Such relocation causes crash of android linker similar to one
described in commit e05d57dcb8c7
("riscv: Fixup __vdso_gettimeofday broke dynamic ftrace").
Looks like this relocation is added by CONFIG_DYNAMIC_FTRACE which is
disabled in the default android kernel.
Before:
readelf -rW arch/riscv/kernel/vdso/vdso.so:
Relocation section '.rela.dyn' at offset 0xd00 contains 1 entry:
Offset Info Type
0000000000000d20 0000000000000003 R_RISCV_RELATIVE
objdump:
0000000000000c86 <__vdso_riscv_hwprobe@@LINUX_4.15>:
c86: 0001 nop
c88: 0001 nop
c8a: 0001 nop
c8c: 0001 nop
c8e: e211 bnez a2,c92 <__vdso_riscv_hwprobe...
After:
readelf -rW arch/riscv/kernel/vdso/vdso.so:
There are no relocations in this file.
objdump:
0000000000000c86 <__vdso_riscv_hwprobe@@LINUX_4.15>:
c86: e211 bnez a2,c8a <__vdso_riscv_hwprobe...
c88: c6b9 beqz a3,cd6 <__vdso_riscv_hwprobe...
c8a: e739 bnez a4,cd8 <__vdso_riscv_hwprobe...
c8c: ffffd797 auipc a5,0xffffd
Also disable SCS since it also should not be available in vdso.
Fixes: aa5af0aa90ba ("RISC-V: Add hwprobe vDSO function and data")
Signed-off-by: Roman Artemev <[email protected]>
Signed-off-by: Vladimir Isaev <[email protected]>
---
arch/riscv/kernel/vdso/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index 9b517fe1b8a8..272c431ac5b9 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -37,6 +37,7 @@ endif
# Disable -pg to prevent insert call site
CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS)
+CFLAGS_REMOVE_hwprobe.o = $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS)
# Disable profiling and instrumentation for VDSO code
GCOV_PROFILE := n
--
2.43.0
On Wed, Mar 13, 2024 at 5:05 PM Vladimir Isaev
<[email protected]> wrote:
>
> Such relocation causes crash of android linker similar to one
> described in commit e05d57dcb8c7
> ("riscv: Fixup __vdso_gettimeofday broke dynamic ftrace").
>
> Looks like this relocation is added by CONFIG_DYNAMIC_FTRACE which is
> disabled in the default android kernel.
>
> Before:
>
> readelf -rW arch/riscv/kernel/vdso/vdso.so:
>
> Relocation section '.rela.dyn' at offset 0xd00 contains 1 entry:
> Offset Info Type
> 0000000000000d20 0000000000000003 R_RISCV_RELATIVE
>
> objdump:
> 0000000000000c86 <__vdso_riscv_hwprobe@@LINUX_4.15>:
> c86: 0001 nop
> c88: 0001 nop
> c8a: 0001 nop
> c8c: 0001 nop
> c8e: e211 bnez a2,c92 <__vdso_riscv_hwprobe...
>
> After:
> readelf -rW arch/riscv/kernel/vdso/vdso.so:
>
> There are no relocations in this file.
>
> objdump:
> 0000000000000c86 <__vdso_riscv_hwprobe@@LINUX_4.15>:
> c86: e211 bnez a2,c8a <__vdso_riscv_hwprobe...
> c88: c6b9 beqz a3,cd6 <__vdso_riscv_hwprobe...
> c8a: e739 bnez a4,cd8 <__vdso_riscv_hwprobe...
> c8c: ffffd797 auipc a5,0xffffd
>
> Also disable SCS since it also should not be available in vdso.
