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Fix atp updating (OpenXiangShan#360)
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* csr:update PPN and VMID field regardless of the new MODE

* This commit correct the updating of hgatp CSR.
* As descriped in spec, VMID and PPN fields in hgatp behavior as WARL in the normal way, regardless of new_val.mode.
* Never set the remaining fields in hgatp to zeros when hgatp.MODE is bare, since this is set by software.

* csr:make the effective bits of vsatp.PPN relies on the hgatp.MODE setting

* When hgatp.MODE=Bare, the width of vsatp.PPN should be the length of PADDR minus the length of in-page address.
* When hgatp.MODE=Sv39x4, the width of vsatp.PPN should be 41 minus the length of in-page address.
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@huxuan0307 @xinhecuican
huxuan0307 authored and xinhecuican committed Aug 31, 2024
1 parent c17e336 commit 932c182
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Showing 2 changed files with 53 additions and 10 deletions.
13 changes: 12 additions & 1 deletion src/isa/riscv64/local-include/csr.h
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
#define __CSR_H__

#include <common.h>
#include <memory/vaddr.h>

/**
* Mapping between CSR name and addr
Expand Down Expand Up @@ -1041,6 +1042,8 @@ MAP(CSRS, CSRS_DECL)
#define IDXVLENB 0xc22

/** CSR satp **/
#define SATP_MODE_BARE 0
#define SATP_MODE_Sv39 8
#define SATP_ASID_LEN 16 // max is 16
#define SATP_PADDR_LEN (CONFIG_PADDRBITS-12) // max is 44
#define SATP_ASID_MAX_LEN 16
Expand All @@ -1055,6 +1058,8 @@ MAP(CSRS, CSRS_DECL)

/** CSR hgatp **/
#ifdef CONFIG_RVH
#define HGATP_MODE_BARE 0
#define HGATP_MODE_Sv39x4 8
#define HGATP_VMID_LEN 14 // max is 14
#define HGATP_PADDR_LEN 44 // max is 44
#define HGATP_VMID_MAX_LEN 16
Expand All @@ -1065,7 +1070,13 @@ MAP(CSRS, CSRS_DECL)
#define HGATP_PADDR_MASK ((1L << HGATP_PADDR_MAX_LEN)-1)

#define HGATP_MASK (HGATP_MODE_MASK | HGATP_VMID_MASK | HGATP_PADDR_MASK)
#define MASKED_HGATP(x) (HGATP_MASK & x)
#endif // CONFIG_RVH

#ifdef CONFIG_RVH
#define HGATP_Bare_GPADDR_LEN CONFIG_PADDRBITS
#define HGATP_Sv39x4_GPADDR_LEN 41
#define VSATP_PPN_HGATP_BARE_MASK BITMASK(HGATP_Bare_GPADDR_LEN - PAGE_SHIFT)
#define VSATP_PPN_HGATP_Sv39x4_MASK BITMASK(HGATP_Sv39x4_GPADDR_LEN - PAGE_SHIFT)
#endif // CONFIG_RVH

/** RVH **/
Expand Down
50 changes: 41 additions & 9 deletions src/isa/riscv64/system/priv.c
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Original file line number Diff line number Diff line change
Expand Up @@ -484,8 +484,26 @@ void disable_time_intr() {
mie->val = mask_bitset(mie->val, MTIE_MASK, 0);
}

#ifdef CONFIG_RVH
void update_vsatp(const vsatp_t new_val) {
vsatp->_64.mode = new_val._64.mode;
vsatp->_64.asid = new_val._64.asid;
switch (hgatp->mode) {
case HGATP_MODE_BARE:
vsatp->_64.ppn = new_val._64.ppn & VSATP_PPN_HGATP_BARE_MASK;
break;
case HGATP_MODE_Sv39x4:
vsatp->_64.ppn = new_val._64.ppn & VSATP_PPN_HGATP_Sv39x4_MASK;
break;
default:
panic("HGATP.mode is illegal value(%lx), when write vsatp\n", (uint64_t)hgatp->mode);
break;
}
}
#endif

static inline void csr_write(word_t *dest, word_t src) {
#ifdef CONFIG_RVH
#ifdef CONFIG_RVH
if(cpu.v == 1 && (is_write(sstatus) || is_write(sie) || is_write(stvec) || is_write(sscratch)
|| is_write(sepc) || is_write(scause) || is_write(stval) || is_write(sip)
|| is_write(satp) || is_write(stvec))){
Expand All @@ -503,9 +521,13 @@ static inline void csr_write(word_t *dest, word_t src) {
if (cpu.mode == MODE_S && hstatus->vtvm == 1) {
longjmp_exception(EX_VI);
}
if ((src & SATP_SV39_MASK) >> 60 == 8 || (src & SATP_SV39_MASK) >> 60 == 0)
vsatp->val = MASKED_SATP(src);
}else if( is_write(stvec)) {vstvec->val = src & ~(0x2UL);}
vsatp_t new_val = (vsatp_t)src;
// legal mode
if (new_val._64.mode == SATP_MODE_BARE || new_val._64.mode == SATP_MODE_Sv39) {
update_vsatp(new_val);
}
}
else if( is_write(stvec)) {vstvec->val = src & ~(0x2UL);}
}else if (is_write(mideleg)){
*dest = (src & 0x222) | MIDELEG_FORCED_MASK;
}else if (is_write(hideleg)){
Expand Down Expand Up @@ -538,8 +560,11 @@ static inline void csr_write(word_t *dest, word_t src) {
if (cpu.mode == MODE_S && hstatus->vtvm == 1) {
longjmp_exception(EX_VI);
}
if ((src & SATP_SV39_MASK) >> 60 == 8 || (src & SATP_SV39_MASK) >> 60 == 0)
vsatp->val = MASKED_SATP(src);
vsatp_t new_val = (vsatp_t)src;
// legal mode
if (new_val._64.mode == SATP_MODE_BARE || new_val._64.mode == SATP_MODE_Sv39) {
update_vsatp(new_val);
}
}else if (is_write(mstatus)) { mstatus->val = mask_bitset(mstatus->val, MSTATUS_WMASK, src); }
#else
if (is_write(mstatus)) {
Expand Down Expand Up @@ -746,9 +771,16 @@ static inline void csr_write(word_t *dest, word_t src) {
}
#ifdef CONFIG_RVH
else if (is_write(hgatp)) {
// Only support Sv39, ignore write that sets other mode
if ((src & SATP_SV39_MASK) >> 60 == 8 || (src & SATP_SV39_MASK) >> 60 == 0)
hgatp->val = MASKED_HGATP(src);
hgatp_t new_val = (hgatp_t)src;
// vmid and ppn WARL in the normal way, regardless of new_val.mode
hgatp->vmid = new_val.vmid;
// Make PPN[1:0] read only zero
hgatp->ppn = new_val.ppn & ~(rtlreg_t)3 & BITMASK(CONFIG_PADDRBITS - PAGE_SHIFT);

// Only support Sv39x4, ignore write that sets other mode
if (new_val.mode == HGATP_MODE_Sv39x4 || new_val.mode == HGATP_MODE_BARE)
hgatp->mode = new_val.mode;
// When MODE=Bare, software should set the remaining fields in hgatp to zeros, not hardware.
}
#endif// CONFIG_RVH
else if (is_mhpmcounter(dest) || is_mhpmevent(dest)) {
Expand Down

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