From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from AGRXSUSMAILB.smiths.aero (host241-chi.smiths-group.com [65.216.75.241]) by ozlabs.org (Postfix) with ESMTP id 20541DDDF5 for ; Wed, 18 Apr 2007 22:19:52 +1000 (EST) Message-ID: <46260CE3.7030503@smiths-aerospace.com> Date: Wed, 18 Apr 2007 08:19:47 -0400 From: Jerry Van Baren MIME-Version: 1.0 To: Jerry Van Baren , linuxppc-dev@ozlabs.org, jdl@jdl.com, david@gibson.dropbear.id.au Subject: Re: [PATCH: dtc] Improve -S handling References: <20070418020535.GA16224@dellserver.lan> <20070418030528.GA27758@localhost.localdomain> In-Reply-To: <20070418030528.GA27758@localhost.localdomain> Content-Type: text/plain; charset=ISO-8859-1; format=flowed List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , David Gibson wrote: > On Tue, Apr 17, 2007 at 10:05:35PM -0400, Jerry Van Baren wrote: >> If the user requests extra space, pad out the blob (previously the unused >> data was undefined). >> >> Signed-off-by: Gerald Van Baren >> --- >> >> Hi Jon, David, Milton, >> >> This improves the -S option to pad out the blob with zeros when the user >> asks for extra space. > > Comment below >> diff --git a/flattree.c b/flattree.c >> index 151d16e..d2ee0dc 100644 >> --- a/flattree.c >> +++ b/flattree.c >> @@ -310,6 +310,7 @@ static struct data flatten_reserve_list(struct reserve_info *reservelist, >> >> return d; >> } >> + >> static void make_bph(struct boot_param_header *bph, >> struct version_info *vi, >> int reservesize, int dtsize, int strsize, >> @@ -358,12 +359,15 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version, >> { >> struct version_info *vi = NULL; >> int i; >> + int size; >> struct data dtbuf = empty_data; >> struct data strbuf = empty_data; >> struct data reservebuf; >> struct boot_param_header bph; >> struct reserve_entry termre = {.address = 0, .size = 0}; >> >> + size = 0; >> + >> for (i = 0; i < ARRAY_SIZE(version_table); i++) { >> if (version_table[i].version == version) >> vi = &version_table[i]; >> @@ -384,10 +388,13 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version, >> boot_cpuid_phys); >> >> fwrite(&bph, vi->hdr_size, 1, f); >> + size += vi->hdr_size; >> >> /* Align the reserve map to an 8 byte boundary */ >> - for (i = vi->hdr_size; i < be32_to_cpu(bph.off_mem_rsvmap); i++) >> + for (i = vi->hdr_size; i < be32_to_cpu(bph.off_mem_rsvmap); i++) { >> fputc(0, f); >> + size += 1; >> + } >> >> /* >> * Reserve map entries. >> @@ -396,9 +403,27 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version, >> */ >> fwrite(reservebuf.val, reservebuf.len, 1, f); >> fwrite(&termre, sizeof(termre), 1, f); >> + size += reservebuf.len + sizeof(termre); >> >> fwrite(dtbuf.val, dtbuf.len, 1, f); >> fwrite(strbuf.val, strbuf.len, 1, f); >> + size += dtbuf.len + strbuf.len; >> + >> + /* >> + * If the user asked for more space than is used, pad it out. >> + */ >> + if (minsize > 0) { >> + int padlen = minsize - size; >> + >> + if (padlen > 0) { >> + char *zeroes = calloc(padlen, 1); >> + >> + if (zeroes != NULL) { >> + fwrite(zeroes, padlen, 1, f); >> + free(zeroes); >> + } >> + } >> + } > > Hrm, rather than all this explicit calloc() mangling, I'd prefer we > use our existing struct data stuff. Use data_append_zeroes() on > empty_data to generate your buffer of padding. > >> if (ferror(f)) >> die("Error writing device tree blob: %s\n", strerror(errno)); >> @@ -504,6 +529,14 @@ void dt_to_asm(FILE *f, struct boot_info *bi, int version, int boot_cpuid_phys) >> >> emit_label(f, symprefix, "blob_end"); >> >> + /* >> + * If the user asked for more space than is used, pad it out. >> + */ >> + if (minsize > 0) { >> + fprintf(f, "\t.space\t%d - (%s_blob_end - %s_blob_start), 0\n", >> + minsize, symprefix, symprefix); >> + } >> + >> data_free(strbuf); >> } Hi David, I started down the data_append_zeroes() path and had to back up and take the branch less traveled ;-). The problem is that data_append_zeros() appends the data to a "struct data" and I don't want to add zeros internally to any of the existing pieces parts since the extra space is external, not internal to the existing parts. I suppose I could create a new "struct data zeroes" and use data_append_zeroes() to create zeros in it, write that out, and then free it, but I fail to see how that is better than simply calloc()ing a bunch of zeros and writing _that_ out. Best regards, gvb P.S. David: I cannot send email to your dropbear.id.au address from home, one of our ISPs apparently has the other blackballed. I mention this just so you know I'm not intentionally cutting you out of the To: list.