffffff81d0f5de>] native_smp_prepare_cpus+0x3dd/0x3f0
[<ffffffff81d02ee9>] kernel_init_freeable+0xc3/0x205
[<ffffffff8177c910>] ? rest_init+0x90/0x90
[<ffffffff8177c91e>] kernel_init+0xe/0x120
[<ffffffff8178deec>] ret_from_fork+0x7c/0xb0
[<ffffffff8177c910>] ? rest_init+0x90/0x90
Prevent this from happening by:
1) Modifying try_msr_calibrate_tsc() to return calibration value or zero
if it fails.
2) Check this return value in native_calibrate_tsc() and in case of zero
fallback to use normal non-MSR based calibration.
[mw: Added subject and changelog]
Reported-and-tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Bin Gao <bin.gao@linux.intel.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/r/1392810750-18660-1-git-send-email-mika.westerberg@linux.intel.com
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/tsc_msr.c')
-rw-r--r-- | arch/x86/kernel/tsc_msr.c | 28 |
1 files changed, 14 insertions, 14 deletions
diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c index 8b5434f4389f..5dfff5809e74 100644 --- a/arch/x86/kernel/tsc_msr.c +++ b/arch/x86/kernel/tsc_msr.c @@ -77,21 +77,18 @@ static int match_cpu(u8 family, u8 model) /* * Do MSR calibration only for known/supported CPUs. - * Return values: - * -1: CPU is unknown/unsupported for MSR based calibration - * 0: CPU is known/supported, but calibration failed - * 1: CPU is known/supported, and calibration succeeded + * + * Returns the calibration value or 0 if MSR calibration failed. */ -int try_msr_calibrate_tsc(unsigned long *fast_calibrate) +unsigned long try_msr_calibrate_tsc(void) { - int cpu_index; u32 lo, hi, ratio, freq_id, freq; + unsigned long res; + int cpu_index; cpu_index = match_cpu(boot_cpu_data.x86, boot_cpu_data.x86_model); if (cpu_index < 0) - return -1; - - *fast_calibrate = 0; + return 0; if (freq_desc_tables[cpu_index].msr_plat) { rdmsr(MSR_PLATFORM_INFO, lo, hi); @@ -103,7 +100,7 @@ int try_msr_calibrate_tsc(unsigned long *fast_calibrate) pr_info("Maximum core-clock to bus-clock ratio: 0x%x\n", ratio); if (!ratio) - return 0; + goto fail; /* Get FSB FREQ ID */ rdmsr(MSR_FSB_FREQ, lo, hi); @@ -112,16 +109,19 @@ int try_msr_calibrate_tsc(unsigned long *fast_calibrate) pr_info("Resolved frequency ID: %u, frequency: %u KHz\n", freq_id, freq); if (!freq) - return 0; + goto fail; /* TSC frequency = maximum resolved freq * maximum resolved bus ratio */ - *fast_calibrate = freq * ratio; - pr_info("TSC runs at %lu KHz\n", *fast_calibrate); + res = freq * ratio; + pr_info("TSC runs at %lu KHz\n", res); #ifdef CONFIG_X86_LOCAL_APIC lapic_timer_frequency = (freq * 1000) / HZ; pr_info("lapic_timer_frequency = %d\n", lapic_timer_frequency); #endif + return res; - return 1; +fail: + pr_warn("Fast TSC calibration using MSR failed\n"); + return 0; } |