>
> Fixes: aa5af0aa90ba ("RISC-V: Add hwprobe vDSO function and data")
> Signed-off-by: Roman Artemev <[email protected]>
> Signed-off-by: Vladimir Isaev <[email protected]>
> ---
> arch/riscv/kernel/vdso/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
> index 9b517fe1b8a8..272c431ac5b9 100644
> --- a/arch/riscv/kernel/vdso/Makefile
> +++ b/arch/riscv/kernel/vdso/Makefile
> @@ -37,6 +37,7 @@ endif
>
> # Disable -pg to prevent insert call site
> CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS)
> +CFLAGS_REMOVE_hwprobe.o = $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS)
LGTM, good catch, thanks :)
Reviewed-by: Guo Ren <[email protected]>
>
> # Disable profiling and instrumentation for VDSO code
> GCOV_PROFILE := n
> --
> 2.43.0
>
--
Best Regards
Guo Ren
Hi Vladimir,
s/frtace/ftrace
On 13/03/2024 08:35, Vladimir Isaev wrote:
> Such relocation causes crash of android linker similar to one
> described in commit e05d57dcb8c7
> ("riscv: Fixup __vdso_gettimeofday broke dynamic ftrace").
>
> Looks like this relocation is added by CONFIG_DYNAMIC_FTRACE which is
> disabled in the default android kernel.
>
> Before:
>
> readelf -rW arch/riscv/kernel/vdso/vdso.so:
>
> Relocation section '.rela.dyn' at offset 0xd00 contains 1 entry:
> Offset Info Type
> 0000000000000d20 0000000000000003 R_RISCV_RELATIVE
>
> objdump:
> 0000000000000c86 <__vdso_riscv_hwprobe@@LINUX_4.15>:
> c86: 0001 nop
> c88: 0001 nop
> c8a: 0001 nop
> c8c: 0001 nop
> c8e: e211 bnez a2,c92 <__vdso_riscv_hwprobe...
>
> After:
> readelf -rW arch/riscv/kernel/vdso/vdso.so:
>
> There are no relocations in this file.
>
> objdump:
> 0000000000000c86 <__vdso_riscv_hwprobe@@LINUX_4.15>:
> c86: e211 bnez a2,c8a <__vdso_riscv_hwprobe...
> c88: c6b9 beqz a3,cd6 <__vdso_riscv_hwprobe...
> c8a: e739 bnez a4,cd8 <__vdso_riscv_hwprobe...
> c8c: ffffd797 auipc a5,0xffffd
>
> Also disable SCS since it also should not be available in vdso.
>
> Fixes: aa5af0aa90ba ("RISC-V: Add hwprobe vDSO function and data")
> Signed-off-by: Roman Artemev <[email protected]>
> Signed-off-by: Vladimir Isaev <[email protected]>
> ---
> arch/riscv/kernel/vdso/Makefile | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
> index 9b517fe1b8a8..272c431ac5b9 100644
> --- a/arch/riscv/kernel/vdso/Makefile
> +++ b/arch/riscv/kernel/vdso/Makefile
> @@ -37,6 +37,7 @@ endif
>
> # Disable -pg to prevent insert call site
> CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS)
> +CFLAGS_REMOVE_hwprobe.o = $(CC_FLAGS_FTRACE) $(CC_FLAGS_SCS)
I did not find a way to remove those flags for all C files
automatically, too bad. But then I noticed that we were the only
architecture which does not check for dynamic relocations in vdso, so at
least we'll fail loudly. I'll send a patch for that soon.
This should go into -fixes.
Anyway, you can add:
Reviewed-by: Alexandre Ghiti <[email protected]>
Thanks,
Alex
>
> # Disable profiling and instrumentation for VDSO code
> GCOV_PROFILE := n
Hello:
This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <[email protected]>:
On Wed, 13 Mar 2024 10:35:46 +0300 you wrote:
> Such relocation causes crash of android linker similar to one
> described in commit e05d57dcb8c7
> ("riscv: Fixup __vdso_gettimeofday broke dynamic ftrace").
>
> Looks like this relocation is added by CONFIG_DYNAMIC_FTRACE which is
> disabled in the default android kernel.
>
> [...]
Here is the summary with links:
- riscv: hwprobe: do not produce frtace relocation
https://git.kernel.org/riscv/c/ad14f7ca9f0d
You are awesome, thank you!
--
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