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lib: Use MTINST CSR in misaligned load/store emulation 

We should use MTINST CSR in misaligned load/store emulation whenever
possible to avoid unpriv read in getting trapped instruction. This will
improve preformance on HW having proper implementation of MTINST CSR.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Anup Patel 2019-12-12 22:51:42 +05:30 committed by Anup Patel
parent 2be424bd28
commit 7219477f7b
1 changed files with 34 additions and 8 deletions
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42
lib/sbi/sbi_misaligned_ldst.c
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@ -26,14 +26,27 @@ int sbi_misaligned_load_handler(u32 hartid, ulong mcause,
struct sbi_trap_regs *regs,
struct sbi_scratch *scratch)
{
ulong insn;
union reg_data val;
struct sbi_trap_info uptrap;
int i, fp = 0, shift = 0, len = 0;
ulong insn = sbi_get_insn(regs->mepc, scratch, &uptrap);
if (uptrap.cause) {
uptrap.epc = regs->mepc;
return sbi_trap_redirect(regs, &uptrap, scratch);
if (tinst & 0x1) {
/*
* Bit[0] == 1 implies trapped instruction value is
* transformed instruction or custom instruction.
*/
insn = tinst | INSN_16BIT_MASK;
} else {
/*
* Bit[0] == 0 implies trapped instruction value is
* zero or special value.
*/
insn = sbi_get_insn(regs->mepc, scratch, &uptrap);
if (uptrap.cause) {
uptrap.epc = regs->mepc;
return sbi_trap_redirect(regs, &uptrap, scratch);
}
}
if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) {
@ -135,14 +148,27 @@ int sbi_misaligned_store_handler(u32 hartid, ulong mcause,
struct sbi_trap_regs *regs,
struct sbi_scratch *scratch)
{
ulong insn;
union reg_data val;
struct sbi_trap_info uptrap;
int i, len = 0;
ulong insn = sbi_get_insn(regs->mepc, scratch, &uptrap);
if (uptrap.cause) {
uptrap.epc = regs->mepc;
return sbi_trap_redirect(regs, &uptrap, scratch);
if (tinst & 0x1) {
/*
* Bit[0] == 1 implies trapped instruction value is
* transformed instruction or custom instruction.
*/
insn = tinst | INSN_16BIT_MASK;
} else {
/*
* Bit[0] == 0 implies trapped instruction value is
* zero or special value.
*/
insn = sbi_get_insn(regs->mepc, scratch, &uptrap);
if (uptrap.cause) {
uptrap.epc = regs->mepc;
return sbi_trap_redirect(regs, &uptrap, scratch);
}
}
val.data_ulong = GET_RS2(insn, regs);