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* x86, gdt, hibernate: Store/load GDT for hibernate path.Konrad Rzeszutek Wilk2013-05-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The git commite7a5cd063c7b4c58417f674821d63f5eb6747e37 ("x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path is not needed.") assumes that for the hibernate path the booting kernel and the resuming kernel MUST be the same. That is certainly the case for a 32-bit kernel (see check_image_kernel and CONFIG_ARCH_HIBERNATION_HEADER config option). However for 64-bit kernels it is OK to have a different kernel version (and size of the image) of the booting and resuming kernels. Hence the above mentioned git commit introduces an regression. This patch fixes it by introducing a 'struct desc_ptr gdt_desc' back in the 'struct saved_context'. However instead of having in the 'save_processor_state' and 'restore_processor_state' the store/load_gdt calls, we are only saving the GDT in the save_processor_state. For the restore path the lgdt operation is done in hibernate_asm_[32|64].S in the 'restore_registers' path. The apt reader of this description will recognize that only 64-bit kernels need this treatment, not 32-bit. This patch adds the logic in the 32-bit path to be more similar to 64-bit so that in the future the unification process can take advantage of this. [ hpa: this also reverts an inadvertent on-disk format change ] Suggested-by: "H. Peter Anvin" <hpa@zytor.com> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1367459610-9656-2-git-send-email-konrad.wilk@oracle.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path is not needed.Konrad Rzeszutek Wilk2013-04-111-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During the ACPI S3 resume path the trampoline code handles it already. During the ACPI S3 suspend phase (acpi_suspend_lowlevel) we set: early_gdt_descr.address = (..)get_cpu_gdt_table(smp_processor_id()); which is then used during the resume path and has the same exact value as what the store/load_gdt do with the saved_context (which is saved/restored via save/restore_processor_state()). The flow during resume is complex and for 64-bit kernels we use three GDTs - one early bootstrap GDT (wakeup_igdt) that we load to workaround broken BIOSes, an early Protected Mode to Long Mode transition one (tr_gdt), and the final one - early_gdt_descr (which points to the real GDT). The early ('wakeup_gdt') is loaded in 'trampoline_start' for working around broken BIOSes, and then when we end up in Protected Mode in the startup_32 (in trampoline_64.s, not head_32.s) we use the 'tr_gdt' (still in trampoline_64.s). This 'tr_gdt' has a a 32-bit code segment, 64-bit code segment with L=1, and a 32-bit data segment. Once we have transitioned from Protected Mode to Long Mode we then set the GDT to 'early_gdt_desc' and then via an iretq emerge in wakeup_long64 (set via 'initial_code' variable in acpi_suspend_lowlevel). In the wakeup_long64 we end up restoring the %rip (which is set to 'resume_point') and jump there. In 'resume_point' we call 'restore_processor_state' which does the load_gdt on the saved context. This load_gdt is redundant as the GDT loaded via early_gdt_desc is the same. Here is the call-chain: wakeup_start |- lgdtl wakeup_gdt [the work-around broken BIOSes] | \-- trampoline_start (trampoline_64.S) |- lgdtl tr_gdt | \-- startup_32 (trampoline_64.S) | \-- startup_64 (trampoline_64.S) | \-- secondary_startup_64 |- lgdtl early_gdt_desc | ... |- movq initial_code(%rip), %eax |-.. lretq \-- wakeup_64 |-- other registers are reloaded |-- call restore_processor_state The hibernate path is much simpler. During the saving of the hibernation image we call save_processor_state() and save the contents of that along with the rest of the kernel in the hibernation image destination. We save the EIP of 'restore_registers' (restore_jump_address) and cr3 (restore_cr3). During hibernate resume, the 'restore_registers' (via the 'restore_jump_address) in hibernate_asm_64.S is invoked which restores the contents of most registers. Naturally the resume path benefits from already being in 64-bit mode, so it does not have to load the GDT. It only reloads the cr3 (from restore_cr3) and continues on. Note that the restoration of the restore image page-tables is done prior to this. After the 'restore_registers' it returns and we end up called restore_processor_state() - where we reload the GDT. The reload of the GDT is not needed as bootup kernel has already loaded the GDT which is at the same physical location as the the restored kernel. Note that the hibernation path assumes the GDT is correct during its 'restore_registers'. The assumption in the code is that the restored image is the same as saved - meaning we are not trying to restore an different kernel in the virtual address space of a new kernel. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1365194544-14648-2-git-send-email-konrad.wilk@oracle.com Cc: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* PM / Hibernate: Remove arch_prepare_suspend()Rafael J. Wysocki2011-05-241-5/+0
| | | | | | | All architectures supporting hibernation define arch_prepare_suspend() as an empty function, so remove it. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / x86: Save/restore MISC_ENABLE registerOndrej Zary2010-06-081-0/+2
| | | | | | | | | | | | | Save/restore MISC_ENABLE register on suspend/resume. This fixes OOPS (invalid opcode) on resume from STR on Asus P4P800-VM, which wakes up with MWAIT disabled. Fixes https://bugzilla.kernel.org/show_bug.cgi?id=15385 Signed-off-by: Ondrej Zary <linux@rainbow-software.org> Tested-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* x86: Fix ASM_X86__ header guardsH. Peter Anvin2008-10-221-3/+3
| | | | | | | | | Change header guards named "ASM_X86__*" to "_ASM_X86_*" since: a. the double underscore is ugly and pointless. b. no leading underscore violates namespace constraints. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* x86, um: ... and asm-x86 moveAl Viro2008-10-221-0/+52
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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