Generic MMIO read/write i.e., __raw_{read,write}{b,l,w,q} accessors
are typically used to read/write from/to memory mapped registers
and can cause hangs or some undefined behaviour in following cases,
* If the access to the register space is unclocked, for example: if
there is an access to multimedia(MM) block registers without MM
clocks.
* If the register space is protected and not set to be accessible from
non-secure world, for example: only EL3 (EL: Exception level) access
is allowed and any EL2/EL1 access is forbidden.
* If xPU(memory/register protection units) is controlling access to
certain memory/register space for specific clients.
and more...
Such cases usually results in instant reboot/SErrors/NOC or interconnect
hangs and tracing these register accesses can be very helpful to debug
such issues during initial development stages and also in later stages.
So use ftrace trace events to log such MMIO register accesses which
provides rich feature set such as early enablement of trace events,
filtering capability, dumping ftrace logs on console and many more.
Sample output:
rwmmio_write: __qcom_geni_serial_console_write+0x160/0x1e0 width=32 val=0xa0d5d addr=0xfffffbfffdbff700
rwmmio_post_write: __qcom_geni_serial_console_write+0x160/0x1e0 width=32 val=0xa0d5d addr=0xfffffbfffdbff700
rwmmio_read: qcom_geni_serial_poll_bit+0x94/0x138 width=32 addr=0xfffffbfffdbff610
rwmmio_post_read: qcom_geni_serial_poll_bit+0x94/0x138 width=32 val=0x0 addr=0xfffffbfffdbff610
This series is a follow-up for the series [1] and a recent series [2] making use
of both.
[1] https://lore.kernel.org/lkml/[email protected]/
[2] https://lore.kernel.org/lkml/[email protected]/
Note in v4 version, Arnd suggested to benchmark and compare size with callback
based implementation, please see [3] for more details on that with brief comparison below.
**Inline version with CONFIG_FTRACE=y and CONFIG_TRACE_MMIO_ACCESS=y**
$ size vmlinux
text data bss dec hex filename
23884219 14284468 532568 38701255 24e88c7 vmlinux
**Callback version with CONFIG_FTRACE=y and CONFIG_TRACE_MMIO_ACCESS=y**
$ size vmlinux
text data bss dec hex filename
24108179 14279596 532568 38920343 251e097 vmlinux
$ ./scripts/bloat-o-meter inline-vmlinux callback-vmlinux
add/remove: 8/3 grow/shrink: 4889/89 up/down: 242244/-11564 (230680)
Total: Before=25812612, After=26043292, chg +0.89%
[3] https://lore.kernel.org/lkml/[email protected]/
Changes in v13:
* Remove the copyright update as one line change doesn't warrant it (Greg and Lawyers :))
* Update the comment about disabling MMIO traces in geni se and uart drivers.
* Add description for the build time flag to asm-generic/io.h.
Changes in v12:
* Split the generic flag addition patch (Greg).
* Move the flag from makefile to driver .c file (Greg).
Changes in v11:
* Use unsigned long for caller ip and current ip addr (Steven Rostedt).
* Include review tags from Arnd.
Changes in v10:
* Use GENMASK(31, 0) for -Woverflow warning in irqchip tegra driver (Marc).
* Convert ETM4x ARM64 driver to use asm-generic IO memory barriers (Catalin).
* Collect ack from Catalin for arm64 change.
Changes in v9:
* Use TRACE_EVENT_CLASS for rwmmio_write and post_write (Steven Rostedt).
Changes in v8:
* Fix build error reported by kernel test robot.
Changes in v7:
* Use lib/ instead of kernel/trace/ based on review comment by Steven Rostedt.
Changes in v6:
* Implemented suggestions by Arnd Bergmann:
- Use arch independent IO barriers in arm64/asm
- Add ARCH_HAVE_TRACE_MMIO_ACCESS
- Add post read and post write logging support
- Remove tracepoint_active check
* Fix build error reported by kernel test robot.
Changes in v5:
* Move arm64 to use asm-generic provided high level MMIO accessors (Arnd).
* Add inline logging for MMIO relaxed and non-relaxed accessors.
* Move nVHE KVM comment to makefile (Marc).
* Fix overflow warning due to switch to inline accessors instead of macro.
* Modify trace event field to include caller and parent details for more detailed logs.
