On Wed, Mar 08, 2023 at 05:12:26AM +0100, Heinrich Schuchardt wrote: > Hello Ilias, hello Tom, > > Tom tried to run qemu_arm_defconfig with CONFIG_LTO=y in gitlab. This > failed as shown in protocol > https://source.denx.de/u-boot/u-boot/-/jobs/589913/raw > > Executing 'HII database protocols' > test_hii_database_new_package_list: > data abort > pc : [<7ff39b98>] lr : [<7ff87328>] > reloc pc : [<00000b98>] lr : [<0004e328>] > sp : 7edf8cc0 ip : 0000000c fp : 7ffe60ec > r10: 00000000 r9 : 7eef8eb0 r8 : 7ffe0d02 > r7 : 00000000 r6 : 7ef0f8c8 r5 : 7ffe0cf0 r4 : 7ffe0cb4 > r3 : 7ffe0cef r2 : 00000000 r1 : ffffffff r0 : 00000000 > Flags: nzcv IRQs off FIQs off Mode SVC_32 > Code: e2403002 e3a00000 e1500001 012fff1e (e1f320b2) > UEFI image [0x00000000:0xffffffff] '/\selftest' > Resetting CPU .. > > Debugging shows: > > efi_hii_sibt_string_ucs2_block_next() calls u16_strnlen() for an > unaligned u16 string. Here "ldrh r2, [r3, #2]!" is executed for > unaligned r3. This should be allowable for SCTLR.A = 0. > > When the crash occurs SCRLR has value 0xc5187f. SCTLR.A is bit 1 with > value 1. > > The implementation of allow_unaligned() in > arch/arm/cpu/armv7 /sctlr.S should have set the flag to 0. > arch/arm/cpu/armv7/sctlr.S is compiled (as demonstrated by adding #error > to the code). > > If I remove the weak implementation of allow_unaligned() in > lib/efi_loader/efi_setup.c, the error does not occur. > > Shouldn't building with LTO ignore the weak implementation? > > If I add a printf() statement to the weak implemenation, the printf() > command is not executed but > > SCTLR 0xc5187d, SCTLR.A=0 > > The test passes as unaligned access is allowable. > > I was building inside the Docker image with the GCC downloaded by > buildman (gcc-12.2.0-nolibc/arm-linux-gnueabi). > > To me this looks like a compiler issue.
Interesting, yes. It seems like it shouldn't be too hard to come up with a condensed example where the assembly function isn't used but instead the weak C function is. And as a work-around, re-doing the code so that path_to_uefi() just checks for ARM && !ARM64 before calling allow_unaligned() and not doing the weak function trick should also be fine. -- Tom
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