[PATCH v2 1/2] arm64: Combine workarounds for speculative AT errata

From: Steven Price
Date: Wed Nov 13 2019 - 06:41:32 EST

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Cortex-A57/A72 have a similar errata to Cortex-A76 regarding speculation
of the AT instruction. Since the workaround for A57/A72 doesn't require
VHE, the restriction enforcing VHE for A76 can be removed by combining
the workaround flag for both errata.

So combine WORKAROUND_1165522 and WORKAROUND_1319367 into
WORKAROUND_SPECULATIVE_AT. The majority of code is contained within VHE
or NVHE specific functions, for the cases where the code is shared extra
checks against has_vhe().

This also paves the way for adding a similar erratum for Cortex-A55.

Signed-off-by: Steven Price <steven.price@xxxxxxx>
---
arch/arm64/Kconfig | 5 +++++
arch/arm64/include/asm/cpucaps.h | 5 ++---
arch/arm64/include/asm/kvm_host.h | 4 ----
arch/arm64/include/asm/kvm_hyp.h | 3 ++-
arch/arm64/kernel/cpu_errata.c | 19 ++++++++++++++-----
arch/arm64/kvm/hyp/switch.c | 6 +++---
arch/arm64/kvm/hyp/sysreg-sr.c | 6 ++++--
arch/arm64/kvm/hyp/tlb.c | 8 ++++----
8 files changed, 34 insertions(+), 22 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3e53441ee067..5a235e724fbb 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -516,9 +516,13 @@ config ARM64_ERRATUM_1418040

If unsure, say Y.

+config ARM64_WORKAROUND_SPECULATIVE_AT
+ bool
+
config ARM64_ERRATUM_1165522
bool "Cortex-A76: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
default y
+ select ARM64_WORKAROUND_SPECULATIVE_AT
help
This option adds a workaround for ARM Cortex-A76 erratum 1165522.

@@ -547,6 +551,7 @@ config ARM64_ERRATUM_1286807
config ARM64_ERRATUM_1319367
bool "Cortex-A57/A72: Speculative AT instruction using out-of-context translation regime could cause subsequent request to generate an incorrect translation"
default y
+ select ARM64_WORKAROUND_SPECULATIVE_AT
help
This option adds work arounds for ARM Cortex-A57 erratum 1319537
and A72 erratum 1319367
diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index b92683871119..b57821e10a8f 100644
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -44,7 +44,7 @@
#define ARM64_SSBS 34
#define ARM64_WORKAROUND_1418040 35
#define ARM64_HAS_SB 36
-#define ARM64_WORKAROUND_1165522 37
+#define ARM64_WORKAROUND_SPECULATIVE_AT 37
#define ARM64_HAS_ADDRESS_AUTH_ARCH 38
#define ARM64_HAS_ADDRESS_AUTH_IMP_DEF 39
#define ARM64_HAS_GENERIC_AUTH_ARCH 40
@@ -55,8 +55,7 @@
#define ARM64_WORKAROUND_CAVIUM_TX2_219_TVM 45
#define ARM64_WORKAROUND_CAVIUM_TX2_219_PRFM 46
#define ARM64_WORKAROUND_1542419 47
-#define ARM64_WORKAROUND_1319367 48

-#define ARM64_NCAPS 49
+#define ARM64_NCAPS 48

#endif /* __ASM_CPUCAPS_H */
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 5ecb091c8576..583ada60d5d9 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -533,10 +533,6 @@ static inline bool kvm_arch_requires_vhe(void)
if (system_supports_sve())
return true;

- /* Some implementations have defects that confine them to VHE */
- if (cpus_have_cap(ARM64_WORKAROUND_1165522))
- return true;
-
return false;
}

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index 97f21cc66657..965a9b4e5454 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -95,7 +95,8 @@ static __always_inline void __hyp_text __load_guest_stage2(struct kvm *kvm)
* before we can switch to the EL1/EL0 translation regime used by
* the guest.
*/
- asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_1165522));
+ if (!has_vhe())
+ asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_SPECULATIVE_AT));
}

#endif /* __ARM64_KVM_HYP_H__ */
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 4f8187a4fc46..b801f8e832aa 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -744,6 +744,16 @@ static const struct midr_range erratum_1418040_list[] = {
};
#endif

+#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_AT
+static const struct midr_range erratum_speculative_at_list[] = {
+#ifdef CONFIG_ARM64_ERRATUM_1165522
+ /* Cortex A76 r0p0 to r2p0 */
+ MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 2, 0),
+#endif
+ {},
+};
+#endif
+
const struct arm64_cpu_capabilities arm64_errata[] = {
#ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE
{
@@ -868,12 +878,11 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
ERRATA_MIDR_RANGE_LIST(erratum_1418040_list),
},
#endif
-#ifdef CONFIG_ARM64_ERRATUM_1165522
+#ifdef CONFIG_ARM64_WORKAROUND_SPECULATIVE_AT
{
- /* Cortex-A76 r0p0 to r2p0 */
.desc = "ARM erratum 1165522",
- .capability = ARM64_WORKAROUND_1165522,
- ERRATA_MIDR_RANGE(MIDR_CORTEX_A76, 0, 0, 2, 0),
+ .capability = ARM64_WORKAROUND_SPECULATIVE_AT,
+ ERRATA_MIDR_RANGE_LIST(erratum_speculative_at_list),
},
#endif
#ifdef CONFIG_ARM64_ERRATUM_1463225
@@ -910,7 +919,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
#ifdef CONFIG_ARM64_ERRATUM_1319367
{
.desc = "ARM erratum 1319367",
- .capability = ARM64_WORKAROUND_1319367,
+ .capability = ARM64_WORKAROUND_SPECULATIVE_AT,
ERRATA_MIDR_RANGE_LIST(ca57_a72),
},
#endif
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index 72fbbd86eb5e..140f467b1f16 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -119,7 +119,7 @@ static void __hyp_text __activate_traps_nvhe(struct kvm_vcpu *vcpu)

write_sysreg(val, cptr_el2);

