Date: Thu, 17 Feb 2011 01:52:11 +0000 From: Alexander Best <arundel@freebsd.org> To: Warner Losh <imp@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r218745 - head/sys/boot/i386/boot2 Message-ID: <20110217015211.GA67933@freebsd.org> In-Reply-To: <201102161805.p1GI5ABX078768@svn.freebsd.org> References: <201102161805.p1GI5ABX078768@svn.freebsd.org>
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--SUOF0GtieIMvvwua Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed Feb 16 11, Warner Losh wrote: > Author: imp > Date: Wed Feb 16 18:05:10 2011 > New Revision: 218745 > URL: http://svn.freebsd.org/changeset/base/218745 > > Log: > Remove reading of symbols from a.out loaded files. Since we are tight > on space for clang and a.out support is only needed for /boot/loader, > they are excess bytes that serve no useful purpose other than to > support really old kernels (FreeBSD < 3.2 or so). Prefer clang > support over support for these old kernels and remove this code. We > gain about 100 bytes of space this way. sorry for my crappy previous attempt to reduce boot2's size. obviously the *.S files aren't the problem, because even with clang we're using GAS. so working on boot2.c is the only way of reducing the size. i've managed to do so (even with another 4 bytes to spare) with the attached patch. i did otaku% grep -r bi_basemem * sys/boot/i386/boot2/boot2.c: bootinfo.bi_basemem = 0; /* XXX will be filled by loader or kernel */ sys/boot/i386/boot2/machine/bootinfo.h: u_int32_t bi_basemem; sys/boot/i386/gptboot/gptboot.c: bootinfo.bi_basemem = 0; /* XXX will be filled by loader or kernel */ sys/boot/i386/libi386/bootinfo32.c: bi.bi_basemem = bios_basemem / 1024; sys/boot/i386/loader/main.c: initial_bootinfo->bi_basemem = bios_basemem / 1024; sys/boot/i386/zfsboot/zfsboot.c: bootinfo.bi_basemem = bios_basemem / 1024; sys/boot/pc98/boot2/boot2.c: bootinfo.bi_basemem = 0; /* XXX will be filled by loader or kernel */ sys/boot/pc98/loader/main.c: initial_bootinfo->bi_basemem = bios_basemem / 1024; sys/i386/include/bootinfo.h: u_int32_t bi_basemem; sys/mips/include/bootinfo.h: u_int32_t bi_basemem; which led me to the conclusion that bootinfo.bi_basemem doesn't need to initialised, because it will always be set by the loader (as the XXX comment says). turning ioctrl from uint8_t to int also saves a few bytes for whatever reason). removing x doesn't save any bytes, but gets rid of a warning (as noted in one of my messages). cheers. alex ...and sorry for the previous noise. :( > > Reviewed by: rdivacky@ > > Modified: > head/sys/boot/i386/boot2/boot2.c > > Modified: head/sys/boot/i386/boot2/boot2.c > ============================================================================== > --- head/sys/boot/i386/boot2/boot2.c Wed Feb 16 17:50:21 2011 (r218744) > +++ head/sys/boot/i386/boot2/boot2.c Wed Feb 16 18:05:10 2011 (r218745) > @@ -347,23 +347,6 @@ load(void) > p += roundup2(hdr.ex.a_text, PAGE_SIZE); > if (xfsread(ino, p, hdr.ex.a_data)) > return; > - p += hdr.ex.a_data + roundup2(hdr.ex.a_bss, PAGE_SIZE); > - bootinfo.bi_symtab = VTOP(p); > - *(uint32_t*)p = hdr.ex.a_syms; > - p += sizeof(hdr.ex.a_syms); > - if (hdr.ex.a_syms) { > - if (xfsread(ino, p, hdr.ex.a_syms)) > - return; > - p += hdr.ex.a_syms; > - if (xfsread(ino, p, sizeof(int))) > - return; > - x = *(uint32_t *)p; > - p += sizeof(int); > - x -= sizeof(int); > - if (xfsread(ino, p, x)) > - return; > - p += x; > - } > } else { > fs_off = hdr.eh.e_phoff; > for (j = i = 0; i < hdr.eh.e_phnum && j < 2; i++) { > @@ -395,8 +378,8 @@ load(void) > } > } > addr = hdr.eh.e_entry & 0xffffff; > + bootinfo.bi_esymtab = VTOP(p); > } > - bootinfo.bi_esymtab = VTOP(p); > bootinfo.bi_kernelname = VTOP(kname); > bootinfo.bi_bios_dev = dsk.drive; > __exec((caddr_t)addr, RB_BOOTINFO | (opts & RBX_MASK), -- a13x --SUOF0GtieIMvvwua Content-Type: text/plain; charset=us-ascii Content-Disposition: attachment; filename="boot2.c.diff" diff --git a/sys/boot/i386/boot2/boot2.c b/sys/boot/i386/boot2/boot2.c index 3849725..d572700 100644 --- a/sys/boot/i386/boot2/boot2.c +++ b/sys/boot/i386/boot2/boot2.c @@ -135,7 +135,7 @@ static char kname[1024]; static uint16_t opts; static int comspeed = SIOSPD; static struct bootinfo bootinfo; -static uint8_t ioctrl = IO_KEYBOARD; +static int ioctrl = IO_KEYBOARD; void exit(int); static void load(void); @@ -245,7 +245,7 @@ main(void) dsk.slice = *(uint8_t *)PTOV(ARGS + 1) + 1; bootinfo.bi_version = BOOTINFO_VERSION; bootinfo.bi_size = sizeof(bootinfo); - bootinfo.bi_basemem = 0; /* XXX will be filled by loader or kernel */ + /* bootinfo.bi_basemem = 0; XXX will be filled by loader or kernel */ bootinfo.bi_extmem = memsize(); bootinfo.bi_memsizes_valid++; @@ -319,7 +319,7 @@ load(void) static Elf32_Shdr es[2]; caddr_t p; ino_t ino; - uint32_t addr, x; + uint32_t addr; int i, j; uint8_t fmt; --SUOF0GtieIMvvwua--
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