diff --git a/docs/sbl-bringup.md b/docs/sbl-bringup.md index a4c362f..1163a99 100644 --- a/docs/sbl-bringup.md +++ b/docs/sbl-bringup.md @@ -125,3 +125,5 @@ - Poll-fn `0x8007748`: `cbz r6` (r6=2 константа caller'а, никогда 0) → вечный re-init (`movs r4,#0`, table loop) вместо poll#2-direct. Патч 2B→2B в `b`. Биты 0,1,2 `[0x73A100]` pref-set (scaffold). +- S16v3: `add sp,#8` перед `bx ip` (снимает helper-фрейм, пропущенный + B66 — un-leak стека вниз). diff --git a/qemu/saimaa.c b/qemu/saimaa.c index 057d69d..066b380 100644 --- a/qemu/saimaa.c +++ b/qemu/saimaa.c @@ -751,18 +751,20 @@ static void saimaa_machine_init(MachineState *machine) cpu_physical_memory_write(0x08006964 + k, &word, 4); } } - /* S16-stublet (b25, 44B @0x08006CC0): smart return for the - * B66 bx-ip chain. ip odd + top 8 (code) => bx ip (legit - * pushed-lr return); else default (restore r7, jump poll + /* S16-stublet (b27, 50B @0x08006CC0): smart return for the + * B66 bx-ip chain. ip odd + top 8 => add sp,#8 (pop the + * helper frame B66 skipped!) + bx ip (legit pushed-lr, + * un-leaks the stack); else default (restore r7, jump poll * resumption 0x8007779 via ip). */ { static const uint8_t s16[] = { - 0x1c, 0xf0, 0x01, 0x0f, 0x09, 0xd0, 0x5f, 0xea, - 0x1c, 0x63, 0x08, 0x2b, 0x00, 0xd1, 0x60, 0x47, - 0x5f, 0xea, 0x1c, 0x73, 0x08, 0x2b, 0x00, 0xd1, - 0x60, 0x47, 0x4a, 0xf2, 0x00, 0x07, 0xc0, 0xf2, - 0x73, 0x07, 0x47, 0xf2, 0x79, 0x7c, 0xc0, 0xf6, - 0x00, 0x08, 0xc0, 0x47, + 0xdd, 0xf8, 0x04, 0xc0, 0x1c, 0xf0, 0x01, 0x0f, + 0x0b, 0xd0, 0x5f, 0xea, 0x1c, 0x63, 0x08, 0x2b, + 0x00, 0xd1, 0x02, 0xb0, 0x60, 0x47, 0x5f, 0xea, + 0x1c, 0x73, 0x08, 0x2b, 0x00, 0xd1, 0x60, 0x47, + 0x4a, 0xf2, 0x00, 0x07, 0xc0, 0xf2, 0x73, 0x07, + 0x47, 0xf2, 0x79, 0x7c, 0xc0, 0xf6, 0x00, 0x0c, + 0x60, 0x47, }; size_t k; for (k = 0; k < sizeof(s16); k += 4) { diff --git a/tools/sbl_uni.py b/tools/sbl_uni.py index 202c605..a5228b5 100644 --- a/tools/sbl_uni.py +++ b/tools/sbl_uni.py @@ -393,12 +393,14 @@ def main(): mu.mem_write(0x08006964, bytes.fromhex( "04c09de50c309fe5002093e5022082e3002083e51eff2fe1" "00a17300")) - # S16-stublet (b25, 44B @0x08006CC0): smart return for B66 bx ip. - # ip odd + top 8 (DDRLOW/DDRHIGH code) => bx ip (legit pushed-lr - # return); else default (restore r7, jump poll resumption 0x8007779). + # S16-stublet (b27, 50B @0x08006CC0): smart return for B66 bx ip. + # ip odd + top 8 (code) => add sp,#8 (pop the helper frame it + # skipped!) + bx ip (legit pushed-lr return, un-leaks the stack); + # else default (restore r7, jump poll resumption 0x8007779). mu.mem_write(0x08006CC0, bytes.fromhex( - "1cf0010f09d05fea1c63082b00d160475fea1c73082b00d" - "160474af20007c0f2730747f2797cc0f6000c6047")) + "ddf804c01cf0010f0bd05fea1c63082b00d102b06047" + "5fea1c73082b00d160474af20007c0f2730747f2797c" + "c0f6000c6047")) # stack zone fill (STUBV odd) mu.mem_write(0x085F0000, struct.pack("