Add logging support for MMIO high level accessors such as read{b,w,l,q}
and their relaxed versions to aid in debugging unexpected crashes/hangs
caused by the corresponding MMIO operation. Also add a generic flag
(__DISABLE_TRACE_MMIO__) which is used to disable MMIO tracing in nVHE KVM
and if required can be used to disable MMIO tracing for specific drivers.
Signed-off-by: Sai Prakash Ranjan <quic_saipraka@xxxxxxxxxxx>
---
arch/arm64/kvm/hyp/nvhe/Makefile | 7 ++++-
include/asm-generic/io.h | 49 ++++++++++++++++++++++++++++++++
2 files changed, 55 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index c3c11974fa3b..2765ec38a269 100644
--- a/arch/arm64/kvm/hyp/nvhe/Makefile
+++ b/arch/arm64/kvm/hyp/nvhe/Makefile
@@ -4,7 +4,12 @@
#
asflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS
-ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS
+
+# Tracepoint and MMIO logging symbols should not be visible at nVHE KVM as
+# there is no way to execute them and any such MMIO access from nVHE KVM
+# will explode instantly (Words of Marc Zyngier). So introduce a generic flag
+# __DISABLE_TRACE_MMIO__ to disable MMIO tracing for nVHE KVM.
+ccflags-y := -D__KVM_NVHE_HYPERVISOR__ -D__DISABLE_EXPORTS -D__DISABLE_TRACE_MMIO__
hostprogs := gen-hyprel
HOST_EXTRACFLAGS += -I$(objtree)/include
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 7ce93aaf69f8..dd5a803c8479 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -61,6 +61,23 @@
#define __io_par(v) __io_ar(v)
#endif
+#if IS_ENABLED(CONFIG_TRACE_MMIO_ACCESS) && !(defined(__DISABLE_TRACE_MMIO__))
+#include <linux/tracepoint-defs.h>
+
+DECLARE_TRACEPOINT(rwmmio_write);
+DECLARE_TRACEPOINT(rwmmio_read);
+
+#define rwmmio_tracepoint_active(t) tracepoint_enabled(t)
+void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr);
+void log_read_mmio(u8 width, const volatile void __iomem *addr);
+
+#else
+
+#define rwmmio_tracepoint_active(t) false
+static inline void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr) {}
+static inline void log_read_mmio(u8 width, const volatile void __iomem *addr) {}
+
+#endif /* CONFIG_TRACE_MMIO_ACCESS */
/*
* __raw_{read,write}{b,w,l,q}() access memory in native endianness.
@@ -149,6 +166,8 @@ static inline u8 readb(const volatile void __iomem *addr)
{
u8 val;
+ if (rwmmio_tracepoint_active(rwmmio_read))
+ log_read_mmio(8, addr);
__io_br();
val = __raw_readb(addr);
__io_ar(val);
@@ -162,6 +181,8 @@ static inline u16 readw(const volatile void __iomem *addr)
{
u16 val;
+ if (rwmmio_tracepoint_active(rwmmio_read))
+ log_read_mmio(16, addr);
__io_br();
val = __le16_to_cpu((__le16 __force)__raw_readw(addr));
__io_ar(val);
@@ -175,6 +196,8 @@ static inline u32 readl(const volatile void __iomem *addr)
{
u32 val;
+ if (rwmmio_tracepoint_active(rwmmio_read))
+ log_read_mmio(32, addr);
__io_br();
val = __le32_to_cpu((__le32 __force)__raw_readl(addr));
__io_ar(val);
@@ -189,6 +212,8 @@ static inline u64 readq(const volatile void __iomem *addr)
{
u64 val;
+ if (rwmmio_tracepoint_active(rwmmio_read))
+ log_read_mmio(64, addr);
__io_br();
val = __le64_to_cpu(__raw_readq(addr));
__io_ar(val);
@@ -201,6 +226,8 @@ static inline u64 readq(const volatile void __iomem *addr)
#define writeb writeb
static inline void writeb(u8 value, volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_write))
+ log_write_mmio(value, 8, addr);
__io_bw();
__raw_writeb(value, addr);
__io_aw();
@@ -211,6 +238,8 @@ static inline void writeb(u8 value, volatile void __iomem *addr)