Changes in v4:
* Drop dynamic debug based filter support since that will be developed later with
the help from Steven (Ftrace maintainer).
* Drop value passed to writel as it is causing hangs when tracing is enabled.
* Code cleanup for trace event as suggested by Steven for earlier version.
* Fixed some build errors reported by 0-day bot.
Changes in v3:
* Create a generic mmio header for instrumented version (Earlier suggested in [1]
by Will Deacon and recently [2] by Greg to have a generic version first).
* Add dynamic debug support to filter out traces which can be very useful for targeted
debugging specific to subsystems or drivers.
* Few modifications to the rwmmio trace event fields to include the mmio width and print
addresses in hex.
* Rewrote commit msg to explain some more about usecases.
Prasad Sodagudi (1):
lib: Add register read/write tracing support
Sai Prakash Ranjan (8):
arm64: io: Use asm-generic high level MMIO accessors
coresight: etm4x: Use asm-generic IO memory barriers
irqchip/tegra: Fix overflow implicit truncation warnings
drm/meson: Fix overflow implicit truncation warnings
KVM: arm64: Add a flag to disable MMIO trace for nVHE KVM
asm-generic/io: Add logging support for MMIO accessors
serial: qcom_geni_serial: Disable MMIO tracing for geni serial
soc: qcom: geni: Disable MMIO tracing for GENI SE
arch/Kconfig | 3 +
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/io.h | 41 ++------
arch/arm64/kvm/hyp/nvhe/Makefile | 7 +-
drivers/gpu/drm/meson/meson_viu.c | 22 ++---
.../coresight/coresight-etm4x-core.c | 8 +-
drivers/hwtracing/coresight/coresight-etm4x.h | 8 +-
drivers/irqchip/irq-tegra.c | 10 +-
drivers/soc/qcom/qcom-geni-se.c | 3 +
drivers/tty/serial/qcom_geni_serial.c | 3 +
include/asm-generic/io.h | 91 ++++++++++++++++-
include/trace/events/rwmmio.h | 97 +++++++++++++++++++
lib/Kconfig | 7 ++
lib/Makefile | 2 +
lib/trace_readwrite.c | 47 +++++++++
15 files changed, 288 insertions(+), 62 deletions(-)
create mode 100644 include/trace/events/rwmmio.h
create mode 100644 lib/trace_readwrite.c
--
2.33.1
Fix -Woverflow warnings for tegra irqchip driver which is a result
of moving arm64 custom MMIO accessor macros to asm-generic function
implementations giving a bonus type-checking now and uncovering these
overflow warnings.
drivers/irqchip/irq-tegra.c: In function ‘tegra_ictlr_suspend’:
drivers/irqchip/irq-tegra.c:151:18: warning: large integer implicitly truncated to unsigned type [-Woverflow]
writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
^
Cc: Marc Zyngier <[email protected]>
Suggested-by: Marc Zyngier <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Signed-off-by: Sai Prakash Ranjan <[email protected]>
---
drivers/irqchip/irq-tegra.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/irqchip/irq-tegra.c b/drivers/irqchip/irq-tegra.c
index e1f771c72fc4..ad3e2c1b3c87 100644
--- a/drivers/irqchip/irq-tegra.c
+++ b/drivers/irqchip/irq-tegra.c
@@ -148,10 +148,10 @@ static int tegra_ictlr_suspend(void)
lic->cop_iep[i] = readl_relaxed(ictlr + ICTLR_COP_IEP_CLASS);
/* Disable COP interrupts */
- writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
+ writel_relaxed(GENMASK(31, 0), ictlr + ICTLR_COP_IER_CLR);
/* Disable CPU interrupts */
- writel_relaxed(~0ul, ictlr + ICTLR_CPU_IER_CLR);
+ writel_relaxed(GENMASK(31, 0), ictlr + ICTLR_CPU_IER_CLR);
/* Enable the wakeup sources of ictlr */
writel_relaxed(lic->ictlr_wake_mask[i], ictlr + ICTLR_CPU_IER_SET);
@@ -172,12 +172,12 @@ static void tegra_ictlr_resume(void)
writel_relaxed(lic->cpu_iep[i],
ictlr + ICTLR_CPU_IEP_CLASS);
- writel_relaxed(~0ul, ictlr + ICTLR_CPU_IER_CLR);
