* [PATCH v2 0/2] Link the PowerPC vDSO with ld.lld
@ 2022-05-11 18:49 ` Nathan Chancellor
0 siblings, 0 replies; 8+ messages in thread
From: Nathan Chancellor @ 2022-05-11 18:49 UTC (permalink / raw)
To: Michael Ellerman
Cc: Benjamin Herrenschmidt, Paul Mackerras, Christophe Leroy,
Alexey Kardashevskiy, Nick Desaulniers, Tom Rix, linuxppc-dev,
llvm, patches, Nathan Chancellor
Hi all,
This series is an alternative to the one proposed by Nick before the
PowerPC vDSO unification in commit fd1feade75fb ("powerpc/vdso: Merge
vdso64 and vdso32 into a single directory"):
https://lore.kernel.org/20200901222523.1941988-1-ndesaulniers@google.com/
Normally, we try to make compiling and linking two separate stages so
that they can be done by $(CC) and $(LD) respectively, which is more in
line with what the user expects, versus using the compiler as a linker
driver and relying on the implicit default linker value. However, as
shown in the above thread, getting this right for the PowerPC vDSO is a
little tricky due to the linker emulation values.
The unification might make this easier but that needs further
investigation. To avoid regressing ld.bfd while enabling support for
linking the vDSO with ld.lld, we can tell the compiler to use ld.lld via
either '--ld-path=' (clang 12.0.0) or '-fuse-ld=lld'.
The first patch avoids a warning from ld.lld when linking both vDSO
objects and the second patch adds the flags.
This should help avoid the issue noticed during Alexey's LTO bring up:
https://lore.kernel.org/CAKwvOdmUMhqhQhDCpWjMNiQQPvwOJB9MbUkF3RR0BL+H+DagmA@mail.gmail.com/
Changelog:
v1 -> v2: https://lore.kernel.org/20220509204635.2539549-1-nathan@kernel.org/
* Flush out the second commit message much more with information from
this cover letter and the other threads (Alexey's LTO enablement and
Nick's initial stab at converting to $(CC) + $(LD)) [Nick].
* Add Nick and Alexey's tags.
Nathan Chancellor (2):
powerpc/vdso: Remove unused ENTRY in linker scripts
powerpc/vdso: Link with ld.lld when requested
arch/powerpc/kernel/vdso/Makefile | 1 +
arch/powerpc/kernel/vdso/vdso32.lds.S | 1 -
arch/powerpc/kernel/vdso/vdso64.lds.S | 1 -
3 files changed, 1 insertion(+), 2 deletions(-)
base-commit: b6b1c3ce06ca438eb24e0f45bf0e63ecad0369f5
--
2.36.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 0/2] Link the PowerPC vDSO with ld.lld
@ 2022-05-11 18:49 ` Nathan Chancellor
0 siblings, 0 replies; 8+ messages in thread
From: Nathan Chancellor @ 2022-05-11 18:49 UTC (permalink / raw)
To: Michael Ellerman
Cc: Alexey Kardashevskiy, llvm, Nick Desaulniers, patches,
Nathan Chancellor, Paul Mackerras, Tom Rix, linuxppc-dev
Hi all,
This series is an alternative to the one proposed by Nick before the
PowerPC vDSO unification in commit fd1feade75fb ("powerpc/vdso: Merge
vdso64 and vdso32 into a single directory"):
https://lore.kernel.org/20200901222523.1941988-1-ndesaulniers@google.com/
Normally, we try to make compiling and linking two separate stages so
that they can be done by $(CC) and $(LD) respectively, which is more in
line with what the user expects, versus using the compiler as a linker
driver and relying on the implicit default linker value. However, as
shown in the above thread, getting this right for the PowerPC vDSO is a
little tricky due to the linker emulation values.
The unification might make this easier but that needs further
investigation. To avoid regressing ld.bfd while enabling support for
linking the vDSO with ld.lld, we can tell the compiler to use ld.lld via
either '--ld-path=' (clang 12.0.0) or '-fuse-ld=lld'.
The first patch avoids a warning from ld.lld when linking both vDSO
objects and the second patch adds the flags.
This should help avoid the issue noticed during Alexey's LTO bring up:
https://lore.kernel.org/CAKwvOdmUMhqhQhDCpWjMNiQQPvwOJB9MbUkF3RR0BL+H+DagmA@mail.gmail.com/
Changelog:
v1 -> v2: https://lore.kernel.org/20220509204635.2539549-1-nathan@kernel.org/
* Flush out the second commit message much more with information from
this cover letter and the other threads (Alexey's LTO enablement and
Nick's initial stab at converting to $(CC) + $(LD)) [Nick].
