- 07 Apr, 2022 4 commits
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Michael Roth authored
CPUID instructions generate a #VC exception for SEV-ES/SEV-SNP guests, for which early handlers are currently set up to handle. In the case of SEV-SNP, guests can use a configurable location in guest memory that has been pre-populated with a firmware-validated CPUID table to look up the relevant CPUID values rather than requesting them from hypervisor via a VMGEXIT. Add the various hooks in the #VC handlers to allow CPUID instructions to be handled via the table. The code to actually configure/enable the table will be added in a subsequent commit. Signed-off-by:
Michael Roth <michael.roth@amd.com> Signed-off-by:
Brijesh Singh <brijesh.singh@amd.com> Signed-off-by:
Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20220307213356.2797205-33-brijesh.singh@amd.com
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Michael Roth authored
This code will also be used later for SEV-SNP-validated CPUID code in some cases, so move it to a common helper. While here, also add a check to terminate in cases where the CPUID function/subfunction is indexed and the subfunction is non-zero, since the GHCB MSR protocol does not support non-zero subfunctions. Suggested-by:
Sean Christopherson <seanjc@google.com> Signed-off-by:
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Michael Roth authored
Determining which CPUID leafs have significant ECX/index values is also needed by guest kernel code when doing SEV-SNP-validated CPUID lookups. Move this to common code to keep future updates in sync. Signed-off-by:
Venu Busireddy <venu.busireddy@oracle.com> Link: https://lore.kernel.org/r/20220307213356.2797205-31-brijesh.singh@amd.com
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Brijesh Singh authored
While launching encrypted guests, the hypervisor may need to provide some additional information during the guest boot. When booting under an EFI-based BIOS, the EFI configuration table contains an entry for the confidential computing blob that contains the required information. To support booting encrypted guests on non-EFI VMs, the hypervisor needs to pass this additional information to the guest kernel using a different method. For this purpose, introduce SETUP_CC_BLOB type in setup_data to hold the physical address of the confidential computing blob location. The boot loader or hypervisor may choose to use this method instead of an EFI configuration table. The CC blob location scanning should give preference to a setup_data blob over an EFI configuration table. In AMD SEV-SNP, the CC blob contains the address of the secrets and CPUID pages. The secrets page includes information such as a VM to PSP communication key and the CPUID page contains PSP-filtered CPUID values. Define the AMD SEV confidential computing blob structure. While at it, define the EFI GUID for the confidential computing blob. [ bp: Massage commit message, mark struct __packed. ] Signed-off-by:
Ard Biesheuvel <ardb@kernel.org> Link: https://lore.kernel.org/r/20220307213356.2797205-30-brijesh.singh@amd.com
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- 06 Apr, 2022 27 commits
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Michael Roth authored
Future patches for SEV-SNP-validated CPUID will also require early parsing of the EFI configuration. Incrementally move the related code into a set of helpers that can be re-used for that purpose. In this instance, the current acpi.c kexec handling is mainly used to get the alternative EFI config table address provided by kexec via a setup_data entry of type SETUP_EFI. If not present, the code then falls back to normal EFI config table address provided by EFI system table. This would need to be done by all call-sites attempting to access the EFI config table, so just have efi_get_conf_table() handle that automatically. Signed-off-by:
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Michael Roth authored
Future patches for SEV-SNP-validated CPUID will also require early parsing of the EFI configuration. Incrementally move the related code into a set of helpers that can be re-used for that purpose. [ bp: Unbreak unnecessarily broken lines. ] Signed-off-by:
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Michael Roth authored
Future patches for SEV-SNP-validated CPUID will also require early parsing of the EFI configuration. Incrementally move the related code into a set of helpers that can be re-used for that purpose. [ bp: Remove superfluous zeroing of a stack variable. ] Signed-off-by:
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Michael Roth authored
Future patches for SEV-SNP-validated CPUID will also require early parsing of the EFI configuration. Incrementally move the related code into a set of helpers that can be re-used for that purpose. Signed-off-by:
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Michael Roth authored
Future patches for SEV-SNP-validated CPUID will also require early parsing of the EFI configuration. Incrementally move the related code into a set of helpers that can be re-used for that purpose. First, carve out the functionality which determines the EFI environment type the machine is booting on. [ bp: Massage commit message. ] Signed-off-by:
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Michael Roth authored