+ writel_relaxed(GENMASK(31, 0), ictlr + ICTLR_CPU_IER_CLR);
writel_relaxed(lic->cpu_ier[i],
ictlr + ICTLR_CPU_IER_SET);
writel_relaxed(lic->cop_iep[i],
ictlr + ICTLR_COP_IEP_CLASS);
- writel_relaxed(~0ul, ictlr + ICTLR_COP_IER_CLR);
+ writel_relaxed(GENMASK(31, 0), ictlr + ICTLR_COP_IER_CLR);
writel_relaxed(lic->cop_ier[i],
ictlr + ICTLR_COP_IER_SET);
}
@@ -312,7 +312,7 @@ static int __init tegra_ictlr_init(struct device_node *node,
lic->base[i] = base;
/* Disable all interrupts */
- writel_relaxed(~0UL, base + ICTLR_CPU_IER_CLR);
+ writel_relaxed(GENMASK(31, 0), base + ICTLR_CPU_IER_CLR);
/* All interrupts target IRQ */
writel_relaxed(0, base + ICTLR_CPU_IEP_CLASS);
--
2.33.1
Disable MMIO tracing for geni serial engine driver as it is a
high frequency operation with many register reads/writes and
not very useful to log all MMIO traces and prevent excessive
logging.
Cc: Bjorn Andersson <[email protected]>
Signed-off-by: Sai Prakash Ranjan <[email protected]>
---
drivers/soc/qcom/qcom-geni-se.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
index 28a8c0dda66c..a0ceeede450f 100644
--- a/drivers/soc/qcom/qcom-geni-se.c
+++ b/drivers/soc/qcom/qcom-geni-se.c
@@ -1,6 +1,9 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
+/* Disable MMIO tracing to prevent excessive logging of unwanted MMIO traces */
+#define __DISABLE_TRACE_MMIO__
+
#include <linux/acpi.h>
#include <linux/clk.h>
#include <linux/slab.h>
--
2.33.1
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.
Signed-off-by: Sai Prakash Ranjan <[email protected]>
---
include/asm-generic/io.h | 91 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 87 insertions(+), 4 deletions(-)
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 7ce93aaf69f8..9c5114335a2d 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -10,6 +10,7 @@
#include <asm/page.h> /* I/O is all done through memory accesses */
#include <linux/string.h> /* for memset() and memcpy() */
#include <linux/types.h>
+#include <linux/instruction_pointer.h>
#ifdef CONFIG_GENERIC_IOMAP
#include <asm-generic/iomap.h>
@@ -61,6 +62,44 @@
#define __io_par(v) __io_ar(v)
#endif
+/*
+ * "__DISABLE_TRACE_MMIO__" flag can be used to disable MMIO tracing for
+ * specific kernel drivers in case of excessive/unwanted logging.
+ *
+ * Usage: Add a #define flag at the beginning of the driver file.
+ * Ex: #define __DISABLE_TRACE_MMIO__
+ * #include <...>
+ * ...
+ */
+#if IS_ENABLED(CONFIG_TRACE_MMIO_ACCESS) && !(defined(__DISABLE_TRACE_MMIO__))
+#include <linux/tracepoint-defs.h>
+
+DECLARE_TRACEPOINT(rwmmio_write);
+DECLARE_TRACEPOINT(rwmmio_post_write);
+DECLARE_TRACEPOINT(rwmmio_read);
+DECLARE_TRACEPOINT(rwmmio_post_read);
+
+void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
+ unsigned long caller_addr);
+void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
+ unsigned long caller_addr);
+void log_read_mmio(u8 width, const volatile void __iomem *addr,
+ unsigned long caller_addr);
+void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr,
+ unsigned long caller_addr);
+
+#else
+
+static inline void log_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
+ unsigned long caller_addr) {}
+static inline void log_post_write_mmio(u64 val, u8 width, volatile void __iomem *addr,
+ unsigned long caller_addr) {}
+static inline void log_read_mmio(u8 width, const volatile void __iomem *addr,
+ unsigned long caller_addr) {}
+static inline void log_post_read_mmio(u64 val, u8 width, const volatile void __iomem *addr,
+ unsigned long caller_addr) {}
+
+#endif /* CONFIG_TRACE_MMIO_ACCESS */
/*
* __raw_{read,write}{b,w,l,q}() access memory in native endianness.