* Add Nick and Alexey's tags.
Nathan Chancellor (2):
powerpc/vdso: Remove unused ENTRY in linker scripts
powerpc/vdso: Link with ld.lld when requested
arch/powerpc/kernel/vdso/Makefile | 1 +
arch/powerpc/kernel/vdso/vdso32.lds.S | 1 -
arch/powerpc/kernel/vdso/vdso64.lds.S | 1 -
3 files changed, 1 insertion(+), 2 deletions(-)
base-commit: b6b1c3ce06ca438eb24e0f45bf0e63ecad0369f5
--
2.36.1
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH v2 1/2] powerpc/vdso: Remove unused ENTRY in linker scripts
2022-05-11 18:49 ` Nathan Chancellor
@ 2022-05-11 18:50 ` Nathan Chancellor
-1 siblings, 0 replies; 8+ messages in thread
From: Nathan Chancellor @ 2022-05-11 18:50 UTC (permalink / raw)
To: Michael Ellerman
Cc: Benjamin Herrenschmidt, Paul Mackerras, Christophe Leroy,
Alexey Kardashevskiy, Nick Desaulniers, Tom Rix, linuxppc-dev,
llvm, patches, Nathan Chancellor
When linking vdso{32,64}.so.dbg with ld.lld, there is a warning about
not finding _start for the starting address:
ld.lld: warning: cannot find entry symbol _start; not setting start address
ld.lld: warning: cannot find entry symbol _start; not setting start address
Looking at GCC + GNU ld, the entry point address is 0x0:
$ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
File: vdso32.so.dbg
Entry point address: 0x0
File: vdso64.so.dbg
Entry point address: 0x0
This matches what ld.lld emits:
$ powerpc64le-linux-gnu-readelf -p .comment vdso{32,64}.so.dbg
File: vdso32.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: vdso64.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
$ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
File: vdso32.so.dbg
Entry point address: 0x0
File: vdso64.so.dbg
Entry point address: 0x0
Remove ENTRY to remove the warning, as it is unnecessary for the vDSO to
function correctly.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
arch/powerpc/kernel/vdso/vdso32.lds.S | 1 -
arch/powerpc/kernel/vdso/vdso64.lds.S | 1 -
2 files changed, 2 deletions(-)
diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S
index 58e0099f70f4..e0d19d74455f 100644
--- a/arch/powerpc/kernel/vdso/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso32.lds.S
@@ -13,7 +13,6 @@ OUTPUT_FORMAT("elf32-powerpcle", "elf32-powerpcle", "elf32-powerpcle")
OUTPUT_FORMAT("elf32-powerpc", "elf32-powerpc", "elf32-powerpc")
#endif
OUTPUT_ARCH(powerpc:common)
-ENTRY(_start)
SECTIONS
{
diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S
index 0288cad428b0..1a4a7bc4c815 100644
--- a/arch/powerpc/kernel/vdso/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso64.lds.S
@@ -13,7 +13,6 @@ OUTPUT_FORMAT("elf64-powerpcle", "elf64-powerpcle", "elf64-powerpcle")
OUTPUT_FORMAT("elf64-powerpc", "elf64-powerpc", "elf64-powerpc")
#endif
OUTPUT_ARCH(powerpc:common64)
-ENTRY(_start)
SECTIONS
{
--
2.36.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 1/2] powerpc/vdso: Remove unused ENTRY in linker scripts
@ 2022-05-11 18:50 ` Nathan Chancellor
0 siblings, 0 replies; 8+ messages in thread
From: Nathan Chancellor @ 2022-05-11 18:50 UTC (permalink / raw)
To: Michael Ellerman
Cc: Alexey Kardashevskiy, llvm, Nick Desaulniers, patches,
Nathan Chancellor, Paul Mackerras, Tom Rix, linuxppc-dev
When linking vdso{32,64}.so.dbg with ld.lld, there is a warning about
not finding _start for the starting address:
ld.lld: warning: cannot find entry symbol _start; not setting start address
ld.lld: warning: cannot find entry symbol _start; not setting start address
Looking at GCC + GNU ld, the entry point address is 0x0:
$ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
File: vdso32.so.dbg
Entry point address: 0x0
File: vdso64.so.dbg
Entry point address: 0x0
This matches what ld.lld emits:
$ powerpc64le-linux-gnu-readelf -p .comment vdso{32,64}.so.dbg
File: vdso32.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: vdso64.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
$ llvm-readelf -h vdso{32,64}.so.dbg &| rg "(File|Entry point address):"
File: vdso32.so.dbg
Entry point address: 0x0
File: vdso64.so.dbg
