Implement MMU access checks

4 files changed, 249 insertions, 73 deletions

diff --git a/rtl/core/mmu/fault.sv b/rtl/core/mmu/fault.sv
new file mode 100644
index 0000000..e922284
--- /dev/null
+++ b/rtl/core/mmu/fault.sv
@@ -0,0 +1,59 @@
+`include "core/mmu/format.sv"
+`include "core/uarch.sv"
+
+module core_mmu_fault
+(
+	input  logic          valid_entry,
+	                      skip_perms,
+	input  word           mmu_dac,
+	input  mmu_domain     domain,
+	input  logic[1:0]     ap,
+
+	output logic          fault, 
+	output mmu_fault_type fault_type
+);
+
+	mmu_domain_ctrl domain_ctrl;
+
+	always_comb begin
+		unique case(domain)
+			4'h0: domain_ctrl = mmu_dac[1:0];
+			4'h1: domain_ctrl = mmu_dac[3:2];
+			4'h2: domain_ctrl = mmu_dac[5:4];
+			4'h3: domain_ctrl = mmu_dac[7:6];
+			4'h4: domain_ctrl = mmu_dac[9:8];
+			4'h5: domain_ctrl = mmu_dac[11:10];
+			4'h6: domain_ctrl = mmu_dac[13:12];
+			4'h7: domain_ctrl = mmu_dac[15:14];
+			4'h8: domain_ctrl = mmu_dac[17:16];
+			4'h9: domain_ctrl = mmu_dac[19:18];
+			4'ha: domain_ctrl = mmu_dac[21:20];
+			4'hb: domain_ctrl = mmu_dac[23:22];
+			4'hc: domain_ctrl = mmu_dac[25:24];
+			4'hd: domain_ctrl = mmu_dac[27:26];
+			4'he: domain_ctrl = mmu_dac[29:28];
+			4'hf: domain_ctrl = mmu_dac[31:30];
+		endcase
+
+		fault = 0;
+		fault_type = `MMU_FAULT_ACCESS;
+
+		if(!valid_entry) begin
+			fault = 1;
+			fault_type = `MMU_FAULT_WALK;
+		end else if(!skip_perms) begin
+			if(!domain_ctrl.allowed) begin
+				fault = 1;
+				fault_type = `MMU_FAULT_DOMAIN;
+			end else if(!domain_ctrl.manager)
+				unique case(ap)
+					2'b00:
+						fault = 1;
+
+					//TODO: los demás solo se tienen efecto para unprivileged
+					default: ;
+				endcase
+		end
+	end
+
+endmodule
diff --git a/rtl/core/mmu/format.sv b/rtl/core/mmu/format.sv
index 83ca3eb..3029b83 100644
--- a/rtl/core/mmu/format.sv
+++ b/rtl/core/mmu/format.sv
@@ -2,6 +2,7 @@
 `define CORE_MMU_FORMAT_SV
 
 typedef logic[17:0] mmu_base;
+typedef logic[3:0]  mmu_domain;
 
 `define MMU_L1_INDEX     [29:18]
 `define MMU_L1_FAULT     2'b00
@@ -10,6 +11,16 @@ typedef logic[17:0] mmu_base;
 
 typedef struct packed
 {
+	logic[31:10] field10;
+	logic[9:9]   imp;
+	logic[8:5]   domain;
+	logic[4:4]   sbz;
+	logic[3:2]   field2;
+	logic[1:0]   typ;
+} mmu_l1_entry;
+
+typedef struct packed
+{
 	logic[31:10] base;
 	logic[9:9]   imp;
 	logic[8:5]   domain;
@@ -65,9 +76,30 @@ typedef struct packed
 	logic[1:0]   typ;
 } mmu_l2_small;
 
-//TODO: struct mmu_l2_smallext
+typedef struct packed
+{
+	logic[31:12] base;
+	logic[11:9]  sbz;
+	logic[8:6]   tex;
+	logic[5:4]   ap;
+	logic[3:3]   c;
+	logic[2:2]   b;
+	logic[1:0]   typ;
+} mmu_l2_smallext;
 
 `define MMU_LARGE_INDEX [13:0]
 `define MMU_SMALL_INDEX [9:0]
 
+typedef logic[1:0] mmu_fault_type;
+
+`define MMU_FAULT_WALK   2'b01
+`define MMU_FAULT_DOMAIN 2'b10
+`define MMU_FAULT_ACCESS 2'b11
+
+typedef struct packed
+{
+	logic manager,
+	      allowed;
+} mmu_domain_ctrl;
+
 `endif
diff --git a/rtl/core/mmu/mmu.sv b/rtl/core/mmu/mmu.sv
index 91986db..17f1e98 100644
--- a/rtl/core/mmu/mmu.sv
+++ b/rtl/core/mmu/mmu.sv
@@ -3,35 +3,39 @@
 
