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lib: Emulate HTIMEDELTA CSR for platforms not having TIME CSR 

For platforms not having TIME CSR, we trap-n-emulate TIME CSR
read/write in OpenSBI. Same rationale applies to HTIMEDELTA CSR
as well so we trap-n-emulate HTIMEDELTA CSR for platforms not
having TIME CSR.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
This commit is contained in:
Anup Patel 2019-08-18 13:14:44 +05:30 committed by Anup Patel
parent 4ee788091c
commit 40c9c86a51
6 changed files with 124 additions and 19 deletions
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4
include/sbi/riscv_encoding.h
View File

@ -276,7 +276,9 @@
#define CSR_HSTATUS 0x600
#define CSR_HEDELEG 0x602
#define CSR_HIDELEG 0x603
#define CSR_HCOUNTERNEN 0x606
#define CSR_HTIMEDELTA 0x605
#define CSR_HTIMEDELTAH 0x615
#define CSR_HCOUNTERNEN 0x606
#define CSR_HGATP 0x680
#define CSR_VSSTATUS 0x200

5
include/sbi/sbi_emulate_csr.h
View File

@ -12,12 +12,13 @@
#include <sbi/sbi_types.h>
struct sbi_trap_regs;
struct sbi_scratch;
int sbi_emulate_csr_read(int csr_num, u32 hartid, ulong mstatus,
int sbi_emulate_csr_read(int csr_num, u32 hartid, struct sbi_trap_regs *regs,
struct sbi_scratch *scratch, ulong *csr_val);
int sbi_emulate_csr_write(int csr_num, u32 hartid, ulong mstatus,
int sbi_emulate_csr_write(int csr_num, u32 hartid, struct sbi_trap_regs *regs,
struct sbi_scratch *scratch, ulong csr_val);
#endif

8
include/sbi/sbi_timer.h
View File

@ -16,6 +16,14 @@ struct sbi_scratch;
u64 sbi_timer_value(struct sbi_scratch *scratch);
u64 sbi_timer_virt_value(struct sbi_scratch *scratch);
u64 sbi_timer_get_delta(struct sbi_scratch *scratch);
void sbi_timer_set_delta(struct sbi_scratch *scratch, ulong delta);
void sbi_timer_set_delta_upper(struct sbi_scratch *scratch, ulong delta_upper);
void sbi_timer_event_stop(struct sbi_scratch *scratch);
void sbi_timer_event_start(struct sbi_scratch *scratch, u64 next_event);