@@ -149,9 +188,11 @@ static inline u8 readb(const volatile void __iomem *addr)
{
u8 val;
+ log_read_mmio(8, addr, _THIS_IP_);
__io_br();
val = __raw_readb(addr);
__io_ar(val);
+ log_post_read_mmio(val, 8, addr, _THIS_IP_);
return val;
}
#endif
@@ -162,9 +203,11 @@ static inline u16 readw(const volatile void __iomem *addr)
{
u16 val;
+ log_read_mmio(16, addr, _THIS_IP_);
__io_br();
val = __le16_to_cpu((__le16 __force)__raw_readw(addr));
__io_ar(val);
+ log_post_read_mmio(val, 16, addr, _THIS_IP_);
return val;
}
#endif
@@ -175,9 +218,11 @@ static inline u32 readl(const volatile void __iomem *addr)
{
u32 val;
+ log_read_mmio(32, addr, _THIS_IP_);
__io_br();
val = __le32_to_cpu((__le32 __force)__raw_readl(addr));
__io_ar(val);
+ log_post_read_mmio(val, 32, addr, _THIS_IP_);
return val;
}
#endif
@@ -189,9 +234,11 @@ static inline u64 readq(const volatile void __iomem *addr)
{
u64 val;
+ log_read_mmio(64, addr, _THIS_IP_);
__io_br();
val = __le64_to_cpu(__raw_readq(addr));
__io_ar(val);
+ log_post_read_mmio(val, 64, addr, _THIS_IP_);
return val;
}
#endif
@@ -201,9 +248,11 @@ static inline u64 readq(const volatile void __iomem *addr)
#define writeb writeb
static inline void writeb(u8 value, volatile void __iomem *addr)
{
+ log_write_mmio(value, 8, addr, _THIS_IP_);
__io_bw();
__raw_writeb(value, addr);
__io_aw();
+ log_post_write_mmio(value, 8, addr, _THIS_IP_);
}
#endif
@@ -211,9 +260,11 @@ static inline void writeb(u8 value, volatile void __iomem *addr)
#define writew writew
static inline void writew(u16 value, volatile void __iomem *addr)
{
+ log_write_mmio(value, 16, addr, _THIS_IP_);
__io_bw();
__raw_writew((u16 __force)cpu_to_le16(value), addr);
__io_aw();
+ log_post_write_mmio(value, 16, addr, _THIS_IP_);
}
#endif
@@ -221,9 +272,11 @@ static inline void writew(u16 value, volatile void __iomem *addr)
#define writel writel
static inline void writel(u32 value, volatile void __iomem *addr)
{
+ log_write_mmio(value, 32, addr, _THIS_IP_);
__io_bw();
__raw_writel((u32 __force)__cpu_to_le32(value), addr);
__io_aw();
+ log_post_write_mmio(value, 32, addr, _THIS_IP_);
}
#endif
@@ -232,9 +285,11 @@ static inline void writel(u32 value, volatile void __iomem *addr)
#define writeq writeq
static inline void writeq(u64 value, volatile void __iomem *addr)
{
+ log_write_mmio(value, 64, addr, _THIS_IP_);
__io_bw();
__raw_writeq(__cpu_to_le64(value), addr);
__io_aw();
+ log_post_write_mmio(value, 64, addr, _THIS_IP_);
}
#endif
#endif /* CONFIG_64BIT */
@@ -248,7 +303,12 @@ 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)
{
- return __raw_readb(addr);
+ u8 val;
+
+ log_read_mmio(8, addr, _THIS_IP_);
+ val = __raw_readb(addr);
+ log_post_read_mmio(val, 8, addr, _THIS_IP_);
+ return val;
}
#endif
@@ -256,7 +316,12 @@ 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)
{
- return __le16_to_cpu(__raw_readw(addr));
+ u16 val;
+
+ log_read_mmio(16, addr, _THIS_IP_);
+ val = __le16_to_cpu(__raw_readw(addr));
+ log_post_read_mmio(val, 16, addr, _THIS_IP_);
+ return val;
}
#endif
@@ -264,7 +329,12 @@ 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)
{
- return __le32_to_cpu(__raw_readl(addr));
+ u32 val;
+
+ log_read_mmio(32, addr, _THIS_IP_);
+ val = __le32_to_cpu(__raw_readl(addr));
+ log_post_read_mmio(val, 32, addr, _THIS_IP_);
+ return val;
}
#endif
@@ -272,7 +342,12 @@ 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)
{
- return __le64_to_cpu(__raw_readq(addr));
+ u64 val;
+
+ log_read_mmio(64, addr, _THIS_IP_);
+ val = __le64_to_cpu(__raw_readq(addr));
+ log_post_read_mmio(val, 64, addr, _THIS_IP_);
+ return val;
}
#endif
@@ -280,7 +355,9 @@ 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)
{
+ log_write_mmio(value, 8, addr, _THIS_IP_);
__raw_writeb(value, addr);
+ log_post_write_mmio(value, 8, addr, _THIS_IP_);
}
#endif
