Trusted Firmware-A's default interrupt routing model is to clear
SCR_EL3.FIQ, which is the only case that GICv3 doesn't support. This series
tries to fix that by detecting it at runtime and using a different priority
value for ICC_PMR_EL1 when masking regular interrupts. As a result, we will
be able to support pseudo-NMIs on all combinations of GIC security states
and firmware configurations.
The first patch was there because when I started working on the PMU NMI
patches I found it confusing that there was no clear message stating that
NMIs were successfully enabled. The second patch is the main patch of the
series, where pseudo-NMIs are enabled even if SCR_EL3.FIQ == 0.
As an aside, the set of priorities that I've added would work in all cases
if there was no need to use GIC_PRIO_PSR_I_SET, but that is a much more
intrusive change and I'm not comfortable attempting it. I'm pretty sure I
will end up breaking things really badly.
I've tested the series using PMU NMIs [1], rebased on top of v5.9-rc4, on
the model and on espressobin-v7. Tests that I've run:
1. On the model:
- Host with SCR_EL3.FIQ == 1 (so using the original priorities), ran
perf record -a -- iperf3 -c 127.0.0.1 -t 30.
- On a KVM guest (security disabled, so using the original priorities),
ran the same command.
2. On an espressobin-v7:
- Host with SCR_EL3.FIQ == 0 (using the priority added by the series),
ran perf record -a -- iperf3 -c 127.0.0.1 -t 60.
- On a KVM guest (security disabled, so using the original priorities),
ran the same command.
- Stress test for one hour with CONFIG_ARM64_DEBUG_PRIORITY_MASKING set
for the host and guest. On the host, I ran in parallel
perf record -a -- iperf3 -c 127.0.0.1 -t 3600 and
perf record -ae L1-dcache-loads -a -- sleep 3600. On the guest, I ran
the same iperf3 command as on the host.
Changes since v2:
* Renamed gic_prio_irqoff() -> GIC_PRIO_IRQOFF, thus avoiding any changes
to daifflags.h and irqflags.h, as per Marc's excellent suggestion.
* Added comment gic_cpu_sys_reg_init() explaining why we cannot get the
warning on the boot CPU.
Changes since v1:
* Rebased on top of v5.9-rc1
* Changed pmr to u64 in arch_local_irq_{enable,disable} to stop
clang from complaining and to match local_daif_restore().
[1] https://lkml.org/lkml/2020/8/19/671
Alexandru Elisei (2):
irqchip/gicv3: Spell out when pseudo-NMIs are enabled
irqchip/gic-v3: Support pseudo-NMIs when SCR_EL3.FIQ == 0
arch/arm64/include/asm/arch_gicv3.h | 8 +++-
arch/arm64/include/asm/ptrace.h | 14 ++++++-
arch/arm64/kernel/image-vars.h | 2 +
drivers/irqchip/irq-gic-v3.c | 60 ++++++++++++++++++++++-------
4 files changed, 68 insertions(+), 16 deletions(-)
--
2.28.0
When NMIs cannot be enabled, the driver prints a message stating that
unambiguously. When they are enabled, the only feedback we get is a message
regarding the use of synchronization for ICC_PMR_EL1 writes, which is not
as useful for a user who is not intimately familiar with how NMIs are
implemented.
Let's make it obvious that pseudo-NMIs are enabled. Keep the message about
using a barrier for ICC_PMR_EL1 writes, because it has a non-negligible
impact on performance.
Signed-off-by: Alexandru Elisei <[email protected]>
---
drivers/irqchip/irq-gic-v3.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 850842f27bee..aa9b43d412b2 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1564,8 +1564,8 @@ static void gic_enable_nmi_support(void)
if (gic_read_ctlr() & ICC_CTLR_EL1_PMHE_MASK)
static_branch_enable(&gic_pmr_sync);
- pr_info("%s ICC_PMR_EL1 synchronisation\n",
- static_branch_unlikely(&gic_pmr_sync) ? "Forcing" : "Relaxing");
+ pr_info("Pseudo-NMIs enabled using %s ICC_PMR_EL1 synchronisation\n",
+ static_branch_unlikely(&gic_pmr_sync) ? "forced" : "relaxed");
static_branch_enable(&supports_pseudo_nmis);
--
2.28.0
The GIC's internal view of the priority mask register and the assigned
interrupt priorities are based on whether GIC security is enabled and
whether firmware routes Group 0 interrupts to EL3. At the moment, we
support priority masking when ICC_PMR_EL1 and interrupt priorities are
either both modified by the GIC, or both left unchanged.
