From d49f7d7376d0c0daf8680984a37bd07581ac7d38 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 31 Jul 2020 18:38:23 +0100 Subject: arm64: Move handling of erratum 1418040 into C code Instead of dealing with erratum 1418040 on each entry and exit, let's move the handling to __switch_to() instead, which has several advantages: - It can be applied when it matters (switching between 32 and 64 bit tasks). - It is written in C (yay!) - It can rely on static keys rather than alternatives Signed-off-by: Marc Zyngier Tested-by: Sai Prakash Ranjan Reviewed-by: Stephen Boyd Acked-by: Will Deacon Link: https://lore.kernel.org/r/20200731173824.107480-2-maz@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/entry.S | 21 --------------------- arch/arm64/kernel/process.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 34 insertions(+), 21 deletions(-) diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S index 2646178c8329..55af8b504b65 100644 --- a/arch/arm64/kernel/entry.S +++ b/arch/arm64/kernel/entry.S @@ -170,19 +170,6 @@ alternative_cb_end stp x28, x29, [sp, #16 * 14] .if \el == 0 - .if \regsize == 32 - /* - * If we're returning from a 32-bit task on a system affected by - * 1418040 then re-enable userspace access to the virtual counter. - */ -#ifdef CONFIG_ARM64_ERRATUM_1418040 -alternative_if ARM64_WORKAROUND_1418040 - mrs x0, cntkctl_el1 - orr x0, x0, #2 // ARCH_TIMER_USR_VCT_ACCESS_EN - msr cntkctl_el1, x0 -alternative_else_nop_endif -#endif - .endif clear_gp_regs mrs x21, sp_el0 ldr_this_cpu tsk, __entry_task, x20 @@ -294,14 +281,6 @@ alternative_else_nop_endif tst x22, #PSR_MODE32_BIT // native task? b.eq 3f -#ifdef CONFIG_ARM64_ERRATUM_1418040 -alternative_if ARM64_WORKAROUND_1418040 - mrs x0, cntkctl_el1 - bic x0, x0, #2 // ARCH_TIMER_USR_VCT_ACCESS_EN - msr cntkctl_el1, x0 -alternative_else_nop_endif -#endif - #ifdef CONFIG_ARM64_ERRATUM_845719 alternative_if ARM64_WORKAROUND_845719 #ifdef CONFIG_PID_IN_CONTEXTIDR diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 84ec630b8ab5..b63ce4c54cfe 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -515,6 +515,39 @@ static void entry_task_switch(struct task_struct *next) __this_cpu_write(__entry_task, next); } +/* + * ARM erratum 1418040 handling, affecting the 32bit view of CNTVCT. + * Assuming the virtual counter is enabled at the beginning of times: + * + * - disable access when switching from a 64bit task to a 32bit task + * - enable access when switching from a 32bit task to a 64bit task + */ +static void erratum_1418040_thread_switch(struct task_struct *prev, + struct task_struct *next) +{ + bool prev32, next32; + u64 val; + + if (!(IS_ENABLED(CONFIG_ARM64_ERRATUM_1418040) && + cpus_have_const_cap(ARM64_WORKAROUND_1418040))) + return; + + prev32 = is_compat_thread(task_thread_info(prev)); + next32 = is_compat_thread(task_thread_info(next)); + + if (prev32 == next32) + return; + + val = read_sysreg(cntkctl_el1); + + if (!next32) + val |= ARCH_TIMER_USR_VCT_ACCESS_EN; + else + val &= ~ARCH_TIMER_USR_VCT_ACCESS_EN; + + write_sysreg(val, cntkctl_el1); +} + /* * Thread switching. */ @@ -530,6 +563,7 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, entry_task_switch(next); uao_thread_switch(next); ssbs_thread_switch(next); + erratum_1418040_thread_switch(prev, next); /* * Complete any pending TLB or cache maintenance on this CPU in case -- cgit v1.2.3 From bf87bb0881d0f59181fe3bbcf29c609f36483ff8 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Fri, 31 Jul 2020 18:38:24 +0100 Subject: arm64: Allow booting of late CPUs affected by erratum 1418040 As we can now switch from a system that isn't affected by 1418040 to a system that globally is affected, let's allow affected CPUs to come in at a later time. Signed-off-by: Marc Zyngier Tested-by: Sai Prakash Ranjan Reviewed-by: Stephen Boyd Reviewed-by: Suzuki K Poulose Acked-by: Will Deacon Link: https://lore.kernel.org/r/20200731173824.107480-3-maz@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kernel/cpu_errata.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 6bd1d3ad037a..c332d49780dc 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -910,6 +910,8 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .desc = "ARM erratum 1418040", .capability = ARM64_WORKAROUND_1418040, ERRATA_MIDR_RANGE_LIST(erratum_1418040_list), + .type = (ARM64_CPUCAP_SCOPE_LOCAL_CPU | + ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU), }, #endif #ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_AT -- cgit v1.2.3 From abf532cceaca9c21a148498091f87de1b8ae9b49 Mon Sep 17 00:00:00 2001 From: Rob Herring Date: Mon, 3 Aug 2020 13:31:25 -0600 Subject: KVM: arm64: Print warning when cpu erratum can cause guests to deadlock If guests don't have certain CPU erratum workarounds implemented, then there is a possibility a guest can deadlock the system. IOW, only trusted guests should be used on systems with the erratum. This is the case for Cortex-A57 erratum 832075. Signed-off-by: Rob Herring Acked-by: Will Deacon Cc: Marc Zyngier Cc: James Morse Cc: Julien Thierry Cc: Suzuki K Poulose Cc: Will Deacon Cc: kvmarm@lists.cs.columbia.edu Link: https://lore.kernel.org/r/20200803193127.3012242-2-robh@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/kvm/arm.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 691d21e4c717..46dc3d75cf13 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1640,6 +1640,10 @@ int kvm_arch_init(void *opaque) return -ENODEV; } + if (cpus_have_final_cap(ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)) + kvm_info("Guests without required CPU erratum workarounds can deadlock system!\n" \ + "Only trusted guests should be used on this system.\n"); + for_each_online_cpu(cpu) { smp_call_function_single(cpu, check_kvm_target_cpu, &ret, 1); if (ret < 0) { -- cgit v1.2.3 From 8d75785a814241587802655cc33e384230744f0c Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Mon, 17 Aug 2020 18:49:50 -0700 Subject: ARM64: vdso32: Install vdso32 from vdso_install Add the 32-bit vdso Makefile to the vdso_install rule so that 'make vdso_install' installs the 32-bit compat vdso when it is compiled. Fixes: a7f71a2c8903 ("arm64: compat: Add vDSO") Signed-off-by: Stephen Boyd Reviewed-by: Vincenzo Frascino Acked-by: Will Deacon Cc: Vincenzo Frascino Link: https://lore.kernel.org/r/20200818014950.42492-1-swboyd@chromium.org Signed-off-by: Catalin Marinas --- arch/arm64/Makefile | 1 + arch/arm64/kernel/vdso32/Makefile | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 55bc8546d9c7..b45f0124cc16 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -165,6 +165,7 @@ zinstall install: PHONY += vdso_install vdso_install: $(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso $@ + $(Q)$(MAKE) $(build)=arch/arm64/kernel/vdso32 $@ # We use MRPROPER_FILES and CLEAN_FILES now archclean: diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile index 5139a5f19256..d6adb4677c25 100644 --- a/arch/arm64/kernel/vdso32/Makefile +++ b/arch/arm64/kernel/vdso32/Makefile @@ -208,7 +208,7 @@ quiet_cmd_vdsosym = VDSOSYM $@ cmd_vdsosym = $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ # Install commands for the unstripped file -quiet_cmd_vdso_install = INSTALL $@ +quiet_cmd_vdso_install = INSTALL32 $@ cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/vdso32.so vdso.so: $(obj)/vdso.so.dbg -- cgit v1.2.3