Changes in V11:
- append a patch that makes the DIRECT_CALL samples support RV32I in
this series fixing the rv32 build failure reported by Palmer
- validated with ftrace boottime selftest and manual sample modules test
in qemu-system for RV32I and RV64I
This series optimizes function trace. The first 3 independent
patches has been picked in the V7 version of this series, the
subsequent version continues the following 4 patches:
select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1] (patch 1)
==========================================================
In RISC-V, -fpatchable-function-entry option is used to support
dynamic ftrace in this commit afc76b8b8011 ("riscv: Using
PATCHABLE_FUNCTION_ENTRY instead of MCOUNT"). So recordmcount
don't have to be called to create the __mcount_loc section before
the vmlinux linking.
Here selects FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to tell
Makefile not to run recordmcount.
Make function graph use ftrace directly [2] (patch 2)
========================================================
In RISC-V architecture, when we enable the ftrace_graph tracer on some
functions, the function tracings on other functions will suffer extra
graph tracing work. In essence, graph_ops isn't limited by its func_hash
due to the global ftrace_graph_[regs]_call label. That should be
corrected.
What inspires me is the commit 0c0593b45c9b ("x86/ftrace: Make function
graph use ftrace directly") that uses graph_ops::func function to
install return_hooker and makes the function called against its
func_hash.
Add WITH_DIRECT_CALLS support [3] (patch 3, 4)
==============================================
This series adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V.
SAMPLE_FTRACE_DIRECT and SAMPLE_FTRACE_DIRECT_MULTI are also included
here as the samples for testing DIRECT_CALLS related interface.
First, select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide
register_ftrace_direct[_multi] interfaces allowing user to register
the customed trampoline (direct_caller) as the mcount for one or
more target functions. And modify_ftrace_direct[_multi] are also
provided for modify direct_caller.
At the same time, the samples in ./samples/ftrace/ can be built
as kerenl module for testing these interfaces with SAMPLE_FTRACE_DIRECT
and SAMPLE_FTRACE_DIRECT_MULTI selected.
Second, to make the direct_caller and the other ftrace hooks
(eg. function/fgraph tracer, k[ret]probes) co-exist, a temporary
register
are nominated to store the address of direct_caller in
ftrace_regs_caller.
After the setting of the address direct_caller by direct_ops->func and
the RESTORE_REGS in ftrace_regs_caller, direct_caller will be jumped to
by the `jr` inst.
The series's old changes related these patches
==========================================
Changes in v10:
https://lore.kernel.org/all/[email protected]/
- add Acked-by from Björn Töpel in patch 2 and patch 4
- replace `move` with `mv` in patch3
- prettify patch 2/4 with proper tabs
Changes in v9:
https://lore.kernel.org/linux-riscv/[email protected]/
1. add Acked-by from Björn Töpel in patch 1
2. rebase patch2/patch3 on Linux v6.4-rc1
- patch 2: to make the `SAVE_ABI_REGS` configurable, revert the
modification of mcount-dyn.S from commit (45b32b946a97 "riscv:
entry: Consolidate general regs saving/restoring")
- patch 3: to pass the trace_selftest, add the implement of
`ftrace_stub_direct_tramp` from commit (fee86a4ed536 "ftrace:
selftest: remove broken trace_direct_tramp") ; and fixup the context
conflict in Kconfig
Changes in v8:
https://lore.kernel.org/linux-riscv/[email protected]/
- Fix incorrect address values in the 4nd patch
- Rebased on v6.3-rc2
Changes in v7:
https://lore.kernel.org/linux-riscv/[email protected]/
- Fixup RESTORE_ABI_REGS by remove PT_T0(sp) overwrite.
- Add FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1]
- Fixup kconfig with HAVE_SAMPLE_FTRACE_DIRECT &
HAVE_SAMPLE_FTRACE_DIRECT_MULTI
Changes in v6:
https://lore.kernel.org/linux-riscv/[email protected]/
- Replace 8 with MCOUNT_INSN_SIZE
- Replace "REG_L a1, PT_RA(sp)" with "mv a1, ra"
- Add Evgenii Shatokhin comment
Changes in v5:
https://lore.kernel.org/linux-riscv/[email protected]/
- Sort Kconfig entries in alphabetical order.