Trusted Firmware-A's default interrupt routing model allows Group 0
interrupts to be delivered to the non-secure world (SCR_EL3.FIQ == 0).
Unfortunately, this is precisely the case that the GIC driver doesn't
support: ICC_PMR_EL1 remains unchanged, but the GIC's view of interrupt
priorities is different from the software programmed values.
Support pseudo-NMIs when SCR_EL3.FIQ == 0 by using a different value to
mask regular interrupts. All the other values remain the same.
Signed-off-by: Alexandru Elisei <[email protected]>
---
arch/arm64/include/asm/arch_gicv3.h | 8 ++++-
arch/arm64/include/asm/ptrace.h | 14 +++++++-
arch/arm64/kernel/image-vars.h | 2 ++
drivers/irqchip/irq-gic-v3.c | 56 ++++++++++++++++++++++-------
4 files changed, 66 insertions(+), 14 deletions(-)
diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h
index 6647ae4f0231..880b9054d75c 100644
--- a/arch/arm64/include/asm/arch_gicv3.h
+++ b/arch/arm64/include/asm/arch_gicv3.h
@@ -153,7 +153,7 @@ static inline bool gic_prio_masking_enabled(void)
static inline void gic_pmr_mask_irqs(void)
{
- BUILD_BUG_ON(GICD_INT_DEF_PRI < (GIC_PRIO_IRQOFF |
+ BUILD_BUG_ON(GICD_INT_DEF_PRI < (__GIC_PRIO_IRQOFF |
GIC_PRIO_PSR_I_SET));
BUILD_BUG_ON(GICD_INT_DEF_PRI >= GIC_PRIO_IRQON);
/*
@@ -162,6 +162,12 @@ static inline void gic_pmr_mask_irqs(void)
* are applied to IRQ priorities
*/
BUILD_BUG_ON((0x80 | (GICD_INT_DEF_PRI >> 1)) >= GIC_PRIO_IRQON);
+ /*
+ * Same situation as above, but now we make sure that we can mask
+ * regular interrupts.
+ */
+ BUILD_BUG_ON((0x80 | (GICD_INT_DEF_PRI >> 1)) < (__GIC_PRIO_IRQOFF_NS |
+ GIC_PRIO_PSR_I_SET));
gic_write_pmr(GIC_PRIO_IRQOFF);
}
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 966ed30ed5f7..997cf8c8cd52 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -31,9 +31,21 @@
* interrupt disabling temporarily does not rely on IRQ priorities.
*/
#define GIC_PRIO_IRQON 0xe0
-#define GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80)
+#define __GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80)
+#define __GIC_PRIO_IRQOFF_NS 0xa0
#define GIC_PRIO_PSR_I_SET (1 << 4)
+#define GIC_PRIO_IRQOFF \
+ ({ \
+ extern struct static_key_false gic_nonsecure_priorities;\
+ u8 __prio = __GIC_PRIO_IRQOFF; \
+ \
+ if (static_branch_unlikely(&gic_nonsecure_priorities)) \
+ __prio = __GIC_PRIO_IRQOFF_NS; \
+ \
+ __prio; \
+ })
+
/* Additional SPSR bits not exposed in the UABI */
#define PSR_MODE_THREAD_BIT (1 << 0)
#define PSR_IL_BIT (1 << 20)
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 8982b68289b7..98a5215c1598 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -101,6 +101,8 @@ KVM_NVHE_ALIAS(vgic_v3_cpuif_trap);
/* Static key checked in pmr_sync(). */
#ifdef CONFIG_ARM64_PSEUDO_NMI
KVM_NVHE_ALIAS(gic_pmr_sync);
+/* Static key checked in GIC_PRIO_IRQOFF. */
+KVM_NVHE_ALIAS(gic_nonsecure_priorities);
#endif
/* EL2 exception handling */
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index aa9b43d412b2..bb55d89d7d49 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -75,16 +75,14 @@ static DEFINE_STATIC_KEY_TRUE(supports_deactivate_key);
*
* If SCR_EL3.FIQ == 1, the values writen to/read from PMR and RPR at non-secure
* EL1 are subject to a similar operation thus matching the priorities presented
- * from the (re)distributor when security is enabled.
