Thanks for your response, Pedro.
I chased this as a toolchain bug originally, but concluded that the ADR indeed
works before GenFw rewrites it. But I see your point regarding the relocation
statement.
As requested, below is the disassembled function along with relocations. This
was generated from the dll using "aarch64-linux-gnu-objdump -r -D". The ADR in
question is at 2ffc.
This code was generated by the current version of the GCC 10.x toolchain on
Ubuntu20. So, if we're concluding this is a toolchain issue, then it's with a
fairly "stock" toolchain.
0000000000002fec <fdt_path_offset>:
2fec: a9b97bfd stp x29, x30, [sp, #-112]!
2ff0: 910003fd mov x29, sp
2ff4: a90363f7 stp x23, x24, [sp, #48]
2ff8: aa0003f8 mov x24, x0
2ffc: 10020020 adr x0, 7000 <_cont+0xe98>
2ffc: R_AARCH64_ADR_GOT_PAGE __stack_chk_guard
3000: a90153f3 stp x19, x20, [sp, #16]
3004: aa0103f3 mov x19, x1
3008: f946cc00 ldr x0, [x0, #3480]
3008: R_AARCH64_LD64_GOT_LO12_NC __stack_chk_guard
300c: a9025bf5 stp x21, x22, [sp, #32]
3010: a9046bf9 stp x25, x26, [sp, #64]
3014: f9002bfb str x27, [sp, #80]
3018: f9400001 ldr x1, [x0]
301c: f90037e1 str x1, [sp, #104]
3020: d2800001 mov x1, #0x0 // #0
3024: aa1303e0 mov x0, x19
3028: 97fffd04 bl 2438 <AsciiStrLen>
3028: R_AARCH64_CALL26 .text+0x1438
302c: aa0003f5 mov x21, x0
3030: aa1803e0 mov x0, x24
3034: 97fff807 bl 1050 <fdt_check_header>
3034: R_AARCH64_CALL26 .text+0x50
3038: 2a0003f4 mov w20, w0
303c: 35000260 cbnz w0, 3088 <fdt_path_offset+0x9c>
3040: 39400260 ldrb w0, [x19]
3044: 93407ea1 sxtw x1, w21
3048: 8b35c275 add x21, x19, w21, sxtw
304c: 7100bc1f cmp w0, #0x2f
3050: 54000420 b.eq 30d4 <fdt_path_offset+0xe8> // b.none
3054: 528005e2 mov w2, #0x2f // #47
3058: aa1303e0 mov x0, x19
305c: 97ffff2f bl 2d18 <ScanMem8>
305c: R_AARCH64_CALL26 .text+0x1d18
3060: f100001f cmp x0, #0x0
3064: 9a951016 csel x22, x0, x21, ne // ne = any
3068: f0000001 adrp x1, 6000 <__stack_chk_fail+0x7c>
3068: R_AARCH64_ADR_PREL_PG_HI21 .text+0x58b6
306c: 9122d821 add x1, x1, #0x8b6
306c: R_AARCH64_ADD_ABS_LO12_NC .text+0x58b6
3070: aa1803e0 mov x0, x24
3074: cb1302d4 sub x20, x22, x19
3078: 97ffffdd bl 2fec <fdt_path_offset>
307c: 2a0003e1 mov w1, w0
3080: 36f80140 tbz w0, #31, 30a8 <fdt_path_offset+0xbc>
3084: 12800094 mov w20, #0xfffffffb // #-5
3088: 90000020 adrp x0, 7000 <_cont+0xe98>
3088: R_AARCH64_ADR_GOT_PAGE __stack_chk_guard
308c: f946cc00 ldr x0, [x0, #3480]
308c: R_AARCH64_LD64_GOT_LO12_NC __stack_chk_guard
3090: f94037e1 ldr x1, [sp, #104]
3094: f9400002 ldr x2, [x0]
3098: eb020021 subs x1, x1, x2
309c: d2800002 mov x2, #0x0 // #0
30a0: 54000a00 b.eq 31e0 <fdt_path_offset+0x1f4> // b.none
30a4: 94000bb8 bl 5f84 <__stack_chk_fail>
30a4: R_AARCH64_CALL26 __stack_chk_fail
30a8: 2a1403e3 mov w3, w20
30ac: aa1303e2 mov x2, x19
30b0: aa1803e0 mov x0, x24