74
lib/sbi/sbi_emulate_csr.c
View File

@ -14,16 +14,30 @@
#include <sbi/sbi_emulate_csr.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_timer.h>
#include <sbi/sbi_trap.h>
int sbi_emulate_csr_read(int csr_num, u32 hartid, ulong mstatus,
int sbi_emulate_csr_read(int csr_num, u32 hartid, struct sbi_trap_regs *regs,
struct sbi_scratch *scratch, ulong *csr_val)
{
int ret = 0;
ulong cen = -1UL;
ulong prev_mode = (regs->mstatus & MSTATUS_MPP) >> MSTATUS_MPP_SHIFT;
#if __riscv_xlen == 32
bool virt = (regs->mstatusH & MSTATUSH_MPV) ? TRUE : FALSE;
#else
bool virt = (regs->mstatus & MSTATUS_MPV) ? TRUE : FALSE;
#endif
if (EXTRACT_FIELD(mstatus, MSTATUS_MPP) == PRV_U)
if (prev_mode == PRV_U)
cen = csr_read(CSR_SCOUNTEREN);
switch (csr_num) {
case CSR_HTIMEDELTA:
if (prev_mode == PRV_S && !virt)
*csr_val = sbi_timer_get_delta(scratch);
else
ret = SBI_ENOTSUPP;
break;
case CSR_CYCLE:
if (!((cen >> (CSR_CYCLE - CSR_CYCLE)) & 1))
return -1;
@ -32,7 +46,8 @@ int sbi_emulate_csr_read(int csr_num, u32 hartid, ulong mstatus,
case CSR_TIME:
if (!((cen >> (CSR_TIME - CSR_CYCLE)) & 1))
return -1;
*csr_val = sbi_timer_value(scratch);
*csr_val = (virt) ? sbi_timer_virt_value(scratch):
sbi_timer_value(scratch);
break;
case CSR_INSTRET:
if (!((cen >> (CSR_INSTRET - CSR_CYCLE)) & 1))
@ -50,6 +65,12 @@ int sbi_emulate_csr_read(int csr_num, u32 hartid, ulong mstatus,
*csr_val = csr_read(CSR_MHPMCOUNTER4);
break;
#if __riscv_xlen == 32
case CSR_HTIMEDELTAH:
if (prev_mode == PRV_S && !virt)
*csr_val = sbi_timer_get_delta(scratch) >> 32;
else
ret = SBI_ENOTSUPP;
break;
case CSR_CYCLEH:
if (!((cen >> (CSR_CYCLE - CSR_CYCLE)) & 1))
return -1;
@ -58,7 +79,8 @@ int sbi_emulate_csr_read(int csr_num, u32 hartid, ulong mstatus,
case CSR_TIMEH:
if (!((cen >> (CSR_TIME - CSR_CYCLE)) & 1))
return -1;
*csr_val = sbi_timer_value(scratch) >> 32;
*csr_val = (virt) ? sbi_timer_virt_value(scratch) >> 32:
sbi_timer_value(scratch) >> 32;
break;
case CSR_INSTRETH:
if (!((cen >> (CSR_INSTRET - CSR_CYCLE)) & 1))
@ -83,18 +105,35 @@ int sbi_emulate_csr_read(int csr_num, u32 hartid, ulong mstatus,
*csr_val = csr_read(CSR_MHPMEVENT4);
break;
default:
sbi_dprintf(scratch, "%s: hartid%d: invalid csr_num=0x%x\n",
__func__, hartid, csr_num);
return SBI_ENOTSUPP;
ret = SBI_ENOTSUPP;
break;
};
return 0;
if (ret)
sbi_dprintf(scratch, "%s: hartid%d: invalid csr_num=0x%x\n",
__func__, hartid, csr_num);
return ret;
}
int sbi_emulate_csr_write(int csr_num, u32 hartid, ulong mstatus,
int sbi_emulate_csr_write(int csr_num, u32 hartid, struct sbi_trap_regs *regs,
struct sbi_scratch *scratch, ulong csr_val)
{
int ret = 0;
ulong prev_mode = (regs->mstatus & MSTATUS_MPP) >> MSTATUS_MPP_SHIFT;
#if __riscv_xlen == 32
bool virt = (regs->mstatusH & MSTATUSH_MPV) ? TRUE : FALSE;
#else
bool virt = (regs->mstatus & MSTATUS_MPV) ? TRUE : FALSE;
#endif
switch (csr_num) {
case CSR_HTIMEDELTA:
if (prev_mode == PRV_S && !virt)
sbi_timer_set_delta(scratch, csr_val);
else
ret = SBI_ENOTSUPP;
break;
case CSR_CYCLE:
csr_write(CSR_MCYCLE, csr_val);
break;
@ -108,6 +147,12 @@ int sbi_emulate_csr_write(int csr_num, u32 hartid, ulong mstatus,
csr_write(CSR_MHPMCOUNTER4, csr_val);
break;
#if __riscv_xlen == 32
case CSR_HTIMEDELTAH:
if (prev_mode == PRV_S && !virt)
sbi_timer_set_delta_upper(scratch, csr_val);
else
ret = SBI_ENOTSUPP;
break;
case CSR_CYCLEH:
csr_write(CSR_MCYCLEH, csr_val);
break;
@ -128,10 +173,13 @@ int sbi_emulate_csr_write(int csr_num, u32 hartid, ulong mstatus,
csr_write(CSR_MHPMEVENT4, csr_val);
break;
default:
sbi_dprintf(scratch, "%s: hartid%d: invalid csr_num=0x%x\n",
__func__, hartid, csr_num);
return SBI_ENOTSUPP;
ret = SBI_ENOTSUPP;
break;
};
return 0;
if (ret)
sbi_dprintf(scratch, "%s: hartid%d: invalid csr_num=0x%x\n",
__func__, hartid, csr_num);
return ret;
}