@@ -288,7 +365,9 @@ 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)
{
+ log_write_mmio(value, 16, addr, _THIS_IP_);
__raw_writew(cpu_to_le16(value), addr);
+ log_post_write_mmio(value, 16, addr, _THIS_IP_);
}
#endif
@@ -296,7 +375,9 @@ 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)
{
+ log_write_mmio(value, 32, addr, _THIS_IP_);
__raw_writel(__cpu_to_le32(value), addr);
+ log_post_write_mmio(value, 32, addr, _THIS_IP_);
}
#endif
@@ -304,7 +385,9 @@ 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)
{
+ log_write_mmio(value, 64, addr, _THIS_IP_);
__raw_writeq(__cpu_to_le64(value), addr);
+ log_post_write_mmio(value, 64, addr, _THIS_IP_);
}
#endif
--
2.33.1
Per discussion in [1], it was decided to move to using architecture
independent/asm-generic IO memory barriers to have just one set of
them and deprecate use of arm64 specific IO memory barriers in driver
code. So replace current usage of __io_rmb()/__iowmb() in drivers to
__io_ar()/__io_bw().
[1] https://lore.kernel.org/lkml/CAK8P3a0L2tLeF1Q0+0ijUxhGNaw+Z0fyPC1oW6_ELQfn0=i4iw@mail.gmail.com/
Cc: Mathieu Poirier <[email protected]>
Cc: Suzuki K Poulose <[email protected]>
Signed-off-by: Sai Prakash Ranjan <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
---
drivers/hwtracing/coresight/coresight-etm4x-core.c | 8 ++++----
drivers/hwtracing/coresight/coresight-etm4x.h | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-core.c b/drivers/hwtracing/coresight/coresight-etm4x-core.c
index 7f416a12000e..81c0faf45b28 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x-core.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x-core.c
@@ -98,7 +98,7 @@ u64 etm4x_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
}
if (!_relaxed)
- __iormb(res); /* Imitate the !relaxed I/O helpers */
+ __io_ar(res); /* Imitate the !relaxed I/O helpers */
return res;
}
@@ -106,7 +106,7 @@ u64 etm4x_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
void etm4x_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
{
if (!_relaxed)
- __iowmb(); /* Imitate the !relaxed I/O helpers */
+ __io_bw(); /* Imitate the !relaxed I/O helpers */
if (!_64bit)
val &= GENMASK(31, 0);
@@ -130,7 +130,7 @@ static u64 ete_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
}
if (!_relaxed)
- __iormb(res); /* Imitate the !relaxed I/O helpers */
+ __io_ar(res); /* Imitate the !relaxed I/O helpers */
return res;
}
@@ -138,7 +138,7 @@ static u64 ete_sysreg_read(u32 offset, bool _relaxed, bool _64bit)
static void ete_sysreg_write(u64 val, u32 offset, bool _relaxed, bool _64bit)
{
if (!_relaxed)
- __iowmb(); /* Imitate the !relaxed I/O helpers */
+ __io_bw(); /* Imitate the !relaxed I/O helpers */
if (!_64bit)
val &= GENMASK(31, 0);
diff --git a/drivers/hwtracing/coresight/coresight-etm4x.h b/drivers/hwtracing/coresight/coresight-etm4x.h
index 3c4d69b096ca..f54698731582 100644
--- a/drivers/hwtracing/coresight/coresight-etm4x.h
+++ b/drivers/hwtracing/coresight/coresight-etm4x.h
@@ -448,14 +448,14 @@
#define etm4x_read32(csa, offset) \
({ \
u32 __val = etm4x_relaxed_read32((csa), (offset)); \
- __iormb(__val); \
+ __io_ar(__val); \
__val; \
})
#define etm4x_read64(csa, offset) \
({ \
u64 __val = etm4x_relaxed_read64((csa), (offset)); \
- __iormb(__val); \
+ __io_ar(__val); \
__val; \
})
@@ -479,13 +479,13 @@
#define etm4x_write32(csa, val, offset) \
do { \
- __iowmb(); \
+ __io_bw(); \
etm4x_relaxed_write32((csa), (val), (offset)); \
} while (0)
#define etm4x_write64(csa, val, offset) \
do { \
- __iowmb(); \
+ __io_bw(); \
etm4x_relaxed_write64((csa), (val), (offset)); \
} while (0)
--
2.33.1
Add a generic flag (__DISABLE_TRACE_MMIO__) to disable MMIO
tracing in nVHE KVM as the tracepoint and MMIO logging symbols
should not be visible at nVHE KVM as there is no way to execute
them. It can also be used to disable MMIO tracing for specific
drivers.
