(unburying an old patch)
On 1/7/20 17:24, LIU Zhiwei wrote:
The unit-stride fault-only-fault load instructions are used to
vectorize loops with data-dependent exit conditions(while loops).
These instructions execute as a regular load except that they
will only take a trap on element 0.
Signed-off-by: LIU Zhiwei <zhiwei_...@c-sky.com>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
---
target/riscv/helper.h | 22 +++++
target/riscv/insn32.decode | 7 ++
target/riscv/insn_trans/trans_rvv.inc.c | 73 ++++++++++++++++
target/riscv/vector_helper.c | 110 ++++++++++++++++++++++++
4 files changed, 212 insertions(+)
+/*
+ *** unit-stride fault-only-fisrt load instructions
+ */
+static inline void
+vext_ldff(void *vd, void *v0, target_ulong base,
+ CPURISCVState *env, uint32_t desc,
+ vext_ldst_elem_fn *ldst_elem,
+ clear_fn *clear_elem,
+ uint32_t esz, uint32_t msz, uintptr_t ra)
+{
+ void *host;
+ uint32_t i, k, vl = 0;
+ uint32_t mlen = vext_mlen(desc);
+ uint32_t nf = vext_nf(desc);
+ uint32_t vm = vext_vm(desc);
+ uint32_t vlmax = vext_maxsz(desc) / esz;
+ target_ulong addr, offset, remain;
+
+ /* probe every access*/
+ for (i = 0; i < env->vl; i++) {
+ if (!vm && !vext_elem_mask(v0, mlen, i)) {
+ continue;
+ }
+ addr = base + nf * i * msz;
+ if (i == 0) {
+ probe_pages(env, addr, nf * msz, ra, MMU_DATA_LOAD);
Shouldn't we check page_check_range() in user-mode here?
+ } else {
+ /* if it triggers an exception, no need to check watchpoint */
+ remain = nf * msz;
+ while (remain > 0) {
+ offset = -(addr | TARGET_PAGE_MASK);
+ host = tlb_vaddr_to_host(env, addr, MMU_DATA_LOAD,
+ cpu_mmu_index(env, false));
+ if (host) {
+#ifdef CONFIG_USER_ONLY
+ if (page_check_range(addr, nf * msz, PAGE_READ) < 0) {
+ vl = i;
+ goto ProbeSuccess;
+ }
+#else
+ probe_pages(env, addr, nf * msz, ra, MMU_DATA_LOAD);
+#endif
+ } else {
+ vl = i;
+ goto ProbeSuccess;
+ }
+ if (remain <= offset) {
+ break;
+ }
+ remain -= offset;
+ addr += offset;
+ }
+ }
+ }
+ProbeSuccess:
+ /* load bytes from guest memory */
+ if (vl != 0) {
+ env->vl = vl;
+ }
+ for (i = 0; i < env->vl; i++) {
+ k = 0;
+ if (!vm && !vext_elem_mask(v0, mlen, i)) {
+ continue;
+ }
+ while (k < nf) {
+ target_ulong addr = base + (i * nf + k) * msz;
+ ldst_elem(env, addr, i + k * vlmax, vd, ra);
+ k++;
+ }
+ }
+ /* clear tail elements */
+ if (vl != 0) {
+ return;
+ }
+ for (k = 0; k < nf; k++) {
+ clear_elem(vd, env->vl + k * vlmax, env->vl * esz, vlmax * esz);
+ }
+}
