Re: [PATCH] pc-bios/s390x: Pack ResetInfo struct

[Jason J. Herne]

On 2/7/20 6:28 AM, Christian Borntraeger wrote:
> Jason,
>
> can you run objdump -Sdr on jump2ipl.o on a broken variant?
To keep the volume lower, I've only pasted the output that I think you're interested in. 
If you want to see the entire thing just let me know.

static void jump_to_IPL_2(void)
{
 1d0:   eb bf f0 58 00 24       stmg    %r11,%r15,88(%r15)
 1d6:   a7 fb ff 50             aghi    %r15,-176
 1da:   b9 04 00 bf             lgr     %r11,%r15
    ResetInfo *current = 0;
 1de:   a7 19 00 00             lghi    %r1,0
 1e2:   e3 10 b0 a8 00 24       stg     %r1,168(%r11)

    void (*ipl)(void) = (void *) (uint64_t) current->ipl_continue;
 1e8:   e3 10 b0 a8 00 04       lg      %r1,168(%r11)
 1ee:   58 10 10 08             l       %r1,8(%r1)
 1f2:   b9 16 00 11             llgfr   %r1,%r1
 1f6:   e3 10 b0 a0 00 24       stg     %r1,160(%r11)
    *current = save;
 1fc:   e3 10 b0 a8 00 04       lg      %r1,168(%r11)
 202:   c0 20 00 00 00 00       larl    %r2,202 <jump_to_IPL_2+0x32>
                        204: R_390_PC32DBL      .bss+0x2
 208:   eb 23 20 00 00 04       lmg     %r2,%r3,0(%r2)
 20e:   eb 23 10 00 00 24       stmg    %r2,%r3,0(%r1)
    ipl(); /* should not return */
 214:   e3 10 b0 a0 00 04       lg      %r1,160(%r11)
 21a:   0d e1                   basr    %r14,%r1
}
 21c:   18 00                   lr      %r0,%r0
 21e:   eb bf b1 08 00 04       lmg     %r11,%r15,264(%r11)
 224:   07 fe                   br      %r14
 226:   07 07                   nopr    %r7

0000000000000228 <jump_to_IPL_code>:

void jump_to_IPL_code(uint64_t address)
{
 228:   eb bf f0 58 00 24       stmg    %r11,%r15,88(%r15)
 22e:   c0 d0 00 00 00 00       larl    %r13,22e <jump_to_IPL_code+0x6>
                        230: R_390_PC32DBL      .rodata+0x2a
 234:   a7 fb ff 50             aghi    %r15,-176
 238:   b9 04 00 bf             lgr     %r11,%r15
 23c:   e3 20 b0 a0 00 24       stg     %r2,160(%r11)
    /* store the subsystem information _after_ the bootmap was loaded */
    write_subsystem_identification();
 242:   c0 e5 00 00 00 00       brasl   %r14,242 <jump_to_IPL_code+0x1a>
                        244: R_390_PLT32DBL     
write_subsystem_identification+0x2

    /* prevent unknown IPL types in the guest */
    if (iplb.pbt == S390_IPL_TYPE_QEMU_SCSI) {
 248:   c0 10 00 00 00 00       larl    %r1,248 <jump_to_IPL_code+0x20>
                        24a: R_390_GOTENT       iplb+0x2
 24e:   e3 10 10 00 00 04       lg      %r1,0(%r1)
 254:   43 10 10 0c             ic      %r1,12(%r1)
 258:   a7 28 00 ff             lhi     %r2,255
 25c:   14 12                   nr      %r1,%r2
 25e:   a7 1e 00 ff             chi     %r1,255
 262:   a7 74 00 15             jne     28c <jump_to_IPL_code+0x64>
        iplb.pbt = S390_IPL_TYPE_CCW;
 266:   c0 10 00 00 00 00       larl    %r1,266 <jump_to_IPL_code+0x3e>
                        268: R_390_GOTENT       iplb+0x2
 26c:   e3 10 10 00 00 04       lg      %r1,0(%r1)
 272:   92 02 10 0c             mvi     12(%r1),2
        set_iplb(&iplb);
 276:   c0 10 00 00 00 00       larl    %r1,276 <jump_to_IPL_code+0x4e>
                        278: R_390_GOTENT       iplb+0x2
 27c:   e3 10 10 00 00 04       lg      %r1,0(%r1)
 282:   b9 04 00 21             lgr     %r2,%r1
 286:   c0 e5 ff ff ff 75       brasl   %r14,170 <set_iplb>
    /*
     * The IPL PSW is at address 0. We also must not overwrite the
     * content of non-BIOS memory after we loaded the guest, so we
     * save the original content and restore it in jump_to_IPL_2.
     */
    ResetInfo *current = 0;
 28c:   a7 19 00 00             lghi    %r1,0
 290:   e3 10 b0 a8 00 24       stg     %r1,168(%r11)