Changes in v4:
https://lore.kernel.org/linux-riscv/[email protected]/
- Include [3] for maintenance. [Song Shuai]
Changes in V3:
https://lore.kernel.org/linux-riscv/[email protected]/
- Include [2] for maintenance. [Song Shuai]
[1]: https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t
[2]: https://lore.kernel.org/lkml/[email protected]/
[3]: https://lore.kernel.org/linux-riscv/[email protected]/
Song Shuai (5):
riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
riscv: ftrace: Add ftrace_graph_func
riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support
samples: ftrace: Add riscv support for SAMPLE_FTRACE_DIRECT[_MULTI]
samples: ftrace: Make the riscv samples support RV32I
arch/riscv/Kconfig | 4 +
arch/riscv/include/asm/ftrace.h | 19 +-
arch/riscv/kernel/ftrace.c | 30 ++-
arch/riscv/kernel/mcount-dyn.S | 200 ++++++++++++++++----
samples/ftrace/ftrace-direct-modify.c | 35 ++++
samples/ftrace/ftrace-direct-multi-modify.c | 41 ++++
samples/ftrace/ftrace-direct-multi.c | 25 +++
samples/ftrace/ftrace-direct-too.c | 28 +++
samples/ftrace/ftrace-direct.c | 24 +++
9 files changed, 350 insertions(+), 56 deletions(-)
--
2.20.1
In RISC-V, -fpatchable-function-entry option is used to support
dynamic ftrace in this commit afc76b8b8011 ("riscv: Using
PATCHABLE_FUNCTION_ENTRY instead of MCOUNT"). So recordmcount
don't have to be called to create the __mcount_loc section before
the vmlinux linking.
Here selects FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to tell
Makefile not to run recordmcount.
Link: https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t
Link: https://lore.kernel.org/linux-riscv/Y4jtfrJt+%2FQ5nMOz@spud/
Signed-off-by: Song Shuai <[email protected]>
Tested-by: Guo Ren <[email protected]>
Signed-off-by: Guo Ren <[email protected]>
Acked-by: Björn Töpel <[email protected]>
---
arch/riscv/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 5966ad97c30c..756d854e6cdd 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -59,6 +59,7 @@ config RISCV
select COMMON_CLK
select CPU_PM if CPU_IDLE || HIBERNATION
select EDAC_SUPPORT
+ select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY if DYNAMIC_FTRACE
select GENERIC_ARCH_TOPOLOGY
select GENERIC_ATOMIC64 if !64BIT
select GENERIC_CLOCKEVENTS_BROADCAST if SMP
--
2.20.1
Ping...
在 2023/6/27 19:16, Song Shuai 写道:
> Changes in V11:
>
> - append a patch that makes the DIRECT_CALL samples support RV32I in
> this series fixing the rv32 build failure reported by Palmer
>
> - validated with ftrace boottime selftest and manual sample modules test
> in qemu-system for RV32I and RV64I
>
> This series optimizes function trace. The first 3 independent
> patches has been picked in the V7 version of this series, the
> subsequent version continues the following 4 patches:
>
> select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1] (patch 1)
> ==========================================================
>
> In RISC-V, -fpatchable-function-entry option is used to support
> dynamic ftrace in this commit afc76b8b8011 ("riscv: Using
> PATCHABLE_FUNCTION_ENTRY instead of MCOUNT"). So recordmcount
> don't have to be called to create the __mcount_loc section before
> the vmlinux linking.
>
> Here selects FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to tell
> Makefile not to run recordmcount.
>
> Make function graph use ftrace directly [2] (patch 2)
> ========================================================
>
> In RISC-V architecture, when we enable the ftrace_graph tracer on some
> functions, the function tracings on other functions will suffer extra
> graph tracing work. In essence, graph_ops isn't limited by its func_hash
> due to the global ftrace_graph_[regs]_call label. That should be
> corrected.
