MIPS VDSO is not built when using LLD #785
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[ARCH] mips
This bug impacts ARCH=mips
[BUG] linux
A bug that should be fixed in the mainline kernel.
[FIXED][LINUX] 5.8
This bug was fixed in Linux 5.8
[TOOL] lld
The issue is relevant to LLD linker
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tpimh
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[BUG] linux
|
samitolvanen@44939ce would solve this so we could just exclude this entire block if using LLD. |
nathanchance
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ld.lld errors out on malta_defconfig currently: ClangBuiltLinux/linux#785 That issue has been identified and a fix has been suggested: https://lore.kernel.org/linux-mips/20200404211252.3540251a@flygoat-x1e/ However, by switching to malta_kvm_guest_defconfig, we avoid that issue altogether because CONFIG_KVM_GUEST gets turned on, which makes the image have a different VMLINUX_LOAD_ADDRESS. As a result, we can turn on ld.lld for MIPS across all of our branches after switching to that config. Signed-off-by: Nathan Chancellor <[email protected]>
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ld.lld errors out on malta_defconfig currently: ClangBuiltLinux/linux#785 That issue has been identified and a fix has been suggested: https://lore.kernel.org/linux-mips/20200404211252.3540251a@flygoat-x1e/ However, by switching to malta_kvm_guest_defconfig, we avoid that issue altogether because CONFIG_KVM_GUEST gets turned on, which makes the image have a different VMLINUX_LOAD_ADDRESS. As a result, we can turn on ld.lld for MIPS across all of our branches after switching to that config. [skip ci] Presubmit: Signed-off-by: Nathan Chancellor <[email protected]>
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ld.lld errors out on malta_defconfig currently: ClangBuiltLinux/linux#785 That issue has been identified and a fix has been suggested: https://lore.kernel.org/linux-mips/20200404211252.3540251a@flygoat-x1e/ However, by switching to malta_kvm_guest_defconfig, we avoid that issue altogether because CONFIG_KVM_GUEST gets turned on, which makes the image have a different VMLINUX_LOAD_ADDRESS. As a result, we can turn on ld.lld for MIPS across all of our branches after switching to that config. [skip ci] Presubmit: https://travis-ci.com/github/nathanchance/continuous-integration/builds/158431604 Signed-off-by: Nathan Chancellor <[email protected]>
|
Patch sent: https://lore.kernel.org/lkml/[email protected]/ |
nathanchance
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[PATCH] Submitted
fengguang
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Apr 21, 2020
Currently, when linking with ld.lld, this warning pops up:
arch/mips/vdso/Makefile:70: MIPS VDSO requires binutils >= 2.25
ld-ifversion calls ld-version, which calls scripts/ld-version.sh, which
is specific to GNU ld. ld.lld has a completely different versioning
scheme (as it follows LLVM's versioning) and it does not have the issue
mentioned in the comment above this block so it should not be subjected
to this check.
With this patch, the VDSO successfully links and shows P_MIPS_PC32 in
vgettimeofday.o.
$ llvm-objdump -Dr arch/mips/vdso/vgettimeofday.o | grep R_MIPS_PC32
00000024: R_MIPS_PC32 _start
000000b0: R_MIPS_PC32 _start
000002bc: R_MIPS_PC32 _start
0000036c: R_MIPS_PC32 _start
00000468: R_MIPS_PC32 _start
Link: ClangBuiltLinux#785
Link: llvm/llvm-project@e364e2e
Reported-by: Dmitry Golovin <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
nickdesaulniers
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[PATCH] Accepted
ruscur
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Currently, the VDSO is being linked through $(CC). This does not match how the rest of the kernel links objects, which is through the $(LD) variable. When clang is built in a default configuration, it first attempts to use the target triple's default linker then the system's default linker, unless told otherwise through -fuse-ld=... We do not use -fuse-ld= because it can be brittle and we have support for invoking $(LD) directly. See commit fe00e50 ("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO") and commit 691efbe ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO") for examples of doing this in the VDSO. Do the same thing here. Replace the custom linking logic with $(cmd_ld) and ldflags-y so that $(LD) is respected. We need to explicitly add two flags to the linker that were implicitly passed by the compiler: -G 0 (which comes from ccflags-vdso) and --eh-frame-hdr. Before this patch (generated by adding '-v' to VDSO_LDFLAGS): <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/collect2 \ -plugin <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/liblto_plugin.so \ -plugin-opt=<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/lto-wrapper \ -plugin-opt=-fresolution=/tmp/ccGEi5Ka.res \ --eh-frame-hdr \ -G 0 \ -EB \ -mips64r2 \ -shared \ -melf64btsmip \ -o arch/mips/vdso/vdso.so.dbg.raw \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/64 \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0 \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/../../../../mips64-linux/lib \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o \ arch/mips/vdso/sigreturn.o After this patch: <gcc_prefix>/bin/mips64-linux-ld \ -m elf64btsmip \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ -nostdlib \ -shared \ -G 0 \ --eh-frame-hdr \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o arch/mips/vdso/sigreturn.o \ -o arch/mips/vdso/vdso.so.dbg.raw Note that we leave behind -mips64r2. Turns out that ld ignores it (see get_emulation in ld/ldmain.c). This is true of current trunk and 2.23, which is the minimum supported version for the kernel: https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=aa4209e7b679afd74a3860ce25659e71cc4847d5#l593 https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=a55e30b51bc6227d8d41f707654d0a5620978dcf#l641 Before this patch, LD=ld.lld did nothing: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] ClangBuiltLinux clang version 11.0.0 After this patch, it does: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] Linker: LLD 11.0.0 [ 62] ClangBuiltLinux clang version 11.0.0 Link: ClangBuiltLinux#785 Signed-off-by: Nathan Chancellor <[email protected]> Signed-off-by: Thomas Bogendoerfer <[email protected]>
ruscur
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Currently, when linking with ld.lld, this warning pops up:
arch/mips/vdso/Makefile:70: MIPS VDSO requires binutils >= 2.25
CONFIG_LD_VERSION is set with scripts/ld-version.sh, which is specific
to GNU ld. It returns 0 for ld.lld so CONFIG_MIPS_LD_CAN_LINK_VDSO does
not set.
ld.lld has a completely different versioning scheme (as it follows
LLVM's versioning) and it does not have the issue mentioned in the
comment block so it should be allowed to link the VDSO.
With this patch, the VDSO successfully links and shows P_MIPS_PC32 in
vgettimeofday.o.
$ llvm-objdump -Dr arch/mips/vdso/vgettimeofday.o | grep R_MIPS_PC32
00000024: R_MIPS_PC32 _start
000000b0: R_MIPS_PC32 _start
000002bc: R_MIPS_PC32 _start
0000036c: R_MIPS_PC32 _start
00000468: R_MIPS_PC32 _start
Reported-by: Dmitry Golovin <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Link: ClangBuiltLinux#785
Link: llvm/llvm-project@e364e2e
Signed-off-by: Thomas Bogendoerfer <[email protected]>
nathanchance
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May 17, 2020
The series to fix ClangBuiltLinux/linux#785 exposed an issue with ld.lld, which breaks the build. Move this target to ld.bfd while we discuss how to fix it so that this target is not blocked for testing. [skip ci] Link: ClangBuiltLinux/linux#1025 Presubmit: Signed-off-by: Nathan Chancellor <[email protected]>
nathanchance
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The series to fix ClangBuiltLinux/linux#785 exposed an issue with ld.lld, which breaks the build. Move this target to ld.bfd while we discuss how to fix it so that this target is not blocked for testing. [skip ci] Link: ClangBuiltLinux/linux#1025 Presubmit: https://travis-ci.com/github/nathanchance/continuous-integration/builds/166566747 Signed-off-by: Nathan Chancellor <[email protected]>
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That's not what we want... That regex lol. |
|
Series merged into mainline :) #1025 is still outstanding. |
nathanchance
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[FIXED][LINUX] 5.8
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If CONFIG_DEBUG_SHIRQ was enabled, r8a77951-salvator-xs could boot
correctly. If we appended "earlycon keep_bootcon" to the kernel
command like, we could get kernel log like below.
