kernel.git/arch/arm/include/asm, branch linux-5.6.y

KVM: arm64: Save the host's PtrAuth keys in non-preemptible context

2020-06-17T14:42:09Z

commit ef3e40a7ea8dbe2abd0a345032cd7d5023b9684f upstream. When using the PtrAuth feature in a guest, we need to save the host's keys before allowing the guest to program them. For that, we dump them in a per-CPU data structure (the so called host context). But both call sites that do this are in preemptible context, which may end up in disaster should the vcpu thread get preempted before reentering the guest. Instead, save the keys eagerly on each vcpu_load(). This has an increased overhead, but is at least safe. Cc: stable@vger.kernel.org Reviewed-by: Mark Rutland Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

KVM: arm64: Synchronize sysreg state on injecting an AArch32 exception

2020-06-17T14:42:08Z

commit 0370964dd3ff7d3d406f292cb443a927952cbd05 upstream. On a VHE system, the EL1 state is left in the CPU most of the time, and only syncronized back to memory when vcpu_put() is called (most of the time on preemption). Which means that when injecting an exception, we'd better have a way to either: (1) write directly to the EL1 sysregs (2) synchronize the state back to memory, and do the changes there For an AArch64, we already do (1), so we are safe. Unfortunately, doing the same thing for AArch32 would be pretty invasive. Instead, we can easily implement (2) by calling the put/load architectural backends, and keep preemption disabled. We can then reload the state back into EL1. Cc: stable@vger.kernel.org Reported-by: James Morse Signed-off-by: Marc Zyngier Signed-off-by: Greg Kroah-Hartman

ARM: uaccess: fix DACR mismatch with nested exceptions

2020-06-03T06:23:14Z

[ Upstream commit 71f8af1110101facfad68989ff91f88f8e2c3e22 ] Tomas Paukrt reports that his SAM9X60 based system (ARM926, ARMv5TJ) fails to fix up alignment faults, eventually resulting in a kernel oops. The problem occurs when using CONFIG_CPU_USE_DOMAINS with commit e6978e4bf181 ("ARM: save and reset the address limit when entering an exception"). This is because the address limit is set back to TASK_SIZE on exception entry, and, although it is restored on exception exit, the domain register is not. Hence, this sequence can occur: interrupt pt_regs->addr_limit = addr_limit // USER_DS addr_limit = USER_DS alignment exception __probe_kernel_read() old_fs = get_fs() // USER_DS set_fs(KERNEL_DS) addr_limit = KERNEL_DS dacr.kernel = DOMAIN_MANAGER interrupt pt_regs->addr_limit = addr_limit // KERNEL_DS addr_limit = USER_DS alignment exception __probe_kernel_read() old_fs = get_fs() // USER_DS set_fs(KERNEL_DS) addr_limit = KERNEL_DS dacr.kernel = DOMAIN_MANAGER ... set_fs(old_fs) addr_limit = USER_DS dacr.kernel = DOMAIN_CLIENT ... addr_limit = pt_regs->addr_limit // KERNEL_DS interrupt returns At this point, addr_limit is correctly restored to KERNEL_DS for __probe_kernel_read() to continue execution, but dacr.kernel is not, it has been reset by the set_fs(old_fs) to DOMAIN_CLIENT. This would not have happened prior to the mentioned commit, because addr_limit would remain KERNEL_DS, so get_fs() would have returned KERNEL_DS, and so would correctly nest. This commit fixes the problem by also saving the DACR on exception entry if either CONFIG_CPU_SW_DOMAIN_PAN or CONFIG_CPU_USE_DOMAINS are enabled, and resetting the DACR appropriately on exception entry to match addr_limit and PAN settings. Fixes: e6978e4bf181 ("ARM: save and reset the address limit when entering an exception") Reported-by: Tomas Paukrt Signed-off-by: Russell King Signed-off-by: Sasha Levin

ARM: uaccess: integrate uaccess_save and uaccess_restore

2020-06-03T06:23:14Z

[ Upstream commit 8ede890b0bcebe8c760aacfe20e934d98c3dc6aa ] Integrate uaccess_save / uaccess_restore macros into the new uaccess_entry / uaccess_exit macros respectively. Signed-off-by: Russell King Signed-off-by: Sasha Levin

ARM: uaccess: consolidate uaccess asm to asm/uaccess-asm.h

2020-06-03T06:23:14Z

[ Upstream commit 747ffc2fcf969eff9309d7f2d1d61cb8b9e1bb40 ] Consolidate the user access assembly code to asm/uaccess-asm.h. This moves the csdb, check_uaccess, uaccess_mask_range_ptr, uaccess_enable, uaccess_disable, uaccess_save, uaccess_restore macros, and creates two new ones for exception entry and exit - uaccess_entry and uaccess_exit. This makes the uaccess_save and uaccess_restore macros private to asm/uaccess-asm.h. Signed-off-by: Russell King Signed-off-by: Sasha Levin

ARM: futex: Address build warning

2020-05-27T15:48:12Z

[ Upstream commit 8101b5a1531f3390b3a69fa7934c70a8fd6566ad ] Stephen reported the following build warning on a ARM multi_v7_defconfig build with GCC 9.2.1: kernel/futex.c: In function 'do_futex': kernel/futex.c:1676:17: warning: 'oldval' may be used uninitialized in this function [-Wmaybe-uninitialized] 1676 | return oldval == cmparg; | ~~~~~~~^~~~~~~~~ kernel/futex.c:1652:6: note: 'oldval' was declared here 1652 | int oldval, ret; | ^~~~~~ introduced by commit a08971e9488d ("futex: arch_futex_atomic_op_inuser() calling conventions change"). While that change should not make any difference it confuses GCC which fails to work out that oldval is not referenced when the return value is not zero. GCC fails to properly analyze arch_futex_atomic_op_inuser(). It's not the early return, the issue is with the assembly macros. GCC fails to detect that those either set 'ret' to 0 and set oldval or set 'ret' to -EFAULT which makes oldval uninteresting. The store to the callsite supplied oldval pointer is conditional on ret == 0. The straight forward way to solve this is to make the store unconditional. Aside of addressing the build warning this makes sense anyway because it removes the conditional from the fastpath. In the error case the stored value is uninteresting and the extra store does not matter at all. Reported-by: Stephen Rothwell Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/87pncao2ph.fsf@nanos.tec.linutronix.de Signed-off-by: Sasha Levin

Merge tag 'kvmarm-fixes-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2020-02-28T10:50:06Z

KVM/arm fixes for 5.6, take #1 - Fix compilation on 32bit - Move VHE guest entry/exit into the VHE-specific entry code - Make sure all functions called by the non-VHE HYP code is tagged as __always_inline

kvm: arm/arm64: Fold VHE entry/exit work into kvm_vcpu_run_vhe()

2020-02-17T14:38:37Z

With VHE, running a vCPU always requires the sequence: 1. kvm_arm_vhe_guest_enter(); 2. kvm_vcpu_run_vhe(); 3. kvm_arm_vhe_guest_exit() ... and as we invoke this from the shared arm/arm64 KVM code, 32-bit arm has to provide stubs for all three functions. To simplify the common code, and make it easier to make further modifications to the arm64-specific portions in the near future, let's fold kvm_arm_vhe_guest_enter() and kvm_arm_vhe_guest_exit() into kvm_vcpu_run_vhe(). The 32-bit stubs for kvm_arm_vhe_guest_enter() and kvm_arm_vhe_guest_exit() are removed, as they are no longer used. The 32-bit stub for kvm_vcpu_run_vhe() is left as-is. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200210114757.2889-1-mark.rutland@arm.com

Merge tag 'irqchip-fixes-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/urgent

2020-02-08T14:54:03Z

Pull irqchip fixes for 5.6, take #1 from Marc Zyngier: - Guarantee allocation of L2 vPE table for GICv4.1 - Fix GICv4.1 VPROPBASER programming - Numerous GICv4.1 tidy ups - Fix disabled GICv3 redistributor provisioning with ACPI - KConfig cleanup for C-SKY

irqchip/gic-v3-its: Rename VPENDBASER/VPROPBASER accessors

2020-02-08T10:01:33Z

V{PEND,PROP}BASER registers are actually located in VLPI_base frame of the *redistributor*. Rename their accessors to reflect this fact. No functional changes. Signed-off-by: Zenghui Yu Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20200206075711.1275-7-yuzenghui@huawei.com