From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Gibson Subject: Re: [PATCH] dtc: Basic cell expressions Date: Wed, 21 Mar 2012 15:00:36 +1100 Message-ID: <20120321040036.GD15997@truffala.fritz.box> References: <1332296951-19797-1-git-send-email-swarren@wwwdotorg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1332296951-19797-1-git-send-email-swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org To: Stephen Warren Cc: devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org List-Id: devicetree@vger.kernel.org On Tue, Mar 20, 2012 at 08:29:11PM -0600, Stephen Warren wrote: > Written by David Gibson . Ported to ToT > dtc by me. Added >> test. Commented a couple of failing tests. Thanks for doing this port. Some recommendations below, though. First, "cell expressions" was a term that made sense when I first wrote this, since cell lists which were always 32-bit were the only real use case. Since then, however, cell lists have become arrays and can have different sizes. So, I'd like to see pretty much a s/cell/integer/g change to this. > > Signed-off-by: Stephen Warren > --- > This is a port of David's cell expressions patch to ToT. It passes all > enabled tests, but a few fail and are commented out. > dtc-lexer.l | 9 +++ > dtc-parser.y | 119 +++++++++++++++++++++++++++++++++++++++++--- > tests/Makefile.tests | 3 +- > tests/cell-expressions.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++ > tests/run_tests.sh | 5 ++ > 5 files changed, 249 insertions(+), 10 deletions(-) > create mode 100644 tests/cell-expressions.c > > diff --git a/dtc-lexer.l b/dtc-lexer.l > index 73d190c..c7d31cc 100644 > --- a/dtc-lexer.l > +++ b/dtc-lexer.l > @@ -164,6 +164,15 @@ static int pop_input_file(void); > <*>{COMMENT}+ /* eat C-style comments */ > <*>{LINECOMMENT}+ /* eat C++-style comments */ > > +<*>"<<" { return DT_LSHIFT; }; > +<*>">>" { return DT_RSHIFT; }; > +<*>"<=" { return DT_LE; }; > +<*>">=" { return DT_GE; }; > +<*>"==" { return DT_EQ; }; > +<*>"!=" { return DT_NE; }; > +<*>"&&" { return DT_AND; }; > +<*>"||" { return DT_OR; }; > + > <*>. { > DPRINT("Char: %c (\\x%02x)\n", yytext[0], > (unsigned)yytext[0]); > diff --git a/dtc-parser.y b/dtc-parser.y > index 348616b..39bef4b 100644 > --- a/dtc-parser.y > +++ b/dtc-parser.y > @@ -56,10 +56,12 @@ static unsigned char eval_char_literal(const char *s); > struct node *node; > struct node *nodelist; > struct reserve_info *re; > + uint64_t cell; > } > > %token DT_V1 > %token DT_MEMRESERVE > +%token DT_LSHIFT DT_RSHIFT DT_LE DT_GE DT_EQ DT_NE DT_AND DT_OR > %token DT_BITS > %token DT_PROPNODENAME > %token DT_LITERAL > @@ -86,6 +88,21 @@ static unsigned char eval_char_literal(const char *s); > %type subnode > %type subnodes > > +%type cell_prim > +%type cell_unary > +%type cell_mul > +%type cell_add > +%type cell_shift > +%type cell_rela > +%type cell_eq > +%type cell_bitand > +%type cell_bitxor > +%type cell_bitor > +%type cell_and > +%type cell_or > +%type cell_trinary > +%type cell_expr > + > %% > > sourcefile: > @@ -267,17 +284,12 @@ arrayprefix: > $$.data = empty_data; > $$.bits = 32; > } > - | arrayprefix DT_LITERAL > - { > - uint64_t val = eval_literal($2, 0, $1.bits); > - > - $$.data = data_append_integer($1.data, val, $1.bits); > - } > - | arrayprefix DT_CHAR_LITERAL > + | arrayprefix cell_prim > { > - uint64_t val = eval_char_literal($2); > + if (($1.bits < 64) && ($2 >= (1ULL << $1.bits))) > + print_error("cell value out of range"); Ok, so all internal arithmetic in 64-bit, then an error if that leads to truncation here. Sounds reasonable, although I do worry slightly if people might expect wraparound arithmetic for 32-bit integers. Meh, it's easy enough for them to add an explicit mask. It is a little inconsistent that final step overflows are trapped, but overflows in intermediate steps are not. > - $$.data = data_append_integer($1.data, val, $1.bits); > + $$.data = data_append_integer($1.data, $2, $1.bits); > } > | arrayprefix DT_REF > { > @@ -299,6 +311,95 @@ arrayprefix: > } > ; > > +cell_prim: > + DT_LITERAL > + { > + $$ = eval_literal($1, 0, 64); > + } > + | DT_CHAR_LITERAL > + { > + $$ = eval_char_literal($1); > + } > + | '(' cell_expr ')' > + { > + $$ = $2; > + } > + ; > + > +cell_expr: > + cell_trinary > + ; > + > +cell_trinary: > + cell_or > + | cell_or '?' cell_expr ':' cell_trinary { $$ = $1 ? $3 : $5 } > + ; > + > +cell_or: > + cell_and > + | cell_or DT_OR cell_and { $$ = $1 || $3 }; > + ; > + > +cell_and: > + cell_bitor > + | cell_and DT_AND cell_bitor { $$ = $1 && $3 }; > + ; > + > +cell_bitor: > + cell_bitxor > + | cell_bitor '|' cell_bitxor { $$ = $1 | $3 }; > + ; > + > +cell_bitxor: > + cell_bitand > + | cell_bitxor '^' cell_bitand { $$ = $1 ^ $3 }; > + ; > + > +cell_bitand: > + cell_eq > + | cell_bitand '&' cell_eq { $$ = $1 & $3 }; > + ; > + > +cell_eq: > + cell_rela > + | cell_eq DT_EQ cell_rela { $$ = $1 == $3; } > + | cell_eq DT_NE cell_rela { $$ = $1 != $3; } > + ; > + > +cell_rela: > + cell_shift > + | cell_rela '<' cell_shift { $$ = $1 < $3; } > + | cell_rela '>' cell_shift { $$ = $1 > $3; } > + | cell_rela DT_LE cell_shift { $$ = $1 <= $3; } > + | cell_rela DT_GE cell_shift { $$ = $1 >= $3; } > + ; > + > +cell_shift: > + cell_shift DT_LSHIFT cell_add { $$ = $1 << $3; } > + | cell_shift DT_RSHIFT cell_add { $$ = $1 >> $3; } > + | cell_add > + ; > + > +cell_add: > + cell_add '+' cell_mul { $$ = $1 + $3; } > + | cell_add '-' cell_mul { $$ = $1 - $3; } > + | cell_mul > + ; > + > +cell_mul: > + cell_mul '*' cell_unary { $$ = $1 * $3; } > + | cell_mul '/' cell_unary { $$ = $1 / $3; } > + | cell_mul '%' cell_unary { $$ = $1 % $3; } > + | cell_unary > + ; > + > +cell_unary: > + cell_prim > + | '-' cell_unary { $$ = -$2; } > + | '~' cell_unary { $$ = ~$2; } > + | '!' cell_unary { $$ = !$2; } > + ; > + > bytestring: > /* empty */ > { > diff --git a/tests/Makefile.tests b/tests/Makefile.tests > index 2eee708..930d1a5 100644 > --- a/tests/Makefile.tests > +++ b/tests/Makefile.tests > @@ -19,7 +19,8 @@ LIB_TESTS_L = get_mem_rsv \ > dtbs_equal_ordered \ > dtb_reverse dtbs_equal_unordered \ > add_subnode_with_nops path_offset_aliases \ > - utilfdt_test > + utilfdt_test \ > + cell-expressions > LIB_TESTS = $(LIB_TESTS_L:%=$(TESTS_PREFIX)%) > > LIBTREE_TESTS_L = truncated_property > diff --git a/tests/cell-expressions.c b/tests/cell-expressions.c > new file mode 100644 > index 0000000..17b601a > --- /dev/null > +++ b/tests/cell-expressions.c > @@ -0,0 +1,123 @@ > +/* > + * libfdt - Flat Device Tree manipulation > + * Testcase for dtc expression support > + * Copyright (C) 2008 David Gibson, IBM Corporation. > + * > + * This library is free software; you can redistribute it and/or > + * modify it under the terms of the GNU Lesser General Public License > + * as published by the Free Software Foundation; either version 2.1 of > + * the License, or (at your option) any later version. > + * > + * This library is distributed in the hope that it will be useful, but > + * WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + * > + * You should have received a copy of the GNU Lesser General Public > + * License along with this library; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA > + */ > + > +#include > +#include > +#include > +#include > +#include > + > + > +#include > +#include > + > +#include "tests.h" > +#include "testdata.h" > + > +struct test_expr { > + const char *expr; > + uint32_t result; > +} expr_table[] = { > +#define TE(expr) { #expr, (expr) } > + TE(0xdeadbeef), > + // Fails: Probably because cell values can't be negative > + //TE(-0x21524111), So, the curly thing is, I think this would work if you specified 64-bit array elements. In the original, the idea was that although the cell values would be treated as unsigned, you