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/* ----------------------------------------------------------------------- *
*
* Copyright 2008 rPath, Inc. - All Rights Reserved
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom
* the Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall
* be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* ----------------------------------------------------------------------- */
/*
* reloc_linux.c
*
* This is the initial program run before the Linux kernel.
* It serves to hoist the initrd as high as permitted.
*
* This runs in protected mode, but in low memory, and should be kept
* as small as possible.
*/
#include "reloc/reloc.h"
#include "setup.h"
static uint32_t initrd_len, initrd_addr;
static uint64_t max_addr;
static int initrd_fit(uint32_t base, uint32_t end)
{
uint64_t ibase;
if (end <= base)
return -1; /* Invalid */
if (base > max_addr)
return -1; /* Not accessible */
if (end > max_addr)
end = max_addr;
if (end < initrd_len)
return -1;
ibase = (end - initrd_len) & ~0xfff;
if (ibase < base)
return -1;
if (initrd_addr < ibase) {
initrd_addr = ibase; /* This is a better one... */
}
return 0;
}
static int probe_memory_e820(void)
{
com32sys_t regs;
struct e820_info {
uint64_t base;
uint64_t len;
uint32_t type;
} buf;
int rv = -1;
uint32_t copied;
memset(®s, 0, sizeof regs);
do {
regs.eax.l = 0x0000e820;
regs.ecx.l = sizeof buf;
regs.edx.l = 0x534d4150;
regs.edi.w[0] = OFFS(&buf);
regs.es = SEG(&buf);
intcall(0x15, ®s, ®s);
copied = (regs.eflags.l & EFLAGS_CF)
? 0 : regs.ecx.l;
if ( regs.eax.l != 0x534d4150 || copied < 20 )
break;
if (buf.type != 1)
continue; /* Not memory */
rv &= initrd_fit(buf.base, buf.base+buf.len);
} while (regs.ebx.l);
return rv;
}
static int probe_memory_e801(void)
{
com32sys_t regs;
uint64_t end;
memset(®s, 0, sizeof regs);
regs.eax.w[0] = 0xe801;
intcall(0x15, ®s, ®s);
if (regs.eflags.l & EFLAGS_CF)
return -1; /* No e801 */
if (regs.eax.w[0] < 15*1024)
end = (uint64_t)(regs.eax.w[0] << 10) + 0x100000;
else
end = (uint64_t)(regs.ebx.w[0] << 16) + 0x1000000;
return initrd_fit(0x100000, end);
}
static int probe_memory_88(void)
{
com32sys_t regs;
memset(®s, 0, sizeof regs);
regs.eax.b[1] = 0x88;
intcall(0x15, ®s, ®s);
if (regs.eflags.l & EFLAGS_CF)
return -1;
return initrd_fit(0x100000, (regs.eax.w[0] << 10)+0x100000);
}
static int place_initrd(void)
{
int rv;
rv = probe_memory_e820();
if (!rv)
return 0;
rv = probe_memory_e801();
if (!rv)
return 0;
return probe_memory_88();
}
extern char _end[];
/* This structure is hacked by the installer */
static const struct startup_info startup_info
__attribute__((section(".startupinfo"))) =
{
.reloc_size = (uint32_t)&_end,
};
int main(void)
{
struct setup_header *hdr = (void *)(startup_info.setup_addr + 0x1f1);
if (startup_info.rd_len) {
initrd_len = startup_info.rd_len;
max_addr = startup_info.rd_maxaddr;
if (place_initrd())
return -1;
/* Move the initrd into place */
memmove((void *)initrd_addr, (void *)startup_info.rd_addr,
startup_info.rd_len);
hdr->ramdisk_image = initrd_addr;
}
jump_to_kernel(startup_info.setup_addr >> 4,
startup_info.cmdline_addr - startup_info.setup_addr);
return -1; /* Shouldn't return... */
}
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