+ * from the (re)distributor when security is enabled. When SCR_EL3.FIQ == 0,
+ * these values are unchanched by the GIC.
*
* see GICv3/GICv4 Architecture Specification (IHI0069D):
* - section 4.8.1 Non-secure accesses to register fields for Secure interrupt
* priorities.
* - Figure 4-7 Secure read of the priority field for a Non-secure Group 1
* interrupt.
- *
- * For now, we only support pseudo-NMIs if we have non-secure view of
- * priorities.
*/
static DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis);
@@ -97,6 +95,9 @@ static DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis);
DEFINE_STATIC_KEY_FALSE(gic_pmr_sync);
EXPORT_SYMBOL(gic_pmr_sync);
+DEFINE_STATIC_KEY_FALSE(gic_nonsecure_priorities);
+EXPORT_SYMBOL(gic_nonsecure_priorities);
+
/* ppi_nmi_refs[n] == number of cpus having ppi[n + 16] set as NMI */
static refcount_t *ppi_nmi_refs;
@@ -932,14 +933,20 @@ static void gic_cpu_sys_reg_init(void)
/* Set priority mask register */
if (!gic_prio_masking_enabled()) {
write_gicreg(DEFAULT_PMR_VALUE, ICC_PMR_EL1);
- } else {
+ } else if (gic_supports_nmi()) {
/*
* Mismatch configuration with boot CPU, the system is likely
* to die as interrupt masking will not work properly on all
* CPUs
+ *
+ * The boot CPU calls this function before enabling NMI support,
+ * and as a result we'll never see this warning in the boot path
+ * for that CPU.
*/
- WARN_ON(gic_supports_nmi() && group0 &&
- !gic_dist_security_disabled());
+ if (static_branch_unlikely(&gic_nonsecure_priorities))
+ WARN_ON(!group0 || gic_dist_security_disabled());
+ else
+ WARN_ON(group0 && !gic_dist_security_disabled());
}
/*
@@ -1544,11 +1551,6 @@ static void gic_enable_nmi_support(void)
if (!gic_prio_masking_enabled())
return;
- if (gic_has_group0() && !gic_dist_security_disabled()) {
- pr_warn("SCR_EL3.FIQ is cleared, cannot enable use of pseudo-NMIs\n");
- return;
- }
-
ppi_nmi_refs = kcalloc(gic_data.ppi_nr, sizeof(*ppi_nmi_refs), GFP_KERNEL);
if (!ppi_nmi_refs)
return;
@@ -1567,6 +1569,36 @@ static void gic_enable_nmi_support(void)
pr_info("Pseudo-NMIs enabled using %s ICC_PMR_EL1 synchronisation\n",
static_branch_unlikely(&gic_pmr_sync) ? "forced" : "relaxed");
+ /*
+ * How priority values are used by the GIC depends on two things:
+ * the security state of the GIC (controlled by the GICD_CTRL.DS bit)
+ * and if Group 0 interrupts can be delivered to Linux in the non-secure
+ * world as FIQs (controlled by the SCR_EL3.FIQ bit). These affect the
+ * the ICC_PMR_EL1 register and the priority that software assigns to
+ * interrupts:
+ *
+ * GICD_CTRL.DS | SCR_EL3.FIQ | ICC_PMR_EL1 | Group 1 priority
+ * -----------------------------------------------------------
+ * 1 | - | unchanged | unchanged
+ * -----------------------------------------------------------
+ * 0 | 1 | non-secure | non-secure
+ * -----------------------------------------------------------
+ * 0 | 0 | unchanged | non-secure
+ *
+ * where non-secure means that the value is right-shifted by one and the
+ * MSB bit set, to make it fit in the non-secure priority range.
+ *
+ * In the first two cases, where ICC_PMR_EL1 and the interrupt priority
+ * are both either modified or unchanged, we can use the same set of
+ * priorities.