30b4: d2800004 mov x4, #0x0 // #0
30b8: 97ffff72 bl 2e80 <fdt_get_property_namelen>
30b8: R_AARCH64_CALL26 .text+0x1e80
30bc: b4fffe40 cbz x0, 3084 <fdt_path_offset+0x98>
30c0: 91003001 add x1, x0, #0xc
30c4: aa1603f3 mov x19, x22
30c8: aa1803e0 mov x0, x24
30cc: 97ffffc8 bl 2fec <fdt_path_offset>
30d0: 2a0003f4 mov w20, w0
30d4: 910193fa add x26, sp, #0x64
30d8: 14000037 b 31b4 <fdt_path_offset+0x1c8>
30dc: 910006d6 add x22, x22, #0x1
30e0: eb1602bf cmp x21, x22
30e4: 54fffd20 b.eq 3088 <fdt_path_offset+0x9c> // b.none
30e8: 394002c0 ldrb w0, [x22]
30ec: 7100bc1f cmp w0, #0x2f
30f0: 54ffff60 b.eq 30dc <fdt_path_offset+0xf0> // b.none
30f4: cb1602a1 sub x1, x21, x22
30f8: aa1603e0 mov x0, x22
30fc: 528005e2 mov w2, #0x2f // #47
3100: 97ffff06 bl 2d18 <ScanMem8>
3100: R_AARCH64_CALL26 .text+0x1d18
3104: f100001f cmp x0, #0x0
3108: 9a951013 csel x19, x0, x21, ne // ne = any
310c: aa1803e0 mov x0, x24
3110: 97fff7d0 bl 1050 <fdt_check_header>
3110: R_AARCH64_CALL26 .text+0x50
3114: 35000620 cbnz w0, 31d8 <fdt_path_offset+0x1ec>
3118: 4b160277 sub w23, w19, w22
311c: b90067ff str wzr, [sp, #100]
3120: 110006fb add w27, w23, #0x1
3124: 93407ef7 sxtw x23, w23
3128: b94067e0 ldr w0, [sp, #100]
312c: 7100029f cmp w20, #0x0
3130: 7a40a801 ccmp w0, #0x0, #0x1, ge // ge = tcont
3134: 5400008a b.ge 3144 <fdt_path_offset+0x158> // b.tcont
3138: 36f803c0 tbz w0, #31, 31b0 <fdt_path_offset+0x1c4>
313c: 12800014 mov w20, #0xffffffff // #-1
3140: 17ffffd2 b 3088 <fdt_path_offset+0x9c>
3144: 7100041f cmp w0, #0x1
3148: 540000e0 b.eq 3164 <fdt_path_offset+0x178> // b.none
314c: 2a1403e1 mov w1, w20
3150: aa1a03e2 mov x2, x26
3154: aa1803e0 mov x0, x24
3158: 97fff87c bl 1348 <fdt_next_node>
3158: R_AARCH64_CALL26 .text+0x348
315c: 2a0003f4 mov w20, w0
3160: 17fffff2 b 3128 <fdt_path_offset+0x13c>
3164: 2a1b03e2 mov w2, w27
3168: 11001281 add w1, w20, #0x4
316c: aa1803e0 mov x0, x24
3170: 97fff7da bl 10d8 <fdt_offset_ptr>
3170: R_AARCH64_CALL26 .text+0xd8
3174: aa0003f9 mov x25, x0
3178: b4fffea0 cbz x0, 314c <fdt_path_offset+0x160>
317c: f10002ff cmp x23, #0x0
3180: fa4012c4 ccmp x22, x0, #0x4, ne // ne = any
3184: 54000201 b.ne 31c4 <fdt_path_offset+0x1d8> // b.any
3188: 38776b20 ldrb w0, [x25, x23]
318c: 34000120 cbz w0, 31b0 <fdt_path_offset+0x1c4>
3190: aa1703e1 mov x1, x23
3194: aa1603e0 mov x0, x22
3198: 52800802 mov w2, #0x40 // #64
319c: 97fffedf bl 2d18 <ScanMem8>
319c: R_AARCH64_CALL26 .text+0x1d18
31a0: b5fffd60 cbnz x0, 314c <fdt_path_offset+0x160>
31a4: 38776b20 ldrb w0, [x25, x23]
31a8: 7101001f cmp w0, #0x40
31ac: 54fffd01 b.ne 314c <fdt_path_offset+0x160> // b.any
31b0: 37fff6d4 tbnz w20, #31, 3088 <fdt_path_offset+0x9c>
31b4: eb1302bf cmp x21, x19
31b8: 54fff689 b.ls 3088 <fdt_path_offset+0x9c> // b.plast
31bc: aa1303f6 mov x22, x19
31c0: 17ffffca b 30e8 <fdt_path_offset+0xfc>