Due to 103a4908 ("x86/head/64: Disable stack protection for head$(BITS).o") kernel/head{32,64}.c are compiled with -fno-stack-protector to allow a call to set_bringup_idt_handler(), which would otherwise have stack protection enabled with CONFIG_STACKPROTECTOR_STRONG. While sufficient for that case, there may still be issues with calls to any external functions that were compiled with stack protection enabled that in-turn make stack-protected calls, or if the exception handlers set up by set_bringup_idt_handler() make calls to stack-protected functions. Subsequent patches for SEV-SNP CPUID validation support will introduce both such cases. Attempting to disable stack protection for everything in scope to address that is prohibitive since much of the code, like the SEV-ES #VC handler, is shared code that remains in use after boot and could benefit from having stack protection enabled. Attempting to inline calls is brittle and can quickly balloon out to library/helper code where that's not really an option. Instead, re-enable stack protection for head32.c/head64.c, and make the appropriate changes to ensure the segment used for the stack canary is initialized in advance of any stack-protected C calls. For head64.c: - The BSP will enter from startup_64() and call into C code (startup_64_setup_env()) shortly after setting up the stack, which may result in calls to stack-protected code. Set up %gs early to allow for this safely. - APs will enter from secondary_startup_64*(), and %gs will be set up soon after. There is one call to C code prior to %gs being setup (__startup_secondary_64()), but it is only to fetch 'sme_me_mask' global, so just load 'sme_me_mask' directly instead, and remove the now-unused __startup_secondary_64() function. For head32.c: - BSPs/APs will set %fs to __BOOT_DS prior to any C calls. In recent kernels, the compiler is configured to access the stack canary at %fs:__stack_chk_guard [1], which overlaps with the initial per-cpu '__stack_chk_guard' variable in the initial/"master" .data..percpu area. This is sufficient to allow access to the canary for use during initial startup, so no changes are needed there. [1] 3fb0fdb3 ("x86/stackprotector/32: Make the canary into a regular percpu variable") [ bp: Massage commit message. ] Suggested-by: Joerg Roedel <jroedel@suse.de> #for 64-bit %gs set up Signed-off-by:
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Tom Lendacky authored
To provide a more secure way to start APs under SEV-SNP, use the SEV-SNP AP Creation NAE event. This allows for guest control over the AP register state rather than trusting the hypervisor with the SEV-ES Jump Table address. During native_smp_prepare_cpus(), invoke an SEV-SNP function that, if SEV-SNP is active, will set/override apic->wakeup_secondary_cpu. This will allow the SEV-SNP AP Creation NAE event method to be used to boot the APs. As a result of installing the override when SEV-SNP is active, this method of starting the APs becomes the required method. The override function will fail to start the AP if the hypervisor does not have support for AP creation. [ bp: Work in forgotten review comments. ] Signed-off-by:
Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by:
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Brijesh Singh authored
Add the needed functionality to change pages state from shared to private and vice-versa using the Page State Change VMGEXIT as documented in the GHCB spec. Signed-off-by:
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Brijesh Singh authored
probe_roms() accesses the memory range (0xc0000 - 0x10000) to probe various ROMs. The memory range is not part of the E820 system RAM range. The memory range is mapped as private (i.e encrypted) in the page table. When SEV-SNP is active, all the private memory must be validated before accessing. The ROM range was not part of E820 map, so the guest BIOS did not validate it. An access to invalidated memory will cause a exception yet, so validate the ROM memory regions before it is accessed. [ bp: Massage commit message. ] Signed-off-by:
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Brijesh Singh authored
The encryption attribute for the .bss..decrypted section is cleared in the initial page table build. This is because the section contains the data that need to be shared between the guest and the hypervisor. When SEV-SNP is active, just clearing the encryption attribute in the page table is not enough. The page state needs to be updated in the RMP table. Signed-off-by:
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Brijesh Singh authored
early_set_memory_{encrypted,decrypted}() are used for changing the page state from decrypted (shared) to encrypted (private) and vice versa. When SEV-SNP is active, the page state transition needs to go through additional steps. If the page is transitioned from shared to private, then perform the following after the encryption attribute is set in the page table: 1. Issue the page state change VMGEXIT to add the page as a private in the RMP table. 2. Validate the page after its successfully added in the RMP table. To maintain the security guarantees, if the page is transitioned from private to shared, then perform the following before clearing the encryption attribute from the page table. 1. Invalidate the page. 2. Issue the page state change VMGEXIT to make the page shared in the RMP table. early_set_memory_{encrypted,decrypted}() can be called before the GHCB is setup so use the SNP page state MSR protocol VMGEXIT defined in the GHCB specification to request the page state change in the RMP table. While at it, add a helper snp_prep_memory() which will be used in probe_roms(), in a later patch. [ bp: Massage commit message. ] Signed-off-by: -