Entry point address: 0x0
Remove ENTRY to remove the warning, as it is unnecessary for the vDSO to
function correctly.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
arch/powerpc/kernel/vdso/vdso32.lds.S | 1 -
arch/powerpc/kernel/vdso/vdso64.lds.S | 1 -
2 files changed, 2 deletions(-)
diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S
index 58e0099f70f4..e0d19d74455f 100644
--- a/arch/powerpc/kernel/vdso/vdso32.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso32.lds.S
@@ -13,7 +13,6 @@ OUTPUT_FORMAT("elf32-powerpcle", "elf32-powerpcle", "elf32-powerpcle")
OUTPUT_FORMAT("elf32-powerpc", "elf32-powerpc", "elf32-powerpc")
#endif
OUTPUT_ARCH(powerpc:common)
-ENTRY(_start)
SECTIONS
{
diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S
index 0288cad428b0..1a4a7bc4c815 100644
--- a/arch/powerpc/kernel/vdso/vdso64.lds.S
+++ b/arch/powerpc/kernel/vdso/vdso64.lds.S
@@ -13,7 +13,6 @@ OUTPUT_FORMAT("elf64-powerpcle", "elf64-powerpcle", "elf64-powerpcle")
OUTPUT_FORMAT("elf64-powerpc", "elf64-powerpc", "elf64-powerpc")
#endif
OUTPUT_ARCH(powerpc:common64)
-ENTRY(_start)
SECTIONS
{
--
2.36.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 2/2] powerpc/vdso: Link with ld.lld when requested
2022-05-11 18:49 ` Nathan Chancellor
@ 2022-05-11 18:50 ` Nathan Chancellor
-1 siblings, 0 replies; 8+ messages in thread
From: Nathan Chancellor @ 2022-05-11 18:50 UTC (permalink / raw)
To: Michael Ellerman
Cc: Benjamin Herrenschmidt, Paul Mackerras, Christophe Leroy,
Alexey Kardashevskiy, Nick Desaulniers, Tom Rix, linuxppc-dev,
llvm, patches, Nathan Chancellor
The PowerPC vDSO uses $(CC) to link, which differs from the rest of the
kernel, which uses $(LD) directly. As a result, the default linker of
the compiler is used, which may differ from the linker requested by the
builder. For example:
$ make ARCH=powerpc LLVM=1 mrproper defconfig arch/powerpc/kernel/vdso/
...
$ llvm-readelf -p .comment arch/powerpc/kernel/vdso/vdso{32,64}.so.dbg
File: arch/powerpc/kernel/vdso/vdso32.so.dbg
String dump of section '.comment':
[ 0] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: arch/powerpc/kernel/vdso/vdso64.so.dbg
String dump of section '.comment':
[ 0] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
LLVM=1 sets LD=ld.lld but ld.lld is not used to link the vDSO; GNU ld is
because "ld" is the default linker for clang on most Linux platforms.
This is a problem for Clang's Link Time Optimization as implemented in
the kernel because use of GNU ld with LTO requires the LLVMgold plugin,
which is not technically supported for ld.bfd per
https://llvm.org/docs/GoldPlugin.html. Furthermore, if LLVMgold.so is
missing from a user's system, the build will fail, even though LTO as it
is implemented in the kernel requires ld.lld to avoid this dependency in
the first place.
Ultimately, the PowerPC vDSO should be converted to compiling and
linking with $(CC) and $(LD) respectively but there were issues last
time this was tried, potentially due to older but supported tool
versions. To avoid regressing GCC + binutils, use the compiler option
'-fuse-ld', which tells the compiler which linker to use when it is
invoked as both the compiler and linker. Use '-fuse-ld=lld' when
LD=ld.lld has been specified (CONFIG_LD_IS_LLD) so that the vDSO is
linked with the same linker as the rest of the kernel.
$ llvm-readelf -p .comment arch/powerpc/kernel/vdso/vdso{32,64}.so.dbg
File: arch/powerpc/kernel/vdso/vdso32.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: arch/powerpc/kernel/vdso/vdso64.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
LD can be a full path to ld.lld, which will not be handled properly by
'-fuse-ld=lld' if the full path to ld.lld is outside of the compiler's
search path. '-fuse-ld' can take a path to the linker but it is
deprecated in clang 12.0.0; '--ld-path' is preferred for this scenario.
Use '--ld-path' if it is supported, as it will handle a full path or
just 'ld.lld' properly. See the LLVM commit below for the full details
of '--ld-path'.