Signed-off-by: Sai Prakash Ranjan <[email protected]>
---
arch/arm64/kvm/hyp/nvhe/Makefile | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/arm64/kvm/hyp/nvhe/Makefile b/arch/arm64/kvm/hyp/nvhe/Makefile
index f9fe4dc21b1f..87d22a18b7a5 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
--
2.33.1
Remove custom arm64 MMIO accessors read{b,w,l,q} and their relaxed
versions in support to use asm-generic defined accessors. Also define
one set of IO barriers (ar/bw version) used by asm-generic code to
override the arm64 specific variants.
Suggested-by: Arnd Bergmann <[email protected]>
Signed-off-by: Sai Prakash Ranjan <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
---
arch/arm64/include/asm/io.h | 41 ++++++++-----------------------------
1 file changed, 8 insertions(+), 33 deletions(-)
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 7fd836bea7eb..1b436810d779 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -91,7 +91,7 @@ static inline u64 __raw_readq(const volatile void __iomem *addr)
}
/* IO barriers */
-#define __iormb(v) \
+#define __io_ar(v) \
({ \
unsigned long tmp; \
\
@@ -108,39 +108,14 @@ static inline u64 __raw_readq(const volatile void __iomem *addr)
: "memory"); \
})
-#define __io_par(v) __iormb(v)
-#define __iowmb() dma_wmb()
-#define __iomb() dma_mb()
-
-/*
- * Relaxed I/O memory access primitives. These follow the Device memory
- * ordering rules but do not guarantee any ordering relative to Normal memory
- * accesses.
- */
-#define readb_relaxed(c) ({ u8 __r = __raw_readb(c); __r; })
-#define readw_relaxed(c) ({ u16 __r = le16_to_cpu((__force __le16)__raw_readw(c)); __r; })
-#define readl_relaxed(c) ({ u32 __r = le32_to_cpu((__force __le32)__raw_readl(c)); __r; })
-#define readq_relaxed(c) ({ u64 __r = le64_to_cpu((__force __le64)__raw_readq(c)); __r; })
+#define __io_bw() dma_wmb()
+#define __io_br(v)
+#define __io_aw(v)
-#define writeb_relaxed(v,c) ((void)__raw_writeb((v),(c)))
-#define writew_relaxed(v,c) ((void)__raw_writew((__force u16)cpu_to_le16(v),(c)))
-#define writel_relaxed(v,c) ((void)__raw_writel((__force u32)cpu_to_le32(v),(c)))
-#define writeq_relaxed(v,c) ((void)__raw_writeq((__force u64)cpu_to_le64(v),(c)))
-
-/*
- * I/O memory access primitives. Reads are ordered relative to any
- * following Normal memory access. Writes are ordered relative to any prior
- * Normal memory access.
