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lib: sbi_misaligned_ldst: Determine transformed instruction length correctly 

If MTINST[0:0] bit is 1 then we have transformed instruction encoding
in MTINST CSR. For transformed instructions, if the MTINST[1:1] bit
is Zero then original trapped instruction was a 16bit instruction
which was converted to 32bit instruction at time of taking trap.

We should use MTINST[1:1] bit to determine correct instruction length
of transformed instruction.

This patch updates misaligned load/store emulation as-per above.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
This commit is contained in:
Anup Patel 2020-07-29 17:10:16 +05:30 committed by Anup Patel
parent 2cfd2fc904
commit 937caee083
1 changed files with 8 additions and 4 deletions
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12
lib/sbi/sbi_misaligned_ldst.c
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@ -24,7 +24,7 @@ union reg_data {
int sbi_misaligned_load_handler(ulong addr, ulong tval2, ulong tinst,
struct sbi_trap_regs *regs)
{
ulong insn;
ulong insn, insn_len;
union reg_data val;
struct sbi_trap_info uptrap;
int i, fp = 0, shift = 0, len = 0;
@ -35,6 +35,7 @@ int sbi_misaligned_load_handler(ulong addr, ulong tval2, ulong tinst,
* transformed instruction or custom instruction.
*/
insn = tinst | INSN_16BIT_MASK;
insn_len = (tinst & 0x2) ? INSN_LEN(insn) : 2;
} else {
/*
* Bit[0] == 0 implies trapped instruction value is
@ -45,6 +46,7 @@ int sbi_misaligned_load_handler(ulong addr, ulong tval2, ulong tinst,
uptrap.epc = regs->mepc;
return sbi_trap_redirect(regs, &uptrap);
}
insn_len = INSN_LEN(insn);
}
if ((insn & INSN_MASK_LW) == INSN_MATCH_LW) {
@ -134,7 +136,7 @@ int sbi_misaligned_load_handler(ulong addr, ulong tval2, ulong tinst,
SET_F32_RD(insn, regs, val.data_ulong);
#endif
regs->mepc += INSN_LEN(insn);
regs->mepc += insn_len;
return 0;
}
@ -142,7 +144,7 @@ int sbi_misaligned_load_handler(ulong addr, ulong tval2, ulong tinst,
int sbi_misaligned_store_handler(ulong addr, ulong tval2, ulong tinst,
struct sbi_trap_regs *regs)
{
ulong insn;
ulong insn, insn_len;
union reg_data val;
struct sbi_trap_info uptrap;
int i, len = 0;
@ -153,6 +155,7 @@ int sbi_misaligned_store_handler(ulong addr, ulong tval2, ulong tinst,
* transformed instruction or custom instruction.
*/
insn = tinst | INSN_16BIT_MASK;
insn_len = (tinst & 0x2) ? INSN_LEN(insn) : 2;
} else {
/*
* Bit[0] == 0 implies trapped instruction value is
@ -163,6 +166,7 @@ int sbi_misaligned_store_handler(ulong addr, ulong tval2, ulong tinst,
uptrap.epc = regs->mepc;
return sbi_trap_redirect(regs, &uptrap);
}
insn_len = INSN_LEN(insn);
}
val.data_ulong = GET_RS2(insn, regs);
@ -233,7 +237,7 @@ int sbi_misaligned_store_handler(ulong addr, ulong tval2, ulong tinst,
}
}
regs->mepc += INSN_LEN(insn);
regs->mepc += insn_len;
return 0;
}