 module core_mmu
 (
-	input  logic      clk,
-	                  rst_n,
-
-	input  logic      mmu_enable /*verilator public*/,
-	input  mmu_base   mmu_ttbr /*verilator public*/,
-
-	input  logic      bus_ready,
-	input  word       bus_data_rd,
-	                  data_data_wr,
-	input  ptr        insn_addr,
-	                  data_addr,
-	input  logic      insn_start,
-	                  data_start,
-	                  data_write,
-	input  logic[3:0] data_data_be,
-
-	output word       bus_data_wr,
-	output logic[3:0] bus_data_be,
-	output ptr        bus_addr,
-	output logic      bus_start,
-	                  bus_write,
-	                  insn_ready,
-	                  data_ready,
-	                  data_fault,
-	output word       insn_data_rd,
-	                  data_data_rd,
-
-	output logic      fault_register,
-	output ptr        fault_addr
+	input  logic          clk,
+	                      rst_n,
+
+	input  logic          mmu_enable /*verilator public*/,
+	input  mmu_base       mmu_ttbr /*verilator public*/,
+	input  word           mmu_dac,
+
+	input  logic          bus_ready,
+	input  word           bus_data_rd,
+	                      data_data_wr,
+	input  ptr            insn_addr,
+	                      data_addr,
+	input  logic          insn_start,
+	                      data_start,
+	                      data_write,
+	input  logic[3:0]     data_data_be,
+
+	output word           bus_data_wr,
+	output logic[3:0]     bus_data_be,
+	output ptr            bus_addr,
+	output logic          bus_start,
+	                      bus_write,
+	                      insn_ready,
+	                      data_ready,
+	                      data_fault,
+	output word           insn_data_rd,
+	                      data_data_rd,
+
+	output logic          fault_register,
+	                      fault_page,
+	output ptr            fault_addr,
+	output mmu_fault_type fault_type,
+	output mmu_domain     fault_domain
 );
 
 	ptr iphys_addr, dphys_addr;
@@ -52,6 +56,9 @@ module core_mmu
 		.core_data_be(0),
 		.core_data_rd(insn_data_rd),
 		.core_fault_addr(),
+		.core_fault_page(),
+		.core_fault_type(),
+		.core_fault_domain(),
 
 		.bus_addr(iphys_addr),
 		.bus_start(iphys_start),
@@ -75,6 +82,9 @@ module core_mmu
 		.core_data_be(data_data_be),
 		.core_data_rd(data_data_rd),
 		.core_fault_addr(fault_addr),
+		.core_fault_page(fault_page),
+		.core_fault_type(fault_type),
+		.core_fault_domain(fault_domain),
 
 		.bus_addr(dphys_addr),
 		.bus_start(dphys_start),
diff --git a/rtl/core/mmu/pagewalk.sv b/rtl/core/mmu/pagewalk.sv
index be4aa8b..c6d51c0 100644
--- a/rtl/core/mmu/pagewalk.sv
+++ b/rtl/core/mmu/pagewalk.sv
@@ -3,31 +3,35 @@
 
 module core_mmu_pagewalk
 (
-	input  logic      clk,
-	                  rst_n,
-
-	input  logic      mmu_enable,
-	input  mmu_base   mmu_ttbr,
-
-	input  logic      bus_ready,
-	input  word       bus_data_rd,
-
-	input  ptr        core_addr,
-	input  word       core_data_wr,
-	input  logic[3:0] core_data_be,
-	input  logic      core_start,
-	                  core_write,
-
-	output ptr        bus_addr,
-	output word       bus_data_wr,
-	output logic[3:0] bus_data_be,
-	output logic      bus_start,
-	                  bus_write,
-
-	output logic      core_ready,
-	                  core_fault,
-	output word       core_data_rd,
-	output ptr        core_fault_addr
+	input  logic          clk,
+	                      rst_n,
+
+	input  logic          mmu_enable,
+	input  mmu_base       mmu_ttbr,
+	input  word           mmu_dac,
+
+	input  logic          bus_ready,
+	input  word           bus_data_rd,
+
+	input  ptr            core_addr,
+	input  word           core_data_wr,
+	input  logic[3:0]     core_data_be,
+	input  logic          core_start,
+	                      core_write,
+
+	output ptr            bus_addr,
+	output word           bus_data_wr,
+	output logic[3:0]     bus_data_be,
+	output logic          bus_start,
+	                      bus_write,
+
+	output word           core_data_rd,
+	output logic          core_ready,
+	                      core_fault,
+	                      core_fault_page,
+	output ptr            core_fault_addr,
+	output mmu_fault_type core_fault_type,
+	output mmu_domain     core_fault_domain
 );
 
 	enum int unsigned
@@ -39,6 +43,25 @@ module core_mmu_pagewalk
 		FAULT
 	} state;
 
