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lib: sbi: Rework and split sbi_misaligned(_v)_tinst_fixup

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The load/store address offset between the uptrap and the orig_trap
can be derived by orig_trap->tval - uptrap->tval, thus refactor
the function prototype for simplicity.

For vector load, sbi_misaligned_v_tinst_fixup is introduced. There's
no transformed instruction for vector load/store, so null out tinst
if the fault is not a guest-page fault.

Signed-off-by: Bo Gan <ganboing@gmail.com>
Tested-by: Anirudh Srinivasan <asrinivasan@oss.tenstorrent.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260609060024.706-3-ganboing@gmail.com
Signed-off-by: Anup Patel <anup@brainfault.org>
This commit is contained in:
Bo Gan
2026-06-08 23:00:22 -07:00
committed by Anup Patel
parent 4120e6dce2
commit 1475f147f6
3 changed files with 59 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/sbi/sbi_trap_ldst.h
-3
View File
@@ -28,9 +28,6 @@ int sbi_load_access_handler(struct sbi_trap_context *tcntx);
int sbi_store_access_handler(struct sbi_trap_context *tcntx);
ulong sbi_misaligned_tinst_fixup(ulong orig_tinst, ulong new_tinst,
ulong addr_offset);
int sbi_misaligned_v_ld_emulator(ulong insn,
struct sbi_trap_context *tcntx);
lib/sbi/sbi_trap_ldst.c
+34 -12
View File
@@ -32,16 +32,40 @@ typedef int (*sbi_trap_st_emulator)(ulong insn, int wlen, ulong waddr,
union sbi_ldst_data in_val,
struct sbi_trap_context *tcntx);
ulong sbi_misaligned_tinst_fixup(ulong orig_tinst, ulong new_tinst,
ulong addr_offset)
/**
* Handling of misaligned fault is done by a collection of smaller, but
* aligned load/store(s). Another fault (load/store, page fault...) can
* arise from any of them, then the handling gets aborted. We must fixup
* the tinst to pretend the fault was rised from the original insn.
* Specifically, fixup the offset field using the tval diff between the
* new trap and the original one (if required).
*/
static inline void sbi_misaligned_tinst_fixup(
const struct sbi_trap_info *orig_trap,
struct sbi_trap_info *uptrap)
{
if (new_tinst == INSN_PSEUDO_VS_LOAD ||
new_tinst == INSN_PSEUDO_VS_STORE)
return new_tinst;
else if (orig_tinst == 0)
return 0UL;
ulong offset = uptrap->tval - orig_trap->tval;
/*
* The function is called in code path for handling a scalar
* load/store misaligned fault, thus the new uptrap can't have
* custom value of tinst
*/
if (uptrap->tinst == INSN_PSEUDO_VS_LOAD ||
uptrap->tinst == INSN_PSEUDO_VS_STORE)
/* Use uptrap as-is for guest-page faults */
return;
/*
* Only fixup if orig tinst is valid. Otherwise, discard the
* new tinst to be on the safe side. Never use new tinst as-is!
* It's load/store width surely mismatches the original width.
* For vector, discard it regardless. It doesn't make sense to
* have a transformed tinst
*/
else if (orig_trap->tinst == 0)
uptrap->tinst = 0;
else
return orig_tinst | (addr_offset << SH_RS1);
uptrap->tinst = orig_trap->tinst | (offset << SH_RS1);
}
static inline bool sbi_trap_tinst_valid(ulong tinst)
@@ -464,8 +488,7 @@ static int sbi_misaligned_ld_emulator(ulong insn, int rlen, ulong addr,
out_val->data_bytes[i] =
sbi_load_u8((void *)(addr + i), &uptrap);
if (uptrap.cause) {
uptrap.tinst = sbi_misaligned_tinst_fixup(
orig_trap->tinst, uptrap.tinst, i);
sbi_misaligned_tinst_fixup(orig_trap, &uptrap);
return sbi_trap_redirect(regs, &uptrap);
}
}
@@ -501,8 +524,7 @@ static int sbi_misaligned_st_emulator(ulong insn, int wlen, ulong addr,
sbi_store_u8((void *)(addr + i),
in_val.data_bytes[i], &uptrap);
if (uptrap.cause) {
uptrap.tinst = sbi_misaligned_tinst_fixup(
orig_trap->tinst, uptrap.tinst, i);
sbi_misaligned_tinst_fixup(orig_trap, &uptrap);
return sbi_trap_redirect(regs, &uptrap);
}
}
lib/sbi/sbi_trap_v_ldst.c
+25 -6
View File
@@ -138,9 +138,31 @@ static inline void vsetvl(ulong vl, ulong vtype)
:: "r" (vl), "r" (vtype));
}
/**
* Handling of misaligned fault is done by a collection of smaller, but
* aligned load/store(s). Another fault (load/store, page fault...) can
* arise from any of them, then the handling gets aborted. We must fixup
* the tinst to pretend the fault was rised from the original insn. For
* vector insn, simply null out tinst if it's not a guest-page fault, as
* there's no transformed insn for vector load/store
*/
static inline void sbi_misaligned_v_tinst_fixup(struct sbi_trap_info *uptrap)
{
/*
* The function is called in code path for handling a vector
* load/store misaligned fault, thus the new uptrap can't have
* custom value of tinst
*/
if (uptrap->tinst == INSN_PSEUDO_VS_LOAD ||
uptrap->tinst == INSN_PSEUDO_VS_STORE)
/* Use uptrap as-is for guest-page faults */
return;
uptrap->tinst = 0;
}
int sbi_misaligned_v_ld_emulator(ulong insn, struct sbi_trap_context *tcntx)
{
const struct sbi_trap_info *orig_trap = &tcntx->trap;
struct sbi_trap_regs *regs = &tcntx->regs;
struct sbi_trap_info uptrap;
ulong vl = csr_read(CSR_VL);
@@ -218,8 +240,7 @@ int sbi_misaligned_v_ld_emulator(ulong insn, struct sbi_trap_context *tcntx)
break;
}
vsetvl(vl, vtype);
uptrap.tinst = sbi_misaligned_tinst_fixup(
orig_trap->tinst, uptrap.tinst, i);
sbi_misaligned_v_tinst_fixup(&uptrap);
return sbi_trap_redirect(regs, &uptrap);
}
}
@@ -240,7 +261,6 @@ int sbi_misaligned_v_ld_emulator(ulong insn, struct sbi_trap_context *tcntx)
int sbi_misaligned_v_st_emulator(ulong insn, struct sbi_trap_context *tcntx)
{
const struct sbi_trap_info *orig_trap = &tcntx->trap;
struct sbi_trap_regs *regs = &tcntx->regs;
struct sbi_trap_info uptrap;
ulong vl = csr_read(CSR_VL);
@@ -317,8 +337,7 @@ int sbi_misaligned_v_st_emulator(ulong insn, struct sbi_trap_context *tcntx)
bytes[seg * len + i], &uptrap);
if (uptrap.cause) {
vsetvl(vl, vtype);
uptrap.tinst = sbi_misaligned_tinst_fixup(
orig_trap->tinst, uptrap.tinst, i);
sbi_misaligned_v_tinst_fixup(&uptrap);
return sbi_trap_redirect(regs, &uptrap);
}
}