#define writew writew
static inline void writew(u16 value, volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_write))
+ log_write_mmio(value, 16, addr);
__io_bw();
__raw_writew((u16 __force)cpu_to_le16(value), addr);
__io_aw();
@@ -221,6 +250,8 @@ static inline void writew(u16 value, volatile void __iomem *addr)
#define writel writel
static inline void writel(u32 value, volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_write))
+ log_write_mmio(value, 32, addr);
__io_bw();
__raw_writel((u32 __force)__cpu_to_le32(value), addr);
__io_aw();
@@ -232,6 +263,8 @@ static inline void writel(u32 value, volatile void __iomem *addr)
#define writeq writeq
static inline void writeq(u64 value, volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_write))
+ log_write_mmio(value, 64, addr);
__io_bw();
__raw_writeq(__cpu_to_le64(value), addr);
__io_aw();
@@ -248,6 +281,8 @@ static inline void writeq(u64 value, volatile void __iomem *addr)
#define readb_relaxed readb_relaxed
static inline u8 readb_relaxed(const volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_read))
+ log_read_mmio(8, addr);
return __raw_readb(addr);
}
#endif
@@ -256,6 +291,8 @@ static inline u8 readb_relaxed(const volatile void __iomem *addr)
#define readw_relaxed readw_relaxed
static inline u16 readw_relaxed(const volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_read))
+ log_read_mmio(16, addr);
return __le16_to_cpu(__raw_readw(addr));
}
#endif
@@ -264,6 +301,8 @@ static inline u16 readw_relaxed(const volatile void __iomem *addr)
#define readl_relaxed readl_relaxed
static inline u32 readl_relaxed(const volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_read))
+ log_read_mmio(32, addr);
return __le32_to_cpu(__raw_readl(addr));
}
#endif
@@ -272,6 +311,8 @@ static inline u32 readl_relaxed(const volatile void __iomem *addr)
#define readq_relaxed readq_relaxed
static inline u64 readq_relaxed(const volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_read))
+ log_read_mmio(64, addr);
return __le64_to_cpu(__raw_readq(addr));
}
#endif
@@ -280,6 +321,8 @@ static inline u64 readq_relaxed(const volatile void __iomem *addr)
#define writeb_relaxed writeb_relaxed
static inline void writeb_relaxed(u8 value, volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_write))
+ log_write_mmio(value, 8, addr);
__raw_writeb(value, addr);
}
#endif
@@ -288,6 +331,8 @@ static inline void writeb_relaxed(u8 value, volatile void __iomem *addr)
#define writew_relaxed writew_relaxed
static inline void writew_relaxed(u16 value, volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_write))
+ log_write_mmio(value, 16, addr);
__raw_writew(cpu_to_le16(value), addr);
}
#endif
@@ -296,6 +341,8 @@ static inline void writew_relaxed(u16 value, volatile void __iomem *addr)
#define writel_relaxed writel_relaxed
static inline void writel_relaxed(u32 value, volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_write))
+ log_write_mmio(value, 32, addr);
__raw_writel(__cpu_to_le32(value), addr);
}
#endif
@@ -304,6 +351,8 @@ static inline void writel_relaxed(u32 value, volatile void __iomem *addr)
#define writeq_relaxed writeq_relaxed
static inline void writeq_relaxed(u64 value, volatile void __iomem *addr)
{
+ if (rwmmio_tracepoint_active(rwmmio_write))
+ log_write_mmio(value, 64, addr);
__raw_writeq(__cpu_to_le64(value), addr);
}
#endif
--
2.33.1