- */
-#define readb(c) ({ u8 __v = readb_relaxed(c); __iormb(__v); __v; })
-#define readw(c) ({ u16 __v = readw_relaxed(c); __iormb(__v); __v; })
-#define readl(c) ({ u32 __v = readl_relaxed(c); __iormb(__v); __v; })
-#define readq(c) ({ u64 __v = readq_relaxed(c); __iormb(__v); __v; })
-
-#define writeb(v,c) ({ __iowmb(); writeb_relaxed((v),(c)); })
-#define writew(v,c) ({ __iowmb(); writew_relaxed((v),(c)); })
-#define writel(v,c) ({ __iowmb(); writel_relaxed((v),(c)); })
-#define writeq(v,c) ({ __iowmb(); writeq_relaxed((v),(c)); })
+/* arm64-specific, don't use in portable drivers */
+#define __iormb(v) __io_ar(v)
+#define __iowmb() __io_bw()
+#define __iomb() dma_mb()
/*
* I/O port access primitives.
--
2.33.1
On Thu, 28 Apr 2022 18:14:12 +0530
Sai Prakash Ranjan <[email protected]> wrote:
> Disable MMIO tracing for geni serial engine driver as it is a
> high frequency operation with many register reads/writes and
> not very useful to log all MMIO traces and prevent excessive
> logging.
This states what it does but does not really state why. Are you using MMIO
tracing in other locations and this is causing too much noise?
What is the real issue. Just saying "excessive logging" is not sufficient.
That would be a reason to disable function tracing ;-)
-- Steve
>
> Cc: Bjorn Andersson <[email protected]>
> Signed-off-by: Sai Prakash Ranjan <[email protected]>
> ---
> drivers/soc/qcom/qcom-geni-se.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
> index 28a8c0dda66c..a0ceeede450f 100644
> --- a/drivers/soc/qcom/qcom-geni-se.c
> +++ b/drivers/soc/qcom/qcom-geni-se.c
> @@ -1,6 +1,9 @@
> // SPDX-License-Identifier: GPL-2.0
> // Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
>
> +/* Disable MMIO tracing to prevent excessive logging of unwanted MMIO traces */
> +#define __DISABLE_TRACE_MMIO__
> +
> #include <linux/acpi.h>
> #include <linux/clk.h>
> #include <linux/slab.h>
Hi Steve,
On 4/28/2022 6:59 PM, Steven Rostedt wrote:
> On Thu, 28 Apr 2022 18:14:12 +0530
> Sai Prakash Ranjan <[email protected]> wrote:
>
>> Disable MMIO tracing for geni serial engine driver as it is a
>> high frequency operation with many register reads/writes and
>> not very useful to log all MMIO traces and prevent excessive
>> logging.
> This states what it does but does not really state why. Are you using MMIO
> tracing in other locations and this is causing too much noise?
> What is the real issue. Just saying "excessive logging" is not sufficient.
> That would be a reason to disable function tracing ;-)
>
> -- Steve
>
Disabling MMIO trace is what it does and why it does is to prevent excessive logging.
I will add more details on why preventing excessive logging is required here.
It is quite known that any access over serial console would involve a lot of TX and RX
register accesses (and few others), so these MMIO read/write trace events in these
drivers cause a lot of unwanted noise because of the high frequency of such operations
and is not very useful tracing these events for such driver. And we want to enable these
trace events on development devices(maybe not production devices) where performance
also really matters since we want to debug and track any crashes with such register
accesses on these devices and not just something which runs with every debug option
out there (meaning we enable this MMIO tracing with almost on par production kernels).
And these traces of such driver add additional overhead both in terms of memory and
CPU cycles.
And also one more reason is that if we try to display trace buffer containing these register
trace events onto serial console, then it would also involve register accesses from these
drivers which would lead to recursive tracing.
I will update the commit text adding these details and since we got your attention, can you
also please look at patch 5 [1] which was updated based on your previous review comments.
If you could review/ack them, then Arnd can take this series into his tree once I post the next
version with these updated commit text.
[1] https://lore.kernel.org/lkml/9827bae40f6f319f294d06859c9e3c7442f067f2.1651149615.git.quic_saipraka@quicinc.com/
Thanks,
Sai
>> Cc: Bjorn Andersson <[email protected]>
>> Signed-off-by: Sai Prakash Ranjan <[email protected]>
>> ---
>> drivers/soc/qcom/qcom-geni-se.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/soc/qcom/qcom-geni-se.c b/drivers/soc/qcom/qcom-geni-se.c
>> index 28a8c0dda66c..a0ceeede450f 100644
>> --- a/drivers/soc/qcom/qcom-geni-se.c
>> +++ b/drivers/soc/qcom/qcom-geni-se.c
>> @@ -1,6 +1,9 @@
>> // SPDX-License-Identifier: GPL-2.0
>> // Copyright (c) 2017-2018, The Linux Foundation. All rights reserved.