5
lib/sbi/sbi_illegal_insn.c
View File

@ -49,8 +49,7 @@ static int system_opcode_insn(ulong insn, u32 hartid, ulong mcause,
return sbi_trap_redirect(regs, scratch,
regs->mepc, mcause, insn);
if (sbi_emulate_csr_read(csr_num, hartid, regs->mstatus,
scratch, &csr_val))
if (sbi_emulate_csr_read(csr_num, hartid, regs, scratch, &csr_val))
return truly_illegal_insn(insn, hartid, mcause,
regs, scratch);
@ -80,7 +79,7 @@ static int system_opcode_insn(ulong insn, u32 hartid, ulong mcause,
return truly_illegal_insn(insn, hartid, mcause, regs, scratch);
};
if (do_write && sbi_emulate_csr_write(csr_num, hartid, regs->mstatus,
if (do_write && sbi_emulate_csr_write(csr_num, hartid, regs,
scratch, new_csr_val))
return truly_illegal_insn(insn, hartid, mcause, regs, scratch);

47
lib/sbi/sbi_timer.c
View File

@ -9,9 +9,12 @@
#include <sbi/riscv_asm.h>
#include <sbi/riscv_encoding.h>
#include <sbi/sbi_error.h>
#include <sbi/sbi_platform.h>
#include <sbi/sbi_timer.h>
static unsigned long time_delta_off;
#if __riscv_xlen == 32
u64 get_ticks(void)
{
@ -44,6 +47,35 @@ u64 sbi_timer_value(struct sbi_scratch *scratch)
return get_ticks();
}
u64 sbi_timer_virt_value(struct sbi_scratch *scratch)
{
u64 *time_delta = sbi_scratch_offset_ptr(scratch, time_delta_off);
return sbi_timer_value(scratch) + *time_delta;
}
u64 sbi_timer_get_delta(struct sbi_scratch *scratch)
{
u64 *time_delta = sbi_scratch_offset_ptr(scratch, time_delta_off);
return *time_delta;
}
void sbi_timer_set_delta(struct sbi_scratch *scratch, ulong delta)
{
u64 *time_delta = sbi_scratch_offset_ptr(scratch, time_delta_off);
*time_delta = (u64)delta;
}
void sbi_timer_set_delta_upper(struct sbi_scratch *scratch, ulong delta_upper)
{
u64 *time_delta = sbi_scratch_offset_ptr(scratch, time_delta_off);
*time_delta &= 0xffffffffULL;
*time_delta |= ((u64)delta_upper << 32);
}
void sbi_timer_event_stop(struct sbi_scratch *scratch)
{
sbi_platform_timer_event_stop(sbi_platform_ptr(scratch));
@ -64,5 +96,20 @@ void sbi_timer_process(struct sbi_scratch *scratch)
int sbi_timer_init(struct sbi_scratch *scratch, bool cold_boot)
{
u64 *time_delta;
if (cold_boot) {
time_delta_off = sbi_scratch_alloc_offset(sizeof(*time_delta),
"TIME_DELTA");
if (!time_delta_off)
return SBI_ENOMEM;
} else {
if (!time_delta_off)
return SBI_ENOMEM;
}
time_delta = sbi_scratch_offset_ptr(scratch, time_delta_off);
*time_delta = 0;
return sbi_platform_timer_init(sbi_platform_ptr(scratch), cold_boot);
}