- if (cpus_have_const_cap(ARM64_WORKAROUND_1319367)) {
+ if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
struct kvm_cpu_context *ctxt = &vcpu->arch.ctxt;

isb();
@@ -162,7 +162,7 @@ static void deactivate_traps_vhe(void)
* before we can switch to the EL2/EL0 translation regime used by
* the host.
*/
- asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_1165522));
+ asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_SPECULATIVE_AT));

write_sysreg(CPACR_EL1_DEFAULT, cpacr_el1);
write_sysreg(vectors, vbar_el1);
@@ -173,7 +173,7 @@ static void __hyp_text __deactivate_traps_nvhe(void)
{
u64 mdcr_el2 = read_sysreg(mdcr_el2);

- if (cpus_have_const_cap(ARM64_WORKAROUND_1319367)) {
+ if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
u64 val;

/*
diff --git a/arch/arm64/kvm/hyp/sysreg-sr.c b/arch/arm64/kvm/hyp/sysreg-sr.c
index 22b8128d19f6..f023f56397b3 100644
--- a/arch/arm64/kvm/hyp/sysreg-sr.c
+++ b/arch/arm64/kvm/hyp/sysreg-sr.c
@@ -118,7 +118,8 @@ static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
write_sysreg(ctxt->sys_regs[MPIDR_EL1], vmpidr_el2);
write_sysreg(ctxt->sys_regs[CSSELR_EL1], csselr_el1);

- if (!cpus_have_const_cap(ARM64_WORKAROUND_1319367)) {
+ if (!cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT) ||
+ has_vhe()) {
write_sysreg_el1(ctxt->sys_regs[SCTLR_EL1], SYS_SCTLR);
write_sysreg_el1(ctxt->sys_regs[TCR_EL1], SYS_TCR);
} else if (!ctxt->__hyp_running_vcpu) {
@@ -149,7 +150,8 @@ static void __hyp_text __sysreg_restore_el1_state(struct kvm_cpu_context *ctxt)
write_sysreg(ctxt->sys_regs[PAR_EL1], par_el1);
write_sysreg(ctxt->sys_regs[TPIDR_EL1], tpidr_el1);

- if (cpus_have_const_cap(ARM64_WORKAROUND_1319367) &&
+ if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT) &&
+ !has_vhe() &&
ctxt->__hyp_running_vcpu) {
/*
* Must only be done for host registers, hence the context
diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c
index c2bc17ca6430..338df7f9149a 100644
--- a/arch/arm64/kvm/hyp/tlb.c
+++ b/arch/arm64/kvm/hyp/tlb.c
@@ -23,7 +23,7 @@ static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm,

local_irq_save(cxt->flags);

- if (cpus_have_const_cap(ARM64_WORKAROUND_1165522)) {
+ if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
/*
* For CPUs that are affected by ARM erratum 1165522, we
* cannot trust stage-1 to be in a correct state at that
@@ -63,7 +63,7 @@ static void __hyp_text __tlb_switch_to_guest_vhe(struct kvm *kvm,
static void __hyp_text __tlb_switch_to_guest_nvhe(struct kvm *kvm,
struct tlb_inv_context *cxt)
{
- if (cpus_have_const_cap(ARM64_WORKAROUND_1319367)) {
+ if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
u64 val;

/*
@@ -103,7 +103,7 @@ static void __hyp_text __tlb_switch_to_host_vhe(struct kvm *kvm,
write_sysreg(HCR_HOST_VHE_FLAGS, hcr_el2);
isb();

- if (cpus_have_const_cap(ARM64_WORKAROUND_1165522)) {
+ if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
/* Restore the registers to what they were */
write_sysreg_el1(cxt->tcr, SYS_TCR);
write_sysreg_el1(cxt->sctlr, SYS_SCTLR);
@@ -117,7 +117,7 @@ static void __hyp_text __tlb_switch_to_host_nvhe(struct kvm *kvm,
{
write_sysreg(0, vttbr_el2);

- if (cpus_have_const_cap(ARM64_WORKAROUND_1319367)) {
+ if (cpus_have_const_cap(ARM64_WORKAROUND_SPECULATIVE_AT)) {
/* Ensure write of the host VMID */
isb();
/* Restore the host's TCR_EL1 */
--
2.20.1

Next message: Masahiro Yamada: "Re: [PATCH] ARM: don't export unused return_address()"
Previous message: Steven Price: "[PATCH v2 0/2] arm64: Workaround for Cortex-A55 erratum 1530923"
In reply to: Steven Price: "[PATCH v2 0/2] arm64: Workaround for Cortex-A55 erratum 1530923"
Next in thread: Marc Zyngier: "Re: [PATCH v2 1/2] arm64: Combine workarounds for speculative AT errata"
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