could specify a signed value and the correct two's complement thing would go in. In your version the check for truncation when we cut the 64-bit intermediate down to 32-bits is defeating that. > + TE(1+1), > + TE(2*3), > + TE(4/2), > + TE(10/3), > + TE(19%4), > + TE(1 << 13), > + TE(0x1000 >> 4), > + TE(3*2+1), TE(3*(2+1)), > + TE(1+2*3), TE((1+2)*3), > + TE(1 < 2), TE(2 < 1), TE(1 < 1), > + TE(1 <= 2), TE(2 <= 1), TE(1 <= 1), > + TE(1 > 2), TE(2 > 1), TE(1 > 1), > + TE(1 >= 2), TE(2 >= 1), TE(1 >= 1), > + TE(1 == 1), TE(1 == 2), > + TE(1 != 1), TE(1 != 2),> + TE(0xabcdabcd & 0xffff0000), > + TE(0xdead4110 ^ 0xf0f0f0f0), > + TE(0xabcd0000 | 0x0000abcd), > + // Fails: Probably related to MSB being set implying negative? > + //TE(~0x21524110), Not exactly, it's the truncation thing again - the ~ sets the high 32-bits, which the truncation check then objects to. > + TE(~~0xdeadbeef), > + TE(0 && 0), TE(17 && 0), TE(0 && 17), TE(17 && 17), > + TE(0 || 0), TE(17 || 0), TE(0 || 17), TE(17 || 17), > + TE(!0), TE(!1), TE(!17), TE(!!0), TE(!!17), > + TE(0 ? 17 : 39), TE(1 ? 17 : 39), TE(17 ? 0xdeadbeef : 0xabcd1234), > + // Fails: > + // tests/cell-expressions.c:69:2: error: integer overflow in expression [-Werror=overflow] > + // Can be fixed by adding ULL to a constant below, but dtc doesn't > + // support that, so dtc errors out. > + //TE(11 * 257 * 1321517), Hrm, yes. Might be worth making dtc accept the C int literal suffixes, even if it basically ignores them. On a tangent, that reminds me of an argument for using actual cpp with hacks for the # problem, rather than our own preprocessor - it lets defines be easily shared between C and dts files in a big project. > + TE(123456790 - 4/2 + 17%4), > +}; > + > +#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) > + > +int main(int argc, char *argv[]) > +{ > + void *fdt; > + const uint32_t *res; > + int reslen; > + int i; > + > + test_init(argc, argv); > + > + if ((argc == 3) && (strcmp(argv[1], "-g") == 0)) { > + FILE *f = fopen(argv[2], "w"); > + > + if (!f) > + FAIL("Couldn't open \"%s\" for output: %s\n", > + argv[2], strerror(errno)); > + > + fprintf(f, "/dts-v1/;\n"); > + fprintf(f, "/ {\n"); > + fprintf(f, "\texpressions = <\n"); > + for (i = 0; i < ARRAY_SIZE(expr_table); i++) > + fprintf(f, "\t\t(%s)\n", expr_table[i].expr); > + fprintf(f, "\t>;\n"); > + fprintf(f, "};\n"); > + fclose(f); > + } else { > + fdt = load_blob_arg(argc, argv); > + > + res = fdt_getprop(fdt, 0, "expressions", &reslen); > + > + if (!res) > + FAIL("Error retreiving expression results: %s\n", > + fdt_strerror(reslen)); > + > + if (reslen != (ARRAY_SIZE(expr_table) * sizeof(uint32_t))) > + FAIL("Unexpected length of results %d instead of %ld\n", > + reslen, ARRAY_SIZE(expr_table) * sizeof(uint32_t)); > + > + for (i = 0; i < ARRAY_SIZE(expr_table); i++) > + if (fdt32_to_cpu(res[i]) != expr_table[i].result) > + FAIL("Incorrect result for expression \"%s\"," > + " 0x%x instead of 0x%x\n", > + expr_table[i].expr, fdt32_to_cpu(res[i]), > + expr_table[i].result); > + } > + > + PASS(); > +} > diff --git a/tests/run_tests.sh b/tests/run_tests.sh > index e470b82..16af5ee 100755 > --- a/tests/run_tests.sh > +++ b/tests/run_tests.sh > @@ -404,6 +404,11 @@ dtc_tests () { > run_dtc_test -I dtb -O dts -o stdin_odts_test_tree1.dtb.test.dts - < test_tree1.dtb > run_wrap_test cmp stdin_odts_test_tree1.dtb.test.dts odts_test_tree1.dtb.test.dts > > + # Check integer expresisons > + run_test cell-expressions -g cell-expressions.test.dts > + run_dtc_test -I dts -O dtb -o cell-expressions.test.dtb cell-expressions.test.dts > + run_test cell-expressions cell-expressions.test.dtb > + > # Check for graceful failure in some error conditions > run_sh_test dtc-fatal.sh -I dts -O dtb nosuchfile.dts > run_sh_test dtc-fatal.sh -I dtb -O dtb nosuchfile.dtb -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson