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authorLinus Torvalds <torvalds@linux-foundation.org>2020-08-22 20:17:36 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-22 20:17:36 +0300
commitdd105d64a0c6976153adea40c034ba26f7cf34ed (patch)
tree5428a5a4e881e84db2302f9c1167b90c5a8238c1 /arch
parentd57ce84004a0d13ada89fbceec21539559cb72f2 (diff)
parent8d75785a814241587802655cc33e384230744f0c (diff)
downloadlinux-dd105d64a0c6976153adea40c034ba26f7cf34ed.tar.xz
Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Catalin Marinas: - Allow booting of late secondary CPUs affected by erratum 1418040 (currently they are parked if none of the early CPUs are affected by this erratum). - 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. - Print a warning that untrusted guests without a CPU erratum workaround (Cortex-A57 832075) may deadlock the affected system. * tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: ARM64: vdso32: Install vdso32 from vdso_install KVM: arm64: Print warning when cpu erratum can cause guests to deadlock arm64: Allow booting of late CPUs affected by erratum 1418040 arm64: Move handling of erratum 1418040 into C code
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/Makefile1
-rw-r--r--arch/arm64/kernel/cpu_errata.c2
-rw-r--r--arch/arm64/kernel/entry.S21
-rw-r--r--arch/arm64/kernel/process.c34
-rw-r--r--arch/arm64/kernel/vdso32/Makefile2
-rw-r--r--arch/arm64/kvm/arm.c4
6 files changed, 42 insertions, 22 deletions
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/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
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
@@ -516,6 +516,39 @@ static void entry_task_switch(struct task_struct *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.
*/
__notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
@@ -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
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
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) {