Hi Bin,
On Fri, 2018-12-07 at 06:14 -0800, Bin Meng wrote:
Implement arch_cpu_init() to do some basic architecture level cpu initialization, like FPU enable, etc.
Signed-off-by: Bin Meng bmeng.cn@gmail.com
Changes in v2:
- use csr_set() to set MSTATUS_FS
- only enabling the cycle, time, and instret counters
- change to use satp
arch/riscv/cpu/cpu.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c index 3858e51..194799c 100644 --- a/arch/riscv/cpu/cpu.c +++ b/arch/riscv/cpu/cpu.c @@ -7,6 +7,7 @@ #include <cpu.h> #include <log.h> #include <asm/csr.h> +#include <asm/encoding.h>
/*
- prior_stage_fdt_address must be stored in the data section since
it is used @@ -67,3 +68,21 @@ int arch_early_init_r(void)
return 0; }
+int arch_cpu_init(void) +{
- /* Enable FPU */
- if (supports_extension('d') || supports_extension('f')) {
supports_extension does not work when running in supervisor mode (unless BBL is patched). Can we maybe use the CPU driver here?
csr_set(MODE_PREFIX(status), MSTATUS_FS);csr_write(fcsr, 0);- }
- /* Enable perf counters for cycle, time, and instret counters
only */
- csr_write(MODE_PREFIX(counteren), GENMASK(2, 0));
I would tend to only enable this in mcounteren, so for the supervisor- mode. Linux can still enable the counters for user-mode if required.
- /* Disable paging */
- if (supports_extension('s'))
csr_write(satp, 0);
This should only be done, when running in machine mode. In supervisor mode this would cause issues if we have something other than an identity-mapping or paging disabled.
Thanks, Lukas
- return 0;
+}