Link: https://github.com/ClangBuiltLinux/linux/issues/774
Link: https://github.com/llvm/llvm-project/commit/1bc5c84710a8c73ef21295e63c19d10a8c71f2f5
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
arch/powerpc/kernel/vdso/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 954974287ee7..096b0bf1335f 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -48,6 +48,7 @@ UBSAN_SANITIZE := n
KASAN_SANITIZE := n
ccflags-y := -shared -fno-common -fno-builtin -nostdlib -Wl,--hash-style=both
+ccflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
CC32FLAGS := -Wl,-soname=linux-vdso32.so.1 -m32
AS32FLAGS := -D__VDSO32__ -s
--
2.36.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* [PATCH v2 2/2] powerpc/vdso: Link with ld.lld when requested
@ 2022-05-11 18:50 ` Nathan Chancellor
0 siblings, 0 replies; 8+ messages in thread
From: Nathan Chancellor @ 2022-05-11 18:50 UTC (permalink / raw)
To: Michael Ellerman
Cc: Alexey Kardashevskiy, llvm, Nick Desaulniers, patches,
Nathan Chancellor, Paul Mackerras, Tom Rix, linuxppc-dev
The PowerPC vDSO uses $(CC) to link, which differs from the rest of the
kernel, which uses $(LD) directly. As a result, the default linker of
the compiler is used, which may differ from the linker requested by the
builder. For example:
$ make ARCH=powerpc LLVM=1 mrproper defconfig arch/powerpc/kernel/vdso/
...
$ llvm-readelf -p .comment arch/powerpc/kernel/vdso/vdso{32,64}.so.dbg
File: arch/powerpc/kernel/vdso/vdso32.so.dbg
String dump of section '.comment':
[ 0] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: arch/powerpc/kernel/vdso/vdso64.so.dbg
String dump of section '.comment':
[ 0] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
LLVM=1 sets LD=ld.lld but ld.lld is not used to link the vDSO; GNU ld is
because "ld" is the default linker for clang on most Linux platforms.
This is a problem for Clang's Link Time Optimization as implemented in
the kernel because use of GNU ld with LTO requires the LLVMgold plugin,
which is not technically supported for ld.bfd per
https://llvm.org/docs/GoldPlugin.html. Furthermore, if LLVMgold.so is
missing from a user's system, the build will fail, even though LTO as it
is implemented in the kernel requires ld.lld to avoid this dependency in
the first place.
Ultimately, the PowerPC vDSO should be converted to compiling and
linking with $(CC) and $(LD) respectively but there were issues last
time this was tried, potentially due to older but supported tool
versions. To avoid regressing GCC + binutils, use the compiler option
'-fuse-ld', which tells the compiler which linker to use when it is
invoked as both the compiler and linker. Use '-fuse-ld=lld' when
LD=ld.lld has been specified (CONFIG_LD_IS_LLD) so that the vDSO is
linked with the same linker as the rest of the kernel.
$ llvm-readelf -p .comment arch/powerpc/kernel/vdso/vdso{32,64}.so.dbg
File: arch/powerpc/kernel/vdso/vdso32.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
File: arch/powerpc/kernel/vdso/vdso64.so.dbg
String dump of section '.comment':
[ 0] Linker: LLD 14.0.0
[ 14] clang version 14.0.0 (Fedora 14.0.0-1.fc37)
LD can be a full path to ld.lld, which will not be handled properly by
'-fuse-ld=lld' if the full path to ld.lld is outside of the compiler's
search path. '-fuse-ld' can take a path to the linker but it is
deprecated in clang 12.0.0; '--ld-path' is preferred for this scenario.
Use '--ld-path' if it is supported, as it will handle a full path or
just 'ld.lld' properly. See the LLVM commit below for the full details
of '--ld-path'.