>
> What inspires me is the commit 0c0593b45c9b ("x86/ftrace: Make function
> graph use ftrace directly") that uses graph_ops::func function to
> install return_hooker and makes the function called against its
> func_hash.
>
> Add WITH_DIRECT_CALLS support [3] (patch 3, 4)
> ==============================================
>
> This series adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V.
> SAMPLE_FTRACE_DIRECT and SAMPLE_FTRACE_DIRECT_MULTI are also included
> here as the samples for testing DIRECT_CALLS related interface.
>
> First, select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide
> register_ftrace_direct[_multi] interfaces allowing user to register
> the customed trampoline (direct_caller) as the mcount for one or
> more target functions. And modify_ftrace_direct[_multi] are also
> provided for modify direct_caller.
>
> At the same time, the samples in ./samples/ftrace/ can be built
> as kerenl module for testing these interfaces with SAMPLE_FTRACE_DIRECT
> and SAMPLE_FTRACE_DIRECT_MULTI selected.
>
> Second, to make the direct_caller and the other ftrace hooks
> (eg. function/fgraph tracer, k[ret]probes) co-exist, a temporary
> register
> are nominated to store the address of direct_caller in
> ftrace_regs_caller.
> After the setting of the address direct_caller by direct_ops->func and
> the RESTORE_REGS in ftrace_regs_caller, direct_caller will be jumped to
> by the `jr` inst.
>
> The series's old changes related these patches
> ==========================================
>
> Changes in v10:
> https://lore.kernel.org/all/[email protected]/
>
> - add Acked-by from Björn Töpel in patch 2 and patch 4
> - replace `move` with `mv` in patch3
> - prettify patch 2/4 with proper tabs
>
> Changes in v9:
> https://lore.kernel.org/linux-riscv/[email protected]/
>
> 1. add Acked-by from Björn Töpel in patch 1
>
> 2. rebase patch2/patch3 on Linux v6.4-rc1
>
> - patch 2: to make the `SAVE_ABI_REGS` configurable, revert the
> modification of mcount-dyn.S from commit (45b32b946a97 "riscv:
> entry: Consolidate general regs saving/restoring")
>
> - patch 3: to pass the trace_selftest, add the implement of
> `ftrace_stub_direct_tramp` from commit (fee86a4ed536 "ftrace:
> selftest: remove broken trace_direct_tramp") ; and fixup the context
> conflict in Kconfig
>
> Changes in v8:
> https://lore.kernel.org/linux-riscv/[email protected]/
> - Fix incorrect address values in the 4nd patch
> - Rebased on v6.3-rc2
>
> Changes in v7:
> https://lore.kernel.org/linux-riscv/[email protected]/
> - Fixup RESTORE_ABI_REGS by remove PT_T0(sp) overwrite.
> - Add FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1]
> - Fixup kconfig with HAVE_SAMPLE_FTRACE_DIRECT &
> HAVE_SAMPLE_FTRACE_DIRECT_MULTI
>
> Changes in v6:
> https://lore.kernel.org/linux-riscv/[email protected]/
> - Replace 8 with MCOUNT_INSN_SIZE
> - Replace "REG_L a1, PT_RA(sp)" with "mv a1, ra"
> - Add Evgenii Shatokhin comment
>
> Changes in v5:
> https://lore.kernel.org/linux-riscv/[email protected]/
> - Sort Kconfig entries in alphabetical order.