Brijesh Singh authored
The SEV-SNP guest is required by the GHCB spec to register the GHCB's Guest Physical Address (GPA). This is because the hypervisor may prefer that a guest uses a consistent and/or specific GPA for the GHCB associated with a vCPU. For more information, see the GHCB specification section "GHCB GPA Registration". [ bp: Cleanup comments. ] Signed-off-by:
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Brijesh Singh authored
The SEV-SNP guest is required by the GHCB spec to register the GHCB's Guest Physical Address (GPA). This is because the hypervisor may prefer that a guest use a consistent and/or specific GPA for the GHCB associated with a vCPU. For more information, see the GHCB specification section "GHCB GPA Registration". If hypervisor can not work with the guest provided GPA then terminate the guest boot. Signed-off-by:
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Brijesh Singh authored
Many of the integrity guarantees of SEV-SNP are enforced through the Reverse Map Table (RMP). Each RMP entry contains the GPA at which a particular page of DRAM should be mapped. The VMs can request the hypervisor to add pages in the RMP table via the Page State Change VMGEXIT defined in the GHCB specification. Inside each RMP entry is a Validated flag; this flag is automatically cleared to 0 by the CPU hardware when a new RMP entry is created for a guest. Each VM page can be either validated or invalidated, as indicated by the Validated flag in the RMP entry. Memory access to a private page that is not validated generates a #VC. A VM must use the PVALIDATE instruction to validate a private page before using it. To maintain the security guarantee of SEV-SNP guests, when transitioning pages from private to shared, the guest must invalidate the pages before asking the hypervisor to change the page state to shared in the RMP table. After the pages are mapped private in the page table, the guest must issue a page state change VMGEXIT to mark the pages private in the RMP table and validate them. Upon boot, BIOS should have validated the entire system memory. During the kernel decompression stage, early_setup_ghcb() uses set_page_decrypted() to make the GHCB page shared (i.e. clear encryption attribute). And while exiting from the decompression, it calls set_page_encrypted() to make the page private. Add snp_set_page_{private,shared}() helpers that are used by set_page_{decrypted,encrypted}() to change the page state in the RMP table. [ bp: Massage commit message and comments. ] Signed-off-by: -
Brijesh Singh authored
The Virtual Machine Privilege Level (VMPL) feature in the SEV-SNP architecture allows a guest VM to divide its address space into four levels. The level can be used to provide hardware isolated abstraction layers within a VM. VMPL0 is the highest privilege level, and VMPL3 is the least privilege level. Certain operations must be done by the VMPL0 software, such as: * Validate or invalidate memory range (PVALIDATE instruction) * Allocate VMSA page (RMPADJUST instruction when VMSA=1) The initial SNP support requires that the guest kernel is running at VMPL0. Add such a check to verify the guest is running at level 0 before continuing the boot. There is no easy method to query the current VMPL level, so use the RMPADJUST instruction to determine whether the guest is running at the VMPL0. [ bp: Massage commit message. ] Signed-off-by:
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Brijesh Singh authored
An SNP-active guest uses the PVALIDATE instruction to validate or rescind the validation of a guest page’s RMP entry. Upon completion, a return code is stored in EAX and rFLAGS bits are set based on the return code. If the instruction completed successfully, the carry flag (CF) indicates if the content of the RMP were changed or not. See AMD APM Volume 3 for additional details. Signed-off-by:
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Brijesh Singh authored
Version 2 of the GHCB specification added the advertisement of features that are supported by the hypervisor. If the hypervisor supports SEV-SNP then it must set the SEV-SNP features bit to indicate that the base functionality is supported. Check that feature bit while establishing the GHCB; if failed, terminate the guest. Version 2 of the GHCB specification adds several new Non-Automatic Exits (NAEs), most of them are optional except the hypervisor feature. Now that the hypervisor feature NAE is implemented, bump the GHCB maximum supported protocol version. While at it, move the GHCB protocol negotiation check from the #VC exception handler to sev_enable() so that all feature detection happens before the first #VC exception. While at it, document why the GHCB page cannot be setup from load_stage2_idt(). [ bp: Massage commit message. ] Signed-off-by:
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Brijesh Singh authored
The SEV-ES guest calls sev_es_negotiate_protocol() to negotiate the GHCB protocol version before establishing the GHCB. Cache the negotiated GHCB version so that it can be used later. Signed-off-by:
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Brijesh Singh authored
The GHCB specification defines the reason code for reason set 0. The reason codes defined in the set 0 do not cover all possible causes for a guest to request termination. The reason sets 1 to 255 are reserved for the vendor-specific codes. Reserve the reason set 1 for the Linux guest. Define the error codes for reason set 1 so that one can have meaningful termination reasons and thus better guest failure diagnosis. While at it, change sev_es_terminate() to accept a reason set parameter. [ bp: Massage commit message. ] Signed-off-by:
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Brijesh Singh authored
The CC_ATTR_GUEST_SEV_SNP can be used by the guest to query whether the SNP (Secure Nested Paging) feature is active. Signed-off-by:
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Michael Roth authored
sme_enable() handles feature detection for both SEV and SME. Future patches will also use it for SEV-SNP feature detection/setup, which will need to be done immediately after the first #VC handler is set up. Move it now in preparation. Signed-off-by:
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Michael Roth authored
With upcoming SEV-SNP support, SEV-related features need to be initialized earlier during boot, at the same point the initial #VC handler is set up, so that the SEV-SNP CPUID table can be utilized during the initial feature checks. Also, SEV-SNP feature detection will rely on EFI helper functions to scan the EFI config table for the Confidential Computing blob, and so would need to be implemented at least partially in C. Currently set_sev_encryption_mask() is used to initialize the sev_status and sme_me_mask globals that advertise what SEV/SME features are available in a guest. Rename it to sev_enable() to better reflect that (SME is only enabled in the case of SEV guests in the boot/compressed kernel), and move it to just after the stage1 #VC handler is set up so that it can be used to initialize SEV-SNP as well in future patches. While at it, re-implement it as C code so that all SEV feature detection can be better consolidated with upcoming SEV-SNP feature detection, which will also be in C. The 32-bit entry path remains unchanged, as it never relied on the set_sev_encryption_mask() initialization to begin with. [ bp: Massage commit message. ] Signed-off-by:
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Michael Roth authored
Update all C code to use the new boot_rdmsr()/boot_wrmsr() helpers instead of relying on inline assembly. Suggested-by:
Borislav Petkov <bp@alien8.de> Signed-off-by:
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Michael Roth authored
The current set of helpers used throughout the run-time kernel have dependencies on code/facilities outside of the boot kernel, so there are a number of call-sites throughout the boot kernel where inline assembly is used instead. More will be added with subsequent patches that add support for SEV-SNP, so take the opportunity to provide a basic set of helpers that can be used by the boot kernel to reduce reliance on inline assembly. Use boot_* prefix so that it's clear these are helpers specific to the boot kernel to avoid any confusion with the various other MSR read/write helpers. [ bp: Disambiguate parameter names and trim comment. ] Suggested-by:
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Tom Lendacky authored
This is the final step in defining the multiple save areas to keep them separate and ensuring proper operation amongst the different types of guests. Update the SEV-ES/SEV-SNP save area to match the APM. This save area will be used for the upcoming SEV-SNP AP Creation NAE event support. Signed-off-by:
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Tom Lendacky authored
The initial implementation of the GHCB spec was based on trying to keep the register state offsets the same relative to the VM save area. However, the save area for SEV-ES has changed within the hardware causing the relation between the SEV-ES save area to change relative to the GHCB save area. This is the second step in defining the multiple save areas to keep them separate and ensuring proper operation amongst the different types of guests. Create a GHCB save area that matches the GHCB specification. Signed-off-by:
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Tom Lendacky authored
The save area for SEV-ES/SEV-SNP guests, as used by the hardware, is different from the save area of a non SEV-ES/SEV-SNP guest. This is the first step in defining the multiple save areas to keep them separate and ensuring proper operation amongst the different types of guests. Create an SEV-ES/SEV-SNP save area and adjust usage to the new save area definition where needed. Signed-off-by:
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- 05 Apr, 2022 1 commit
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Brijesh Singh authored
The hypervisor uses the sev_features field (offset 3B0h) in the Save State Area to control the SEV-SNP guest features such as SNPActive, vTOM, ReflectVC etc. An SEV-SNP guest can read the sev_features field through the SEV_STATUS MSR. While at it, update dump_vmcb() to log the VMPL level. See APM2 Table 15-34 and B-4 for more details. Signed-off-by:
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- 03 Apr, 2022 8 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-traceLinus Torvalds authored
