Metavalue cleanup for icache.vhdl

Signed-off-by: Michael Neuling <mikey@neuling.org>
pull/378/head
Michael Neuling 2 years ago
parent 43dadca052
commit 404abefd92

@ -207,7 +207,6 @@ architecture rtl of icache is
signal req_is_miss : std_ulogic; signal req_is_miss : std_ulogic;
signal req_raddr : real_addr_t; signal req_raddr : real_addr_t;


signal tlb_req_index : tlb_index_t;
signal real_addr : real_addr_t; signal real_addr : real_addr_t;
signal ra_valid : std_ulogic; signal ra_valid : std_ulogic;
signal priv_fault : std_ulogic; signal priv_fault : std_ulogic;
@ -317,14 +316,15 @@ architecture rtl of icache is
end; end;


-- Simple hash for direct-mapped TLB index -- Simple hash for direct-mapped TLB index
function hash_ea(addr: std_ulogic_vector(63 downto 0)) return tlb_index_t is function hash_ea(addr: std_ulogic_vector(63 downto 0)) return std_ulogic_vector is
variable hash : std_ulogic_vector(TLB_BITS - 1 downto 0); variable hash : std_ulogic_vector(TLB_BITS - 1 downto 0);
begin begin
hash := addr(TLB_LG_PGSZ + TLB_BITS - 1 downto TLB_LG_PGSZ) hash := addr(TLB_LG_PGSZ + TLB_BITS - 1 downto TLB_LG_PGSZ)
xor addr(TLB_LG_PGSZ + 2 * TLB_BITS - 1 downto TLB_LG_PGSZ + TLB_BITS) xor addr(TLB_LG_PGSZ + 2 * TLB_BITS - 1 downto TLB_LG_PGSZ + TLB_BITS)
xor addr(TLB_LG_PGSZ + 3 * TLB_BITS - 1 downto TLB_LG_PGSZ + 2 * TLB_BITS); xor addr(TLB_LG_PGSZ + 3 * TLB_BITS - 1 downto TLB_LG_PGSZ + 2 * TLB_BITS);
return to_integer(unsigned(hash)); return hash;
end; end;

begin begin


assert LINE_SIZE mod ROW_SIZE = 0; assert LINE_SIZE mod ROW_SIZE = 0;
@ -435,7 +435,9 @@ begin
process(all) process(all)
begin begin
-- PLRU interface -- PLRU interface
if get_index(r.hit_nia) = i then if is_X(r.hit_nia) then
plru_acc_en <= 'X';
elsif get_index(r.hit_nia) = i then
plru_acc_en <= r.hit_valid; plru_acc_en <= r.hit_valid;
else else
plru_acc_en <= '0'; plru_acc_en <= '0';
@ -450,15 +452,25 @@ begin
itlb_lookup : process(all) itlb_lookup : process(all)
variable pte : tlb_pte_t; variable pte : tlb_pte_t;
variable ttag : tlb_tag_t; variable ttag : tlb_tag_t;
variable tlb_req_index : std_ulogic_vector(TLB_BITS - 1 downto 0);
begin begin
tlb_req_index <= hash_ea(i_in.nia); tlb_req_index := hash_ea(i_in.nia);
pte := itlb_ptes(tlb_req_index); if is_X(tlb_req_index) then
ttag := itlb_tags(tlb_req_index); pte := (others => 'X');
ttag := (others => 'X');
else
pte := itlb_ptes(to_integer(unsigned(tlb_req_index)));
ttag := itlb_tags(to_integer(unsigned(tlb_req_index)));
end if;
if i_in.virt_mode = '1' then if i_in.virt_mode = '1' then
real_addr <= pte(REAL_ADDR_BITS - 1 downto TLB_LG_PGSZ) & real_addr <= pte(REAL_ADDR_BITS - 1 downto TLB_LG_PGSZ) &
i_in.nia(TLB_LG_PGSZ - 1 downto 0); i_in.nia(TLB_LG_PGSZ - 1 downto 0);
if ttag = i_in.nia(63 downto TLB_LG_PGSZ + TLB_BITS) then if ttag = i_in.nia(63 downto TLB_LG_PGSZ + TLB_BITS) then
ra_valid <= itlb_valids(tlb_req_index); if is_X(tlb_req_index) then
ra_valid <= 'X';
else
ra_valid <= itlb_valids(to_integer(unsigned(tlb_req_index)));
end if;
else else
ra_valid <= '0'; ra_valid <= '0';
end if; end if;
@ -476,7 +488,7 @@ begin


