[PATCH v4 09/10] tools: lib: perf: Implement riscv mmap support

Alexandre Ghiti
2023-07-03T12:56:04Z

riscv now supports mmaping hardware counters so add what's needed to
take advantage of that in libperf.

Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
tools/lib/perf/mmap.c | 65 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)

diff --git a/tools/lib/perf/mmap.c b/tools/lib/perf/mmap.c
index 0d1634cedf44..378a163f0554 100644
--- a/tools/lib/perf/mmap.c
+++ b/tools/lib/perf/mmap.c
@@ -392,6 +392,71 @@ static u64 read_perf_counter(unsigned int counter)

static u64 read_timestamp(void) { return read_sysreg(cntvct_el0); }

+#elif __riscv_xlen == 64
+
+/* TODO: implement rv32 support */
+
+#define CSR_CYCLE 0xc00
+#define CSR_TIME 0xc01
+
+#define csr_read(csr) \
+({ \
+ register unsigned long __v; \
+ __asm__ __volatile__ ("csrr %0, " #csr \
+ : "=r" (__v) : \
+ : "memory"); \
+ __v; \
+})
+
+static unsigned long csr_read_num(int csr_num)
+{
+#define switchcase_csr_read(__csr_num, __val) {\
+ case __csr_num: \
+ __val = csr_read(__csr_num); \
+ break; }
+#define switchcase_csr_read_2(__csr_num, __val) {\
+ switchcase_csr_read(__csr_num + 0, __val) \
+ switchcase_csr_read(__csr_num + 1, __val)}
+#define switchcase_csr_read_4(__csr_num, __val) {\
+ switchcase_csr_read_2(__csr_num + 0, __val) \
+ switchcase_csr_read_2(__csr_num + 2, __val)}
+#define switchcase_csr_read_8(__csr_num, __val) {\
+ switchcase_csr_read_4(__csr_num + 0, __val) \
+ switchcase_csr_read_4(__csr_num + 4, __val)}
+#define switchcase_csr_read_16(__csr_num, __val) {\
+ switchcase_csr_read_8(__csr_num + 0, __val) \
+ switchcase_csr_read_8(__csr_num + 8, __val)}
+#define switchcase_csr_read_32(__csr_num, __val) {\
+ switchcase_csr_read_16(__csr_num + 0, __val) \
+ switchcase_csr_read_16(__csr_num + 16, __val)}
+
+ unsigned long ret = 0;
+
+ switch (csr_num) {
+ switchcase_csr_read_32(CSR_CYCLE, ret)
+ default:
+ break;
+ }
+
+ return ret;
+#undef switchcase_csr_read_32
+#undef switchcase_csr_read_16
+#undef switchcase_csr_read_8
+#undef switchcase_csr_read_4
+#undef switchcase_csr_read_2
+#undef switchcase_csr_read
+}
+
+static u64 read_perf_counter(unsigned int counter)
+{
+ return csr_read_num(CSR_CYCLE + counter);
+}
+
+static u64 read_timestamp(void)
+{
+ return csr_read_num(CSR_TIME);
+}
+
#else
static u64 read_perf_counter(unsigned int counter __maybe_unused) { return 0; }
static u64 read_timestamp(void) { return 0; }
--
2.39.2