31c4: aa1703e2 mov x2, x23
31c8: aa1603e1 mov x1, x22
31cc: 97fffef7 bl 2da8 <CompareMem.part.0>
31cc: R_AARCH64_CALL26 .text+0x1da8
31d0: 35fffbe0 cbnz w0, 314c <fdt_path_offset+0x160>
31d4: 17ffffed b 3188 <fdt_path_offset+0x19c>
31d8: 2a0003f4 mov w20, w0
31dc: 17fffff5 b 31b0 <fdt_path_offset+0x1c4>
31e0: 2a1403e0 mov w0, w20
31e4: a94153f3 ldp x19, x20, [sp, #16]
31e8: a9425bf5 ldp x21, x22, [sp, #32]
31ec: a94363f7 ldp x23, x24, [sp, #48]
31f0: a9446bf9 ldp x25, x26, [sp, #64]
31f4: f9402bfb ldr x27, [sp, #80]
31f8: a8c77bfd ldp x29, x30, [sp], #112
31fc: d65f03c0 ret
3200: 14000400 b 4200 <MmioWrite32.isra.0>
3204: d503201f nop
3208: f946cc00 ldr x0, [x0, #3480]
320c: 17ffff80 b 300c <fdt_path_offset+0x20>
Jake
________________________________
From: Pedro Falcato <pedro.falc...@gmail.com>
Sent: Thursday, October 26, 2023 2:46 PM
To: devel@edk2.groups.io <devel@edk2.groups.io>; Jake Garver <j...@nvidia.com>
Cc: rebe...@bsdio.com <rebe...@bsdio.com>; gaolim...@byosoft.com.cn
<gaolim...@byosoft.com.cn>; bob.c.f...@intel.com <bob.c.f...@intel.com>;
yuwei.c...@intel.com <yuwei.c...@intel.com>; ardb+tianoc...@kernel.org
<ardb+tianoc...@kernel.org>
Subject: Re: [edk2-devel] [PATCH] BaseTools/GenFw: Change opcode when
converting ADR to ADRP
External email: Use caution opening links or attachments
On Thu, Oct 26, 2023 at 4:32 PM Jake Garver via groups.io
<jake=nvidia....@groups.io> wrote:
>
> In the R_AARCH64_ADR_GOT_PAGE case on AARCH64, be sure to change the
> opcode to ADRP. Prior to this change, we updated the address, but not
> the opcode.
>
> This resolves an issue experienced when building a StandaloneMm image
> with stack protection enabled on GCC 10.5. This scenario generates an
> ADR where an ADRP is more common in other versions of GCC tested. That
> explains the obscurity of the issue. However, an ADR is valid and
> should be handled by GenFw.
Is this not a toolchain bug?
The aarch64 ELF ABI
(https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2FARM-software%2Fabi-aa%2Fblob%2Fmain%2Faaelf64%2Faaelf64.rst&data=05%7C01%7Cjake%40nvidia.com%7C607b433f7ddc40266e3c08dbd653f1c1%7C43083d15727340c1b7db39efd9ccc17a%7C0%7C0%7C638339428273243439%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=6DcbbXjY4UfjTwAUpd525B%2BvqPEWkZ1RStdc62%2F2er4%3D&reserved=0<https://github.com/ARM-software/abi-aa/blob/main/aaelf64/aaelf64.rst>)
says:
"Set the immediate value of an ADRP to bits [32:12] of X; check that
–232 <= X < 232"
So it mentions this relocation pointing *to an ADRP* specifically. And
AFAIK there's no way
Page(G(GDAT(S+A)))-Page(P)
would ever make sense if we're looking at an adr and not an adrp.
Can you post the full disassembly for the function, plus relevant relocations?
--
Pedro
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