>
> Changes in v4:
> https://lore.kernel.org/linux-riscv/[email protected]/
> - Include [3] for maintenance. [Song Shuai]
>
> Changes in V3:
> https://lore.kernel.org/linux-riscv/[email protected]/
> - Include [2] for maintenance. [Song Shuai]
>
> [1]: https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t
> [2]: https://lore.kernel.org/lkml/[email protected]/
> [3]: https://lore.kernel.org/linux-riscv/[email protected]/
>
> Song Shuai (5):
> riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
> riscv: ftrace: Add ftrace_graph_func
> riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support
> samples: ftrace: Add riscv support for SAMPLE_FTRACE_DIRECT[_MULTI]
> samples: ftrace: Make the riscv samples support RV32I
>
> arch/riscv/Kconfig | 4 +
> arch/riscv/include/asm/ftrace.h | 19 +-
> arch/riscv/kernel/ftrace.c | 30 ++-
> arch/riscv/kernel/mcount-dyn.S | 200 ++++++++++++++++----
> samples/ftrace/ftrace-direct-modify.c | 35 ++++
> samples/ftrace/ftrace-direct-multi-modify.c | 41 ++++
> samples/ftrace/ftrace-direct-multi.c | 25 +++
> samples/ftrace/ftrace-direct-too.c | 28 +++
> samples/ftrace/ftrace-direct.c | 24 +++
> 9 files changed, 350 insertions(+), 56 deletions(-)
>
--
Thanks
Song Shuai
On Thu, Jul 06, 2023 at 05:35:49PM +0800, Song Shuai wrote:
> Ping...
A context-less ping is not very helpful - what are you looking for here?
More reviews? For example, someone to look at 5/5?
> 在 2023/6/27 19:16, Song Shuai 写道:
If it's application you want, you sent the patch only last week - which
was during the merge window, making it unlikely to be applied.
Either way, please try to explain what it is that you are looking for
when you do a ping!
Cheers,
Conor.
在 2023/7/6 17:53, Conor Dooley 写道:
> On Thu, Jul 06, 2023 at 05:35:49PM +0800, Song Shuai wrote:
>> Ping...
>
> A context-less ping is not very helpful - what are you looking for here?
> More reviews? For example, someone to look at 5/5? >
Sorry for the context-less ping. I hoped someone could look at the 5th
patch.
>> 在 2023/6/27 19:16, Song Shuai 写道:
>
> If it's application you want, you sent the patch only last week - which
> was during the merge window, making it unlikely to be applied.
> > Either way, please try to explain what it is that you are looking for
> when you do a ping!
Thanks for your correction, I'll follow this thread after the merge
window closes.
>
> Cheers,
> Conor.
>
--
Thanks
Song Shuai
Song Shuai <[email protected]> writes:
[...]
> Add WITH_DIRECT_CALLS support [3] (patch 3, 4)
> ==============================================
We've had some offlist discussions, so here's some input for a wider
audience! Most importantly, this is for Palmer, so that this series is
not merged until a proper BPF trampoline fix is in place.
Note that what's currently usable from BPF trampoline *works*. It's
when this series is added that it breaks.
TL;DR This series adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS, which enables
fentry/fexit BPF trampoline support. Unfortunately the
fexit/BPF_TRAMP_F_SKIP_FRAME parts of the RV BPF trampoline breaks
with this addition, and need to be addressed *prior* merging this
series. An easy way to reproduce, is just calling any of the kselftest
tests that uses fexit patching.
The issue is around the nop seld, and how a call is done; The nop sled
(patchable-function-entry) size changed from 16B to 8B in commit
6724a76cff85 ("riscv: ftrace: Reduce the detour code size to half"), but
BPF code still uses the old 16B. So it'll work for BPF programs, but not
for regular kernel functions.
An example:
| ffffffff80fa4150 <bpf_fentry_test1>:
| ffffffff80fa4150: 0001 nop
| ffffffff80fa4152: 0001 nop
| ffffffff80fa4154: 0001 nop
| ffffffff80fa4156: 0001 nop
| ffffffff80fa4158: 1141 add sp,sp,-16
| ffffffff80fa415a: e422 sd s0,8(sp)
| ffffffff80fa415c: 0800 add s0,sp,16
| ffffffff80fa415e: 6422 ld s0,8(sp)
| ffffffff80fa4160: 2505 addw a0,a0,1
| ffffffff80fa4162: 0141 add sp,sp,16
| ffffffff80fa4164: 8082 ret
is patched to:
| ffffffff80fa4150: f70c0297 auipc t0,-150208512
| ffffffff80fa4154: eb0282e7 jalr t0,t0,-336
The return address to bpf_fentry_test1 is stored in t0 at BPF
trampoline entry. Return to the *parent* is in ra. The trampline has
to deal with this.
