From d49f7d7376d0c0daf8680984a37bd07581ac7d38 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
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 <maz@kernel.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200731173824.107480-2-maz@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
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 <maz@kernel.org>
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 <maz@kernel.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200731173824.107480-3-maz@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
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 <robh@kernel.org>
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 <robh@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: kvmarm@lists.cs.columbia.edu
Link: https://lore.kernel.org/r/20200803193127.3012242-2-robh@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
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 <swboyd@chromium.org>
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 <swboyd@chromium.org>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lore.kernel.org/r/20200818014950.42492-1-swboyd@chromium.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
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