-- iTLB update -- iTLB update
itlb_update: process(clk) itlb_update: process(clk)
variable wr_index : tlb_index_t; variable wr_index : std_ulogic_vector(TLB_BITS - 1 downto 0);
begin begin
if rising_edge(clk) then if rising_edge(clk) then
wr_index := hash_ea(m_in.addr); wr_index := hash_ea(m_in.addr);
@ -486,12 +498,14 @@ begin
itlb_valids(i) <= '0'; itlb_valids(i) <= '0';
end loop; end loop;
elsif m_in.tlbie = '1' then elsif m_in.tlbie = '1' then
assert not is_X(wr_index) report "icache index invalid on write" severity FAILURE;
-- clear entry regardless of hit or miss -- clear entry regardless of hit or miss
itlb_valids(wr_index) <= '0'; itlb_valids(to_integer(unsigned(wr_index))) <= '0';
elsif m_in.tlbld = '1' then elsif m_in.tlbld = '1' then
itlb_tags(wr_index) <= m_in.addr(63 downto TLB_LG_PGSZ + TLB_BITS); assert not is_X(wr_index) report "icache index invalid on write" severity FAILURE;
itlb_ptes(wr_index) <= m_in.pte; itlb_tags(to_integer(unsigned(wr_index))) <= m_in.addr(63 downto TLB_LG_PGSZ + TLB_BITS);
itlb_valids(wr_index) <= '1'; itlb_ptes(to_integer(unsigned(wr_index))) <= m_in.pte;
itlb_valids(to_integer(unsigned(wr_index))) <= '1';
end if; end if;
ev.itlb_miss_resolved <= m_in.tlbld and not rst; ev.itlb_miss_resolved <= m_in.tlbld and not rst;
end if; end if;
@ -503,9 +517,11 @@ begin
variable hit_way : way_t; variable hit_way : way_t;
begin begin
-- Extract line, row and tag from request -- Extract line, row and tag from request
req_index <= get_index(i_in.nia); if not is_X(i_in.nia) then
req_row <= get_row(i_in.nia); req_index <= get_index(i_in.nia);
req_tag <= get_tag(real_addr, i_in.big_endian); req_row <= get_row(i_in.nia);
end if;
req_tag <= get_tag(real_addr, i_in.big_endian);


-- Calculate address of beginning of cache row, will be -- Calculate address of beginning of cache row, will be
-- used for cache miss processing if needed -- used for cache miss processing if needed
@ -517,7 +533,11 @@ begin
hit_way := 0; hit_way := 0;
is_hit := '0'; is_hit := '0';
for i in way_t loop for i in way_t loop
if i_in.req = '1' and if is_X(i_in.nia) then
-- FIXME: This is fragile
-- req_index or req_row could be a metavalue
is_hit := 'X';
elsif i_in.req = '1' and
(cache_valids(req_index)(i) = '1' or (cache_valids(req_index)(i) = '1' or
(r.state = WAIT_ACK and (r.state = WAIT_ACK and
req_index = r.store_index and req_index = r.store_index and
@ -556,7 +576,7 @@ begin
-- some of the cache geometry information. -- some of the cache geometry information.
-- --
if r.hit_valid = '1' then if r.hit_valid = '1' then
i_out.insn <= read_insn_word(r.hit_nia, cache_out(r.hit_way)); i_out.insn <= read_insn_word(r.hit_nia, cache_out(r.hit_way));
else else
i_out.insn <= (others => '0'); i_out.insn <= (others => '0');
end if; end if;
@ -592,6 +612,8 @@ begin
r.hit_valid <= req_is_hit; r.hit_valid <= req_is_hit;
if req_is_hit = '1' then if req_is_hit = '1' then
r.hit_way <= req_hit_way; r.hit_way <= req_hit_way;
-- this is a bit fragile but better than propogating bad values
assert not is_X(i_in.nia) report "metavalue in NIA" severity FAILURE;


report "cache hit nia:" & to_hstring(i_in.nia) & report "cache hit nia:" & to_hstring(i_in.nia) &
" IR:" & std_ulogic'image(i_in.virt_mode) & " IR:" & std_ulogic'image(i_in.virt_mode) &
@ -648,6 +670,9 @@ begin
snoop_addr := addr_to_real(wb_to_addr(wb_snoop_in.adr)); snoop_addr := addr_to_real(wb_to_addr(wb_snoop_in.adr));
snoop_index <= get_index(snoop_addr); snoop_index <= get_index(snoop_addr);
snoop_cache_tags := cache_tags(get_index(snoop_addr)); snoop_cache_tags := cache_tags(get_index(snoop_addr));
if snoop_valid = '1' and is_X(snoop_addr) then
report "metavalue in snoop_addr" severity FAILURE;
end if;
snoop_tag := get_tag(snoop_addr, '0'); snoop_tag := get_tag(snoop_addr, '0');
snoop_hits <= (others => '0'); snoop_hits <= (others => '0');
for i in way_t loop for i in way_t loop

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