>>
>> +/* Disable MMIO tracing to prevent excessive logging of unwanted MMIO traces */
>> +#define __DISABLE_TRACE_MMIO__
>> +
>> #include <linux/acpi.h>
>> #include <linux/clk.h>
>> #include <linux/slab.h>
Fix -Woverflow warnings for drm/meson driver which is a result
of moving arm64 custom MMIO accessor macros to asm-generic function
implementations giving a bonus type-checking now and uncovering these
overflow warnings.
drivers/gpu/drm/meson/meson_viu.c: In function ‘meson_viu_init’:
drivers/gpu/drm/meson/meson_registers.h:1826:48: error: large integer implicitly truncated to unsigned type [-Werror=overflow]
#define VIU_OSD_BLEND_REORDER(dest, src) ((src) << (dest * 4))
^
drivers/gpu/drm/meson/meson_viu.c:472:18: note: in expansion of macro ‘VIU_OSD_BLEND_REORDER’
writel_relaxed(VIU_OSD_BLEND_REORDER(0, 1) |
^~~~~~~~~~~~~~~~~~~~~
Cc: Arnd Bergmann <[email protected]>
Cc: Neil Armstrong <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Sai Prakash Ranjan <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
---
drivers/gpu/drm/meson/meson_viu.c | 22 +++++++++++-----------
1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/meson/meson_viu.c b/drivers/gpu/drm/meson/meson_viu.c
index 259f3e6bec90..bb7e109534de 100644
--- a/drivers/gpu/drm/meson/meson_viu.c
+++ b/drivers/gpu/drm/meson/meson_viu.c
@@ -469,17 +469,17 @@ void meson_viu_init(struct meson_drm *priv)
priv->io_base + _REG(VD2_IF0_LUMA_FIFO_SIZE));
if (meson_vpu_is_compatible(priv, VPU_COMPATIBLE_G12A)) {
- writel_relaxed(VIU_OSD_BLEND_REORDER(0, 1) |
- VIU_OSD_BLEND_REORDER(1, 0) |
- VIU_OSD_BLEND_REORDER(2, 0) |
- VIU_OSD_BLEND_REORDER(3, 0) |
- VIU_OSD_BLEND_DIN_EN(1) |
- VIU_OSD_BLEND1_DIN3_BYPASS_TO_DOUT1 |
- VIU_OSD_BLEND1_DOUT_BYPASS_TO_BLEND2 |
- VIU_OSD_BLEND_DIN0_BYPASS_TO_DOUT0 |
- VIU_OSD_BLEND_BLEN2_PREMULT_EN(1) |
- VIU_OSD_BLEND_HOLD_LINES(4),
- priv->io_base + _REG(VIU_OSD_BLEND_CTRL));
+ u32 val = (u32)VIU_OSD_BLEND_REORDER(0, 1) |
+ (u32)VIU_OSD_BLEND_REORDER(1, 0) |
+ (u32)VIU_OSD_BLEND_REORDER(2, 0) |
+ (u32)VIU_OSD_BLEND_REORDER(3, 0) |
+ (u32)VIU_OSD_BLEND_DIN_EN(1) |
+ (u32)VIU_OSD_BLEND1_DIN3_BYPASS_TO_DOUT1 |
+ (u32)VIU_OSD_BLEND1_DOUT_BYPASS_TO_BLEND2 |
+ (u32)VIU_OSD_BLEND_DIN0_BYPASS_TO_DOUT0 |
+ (u32)VIU_OSD_BLEND_BLEN2_PREMULT_EN(1) |
+ (u32)VIU_OSD_BLEND_HOLD_LINES(4);
+ writel_relaxed(val, priv->io_base + _REG(VIU_OSD_BLEND_CTRL));
writel_relaxed(OSD_BLEND_PATH_SEL_ENABLE,
priv->io_base + _REG(OSD1_BLEND_SRC_CTRL));
--
2.33.1