Pull more tracing updates from Steven Rostedt: - Rename the staging files to give them some meaning. Just stage1,stag2,etc, does not show what they are for - Check for NULL from allocation in bootconfig - Hold event mutex for dyn_event call in user events - Mark user events to broken (to work on the API) - Remove eBPF updates from user events - Remove user events from uapi header to keep it from being installed. - Move ftrace_graph_is_dead() into inline as it is called from hot paths and also convert it into a static branch. * tag 'trace-v5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Move user_events.h temporarily out of include/uapi ftrace: Make ftrace_graph_is_dead() a static branch tracing: Set user_events to BROKEN tracing/user_events: Remove eBPF interfaces tracing/user_events: Hold event_mutex during dyn_event_add proc: bootconfig: Add null pointer check tracing: Rename the staging files for trace_events
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git://git.kernel.org/pub/scm/linux/kernel/git/clk/linuxLinus Torvalds authored
Pull clk fix from Stephen Boyd: "A single revert to fix a boot regression seen when clk_put() started dropping rate range requests. It's best to keep various systems booting so we'll kick this out and try again next time" * tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux: Revert "clk: Drop the rate range on clk_put()"
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Thomas Gleixner: "A set of x86 fixes and updates: - Make the prctl() for enabling dynamic XSTATE components correct so it adds the newly requested feature to the permission bitmap instead of overwriting it. Add a selftest which validates that. - Unroll string MMIO for encrypted SEV guests as the hypervisor cannot emulate it. - Handle supervisor states correctly in the FPU/XSTATE code so it takes the feature set of the fpstate buffer into account. The feature sets can differ between host and guest buffers. Guest buffers do not contain supervisor states. So far this was not an issue, but with enabling PASID it needs to be handled in the buffer offset calculation and in the permission bitmaps. - Avoid a gazillion of repeated CPUID invocations in by caching the values early in the FPU/XSTATE code. - Enable CONFIG_WERROR in x86 defconfig. - Make the X86 defconfigs more useful by adapting them to Y2022 reality" * tag 'x86-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/fpu/xstate: Consolidate size calculations x86/fpu/xstate: Handle supervisor states in XSTATE permissions x86/fpu/xsave: Handle compacted offsets correctly with supervisor states x86/fpu: Cache xfeature flags from CPUID x86/fpu/xsave: Initialize offset/size cache early x86/fpu: Remove unused supervisor only offsets x86/fpu: Remove redundant XCOMP_BV initialization x86/sev: Unroll string mmio with CC_ATTR_GUEST_UNROLL_STRING_IO x86/config: Make the x86 defconfigs a bit more usable x86/defconfig: Enable WERROR selftests/x86/amx: Update the ARCH_REQ_XCOMP_PERM test x86/fpu/xstate: Fix the ARCH_REQ_XCOMP_PERM implementation -
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull RT signal fix from Thomas Gleixner: "Revert the RT related signal changes. They need to be reworked and generalized" * tag 'core-urgent-2022-04-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Revert "signal, x86: Delay calling signals in atomic on RT enabled kernels"
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git://git.infradead.org/users/hch/dma-mappingLinus Torvalds authored
Pull more dma-mapping updates from Christoph Hellwig: - fix a regression in dma remap handling vs AMD memory encryption (me) - finally kill off the legacy PCI DMA API (Christophe JAILLET) * tag 'dma-mapping-5.18-1' of git://git.infradead.org/users/hch/dma-mapping: dma-mapping: move pgprot_decrypted out of dma_pgprot PCI/doc: cleanup references to the legacy PCI DMA API PCI: Remove the deprecated "pci-dma-compat.h" API
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git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds authored
Pull ARM fixes from Russell King: - avoid unnecessary rebuilds for library objects - fix return value of __setup handlers - fix invalid input check for "crashkernel=" kernel option - silence KASAN warnings in unwind_frame * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 9191/1: arm/stacktrace, kasan: Silence KASAN warnings in unwind_frame() ARM: 9190/1: kdump: add invalid input check for 'crashkernel=0' ARM: 9187/1: JIVE: fix return value of __setup handler ARM: 9189/1: decompressor: fix unneeded rebuilds of library objects
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Stephen Boyd authored
This reverts commit 7dabfa2b. There are multiple reports that this breaks boot on various systems. The common theme is that orphan clks are having rates set on them when that isn't expected. Let's revert it out for now so that -rc1 boots. Reported-by:
Marek Szyprowski <m.szyprowski@samsung.com> Reported-by:
Tony Lindgren <tony@atomide.com> Reported-by:
Alexander Stein <alexander.stein@ew.tq-group.com> Reported-by:
Naresh Kamboju <naresh.kamboju@linaro.org> Link: https://lore.kernel.org/r/366a0232-bb4a-c357-6aa8-636e398e05eb@samsung.com Cc: Maxime Ripard <maxime@cerno.tech> Signed-off-by:
Stephen Boyd <sboyd@kernel.org> Link: https://lore.kernel.org/r/20220403022818.39572-1-sboyd@kernel.org
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