For BPF_TRAMP_F_SKIP_FRAME/CALL_ORIG, the BPF trampoline will skip too
many bytes, and not correctly handle parent calls.
Further; The BPF trampoline currently has a different way of patching
the nops for BPF programs, than what ftrace does. That should be changed
to match what ftrace does (auipc/jalr t0).
To summarize:
* Align BPF nop sled with patchable-function-entry: 8B.
* Adapt BPF trampoline for 8B nop sleds.
* Adapt BPF trampoline t0 return, ra parent scheme.
Cheers,
Björn
On Wed, 12 Jul 2023 11:11:08 PDT (-0700), [email protected] wrote:
> Song Shuai <[email protected]> writes:
>
> [...]
>
>> Add WITH_DIRECT_CALLS support [3] (patch 3, 4)
>> ==============================================
>
> We've had some offlist discussions, so here's some input for a wider
> audience! Most importantly, this is for Palmer, so that this series is
> not merged until a proper BPF trampoline fix is in place.
>
> Note that what's currently usable from BPF trampoline *works*. It's
> when this series is added that it breaks.
>
> TL;DR This series adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS, which enables
> fentry/fexit BPF trampoline support. Unfortunately the
> fexit/BPF_TRAMP_F_SKIP_FRAME parts of the RV BPF trampoline breaks
> with this addition, and need to be addressed *prior* merging this
> series. An easy way to reproduce, is just calling any of the kselftest
> tests that uses fexit patching.
>
> The issue is around the nop seld, and how a call is done; The nop sled
> (patchable-function-entry) size changed from 16B to 8B in commit
> 6724a76cff85 ("riscv: ftrace: Reduce the detour code size to half"), but
> BPF code still uses the old 16B. So it'll work for BPF programs, but not
> for regular kernel functions.
>
> An example:
>
> | ffffffff80fa4150 <bpf_fentry_test1>:
> | ffffffff80fa4150: 0001 nop
> | ffffffff80fa4152: 0001 nop
> | ffffffff80fa4154: 0001 nop
> | ffffffff80fa4156: 0001 nop
> | ffffffff80fa4158: 1141 add sp,sp,-16
> | ffffffff80fa415a: e422 sd s0,8(sp)
> | ffffffff80fa415c: 0800 add s0,sp,16
> | ffffffff80fa415e: 6422 ld s0,8(sp)
> | ffffffff80fa4160: 2505 addw a0,a0,1
> | ffffffff80fa4162: 0141 add sp,sp,16
> | ffffffff80fa4164: 8082 ret
>
> is patched to:
>
> | ffffffff80fa4150: f70c0297 auipc t0,-150208512
> | ffffffff80fa4154: eb0282e7 jalr t0,t0,-336
>
> The return address to bpf_fentry_test1 is stored in t0 at BPF
> trampoline entry. Return to the *parent* is in ra. The trampline has
> to deal with this.
>
> For BPF_TRAMP_F_SKIP_FRAME/CALL_ORIG, the BPF trampoline will skip too
> many bytes, and not correctly handle parent calls.
>
> Further; The BPF trampoline currently has a different way of patching
> the nops for BPF programs, than what ftrace does. That should be changed
> to match what ftrace does (auipc/jalr t0).
>
> To summarize:
> * Align BPF nop sled with patchable-function-entry: 8B.
> * Adapt BPF trampoline for 8B nop sleds.
> * Adapt BPF trampoline t0 return, ra parent scheme.
Thanks for digging into this one, I agree we need to sort out the BPF
breakages before we merge this. Sounds like there's a rabbit hole here,
but hopefully we can get it sorted out.
I've dropped this from patchwork and such, as we'll need at least
another spin.
