int syslinux_shuffle_boot_pm(struct syslinux_movelist *fraglist,
struct syslinux_memmap *memmap,
uint16_t bootflags,
struct syslinux_pm_regs *regs)
{
int nd;
com32sys_t ireg;
char *regbuf;
uint8_t handoff_code[9*5], *p;
const uint32_t *rp;
int i, rv;
struct syslinux_memmap *tmap;
addr_t regstub, stublen, safe;
tmap = syslinux_target_memmap(fraglist, memmap);
if (!tmap)
return -1;
regstub = 0x800; /* Locate anywhere above this point */
stublen = sizeof handoff_code;
rv = syslinux_memmap_find(tmap, SMT_FREE, ®stub, &stublen, 1);
syslinux_free_memmap(tmap);
if (rv)
return -1;
/* Build register-setting stub */
p = handoff_code;
rp = (const uint32_t *)regs;
for (i = 0; i < 8; i++) {
*p = 0xb8 + i; /* MOV gpr,imm32 */
*(uint32_t *)(p+1) = *rp++;
p += 5;
}
*p = 0xe9; /* JMP */
*(uint32_t *)(p+1) = regs->eip - regstub - sizeof handoff_code;
/* Add register-setting stub to shuffle list */
if (syslinux_add_movelist(&fraglist, regstub, (addr_t)handoff_code,
sizeof handoff_code))
return -1;
return syslinux_do_shuffle(fraglist, memmap, regstub, 1, bootflags);
}
int syslinux_shuffle_boot_rm(struct syslinux_movelist *fraglist,
struct syslinux_memmap *memmap,
uint16_t bootflags, struct syslinux_rm_regs *regs)
{
const struct syslinux_rm_regs_alt {
uint16_t seg[6];
uint32_t gpr[8];
uint32_t csip;
bool sti;
} *rp;
int i, rv;
uint8_t handoff_code[8 + 5 * 5 + 8 * 6 + 1 + 5], *p;
uint16_t off;
struct syslinux_memmap *tmap;
addr_t regstub, stublen;
/* Assign GPRs for each sreg, don't use AX and SP */
static const uint8_t gpr_for_seg[6] =
{ R_CX, R_DX, R_BX, R_BP, R_SI, R_DI };
tmap = syslinux_target_memmap(fraglist, memmap);
if (!tmap)
return -1;
/*
* Search for a good place to put the real-mode register stub.
* We prefer it as low as possible above 0x800. KVM barfs horribly
* if we're not aligned to a paragraph boundary, so set the alignment
* appropriately.
*/
regstub = 0x800;
stublen = sizeof handoff_code;
rv = syslinux_memmap_find_type(tmap, SMT_FREE, ®stub, &stublen, 16);
if (rv || (regstub > 0x100000 - sizeof handoff_code)) {
/*
* Uh-oh. This isn't real-mode accessible memory.
* It might be possible to do something insane here like
* putting the stub in the IRQ vectors, or in the 0x5xx segment.
* This code tries the 0x510-0x7ff range and hopes for the best.
*/
regstub = 0x510; /* Try the 0x5xx segment... */
stublen = sizeof handoff_code;
rv = syslinux_memmap_find_type(tmap, SMT_FREE, ®stub, &stublen, 16);
if (!rv && (regstub > 0x100000 - sizeof handoff_code))
rv = -1; /* No acceptable memory found */
}
syslinux_free_memmap(tmap);
if (rv)
return -1;
/* Build register-setting stub */
p = handoff_code;
rp = (const struct syslinux_rm_regs_alt *)regs;
/* Set up GPRs with segment registers - don't use AX */
for (i = 0; i < 6; i++) {
if (i != R_CS)
MOV_TO_R16(p, gpr_for_seg[i], rp->seg[i]);
}
/* Actual transition to real mode */
ST32(p, 0xeac0220f); /* MOV CR0,EAX; JMP FAR */
off = (p - handoff_code) + 4;
ST16(p, off); /* Offset */
ST16(p, regstub >> 4); /* Segment */
/* Load SS and ESP immediately */
MOV_TO_SEG(p, R_SS, R_BX);
MOV_TO_R32(p, R_SP, rp->gpr[R_SP]);
/* Load the other segments */
MOV_TO_SEG(p, R_ES, R_CX);
MOV_TO_SEG(p, R_DS, R_BP);
MOV_TO_SEG(p, R_FS, R_SI);
MOV_TO_SEG(p, R_GS, R_DI);
for (i = 0; i < 8; i++) {
if (i != R_SP)
MOV_TO_R32(p, i, rp->gpr[i]);
}
ST8(p, rp->sti ? 0xfb : 0xfa); /* STI/CLI */
ST8(p, 0xea); /* JMP FAR */
ST32(p, rp->csip);
/* Add register-setting stub to shuffle list */
if (syslinux_add_movelist(&fraglist, regstub, (addr_t) handoff_code,
sizeof handoff_code))
return -1;
return syslinux_do_shuffle(fraglist, memmap, regstub, 0, bootflags);
}