Link: https://github.com/ClangBuiltLinux/linux/issues/774
Link: https://github.com/llvm/llvm-project/commit/1bc5c84710a8c73ef21295e63c19d10a8c71f2f5
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
---
arch/powerpc/kernel/vdso/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/powerpc/kernel/vdso/Makefile b/arch/powerpc/kernel/vdso/Makefile
index 954974287ee7..096b0bf1335f 100644
--- a/arch/powerpc/kernel/vdso/Makefile
+++ b/arch/powerpc/kernel/vdso/Makefile
@@ -48,6 +48,7 @@ UBSAN_SANITIZE := n
KASAN_SANITIZE := n
ccflags-y := -shared -fno-common -fno-builtin -nostdlib -Wl,--hash-style=both
+ccflags-$(CONFIG_LD_IS_LLD) += $(call cc-option,--ld-path=$(LD),-fuse-ld=lld)
CC32FLAGS := -Wl,-soname=linux-vdso32.so.1 -m32
AS32FLAGS := -D__VDSO32__ -s
--
2.36.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v2 0/2] Link the PowerPC vDSO with ld.lld
2022-05-11 18:49 ` Nathan Chancellor
@ 2022-05-24 11:08 ` Michael Ellerman
-1 siblings, 0 replies; 8+ messages in thread
From: Michael Ellerman @ 2022-05-24 11:08 UTC (permalink / raw)
To: Nathan Chancellor, Michael Ellerman
Cc: Alexey Kardashevskiy, Tom Rix, llvm, Nick Desaulniers, patches,
Paul Mackerras, linuxppc-dev
On Wed, 11 May 2022 11:49:59 -0700, Nathan Chancellor wrote:
> This series is an alternative to the one proposed by Nick before the
> PowerPC vDSO unification in commit fd1feade75fb ("powerpc/vdso: Merge
> vdso64 and vdso32 into a single directory"):
>
> https://lore.kernel.org/20200901222523.1941988-1-ndesaulniers@google.com/
>
> Normally, we try to make compiling and linking two separate stages so
> that they can be done by $(CC) and $(LD) respectively, which is more in
> line with what the user expects, versus using the compiler as a linker
> driver and relying on the implicit default linker value. However, as
> shown in the above thread, getting this right for the PowerPC vDSO is a
> little tricky due to the linker emulation values.
>
> [...]
Applied to powerpc/next.
[1/2] powerpc/vdso: Remove unused ENTRY in linker scripts
https://git.kernel.org/powerpc/c/e247172854a57d1a7213bb835ecb4a40ce9bb2b9
[2/2] powerpc/vdso: Link with ld.lld when requested
https://git.kernel.org/powerpc/c/4406b12214f6592909b63dabdea86d69f1b5ba2e
cheers
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v2 0/2] Link the PowerPC vDSO with ld.lld
@ 2022-05-24 11:08 ` Michael Ellerman
0 siblings, 0 replies; 8+ messages in thread
From: Michael Ellerman @ 2022-05-24 11:08 UTC (permalink / raw)
To: Nathan Chancellor, Michael Ellerman
Cc: llvm, Alexey Kardashevskiy, patches, Tom Rix, Paul Mackerras,
Christophe Leroy, Benjamin Herrenschmidt, Nick Desaulniers,
linuxppc-dev
On Wed, 11 May 2022 11:49:59 -0700, Nathan Chancellor wrote:
> This series is an alternative to the one proposed by Nick before the
> PowerPC vDSO unification in commit fd1feade75fb ("powerpc/vdso: Merge
> vdso64 and vdso32 into a single directory"):
>
> https://lore.kernel.org/20200901222523.1941988-1-ndesaulniers@google.com/
>
> Normally, we try to make compiling and linking two separate stages so
> that they can be done by $(CC) and $(LD) respectively, which is more in
> line with what the user expects, versus using the compiler as a linker
> driver and relying on the implicit default linker value. However, as
> shown in the above thread, getting this right for the PowerPC vDSO is a
> little tricky due to the linker emulation values.
>
> [...]
Applied to powerpc/next.
[1/2] powerpc/vdso: Remove unused ENTRY in linker scripts
https://git.kernel.org/powerpc/c/e247172854a57d1a7213bb835ecb4a40ce9bb2b9
[2/2] powerpc/vdso: Link with ld.lld when requested
https://git.kernel.org/powerpc/c/4406b12214f6592909b63dabdea86d69f1b5ba2e
cheers
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2022-05-24 11:24 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
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2022-05-11 18:49 [PATCH v2 0/2] Link the PowerPC vDSO with ld.lld Nathan Chancellor
2022-05-11 18:49 ` Nathan Chancellor
2022-05-11 18:50 ` [PATCH v2 1/2] powerpc/vdso: Remove unused ENTRY in linker scripts Nathan Chancellor
2022-05-11 18:50 ` Nathan Chancellor
2022-05-11 18:50 ` [PATCH v2 2/2] powerpc/vdso: Link with ld.lld when requested Nathan Chancellor
2022-05-11 18:50 ` Nathan Chancellor
2022-05-24 11:08 ` [PATCH v2 0/2] Link the PowerPC vDSO with ld.lld Michael Ellerman
2022-05-24 11:08 ` Michael Ellerman
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