@@ -1436,6 +1436,17 @@ config ARM64_PSEUDO_NMI
If unsure, say N
+if ARM64_PSEUDO_NMI
+config ARM64_DEBUG_PRIORITY_MASKING
+ bool "Debug interrupt priority masking"
+ help
+ This adds runtime checks to functions enabling/disabling
+ interrupts when using priority masking. The additional checks verify
+ the validity of ICC_PMR_EL1 when calling concerned functions.
+
+ If unsure, say N
+endif
+
config RELOCATABLE
bool
help
@@ -617,6 +617,12 @@ static inline bool system_uses_irq_prio_masking(void)
cpus_have_const_cap(ARM64_HAS_IRQ_PRIO_MASKING);
}
+static inline bool system_has_prio_mask_debugging(void)
+{
+ return IS_ENABLED(CONFIG_ARM64_DEBUG_PRIORITY_MASKING) &&
+ system_uses_irq_prio_masking();
+}
+
#define ARM64_SSBD_UNKNOWN -1
#define ARM64_SSBD_FORCE_DISABLE 0
#define ARM64_SSBD_KERNEL 1
@@ -28,6 +28,10 @@
/* mask/save/unmask/restore all exceptions, including interrupts. */
static inline void local_daif_mask(void)
{
+ WARN_ON(system_has_prio_mask_debugging() &&
+ (read_sysreg_s(SYS_ICC_PMR_EL1) == (GIC_PRIO_IRQOFF |
+ GIC_PRIO_PSR_I_SET)));
+
asm volatile(
"msr daifset, #0xf // local_daif_mask\n"
:
@@ -62,6 +66,9 @@ static inline void local_daif_restore(unsigned long flags)
{
bool irq_disabled = flags & PSR_I_BIT;
+ WARN_ON(system_has_prio_mask_debugging() &&
+ !(read_sysreg(daif) & PSR_I_BIT));
+
if (!irq_disabled) {
trace_hardirqs_on();
@@ -40,6 +40,12 @@
*/
static inline void arch_local_irq_enable(void)
{
+ if (system_has_prio_mask_debugging()) {
+ u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
+
+ WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
+ }
+
asm volatile(ALTERNATIVE(
"msr daifclr, #2 // arch_local_irq_enable\n"
"nop",
@@ -53,6 +59,12 @@ static inline void arch_local_irq_enable(void)
static inline void arch_local_irq_disable(void)
{
+ if (system_has_prio_mask_debugging()) {
+ u32 pmr = read_sysreg_s(SYS_ICC_PMR_EL1);
+
+ WARN_ON_ONCE(pmr != GIC_PRIO_IRQON && pmr != GIC_PRIO_IRQOFF);
+ }
+
asm volatile(ALTERNATIVE(
"msr daifset, #2 // arch_local_irq_disable",
__msr_s(SYS_ICC_PMR_EL1, "%0"),
Using IRQ priority masking to enable/disable interrupts is a bit sensitive as it requires to deal with both ICC_PMR_EL1 and PSR.I. Introduce some validity checks to both highlight the states in which functions dealing with IRQ enabling/disabling can (not) be called, and bark a warning when called in an unexpected state. Since these checks are done on hotpaths, introduce a build option to choose whether to do the checking. Signed-off-by: Julien Thierry <julien.thierry@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> --- arch/arm64/Kconfig | 11 +++++++++++ arch/arm64/include/asm/cpufeature.h | 6 ++++++ arch/arm64/include/asm/daifflags.h | 7 +++++++ arch/arm64/include/asm/irqflags.h | 12 ++++++++++++ 4 files changed, 36 insertions(+) -- 1.9.1