+ *
+ * In the last case, where only the interrupt priorities are modified to
+ * be in the non-secure range, we use a different PMR value to mask IRQs
+ * and the rest of the values that we use remain unchanged.
+ */
+ if (gic_has_group0() && !gic_dist_security_disabled())
+ static_branch_enable(&gic_nonsecure_priorities);
+
static_branch_enable(&supports_pseudo_nmis);
if (static_branch_likely(&supports_deactivate_key))
--
2.28.0
On Sat, 12 Sep 2020 16:37:05 +0100, Alexandru Elisei wrote:
> Trusted Firmware-A's default interrupt routing model is to clear
> SCR_EL3.FIQ, which is the only case that GICv3 doesn't support. This series
> tries to fix that by detecting it at runtime and using a different priority
> value for ICC_PMR_EL1 when masking regular interrupts. As a result, we will
> be able to support pseudo-NMIs on all combinations of GIC security states
> and firmware configurations.
>
> [...]
Applied to irq/irqchip-next, thanks!
[1/2] irqchip/gic-v3: Spell out when pseudo-NMIs are enabled
commit: 4e594ad1068ea1db359d6161f580f03edecf6cb0
[2/2] irqchip/gic-v3: Support pseudo-NMIs when SCR_EL3.FIQ == 0
commit: 336780590990efa69596884114cad3f517b6333b
Cheers,
M.
--
Without deviation from the norm, progress is not possible.
The following commit has been merged into the irq/core branch of tip:
Commit-ID: 336780590990efa69596884114cad3f517b6333b
Gitweb: https://git.kernel.org/tip/336780590990efa69596884114cad3f517b6333b
Author: Alexandru Elisei <[email protected]>
AuthorDate: Sat, 12 Sep 2020 16:37:07 +01:00
Committer: Marc Zyngier <[email protected]>
CommitterDate: Sun, 13 Sep 2020 17:52:04 +01:00
irqchip/gic-v3: Support pseudo-NMIs when SCR_EL3.FIQ == 0
The GIC's internal view of the priority mask register and the assigned
interrupt priorities are based on whether GIC security is enabled and
whether firmware routes Group 0 interrupts to EL3. At the moment, we
support priority masking when ICC_PMR_EL1 and interrupt priorities are
either both modified by the GIC, or both left unchanged.
Trusted Firmware-A's default interrupt routing model allows Group 0
interrupts to be delivered to the non-secure world (SCR_EL3.FIQ == 0).
Unfortunately, this is precisely the case that the GIC driver doesn't
support: ICC_PMR_EL1 remains unchanged, but the GIC's view of interrupt
priorities is different from the software programmed values.
Support pseudo-NMIs when SCR_EL3.FIQ == 0 by using a different value to
mask regular interrupts. All the other values remain the same.
Signed-off-by: Alexandru Elisei <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
arch/arm64/include/asm/arch_gicv3.h | 8 +++-
arch/arm64/include/asm/ptrace.h | 14 ++++++-
arch/arm64/kernel/image-vars.h | 2 +-
drivers/irqchip/irq-gic-v3.c | 56 ++++++++++++++++++++++------
4 files changed, 66 insertions(+), 14 deletions(-)
diff --git a/arch/arm64/include/asm/arch_gicv3.h b/arch/arm64/include/asm/arch_gicv3.h
index 6647ae4..880b905 100644
--- a/arch/arm64/include/asm/arch_gicv3.h
+++ b/arch/arm64/include/asm/arch_gicv3.h
@@ -153,7 +153,7 @@ static inline bool gic_prio_masking_enabled(void)
static inline void gic_pmr_mask_irqs(void)
{
- BUILD_BUG_ON(GICD_INT_DEF_PRI < (GIC_PRIO_IRQOFF |
+ BUILD_BUG_ON(GICD_INT_DEF_PRI < (__GIC_PRIO_IRQOFF |
GIC_PRIO_PSR_I_SET));
BUILD_BUG_ON(GICD_INT_DEF_PRI >= GIC_PRIO_IRQON);
/*
@@ -162,6 +162,12 @@ static inline void gic_pmr_mask_irqs(void)
* are applied to IRQ priorities
*/
BUILD_BUG_ON((0x80 | (GICD_INT_DEF_PRI >> 1)) >= GIC_PRIO_IRQON);
+ /*
+ * Same situation as above, but now we make sure that we can mask
+ * regular interrupts.