    save = *current;
 296:   c0 10 00 00 00 00       larl    %r1,296 <jump_to_IPL_code+0x6e>
                        298: R_390_PC32DBL      .bss+0x2
 29c:   e3 20 b0 a8 00 04       lg      %r2,168(%r11)
 2a2:   eb 23 20 00 00 04       lmg     %r2,%r3,0(%r2)
 2a8:   eb 23 10 00 00 24       stmg    %r2,%r3,0(%r1)

    current->ipl_psw = (uint64_t) &jump_to_IPL_2;
 2ae:   c0 20 ff ff ff 91       larl    %r2,1d0 <jump_to_IPL_2>
 2b4:   e3 10 b0 a8 00 04       lg      %r1,168(%r11)
 2ba:   e3 20 10 00 00 24       stg     %r2,0(%r1)
    current->ipl_psw |= RESET_PSW_MASK;
 2c0:   e3 10 b0 a8 00 04       lg      %r1,168(%r11)
 2c6:   e3 10 10 00 00 04       lg      %r1,0(%r1)
 2cc:   e3 20 d0 00 00 04       lg      %r2,0(%r13)
 2d2:   b9 81 00 21             ogr     %r2,%r1
 2d6:   e3 10 b0 a8 00 04       lg      %r1,168(%r11)
 2dc:   e3 20 10 00 00 24       stg     %r2,0(%r1)
    current->ipl_continue = address & 0x7fffffff;
 2e2:   e3 10 b0 a0 00 04       lg      %r1,160(%r11)
 2e8:   b9 17 00 21             llgtr   %r2,%r1
 2ec:   e3 10 b0 a8 00 04       lg      %r1,168(%r11)
 2f2:   50 20 10 08             st      %r2,8(%r1)

    debug_print_int("set IPL addr to", current->ipl_continue);
 2f6:   e3 10 b0 a8 00 04       lg      %r1,168(%r11)
 2fc:   58 10 10 08             l       %r1,8(%r1)
 300:   b9 16 00 11             llgfr   %r1,%r1
 304:   b9 04 00 31             lgr     %r3,%r1
 308:   c0 20 00 00 00 00       larl    %r2,308 <jump_to_IPL_code+0xe0>
                        30a: R_390_PC32DBL      .rodata+0x2
 30e:   c0 e5 ff ff ff 4d       brasl   %r14,1a8 <debug_print_int>

    /* Ensure the guest output starts fresh */
    sclp_print("\n");
 314:   c0 20 00 00 00 00       larl    %r2,314 <jump_to_IPL_code+0xec>
                        316: R_390_PC32DBL      .rodata+0x12
 31a:   c0 e5 00 00 00 00       brasl   %r14,31a <jump_to_IPL_code+0xf2>
                        31c: R_390_PLT32DBL     sclp_print+0x2
    /*
     * HACK ALERT.
     * We use the load normal reset to keep r15 unchanged. jump_to_IPL_2
     * can then use r15 as its stack pointer.
     */
    asm volatile("lghi 1,1\n\t"
 320:   a7 19 00 01             lghi    %r1,1
 324:   83 11 03 08             diag    %r1,%r1,776
                 "diag 1,1,0x308\n\t"
                 : : : "1", "memory");
    panic("\n! IPL returns !\n");
 328:   c0 20 00 00 00 00       larl    %r2,328 <jump_to_IPL_code+0x100>
                        32a: R_390_PC32DBL      .rodata+0x14
 32e:   c0 e5 00 00 00 00       brasl   %r14,32e <jump_to_IPL_code+0x106>
                        330: R_390_PLT32DBL     panic+0x2
}
 334:   18 00                   lr      %r0,%r0
 336:   eb bf b1 08 00 04       lmg     %r11,%r15,264(%r11)
 33c:   07 fe                   br      %r14
 33e:   07 07                   nopr    %r7



--
-- Jason J. Herne (address@hidden)