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sbl: b12 chain, slots, maze, stubs, docs current

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SashegDev
2026-09-07 13:35:39 +00:00
parent c7e95b4194
commit 7d57f138a5
2 changed files with 57 additions and 16 deletions
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qemu/saimaa.c
+32 -16
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@@ -290,42 +290,58 @@ static void saimaa_machine_init(MachineState *machine)
ARM_CPU(first_cpu)->env.cp15.nsacr |= (3u << 10);
ARM_CPU(first_cpu)->env.vfp.xregs[ARM_VFP_FPEXC] |= (1u << 30);
/* Boot scaffolding for SBL1 BringUp (WIP stub-driven PBL):
* pop-compensation stublets at 0x08062000 pin sp and route onward,
* so repeated pops always hit valid slots. */
* static continuation slots for shared-epilogue pops.
* sp advances linearly (no compensation); one slot per pop site.
* (sp values from cpu traces, b10 image) */
{
static const unsigned char stub_blob[] = { 0xf0, 0xb4, 0x2d, 0xe9, 0x00, 0x5f, 0xdf, 0xf8, 0x6c, 0xc0, 0xcd, 0xf8, 0x24, 0xc0, 0xdf, 0xf8, 0x68, 0xf0, 0x30, 0xb4, 0xdf, 0xf8, 0x64, 0xc0, 0xcd, 0xf8, 0x04, 0xc0, 0xdf, 0xf8, 0x60, 0xf0, 0xf0, 0xb4, 0x2d, 0xe9, 0x00, 0x5f, 0xdf, 0xf8, 0x5c, 0xc0, 0xcd, 0xf8, 0x24, 0xc0, 0xdf, 0xf8, 0x58, 0xf0, 0xf0, 0xb5, 0x01, 0xb4, 0xdf, 0xf8, 0x54, 0xc0, 0xcd, 0xf8, 0x14, 0xc0, 0xdf, 0xf8, 0x50, 0xf0, 0xf0, 0xb4, 0x2d, 0xe9, 0x00, 0x5f, 0xdf, 0xf8, 0x48, 0xc0, 0xcd, 0xf8, 0x24, 0xc0, 0xdf, 0xf8, 0x44, 0xf0, 0xf0, 0xb5, 0x01, 0xb4, 0xdf, 0xf8, 0x40, 0xc0, 0xcd, 0xf8, 0x14, 0xc0, 0xdf, 0xf8, 0x3c, 0xf0, 0xf0, 0xb5, 0x07, 0xb4, 0xdf, 0xf8, 0x38, 0xc0, 0xcd, 0xf8, 0x1c, 0xc0, 0xdf, 0xf8, 0x34, 0xf0, 0x01, 0x20, 0x06, 0x08, 0x5d, 0xf6, 0x02, 0x08, 0x13, 0x20, 0x06, 0x08, 0x65, 0xf6, 0x02, 0x08, 0x21, 0x20, 0x06, 0x08, 0xa5, 0x3b, 0x01, 0x08, 0x43, 0x20, 0x06, 0x08, 0x81, 0xf6, 0x02, 0x08, 0x33, 0x20, 0x06, 0x08, 0x83, 0x61, 0x01, 0x08, 0x55, 0x20, 0x06, 0x08, 0x8d, 0x8a, 0x01, 0x08, 0x65, 0x20, 0x06, 0x08, 0x7d, 0xf6, 0x02, 0x08 };
uint32_t magic = 0x00000000; /* IMEM poll spins WHILE equal */
uint32_t S = 0x08062100, STUB = 0x08062120;
uint32_t w;
uint16_t h0 = 0x2000, h1 = 0x4770; /* movs r0,#0; bx lr */
size_t k;
uint32_t v;
for (k = 0; k < sizeof(stub_blob); k += 4) {
uint32_t word;
__builtin_memcpy(&word, &stub_blob[k], 4);
cpu_physical_memory_write(0x08062000 + k, &word, 4);
}
/* pointer maze in owned RAM for SBL1 struct chains */
w = S + 8;
cpu_physical_memory_write(S, &w, 4);
cpu_physical_memory_write(S + 8, &STUB, 4);
cpu_physical_memory_write(STUB, &h0, 2);
cpu_physical_memory_write(STUB + 2, &h1, 2);
cpu_physical_memory_write(STUB + 4, &STUB, 4);
cpu_physical_memory_write(0x087c29d18, &S, 4);
cpu_physical_memory_write(0x08050b28, &S, 4);
cpu_physical_memory_write(0x08070000, &S, 4);
/* stack zone defaults to plain-stub addr: every register
* popped from untouched stack becomes callable (returns 0). */
{
uint32_t fill = 0x08062121;
uint32_t a;
for (a = 0x085F0000; a < 0x08600000; a += 4) {
cpu_physical_memory_write(a, &fill, 4);
}
}
/* pop-site slots -> stublets (sp values from cpu traces) */
v = 0x08062001; /* S1 pop10 */
v = 0x802f65d; /* S1 pop10 @fef0: resume sbl_main */
cpu_physical_memory_write(0x085FFF14, &v, 4);
v = 0x08062013; /* S2 pop2 */
v = 0x802f665; /* S2 pop2 @ff18: walker site (NOP) */
cpu_physical_memory_write(0x085FFF1C, &v, 4);
v = 0x08062021; /* S3 pop10 */
v = 0x8013ba5; /* S3 pop10 @ff20: 0x8013b7c loop */
cpu_physical_memory_write(0x085FFF44, &v, 4);
cpu_physical_memory_write(0x085FFF7C, &v, 4);
v = 0x08062033; /* S4 pop6 (stublet chains S5) */
cpu_physical_memory_write(0x085FFF34, &v, 4);
v = 0x802f681; /* S4 pop6 @ff48: back to sbl_main */
cpu_physical_memory_write(0x085FFF5C, &v, 4);
v = 0x8016183; /* S5 pop10 @ff50: 0x8013ae4 caller */
cpu_physical_memory_write(0x085FFF74, &v, 4);
{ /* words that popped regs must read as 0 (not stub-fill) */
uint32_t z = 0;
cpu_physical_memory_write(0x085FFF58, &z, 4); /* r7 src */
}
{ /* installer-path slots + zero words */
uint32_t z = 0;
uint32_t z2 = 0;
cpu_physical_memory_write(0x085FFF34, &z2, 4); /* S3 r7 */
cpu_physical_memory_write(0x085FFF54, &z2, 4);
cpu_physical_memory_write(0x085FFF6C, &z, 4); /* r7 src */
}
cpu_physical_memory_write(0x08600944, &magic, 4);
printf("saimaa: stub-scaffold live\n");
printf("saimaa: slots live\n");
}
printf("saimaa: SBL1 %s loaded (%zd bytes), entry 0x%lx\n",
sms->sbl1, sz, (unsigned long)entry);