+ */
+ BUILD_BUG_ON((0x80 | (GICD_INT_DEF_PRI >> 1)) < (__GIC_PRIO_IRQOFF_NS |
+ GIC_PRIO_PSR_I_SET));
gic_write_pmr(GIC_PRIO_IRQOFF);
}
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 966ed30..997cf8c 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -31,9 +31,21 @@
* interrupt disabling temporarily does not rely on IRQ priorities.
*/
#define GIC_PRIO_IRQON 0xe0
-#define GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80)
+#define __GIC_PRIO_IRQOFF (GIC_PRIO_IRQON & ~0x80)
+#define __GIC_PRIO_IRQOFF_NS 0xa0
#define GIC_PRIO_PSR_I_SET (1 << 4)
+#define GIC_PRIO_IRQOFF \
+ ({ \
+ extern struct static_key_false gic_nonsecure_priorities;\
+ u8 __prio = __GIC_PRIO_IRQOFF; \
+ \
+ if (static_branch_unlikely(&gic_nonsecure_priorities)) \
+ __prio = __GIC_PRIO_IRQOFF_NS; \
+ \
+ __prio; \
+ })
+
/* Additional SPSR bits not exposed in the UABI */
#define PSR_MODE_THREAD_BIT (1 << 0)
#define PSR_IL_BIT (1 << 20)
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 8982b68..98a5215 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -101,6 +101,8 @@ KVM_NVHE_ALIAS(vgic_v3_cpuif_trap);
/* Static key checked in pmr_sync(). */
#ifdef CONFIG_ARM64_PSEUDO_NMI
KVM_NVHE_ALIAS(gic_pmr_sync);
+/* Static key checked in GIC_PRIO_IRQOFF. */
+KVM_NVHE_ALIAS(gic_nonsecure_priorities);
#endif
/* EL2 exception handling */
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index aa9b43d..bb55d89 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -75,16 +75,14 @@ static DEFINE_STATIC_KEY_TRUE(supports_deactivate_key);
*
* If SCR_EL3.FIQ == 1, the values writen to/read from PMR and RPR at non-secure
* EL1 are subject to a similar operation thus matching the priorities presented
- * from the (re)distributor when security is enabled.
+ * from the (re)distributor when security is enabled. When SCR_EL3.FIQ == 0,
+ * these values are unchanched by the GIC.
*
* see GICv3/GICv4 Architecture Specification (IHI0069D):
* - section 4.8.1 Non-secure accesses to register fields for Secure interrupt
* priorities.
* - Figure 4-7 Secure read of the priority field for a Non-secure Group 1
* interrupt.
- *
- * For now, we only support pseudo-NMIs if we have non-secure view of
- * priorities.
*/
static DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis);
@@ -97,6 +95,9 @@ static DEFINE_STATIC_KEY_FALSE(supports_pseudo_nmis);
DEFINE_STATIC_KEY_FALSE(gic_pmr_sync);
EXPORT_SYMBOL(gic_pmr_sync);
+DEFINE_STATIC_KEY_FALSE(gic_nonsecure_priorities);
+EXPORT_SYMBOL(gic_nonsecure_priorities);
+
/* ppi_nmi_refs[n] == number of cpus having ppi[n + 16] set as NMI */
static refcount_t *ppi_nmi_refs;
@@ -932,14 +933,20 @@ static void gic_cpu_sys_reg_init(void)
/* Set priority mask register */
if (!gic_prio_masking_enabled()) {
write_gicreg(DEFAULT_PMR_VALUE, ICC_PMR_EL1);
- } else {
+ } else if (gic_supports_nmi()) {
/*
* Mismatch configuration with boot CPU, the system is likely
* to die as interrupt masking will not work properly on all
* CPUs
+ *
+ * The boot CPU calls this function before enabling NMI support,
+ * and as a result we'll never see this warning in the boot path
+ * for that CPU.