SError Interrupt on CPU0, code 0xbf000002 -- SError
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.8.0-rc3-salvator-x-00505-g6c843129e6faaf01 #785
Hardware name: Renesas Salvator-X 2nd version board based on r8a77951 (DT)
pstate: 60400085 (nZCv daIf +PAN -UAO BTYPE=--)
pc : rcar_gen3_phy_usb2_irq+0x14/0x54
lr : free_irq+0xf4/0x27c
This means free_irq() calls the interrupt handler while PM runtime
is not getting if DEBUG_SHIRQ is enabled and rcar_gen3_phy_usb2_probe()
failed. To fix the issue, move the irq registration place to
rcar_gen3_phy_usb2_init() which is ready to handle the interrupts.
Note that after the commit 549b6b5 ("phy: renesas: rcar-gen3-usb2:
enable/disable independent irqs") which is merged into v5.2, since this
driver creates multiple phy instances, needs to check whether one of
phy instances is initialized. However, if we backport this patch to v5.1
or less, we don't need to check it because such kernel have single
phy instance.
Reported-by: Wolfram Sang <[email protected]>
Reported-by: Geert Uytterhoeven <[email protected]>
Fixes: 9f391c5 ("phy: rcar-gen3-usb2: add runtime ID/VBUS pin detection")
Signed-off-by: Yoshihiro Shimoda <[email protected]>
Link: https://lore.kernel.org/r/1594986297-12434-2-git-send-email-yoshihiro.shimoda.uh@renesas.com
Signed-off-by: Vinod Koul <[email protected]>
Kendrenogen
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Currently, the VDSO is being linked through $(CC). This does not match how the rest of the kernel links objects, which is through the $(LD) variable. When clang is built in a default configuration, it first attempts to use the target triple's default linker then the system's default linker, unless told otherwise through -fuse-ld=... We do not use -fuse-ld= because it can be brittle and we have support for invoking $(LD) directly. See commit 46faaab ("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO") and commit 45ca7fb ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO") for examples of doing this in the VDSO. Do the same thing here. Replace the custom linking logic with $(cmd_ld) and ldflags-y so that $(LD) is respected. We need to explicitly add two flags to the linker that were implicitly passed by the compiler: -G 0 (which comes from ccflags-vdso) and --eh-frame-hdr. Before this patch (generated by adding '-v' to VDSO_LDFLAGS): <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/collect2 \ -plugin <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/liblto_plugin.so \ -plugin-opt=<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/lto-wrapper \ -plugin-opt=-fresolution=/tmp/ccGEi5Ka.res \ --eh-frame-hdr \ -G 0 \ -EB \ -mips64r2 \ -shared \ -melf64btsmip \ -o arch/mips/vdso/vdso.so.dbg.raw \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/64 \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0 \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/../../../../mips64-linux/lib \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o \ arch/mips/vdso/sigreturn.o After this patch: <gcc_prefix>/bin/mips64-linux-ld \ -m elf64btsmip \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ -nostdlib \ -shared \ -G 0 \ --eh-frame-hdr \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o arch/mips/vdso/sigreturn.o \ -o arch/mips/vdso/vdso.so.dbg.raw Note that we leave behind -mips64r2. Turns out that ld ignores it (see get_emulation in ld/ldmain.c). This is true of current trunk and 2.23, which is the minimum supported version for the kernel: https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=aa4209e7b679afd74a3860ce25659e71cc4847d5#l593 https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=a55e30b51bc6227d8d41f707654d0a5620978dcf#l641 Before this patch, LD=ld.lld did nothing: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] ClangBuiltLinux clang version 11.0.0 After this patch, it does: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] Linker: LLD 11.0.0 [ 62] ClangBuiltLinux clang version 11.0.0 Link: ClangBuiltLinux/linux#785 Signed-off-by: Nathan Chancellor <[email protected]> Signed-off-by: Thomas Bogendoerfer <[email protected]>
Kendrenogen
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Currently, the VDSO is being linked through $(CC). This does not match how the rest of the kernel links objects, which is through the $(LD) variable. When clang is built in a default configuration, it first attempts to use the target triple's default linker then the system's default linker, unless told otherwise through -fuse-ld=... We do not use -fuse-ld= because it can be brittle and we have support for invoking $(LD) directly. See commit 46faaab ("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO") and commit 45ca7fb ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO") for examples of doing this in the VDSO. Do the same thing here. Replace the custom linking logic with $(cmd_ld) and ldflags-y so that $(LD) is respected. We need to explicitly add two flags to the linker that were implicitly passed by the compiler: -G 0 (which comes from ccflags-vdso) and --eh-frame-hdr. Before this patch (generated by adding '-v' to VDSO_LDFLAGS): <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/collect2 \ -plugin <gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/liblto_plugin.so \ -plugin-opt=<gcc_prefix>/libexec/gcc/mips64-linux/9.3.0/lto-wrapper \ -plugin-opt=-fresolution=/tmp/ccGEi5Ka.res \ --eh-frame-hdr \ -G 0 \ -EB \ -mips64r2 \ -shared \ -melf64btsmip \ -o arch/mips/vdso/vdso.so.dbg.raw \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/64 \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0 \ -L<gcc_prefix>/lib/gcc/mips64-linux/9.3.0/../../../../mips64-linux/lib \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o \ arch/mips/vdso/sigreturn.o After this patch: <gcc_prefix>/bin/mips64-linux-ld \ -m elf64btsmip \ -Bsymbolic \ --no-undefined \ -soname=linux-vdso.so.1 \ -EB \ -nostdlib \ -shared \ -G 0 \ --eh-frame-hdr \ --hash-style=sysv \ --build-id \ -T arch/mips/vdso/vdso.lds \ arch/mips/vdso/elf.o \ arch/mips/vdso/vgettimeofday.o arch/mips/vdso/sigreturn.o \ -o arch/mips/vdso/vdso.so.dbg.raw Note that we leave behind -mips64r2. Turns out that ld ignores it (see get_emulation in ld/ldmain.c). This is true of current trunk and 2.23, which is the minimum supported version for the kernel: https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=aa4209e7b679afd74a3860ce25659e71cc4847d5#l593 https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=ld/ldmain.c;hb=a55e30b51bc6227d8d41f707654d0a5620978dcf#l641 Before this patch, LD=ld.lld did nothing: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] ClangBuiltLinux clang version 11.0.0 After this patch, it does: $ llvm-readelf -p.comment arch/mips/vdso/vdso.so.dbg | sed 's/(.*//' String dump of section '.comment': [ 0] Linker: LLD 11.0.0 [ 62] ClangBuiltLinux clang version 11.0.0 Link: ClangBuiltLinux/linux#785 Signed-off-by: Nathan Chancellor <[email protected]> Signed-off-by: Thomas Bogendoerfer <[email protected]>
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Currently, when linking with ld.lld, this warning pops up:
arch/mips/vdso/Makefile:70: MIPS VDSO requires binutils >= 2.25
CONFIG_LD_VERSION is set with scripts/ld-version.sh, which is specific
to GNU ld. It returns 0 for ld.lld so CONFIG_MIPS_LD_CAN_LINK_VDSO does
not set.
ld.lld has a completely different versioning scheme (as it follows
LLVM's versioning) and it does not have the issue mentioned in the
comment block so it should be allowed to link the VDSO.
With this patch, the VDSO successfully links and shows P_MIPS_PC32 in
vgettimeofday.o.
$ llvm-objdump -Dr arch/mips/vdso/vgettimeofday.o | grep R_MIPS_PC32
00000024: R_MIPS_PC32 _start
000000b0: R_MIPS_PC32 _start
000002bc: R_MIPS_PC32 _start
0000036c: R_MIPS_PC32 _start
00000468: R_MIPS_PC32 _start
Reported-by: Dmitry Golovin <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Link: ClangBuiltLinux/linux#785
Link: llvm/llvm-project@e364e2e
Signed-off-by: Thomas Bogendoerfer <[email protected]>
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When using lld to link MIPS kernel, the following warning is triggered:
With with this segment removed, VDSO is built:
linux/arch/mips/vdso/Makefile
Lines 50 to 66 in dcf78ee
R_MIPS_PC32 relocation is supported by LLD: https://reviews.llvm.org/rLLD259782.
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