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[fcov] Add coverage for making PMP regions executable.

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Greg Chadwick 2022-11-17 16:43:41 +00:00 • committed by Greg Chadwick
parent bf0397f37a
commit 99c8a7ce00
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5
doc/03_reference/coverage_plan.rst
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@ -280,6 +280,11 @@ PMP
* Access close to PMP region modification that allows/disallows that access.
* ``pmp_wr_exec_region`` - Explores behaviour around adding executable regions when MML is enabled.
Cross of current region configuration with region configuration that is being written and RLB setting.
It only considers regions that aren't currently executable with writes attempted to make them executable.
Non MML configurations are not sampled.
CSRs
^^^^
Basic read/write functionality must be tested on all implemented CSRs.

35
dv/uvm/core_ibex/fcov/core_ibex_pmp_fcov_if.sv
View file

@ -138,12 +138,20 @@ interface core_ibex_pmp_fcov_if import ibex_pkg::*; #(
for (genvar i_region = 0; i_region < PMPNumRegions; i_region += 1) begin : g_pmp_region_fcov
pmp_priv_bits_e pmp_region_priv_bits;
pmp_priv_bits_e pmp_region_priv_bits_wr;
assign pmp_region_priv_bits = pmp_priv_bits_e'({csr_pmp_mseccfg.mml,
csr_pmp_cfg[i_region].lock,
csr_pmp_cfg[i_region].exec,
csr_pmp_cfg[i_region].write,
csr_pmp_cfg[i_region].read});
assign pmp_region_priv_bits_wr =
pmp_priv_bits_e'({csr_pmp_mseccfg.mml,
cs_registers_i.g_pmp_registers.pmp_cfg_wdata[i_region].lock,
cs_registers_i.g_pmp_registers.pmp_cfg_wdata[i_region].exec,
cs_registers_i.g_pmp_registers.pmp_cfg_wdata[i_region].write,
cs_registers_i.g_pmp_registers.pmp_cfg_wdata[i_region].read});
// Do the permission check for Data channel with the privilege level from Instruction channels.
// This way we can check the effect of mstatus.mprv changing privilege levels for LSU related
// operations.
@ -431,6 +439,33 @@ interface core_ibex_pmp_fcov_if import ibex_pkg::*; #(
csr_pmp_cfg[i_region].lock &&
cs_registers_i.g_pmp_registers.g_pmp_csrs[i_region].u_pmp_addr_csr.wr_en_i &&
csr_pmp_mseccfg.rlb)
// Only sample this cross when we attempt to write to a PMP config that doesn't currently
// allow execution with MML enabled
pmp_wr_exec_region :
cross pmp_region_priv_bits, pmp_region_priv_bits_wr, csr_pmp_mseccfg.rlb iff
(fcov_csr_write &&
csr_pmp_mseccfg.mml &&
cs_registers_i.csr_we_int &&
cs_registers_i.csr_addr == (CSR_OFF_PMP_CFG + (i_region[11:0] >> 2)) &&
((!pmp_region_priv_bits[2] && pmp_region_priv_bits != MML_XM_XU) ||
pmp_region_priv_bits inside {MML_WRM_WRU, MML_RM_RU})) {
// Only interested in MML configuration
ignore_bins non_mml_in = binsof(pmp_region_priv_bits) with (!pmp_region_priv_bits[4]);
ignore_bins non_mml_out =
binsof(pmp_region_priv_bits_wr) with (!pmp_region_priv_bits_wr[4]);
// Only interested in starting configs that weren't executable so ignore executable
// regions
ignore_bins from_exec_bins = binsof(pmp_region_priv_bits) intersect {MML_XU, MML_XRU,
MML_XWRU, MML_XM_XU, MML_XM, MML_XRM, MML_XRM_XU};
// Only interested in writes that give executable regions so ignore non executable regions
ignore_bins to_non_exec_bins = binsof(pmp_region_priv_bits_wr) intersect {MML_NONE,
MML_RU, MML_WRM_RU, MML_WRU, MML_WRM_WRU, MML_L, MML_RM, MML_WRM, MML_RM_RU};
}
endgroup
`DV_FCOV_INSTANTIATE_CG(pmp_region_cg, en_pmp_fcov)