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target/arm: Report VNCR_EL2 based faults correctly 

If FEAT_NV2 redirects a system register access to a memory offset
from VNCR_EL2, that access might fault.  In this case we need to
report the correct syndrome information:
 * Data Abort, from same-EL
 * no ISS information
 * the VNCR bit (bit 13) is set

and the exception must be taken to EL2.

Save an appropriate syndrome template when generating code; we can
then use that to:
 * select the right target EL
 * reconstitute a correct final syndrome for the data abort
 * report the right syndrome if we take a FEAT_RME granule protection
   fault on the VNCR-based write

Note that because VNCR is bit 13, we must start keeping bit 13 in
template syndromes, by adjusting ARM_INSN_START_WORD2_SHIFT.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Miguel Luis <miguel.luis@oracle.com>
This commit is contained in:
Peter Maydell 2024-01-09 14:43:54 +00:00
parent daf9b4a00f
commit 674e534527
4 changed files with 47 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
target/arm/cpu.h
View File

@ -120,12 +120,12 @@ enum {
#define TARGET_INSN_START_EXTRA_WORDS 2
/* The 2nd extra word holding syndrome info for data aborts does not use
* the upper 6 bits nor the lower 14 bits. We mask and shift it down to
* the upper 6 bits nor the lower 13 bits. We mask and shift it down to
* help the sleb128 encoder do a better job.
* When restoring the CPU state, we shift it back up.
*/
#define ARM_INSN_START_WORD2_MASK ((1 << 26) - 1)
#define ARM_INSN_START_WORD2_SHIFT 14
#define ARM_INSN_START_WORD2_SHIFT 13
/* We currently assume float and double are IEEE single and double
precision respectively.

20
target/arm/syndrome.h
View File

@ -86,6 +86,9 @@ typedef enum {
#define ARM_EL_IL (1 << ARM_EL_IL_SHIFT)
#define ARM_EL_ISV (1 << ARM_EL_ISV_SHIFT)
/* In the Data Abort syndrome */
#define ARM_EL_VNCR (1 << 13)
static inline uint32_t syn_get_ec(uint32_t syn)
{
return syn >> ARM_EL_EC_SHIFT;
@ -256,13 +259,12 @@ static inline uint32_t syn_bxjtrap(int cv, int cond, int rm)
(cv << 24) | (cond << 20) | rm;
}
static inline uint32_t syn_gpc(int s2ptw, int ind, int gpcsc,
static inline uint32_t syn_gpc(int s2ptw, int ind, int gpcsc, int vncr,
int cm, int s1ptw, int wnr, int fsc)
{
/* TODO: FEAT_NV2 adds VNCR */
return (EC_GPC << ARM_EL_EC_SHIFT) | ARM_EL_IL | (s2ptw << 21)
| (ind << 20) | (gpcsc << 14) | (cm << 8) | (s1ptw << 7)
| (wnr << 6) | fsc;
| (ind << 20) | (gpcsc << 14) | (vncr << 13) | (cm << 8)
| (s1ptw << 7) | (wnr << 6) | fsc;
}
static inline uint32_t syn_insn_abort(int same_el, int ea, int s1ptw, int fsc)
@ -295,6 +297,16 @@ static inline uint32_t syn_data_abort_with_iss(int same_el,
| (ea << 9) | (cm << 8) | (s1ptw << 7) | (wnr << 6) | fsc;
}
/*
* Faults due to FEAT_NV2 VNCR_EL2-based accesses report as same-EL
* Data Aborts with the VNCR bit set.
*/
static inline uint32_t syn_data_abort_vncr(int ea, int wnr, int fsc)
{
return (EC_DATAABORT << ARM_EL_EC_SHIFT) | (1 << ARM_EL_EC_SHIFT)
| ARM_EL_IL | ARM_EL_VNCR | (wnr << 6) | fsc;
}
static inline uint32_t syn_swstep(int same_el, int isv, int ex)
{
return (EC_SOFTWARESTEP << ARM_EL_EC_SHIFT) | (same_el << ARM_EL_EC_SHIFT)

27
target/arm/tcg/tlb_helper.c
View File

@ -50,7 +50,15 @@ static inline uint32_t merge_syn_data_abort(uint32_t template_syn,
* ST64BV, or ST64BV0 insns report syndrome info even for stage-1
* faults and regardless of the target EL.
*/
if (!(template_syn & ARM_EL_ISV) || target_el != 2
if (template_syn & ARM_EL_VNCR) {
/*
* FEAT_NV2 faults on accesses via VNCR_EL2 are a special case:
* they are always reported as "same EL", even though we are going
* from EL1 to EL2.
*/
assert(!fi->stage2);
syn = syn_data_abort_vncr(fi->ea, is_write, fsc);
} else if (!(template_syn & ARM_EL_ISV) || target_el != 2
|| fi->s1ptw || !fi->stage2) {
syn = syn_data_abort_no_iss(same_el, 0,
fi->ea, 0, fi->s1ptw, is_write, fsc);
@ -169,6 +177,20 @@ void arm_deliver_fault(ARMCPU *cpu, vaddr addr,
int current_el = arm_current_el(env);
bool same_el;
uint32_t syn, exc, fsr, fsc;
/*
* We know this must be a data or insn abort, and that
* env->exception.syndrome contains the template syndrome set
* up at translate time. So we can check only the VNCR bit
* (and indeed syndrome does not have the EC field in it,
* because we masked that out in disas_set_insn_syndrome())
*/
bool is_vncr = (mmu_idx != MMU_INST_FETCH) &&
(env->exception.syndrome & ARM_EL_VNCR);
if (is_vncr) {
/* FEAT_NV2 faults on accesses via VNCR_EL2 go to EL2 */
target_el = 2;
}
if (report_as_gpc_exception(cpu, current_el, fi)) {
target_el = 3;
@ -177,7 +199,8 @@ void arm_deliver_fault(ARMCPU *cpu, vaddr addr,
syn = syn_gpc(fi->stage2 && fi->type == ARMFault_GPCFOnWalk,
access_type == MMU_INST_FETCH,
encode_gpcsc(fi), 0, fi->s1ptw,
encode_gpcsc(fi), is_vncr,
0, fi->s1ptw,
access_type == MMU_DATA_STORE, fsc);
env->cp15.mfar_el3 = fi->paddr;

4
target/arm/tcg/translate-a64.c
View File

@ -2294,6 +2294,7 @@ static void handle_sys(DisasContext *s, bool isread,
MemOp mop = MO_64 | MO_ALIGN | MO_ATOM_IFALIGN;
ARMMMUIdx armmemidx = s->nv2_mem_e20 ? ARMMMUIdx_E20_2 : ARMMMUIdx_E2;
int memidx = arm_to_core_mmu_idx(armmemidx);
uint32_t syn;
mop |= (s->nv2_mem_be ? MO_BE : MO_LE);
@ -2301,6 +2302,9 @@ static void handle_sys(DisasContext *s, bool isread,
tcg_gen_addi_i64(ptr, ptr,
(ri->nv2_redirect_offset & ~NV2_REDIR_FLAG_MASK));
tcg_rt = cpu_reg(s, rt);
syn = syn_data_abort_vncr(0, !isread, 0);
disas_set_insn_syndrome(s, syn);
if (isread) {
tcg_gen_qemu_ld_i64(tcg_rt, ptr, memidx, mop);
} else {