+	logic access_fault, valid_entry, skip_perms;
+	logic[1:0] ap, entry_type;
+	mmu_domain domain, entry_domain;
+	mmu_fault_type access_fault_type;
+
+	assign entry_type = bus_data_rd[1:0];
+	assign core_fault_domain = domain;
+
+	core_mmu_fault access_check
+	(
+		.fault(access_fault),
+		.domain(entry_domain),
+		.fault_type(access_fault_type),
+		.*
+	);
+
+	mmu_l1_entry l1;
+	assign l1 = bus_data_rd;
+
 	mmu_l1_pagetable pagetable;
 	assign pagetable = bus_data_rd;
 
@@ -51,16 +74,64 @@ module core_mmu_pagewalk
 	mmu_l2_small ptentry_small;
 	assign ptentry_small = bus_data_rd;
 
+	mmu_l2_smallext ptentry_smallext;
+	assign ptentry_smallext = bus_data_rd;
+
 	ptr target;
 	word hold_data;
+	logic hold_write;
 	logic[3:0] hold_be;
 
-	logic hold_write;
+	always_comb begin
+		ap = 2'bxx;
+		skip_perms = 0;
+		valid_entry = 1;
+		entry_domain = domain;
+
+		unique case(state)
+			L1:
+				unique case(entry_type)
+					`MMU_L1_PAGETABLE: begin
+						ap = 2'bxx;
+						skip_perms = 1;
+					end
+
+					`MMU_L1_SECTION: begin
+						ap = section.ap;
+						entry_domain = l1.domain;
+					end
+
+					// Tiny (1KiB wtf?) pages and supersections not supported
+					default:
+						valid_entry = 0;
+				endcase
+
+			L2:
+				unique case(entry_type)
+					`MMU_L2_FAULT:
+						valid_entry = 0;
+
+					`MMU_L2_LARGE:
+						//TODO: ap3-ap2 (también en L2_SMALL)
+						ap = ptentry_large.ap0;
+
+					`MMU_L2_SMALL:
+						ap = ptentry_small.ap0;
+
+					`MMU_L2_SMALLEXT:
+						ap = ptentry_smallext.ap;
+				endcase
+
+			default:
+				valid_entry = 1'bx;
+		endcase
+	end
 
 	always @(posedge clk or negedge rst_n)
 		if(!rst_n) begin
 			state <= IDLE;
 			target <= 0;
+			domain <= 0;
 
 			hold_be <= 0;
 			hold_data <= 0;
@@ -75,7 +146,9 @@ module core_mmu_pagewalk
 			core_ready <= 0;
 			core_fault <= 0;
 			core_data_rd <= 0;
+			core_fault_page <= 0;
 			core_fault_addr <= 0;
+			core_fault_type <= 0;
 		end else begin
 			if(bus_start)
 				bus_start <= 0;
@@ -109,28 +182,26 @@ module core_mmu_pagewalk
 					end
 
 				L1:
-					if(bus_ready)
-						unique case(bus_data_rd[1:0])
+					if(bus_ready) begin
+						domain <= l1.domain;
+
+						unique case(entry_type)
 							`MMU_L1_PAGETABLE: begin
 								state <= L2;
 								bus_addr <= {pagetable.base, target `MMU_L2_INDEX};
-								bus_start <= 1;
 							end
 
 							`MMU_L1_SECTION: begin
 								state <= DATA;
-
 								bus_addr <= {section.base, target `MMU_SECTION_INDEX};
-								bus_start <= 1;
 								bus_write <= hold_write;
 								bus_data_wr <= hold_data;
 								bus_data_be <= hold_be;
 							end
 
-							// Tiny (1KiB wtf?) pages and supersections not supported
-							default:
-								state <= FAULT;
+							default: ;
 						endcase
+					end
 
 				L2:
 					if(bus_ready) begin
@@ -140,19 +211,14 @@ module core_mmu_pagewalk
 						bus_data_wr <= hold_data;
 						bus_data_be <= hold_be;
 
-						unique case(bus_data_rd[1:0])
-							`MMU_L2_FAULT:
-								state <= FAULT;
+						unique case(entry_type)
+							`MMU_L2_FAULT: ;
 
-							`MMU_L2_LARGE: begin
+							`MMU_L2_LARGE:
 								bus_addr <= {ptentry_large.base, target `MMU_LARGE_INDEX};
-								bus_start <= 1;
-							end
 
-							`MMU_L2_SMALL, `MMU_L2_SMALLEXT: begin
+							`MMU_L2_SMALL, `MMU_L2_SMALLEXT:
 								bus_addr <= {ptentry_small.base, target `MMU_SMALL_INDEX};
-								bus_start <= 1;
-							end
 						endcase
 					end
 
@@ -171,6 +237,15 @@ module core_mmu_pagewalk
 					core_fault_addr <= target;
 				end
 			endcase
+
+			if((state == L1 || state == L2) && bus_ready) begin
+				if(access_fault) begin
+					state <= FAULT;
+					core_fault_type <= access_fault_type;
+					core_fault_page <= state == L2;
+				end else
+					bus_start <= 1;
+			end
 		end
 
 endmodule