RISC-V: Cache SBI vendor values
From: Heiko Stuebner <heiko@...> Date: Tue, 4 Oct 2022 21:18:54 +0200
Commit-Message
sbi_get_mvendorid(), sbi_get_marchid() and sbi_get_mimpid() might get called multiple times, though the values of these CSRs should not change during the runtime of a specific machine. So cache the values in the functions and prevent multiple ecalls to read these values. Suggested-by: Atish Patra <atishp@...> Signed-off-by: Heiko Stuebner <heiko@...>
Patch-Comment
arch/riscv/kernel/sbi.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-)
Statistics
- 18 lines added
- 3 lines removed
Changes
--------------------------- arch/riscv/kernel/sbi.c ----------------------------
index 775d3322b422..5be8f90f325e 100644
@@ -625,17 +625,32 @@ static inline long sbi_get_firmware_version(void)
long sbi_get_mvendorid(void)
{
+ static long id = -1;
+
+ if (id < 0)
+ id = __sbi_base_ecall(SBI_EXT_BASE_GET_MVENDORID);
+
+ return id;
}
long sbi_get_marchid(void)
{
+ static long id = -1;
+
+ if (id < 0)
+ id = __sbi_base_ecall(SBI_EXT_BASE_GET_MARCHID);
+
+ return id;
}
long sbi_get_mimpid(void)
{
+ static long id = -1;
+
+ if (id < 0)
+ id = __sbi_base_ecall(SBI_EXT_BASE_GET_MIMPID);
+
+ return id;
}
static void sbi_send_cpumask_ipi(const struct cpumask *target)