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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-04-26 13:13:21 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-04-26 17:46:20 -0400
commitdf88b2d96e36d9a9e325bfcd12eb45671cbbc937 (patch)
tree6e370456404b94aa4ddbb4eb3d4b91a0f6b9affe /arch/x86
parent3d81acb1cdb242378a1acb3eb1bc28c6bb5895f1 (diff)
xen/enlighten: Disable MWAIT_LEAF so that acpi-pad won't be loaded.
There are exactly four users of __monitor and __mwait: - cstate.c (which allows acpi_processor_ffh_cstate_enter to be called when the cpuidle API drivers are used. However patch "cpuidle: replace xen access to x86 pm_idle and default_idle" provides a mechanism to disable the cpuidle and use safe_halt. - smpboot (which allows mwait_play_dead to be called). However safe_halt is always used so we skip that. - intel_idle (same deal as above). - acpi_pad.c. This the one that we do not want to run as we will hit the below crash. Why do we want to expose MWAIT_LEAF in the first place? We want it for the xen-acpi-processor driver - which uploads C-states to the hypervisor. If MWAIT_LEAF is set, the cstate.c sets the proper address in the C-states so that the hypervisor can benefit from using the MWAIT functionality. And that is the sole reason for using it. Without this patch, if a module performs mwait or monitor we get this: invalid opcode: 0000 [#1] SMP CPU 2 .. snip.. Pid: 5036, comm: insmod Tainted: G O 3.4.0-rc2upstream-dirty #2 Intel Corporation S2600CP/S2600CP RIP: e030:[<ffffffffa000a017>] [<ffffffffa000a017>] mwait_check_init+0x17/0x1000 [mwait_check] RSP: e02b:ffff8801c298bf18 EFLAGS: 00010282 RAX: ffff8801c298a010 RBX: ffffffffa03b2000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff8801c29800d8 RDI: ffff8801ff097200 RBP: ffff8801c298bf18 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: ffffffffa000a000 R14: 0000005148db7294 R15: 0000000000000003 FS: 00007fbb364f2700(0000) GS:ffff8801ff08c000(0000) knlGS:0000000000000000 CS: e033 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 000000000179f038 CR3: 00000001c9469000 CR4: 0000000000002660 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process insmod (pid: 5036, threadinfo ffff8801c298a000, task ffff8801c29cd7e0) Stack: ffff8801c298bf48 ffffffff81002124 ffffffffa03b2000 00000000000081fd 000000000178f010 000000000178f030 ffff8801c298bf78 ffffffff810c41e6 00007fff3fb30db9 00007fff3fb30db9 00000000000081fd 0000000000010000 Call Trace: [<ffffffff81002124>] do_one_initcall+0x124/0x170 [<ffffffff810c41e6>] sys_init_module+0xc6/0x220 [<ffffffff815b15b9>] system_call_fastpath+0x16/0x1b Code: <0f> 01 c8 31 c0 0f 01 c9 c9 c3 00 00 00 00 00 00 00 00 00 00 00 00 RIP [<ffffffffa000a017>] mwait_check_init+0x17/0x1000 [mwait_check] RSP <ffff8801c298bf18> ---[ end trace 16582fc8a3d1e29a ]--- Kernel panic - not syncing: Fatal exception With this module (which is what acpi_pad.c would hit): MODULE_AUTHOR("Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>"); MODULE_DESCRIPTION("mwait_check_and_back"); MODULE_LICENSE("GPL"); MODULE_VERSION(); static int __init mwait_check_init(void) { __monitor((void *)&current_thread_info()->flags, 0, 0); __mwait(0, 0); return 0; } static void __exit mwait_check_exit(void) { } module_init(mwait_check_init); module_exit(mwait_check_exit); Reported-by: Liu, Jinsong <jinsong.liu@intel.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/xen/enlighten.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 4f51bebac02..a8f8844b8d3 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -261,7 +261,8 @@ static void xen_cpuid(unsigned int *ax, unsigned int *bx,
static bool __init xen_check_mwait(void)
{
-#ifdef CONFIG_ACPI
+#if defined(CONFIG_ACPI) && !defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR) && \
+ !defined(CONFIG_ACPI_PROCESSOR_AGGREGATOR_MODULE)
struct xen_platform_op op = {
.cmd = XENPF_set_processor_pminfo,
.u.set_pminfo.id = -1,
@@ -349,7 +350,6 @@ static void __init xen_init_cpuid_mask(void)
/* Xen will set CR4.OSXSAVE if supported and not disabled by force */
if ((cx & xsave_mask) != xsave_mask)
cpuid_leaf1_ecx_mask &= ~xsave_mask; /* disable XSAVE & OSXSAVE */
-
if (xen_check_mwait())
cpuid_leaf1_ecx_set_mask = (1 << (X86_FEATURE_MWAIT % 32));
}