> Cheers,
> Björn
Björn Töpel <[email protected]> writes:
> Palmer Dabbelt <[email protected]> writes:
>
>> On Wed, 12 Jul 2023 11:11:08 PDT (-0700), [email protected] wrote:
>>> Song Shuai <[email protected]> writes:
>>>
>>> [...]
>>>
>>>> Add WITH_DIRECT_CALLS support [3] (patch 3, 4)
>>>> ==============================================
>>>
>>> We've had some offlist discussions, so here's some input for a wider
>>> audience! Most importantly, this is for Palmer, so that this series is
>>> not merged until a proper BPF trampoline fix is in place.
>>>
>>> Note that what's currently usable from BPF trampoline *works*. It's
>>> when this series is added that it breaks.
>>>
>>> TL;DR This series adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS, which enables
>>> fentry/fexit BPF trampoline support. Unfortunately the
>>> fexit/BPF_TRAMP_F_SKIP_FRAME parts of the RV BPF trampoline breaks
>>> with this addition, and need to be addressed *prior* merging this
>>> series. An easy way to reproduce, is just calling any of the kselftest
>>> tests that uses fexit patching.
>>>
>>> The issue is around the nop seld, and how a call is done; The nop sled
>>> (patchable-function-entry) size changed from 16B to 8B in commit
>>> 6724a76cff85 ("riscv: ftrace: Reduce the detour code size to half"), but
>>> BPF code still uses the old 16B. So it'll work for BPF programs, but not
>>> for regular kernel functions.
>>>
>>> An example:
>>>
>>> | ffffffff80fa4150 <bpf_fentry_test1>:
>>> | ffffffff80fa4150: 0001 nop
>>> | ffffffff80fa4152: 0001 nop
>>> | ffffffff80fa4154: 0001 nop
>>> | ffffffff80fa4156: 0001 nop
>>> | ffffffff80fa4158: 1141 add sp,sp,-16
>>> | ffffffff80fa415a: e422 sd s0,8(sp)
>>> | ffffffff80fa415c: 0800 add s0,sp,16
>>> | ffffffff80fa415e: 6422 ld s0,8(sp)
>>> | ffffffff80fa4160: 2505 addw a0,a0,1
>>> | ffffffff80fa4162: 0141 add sp,sp,16
>>> | ffffffff80fa4164: 8082 ret
>>>
>>> is patched to:
>>>
>>> | ffffffff80fa4150: f70c0297 auipc t0,-150208512
>>> | ffffffff80fa4154: eb0282e7 jalr t0,t0,-336
>>>
>>> The return address to bpf_fentry_test1 is stored in t0 at BPF
>>> trampoline entry. Return to the *parent* is in ra. The trampline has
>>> to deal with this.
>>>
>>> For BPF_TRAMP_F_SKIP_FRAME/CALL_ORIG, the BPF trampoline will skip too
>>> many bytes, and not correctly handle parent calls.
>>>
>>> Further; The BPF trampoline currently has a different way of patching
>>> the nops for BPF programs, than what ftrace does. That should be changed
>>> to match what ftrace does (auipc/jalr t0).
>>>
>>> To summarize:
>>> * Align BPF nop sled with patchable-function-entry: 8B.
>>> * Adapt BPF trampoline for 8B nop sleds.
>>> * Adapt BPF trampoline t0 return, ra parent scheme.
>>
>> Thanks for digging into this one, I agree we need to sort out the BPF
>> breakages before we merge this. Sounds like there's a rabbit hole here,
>> but hopefully we can get it sorted out.
>>
>> I've dropped this from patchwork and such, as we'll need at least
>> another spin.
>
> Palmer,
>
> The needed BPF patch is upstream in the bpf-next tree, and has been for
> a couple of weeks.
>
> I think this series is a candidate for RISC-V -next! It would help
> RISC-V BPF a lot in terms of completeness.
Palmer,
The needed fix for BPF is now in Linus' tree, commit 25ad10658dc1
("riscv, bpf: Adapt bpf trampoline to optimized riscv ftrace
framework"). IOW, this ftrace series can be merged now.
Björn