*/
- WARN_ON(gic_supports_nmi() && group0 &&
- !gic_dist_security_disabled());
+ if (static_branch_unlikely(&gic_nonsecure_priorities))
+ WARN_ON(!group0 || gic_dist_security_disabled());
+ else
+ WARN_ON(group0 && !gic_dist_security_disabled());
}
/*
@@ -1544,11 +1551,6 @@ static void gic_enable_nmi_support(void)
if (!gic_prio_masking_enabled())
return;
- if (gic_has_group0() && !gic_dist_security_disabled()) {
- pr_warn("SCR_EL3.FIQ is cleared, cannot enable use of pseudo-NMIs\n");
- return;
- }
-
ppi_nmi_refs = kcalloc(gic_data.ppi_nr, sizeof(*ppi_nmi_refs), GFP_KERNEL);
if (!ppi_nmi_refs)
return;
@@ -1567,6 +1569,36 @@ static void gic_enable_nmi_support(void)
pr_info("Pseudo-NMIs enabled using %s ICC_PMR_EL1 synchronisation\n",
static_branch_unlikely(&gic_pmr_sync) ? "forced" : "relaxed");
+ /*
+ * How priority values are used by the GIC depends on two things:
+ * the security state of the GIC (controlled by the GICD_CTRL.DS bit)
+ * and if Group 0 interrupts can be delivered to Linux in the non-secure
+ * world as FIQs (controlled by the SCR_EL3.FIQ bit). These affect the
+ * the ICC_PMR_EL1 register and the priority that software assigns to
+ * interrupts:
+ *
+ * GICD_CTRL.DS | SCR_EL3.FIQ | ICC_PMR_EL1 | Group 1 priority
+ * -----------------------------------------------------------
+ * 1 | - | unchanged | unchanged
+ * -----------------------------------------------------------
+ * 0 | 1 | non-secure | non-secure
+ * -----------------------------------------------------------
+ * 0 | 0 | unchanged | non-secure
+ *
+ * where non-secure means that the value is right-shifted by one and the
+ * MSB bit set, to make it fit in the non-secure priority range.
+ *
+ * In the first two cases, where ICC_PMR_EL1 and the interrupt priority
+ * are both either modified or unchanged, we can use the same set of
+ * priorities.
+ *
+ * In the last case, where only the interrupt priorities are modified to
+ * be in the non-secure range, we use a different PMR value to mask IRQs
+ * and the rest of the values that we use remain unchanged.
+ */
+ if (gic_has_group0() && !gic_dist_security_disabled())
+ static_branch_enable(&gic_nonsecure_priorities);
+
static_branch_enable(&supports_pseudo_nmis);
if (static_branch_likely(&supports_deactivate_key))
The following commit has been merged into the irq/core branch of tip:
Commit-ID: 4e594ad1068ea1db359d6161f580f03edecf6cb0
Gitweb: https://git.kernel.org/tip/4e594ad1068ea1db359d6161f580f03edecf6cb0
Author: Alexandru Elisei <[email protected]>
AuthorDate: Sat, 12 Sep 2020 16:37:06 +01:00
Committer: Marc Zyngier <[email protected]>
CommitterDate: Sun, 13 Sep 2020 17:51:35 +01:00
irqchip/gic-v3: Spell out when pseudo-NMIs are enabled
When NMIs cannot be enabled, the driver prints a message stating that
unambiguously. When they are enabled, the only feedback we get is a message
regarding the use of synchronization for ICC_PMR_EL1 writes, which is not
as useful for a user who is not intimately familiar with how NMIs are
implemented.
Let's make it obvious that pseudo-NMIs are enabled. Keep the message about
using a barrier for ICC_PMR_EL1 writes, because it has a non-negligible
impact on performance.
Signed-off-by: Alexandru Elisei <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
drivers/irqchip/irq-gic-v3.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 850842f..aa9b43d 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -1564,8 +1564,8 @@ static void gic_enable_nmi_support(void)
if (gic_read_ctlr() & ICC_CTLR_EL1_PMHE_MASK)
static_branch_enable(&gic_pmr_sync);
- pr_info("%s ICC_PMR_EL1 synchronisation\n",
- static_branch_unlikely(&gic_pmr_sync) ? "Forcing" : "Relaxing");
+ pr_info("Pseudo-NMIs enabled using %s ICC_PMR_EL1 synchronisation\n",
+ static_branch_unlikely(&gic_pmr_sync) ? "forced" : "relaxed");
static_branch_enable(&supports_pseudo_nmis);