From 7a9c2dd08eadd5c6943115dbbec040c38d2e0822 Mon Sep 17 00:00:00 2001 From: Chen Yu Date: Wed, 25 Nov 2015 01:03:41 +0800 Subject: x86/pm: Introduce quirk framework to save/restore extra MSR registers around suspend/resume A bug was reported that on certain Broadwell platforms, after resuming from S3, the CPU is running at an anomalously low speed. It turns out that the BIOS has modified the value of the THERM_CONTROL register during S3, and changed it from 0 to 0x10, thus enabled clock modulation(bit4), but with undefined CPU Duty Cycle(bit1:3) - which causes the problem. Here is a simple scenario to reproduce the issue: 1. Boot up the system 2. Get MSR 0x19a, it should be 0 3. Put the system into sleep, then wake it up 4. Get MSR 0x19a, it shows 0x10, while it should be 0 Although some BIOSen want to change the CPU Duty Cycle during S3, in our case we don't want the BIOS to do any modification. Fix this issue by introducing a more generic x86 framework to save/restore specified MSR registers(THERM_CONTROL in this case) for suspend/resume. This allows us to fix similar bugs in a much simpler way in the future. When the kernel wants to protect certain MSRs during suspending, we simply add a quirk entry in msr_save_dmi_table, and customize the MSR registers inside the quirk callback, for example: u32 msr_id_need_to_save[] = {MSR_ID0, MSR_ID1, MSR_ID2...}; and the quirk mechanism ensures that, once resumed from suspend, the MSRs indicated by these IDs will be restored to their original, pre-suspend values. Since both 64-bit and 32-bit kernels are affected, this patch covers the common 64/32-bit suspend/resume code path. And because the MSRs specified by the user might not be available or readable in any situation, we use rdmsrl_safe() to safely save these MSRs. Reported-and-tested-by: Marcin Kaszewski Signed-off-by: Chen Yu Acked-by: Rafael J. Wysocki Acked-by: Pavel Machek Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: bp@suse.de Cc: len.brown@intel.com Cc: linux@horizon.com Cc: luto@kernel.org Cc: rjw@rjwysocki.net Link: http://lkml.kernel.org/r/c9abdcbc173dd2f57e8990e304376f19287e92ba.1448382971.git.yu.c.chen@intel.com [ More edits to the naming of data structures. ] Signed-off-by: Ingo Molnar --- arch/x86/include/asm/msr.h | 10 ++++++++++ arch/x86/include/asm/suspend_32.h | 1 + arch/x86/include/asm/suspend_64.h | 1 + 3 files changed, 12 insertions(+) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/msr.h b/arch/x86/include/asm/msr.h index 77d8b28..24feb3c 100644 --- a/arch/x86/include/asm/msr.h +++ b/arch/x86/include/asm/msr.h @@ -32,6 +32,16 @@ struct msr_regs_info { int err; }; +struct saved_msr { + bool valid; + struct msr_info info; +}; + +struct saved_msrs { + unsigned int num; + struct saved_msr *array; +}; + static inline unsigned long long native_read_tscp(unsigned int *aux) { unsigned long low, high; diff --git a/arch/x86/include/asm/suspend_32.h b/arch/x86/include/asm/suspend_32.h index d1793f0..8e9dbe7 100644 --- a/arch/x86/include/asm/suspend_32.h +++ b/arch/x86/include/asm/suspend_32.h @@ -15,6 +15,7 @@ struct saved_context { unsigned long cr0, cr2, cr3, cr4; u64 misc_enable; bool misc_enable_saved; + struct saved_msrs saved_msrs; struct desc_ptr gdt_desc; struct desc_ptr idt; u16 ldt; diff --git a/arch/x86/include/asm/suspend_64.h b/arch/x86/include/asm/suspend_64.h index 7ebf0eb..6136a18 100644 --- a/arch/x86/include/asm/suspend_64.h +++ b/arch/x86/include/asm/suspend_64.h @@ -24,6 +24,7 @@ struct saved_context { unsigned long cr0, cr2, cr3, cr4, cr8; u64 misc_enable; bool misc_enable_saved; + struct saved_msrs saved_msrs; unsigned long efer; u16 gdt_pad; /* Unused */ struct desc_ptr gdt_desc; -- cgit v1.1 From d6b56b0bc68ba7927b286da86eda1d4d4dbe63f6 Mon Sep 17 00:00:00 2001 From: Julia Lawall Date: Sat, 28 Nov 2015 16:58:15 +0100 Subject: x86/platform/calgary: Constify cal_chipset_ops structures The cal_chipset_ops structures are never modified, so declare them as const. Done with the help of Coccinelle. Signed-off-by: Julia Lawall Cc: Borislav Petkov Cc: H. Peter Anvin Cc: Jon D. Mason Cc: Linus Torvalds Cc: Muli Ben-Yehuda Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1448726295-10959-1-git-send-email-Julia.Lawall@lip6.fr Signed-off-by: Ingo Molnar --- arch/x86/include/asm/calgary.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/include/asm') diff --git a/arch/x86/include/asm/calgary.h b/arch/x86/include/asm/calgary.h index 0d467b3..a8303eb 100644 --- a/arch/x86/include/asm/calgary.h +++ b/arch/x86/include/asm/calgary.h @@ -31,7 +31,7 @@ #include struct iommu_table { - struct cal_chipset_ops *chip_ops; /* chipset specific funcs */ + const struct cal_chipset_ops *chip_ops; /* chipset specific funcs */ unsigned long it_base; /* mapped address of tce table */ unsigned long it_hint; /* Hint for next alloc */ unsigned long *it_map; /* A simple allocation bitmap for now */ -- cgit v1.1