riscv: Add tracepoints for SBI calls and returns

These are useful for measuring the latency of SBI calls. The SBI HSM
extension is excluded because those functions are called from contexts
such as cpuidle where instrumentation is not allowed.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Link: https://lore.kernel.org/r/20240321230131.1838105-1-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/include/asm/trace.h b/arch/riscv/include/asm/trace.h
new file mode 100644 (file)
index 0000000..6151cee
--- /dev/null
+++ b/arch/riscv/include/asm/trace.h
@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM riscv
+
+#if !defined(_TRACE_RISCV_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_RISCV_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT_CONDITION(sbi_call,
+       TP_PROTO(int ext, int fid),
+       TP_ARGS(ext, fid),
+       TP_CONDITION(ext != SBI_EXT_HSM),
+
+       TP_STRUCT__entry(
+               __field(int, ext)
+               __field(int, fid)
+       ),
+
+       TP_fast_assign(
+               __entry->ext = ext;
+               __entry->fid = fid;
+       ),
+
+       TP_printk("ext=0x%x fid=%d", __entry->ext, __entry->fid)
+);
+
+TRACE_EVENT_CONDITION(sbi_return,
+       TP_PROTO(int ext, long error, long value),
+       TP_ARGS(ext, error, value),
+       TP_CONDITION(ext != SBI_EXT_HSM),
+
+       TP_STRUCT__entry(
+               __field(long, error)
+               __field(long, value)
+       ),
+
+       TP_fast_assign(
+               __entry->error = error;
+               __entry->value = value;
+       ),
+
+       TP_printk("error=%ld value=0x%lx", __entry->error, __entry->value)
+);
+
+#endif /* _TRACE_RISCV_H */
+
+#undef TRACE_INCLUDE_PATH
+#undef TRACE_INCLUDE_FILE
+
+#define TRACE_INCLUDE_PATH asm
+#define TRACE_INCLUDE_FILE trace
+
+#include <trace/define_trace.h>

diff --git a/arch/riscv/kernel/sbi.c b/arch/riscv/kernel/sbi.c
index e66e0999a80057058c66c71fa907a0fb0152bc00..a1d21d8f529365328b1b2a48f0def4710c137df3 100644 (file)
--- a/arch/riscv/kernel/sbi.c
+++ b/arch/riscv/kernel/sbi.c
@@ -14,6 +14,9 @@
 #include <asm/smp.h>
 #include <asm/tlbflush.h>
 
+#define CREATE_TRACE_POINTS
+#include <asm/trace.h>
+
 /* default SBI version is 0.1 */
 unsigned long sbi_spec_version __ro_after_init = SBI_SPEC_VERSION_DEFAULT;
 EXPORT_SYMBOL(sbi_spec_version);
@@ -31,6 +34,8 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
 {
        struct sbiret ret;
 
+       trace_sbi_call(ext, fid);
+
        register uintptr_t a0 asm ("a0") = (uintptr_t)(arg0);
        register uintptr_t a1 asm ("a1") = (uintptr_t)(arg1);
        register uintptr_t a2 asm ("a2") = (uintptr_t)(arg2);
@@ -46,6 +51,8 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
        ret.error = a0;
        ret.value = a1;
 
+       trace_sbi_return(ext, ret.error, ret.value);
+
        return ret;
 }
 EXPORT_SYMBOL(sbi_ecall);