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riscv: kexec: cleanup and fixups #122

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riscv: kexec: cleanup and fixups #122

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bjoto
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@bjoto bjoto commented Oct 11, 2023

Pull request for series with
subject: riscv: kexec: cleanup and fixups
version: 2
url: https://patchwork.kernel.org/project/linux-riscv/list/?series=792102

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bjoto commented Oct 11, 2023

Upstream branch: 0bb80ec
series: https://patchwork.kernel.org/project/linux-riscv/list/?series=792102
version: 2

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bjoto commented Oct 12, 2023

Upstream branch: 0bb80ec
series: https://patchwork.kernel.org/project/linux-riscv/list/?series=792102
version: 2

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bjoto commented Oct 13, 2023

Upstream branch: 0bb80ec
series: https://patchwork.kernel.org/project/linux-riscv/list/?series=792102
version: 2

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bjoto commented Oct 17, 2023

Upstream branch: 0bb80ec
series: https://patchwork.kernel.org/project/linux-riscv/list/?series=792102
version: 2

Song Shuai added 2 commits October 17, 2023 15:12
riscv: kexec: Cleanup riscv_kexec_relocate
b5e13b0 
For readability and simplicity, cleanup the riscv_kexec_relocate code:

- Re-sort the first 4 `mv` instructions against `riscv_kexec_method()`
- Eliminate registers for debugging (s9,s10,s11) and storing const-value (s5,s6)
- Replace `jalr` with `jr` for no-link jump

I tested this on Qemu virt machine and works as it was.

Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
riscv: kexec: Remove -fPIE for PURGATORY_CFLAGS
66edc1e 
With CONFIG_RELOCATABLE enabled, KBUILD_CFLAGS had a -fPIE option
and then the purgatory/string.o was built to reference _ctype symbol
via R_RISCV_GOT_HI20 relocations which can't be handled by purgatory.

As a consequence, the kernel failed kexec_load_file() with:

[  880.386562] kexec_image: The entry point of kernel at 0x80200000
[  880.388650] kexec_image: Unknown rela relocation: 20
[  880.389173] kexec_image: Error loading purgatory ret=-8

So remove the -fPIE option for PURGATORY_CFLAGS to generate
R_RISCV_PCREL_HI20 relocations type making puragtory work as it was.

Fixes: 39b3307 ("riscv: Introduce CONFIG_RELOCATABLE")
Signed-off-by: Song Shuai <songshuaishuai@tinylab.org>
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
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bjoto commented Oct 27, 2023

Upstream branch: ec8c6c7
series: https://patchwork.kernel.org/project/linux-riscv/list/?series=792102
version: 2

Pull request is NOT updated. Failed to apply https://patchwork.kernel.org/project/linux-riscv/list/?series=792102
error message:

Cmd('git') failed due to: exit code(128)
  cmdline: git am -s --3way
  stdout: 'Applying: riscv: kexec: Cleanup riscv_kexec_relocate
Using index info to reconstruct a base tree...
M	arch/riscv/kernel/kexec_relocate.S
Falling back to patching base and 3-way merge...
Auto-merging arch/riscv/kernel/kexec_relocate.S
CONFLICT (content): Merge conflict in arch/riscv/kernel/kexec_relocate.S
Patch failed at 0001 riscv: kexec: Cleanup riscv_kexec_relocate
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".'
  stderr: 'error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch'

conflict:

diff --cc arch/riscv/kernel/kexec_relocate.S
index de0a4b35d01e,ece5591abc4e..000000000000
--- a/arch/riscv/kernel/kexec_relocate.S
+++ b/arch/riscv/kernel/kexec_relocate.S
@@@ -48,7 -48,7 +48,11 @@@ SYM_CODE_START(riscv_kexec_relocate
  
  	/*
  	 * With C-extension, here we get 42 Bytes and the next
++<<<<<<< HEAD
 +	 * .align directive would pad zeros here up to 44 Bytes.
++=======
+ 	 * .balign directive would pad zeros here up to 44 Bytes.
++>>>>>>> riscv: kexec: Cleanup riscv_kexec_relocate
  	 * So manually put a nop here to avoid zeros padding.
  	*/
  	nop

@bjoto bjoto force-pushed the for-next_base branch 5 times, most recently from 3119b42 to a1c09bf Compare November 7, 2023 06:52
@bjoto bjoto force-pushed the for-next_base branch 6 times, most recently from 6610b8c to f71180c Compare November 9, 2023 22:34
@bjoto bjoto force-pushed the for-next_base branch 3 times, most recently from cd54c39 to fb37e30 Compare December 12, 2023 23:51
@bjoto bjoto closed this Jan 3, 2024
@bjoto bjoto deleted the series/782186=>for-next branch January 5, 2024 11:43
bjoto pushed a commit that referenced this pull request Jan 22, 2024
@chenhengqi @chenhuacai
LoongArch: BPF: Support 64-bit pointers to kfuncs
21c5ae5 
Like commit 1cf3bfc ("bpf: Support 64-bit pointers to kfuncs")
for s390x, add support for 64-bit pointers to kfuncs for LoongArch.
Since the infrastructure is already implemented in BPF core, the only
thing need to be done is to override bpf_jit_supports_far_kfunc_call().

Before this change, several test_verifier tests failed:

  # ./test_verifier | grep # | grep FAIL
  #119/p calls: invalid kfunc call: ptr_to_mem to struct with non-scalar FAIL
  #120/p calls: invalid kfunc call: ptr_to_mem to struct with nesting depth > 4 FAIL
  #121/p calls: invalid kfunc call: ptr_to_mem to struct with FAM FAIL
  #122/p calls: invalid kfunc call: reg->type != PTR_TO_CTX FAIL
  #123/p calls: invalid kfunc call: void * not allowed in func proto without mem size arg FAIL
  #124/p calls: trigger reg2btf_ids[reg->type] for reg->type > __BPF_REG_TYPE_MAX FAIL
  #125/p calls: invalid kfunc call: reg->off must be zero when passed to release kfunc FAIL
  #126/p calls: invalid kfunc call: don't match first member type when passed to release kfunc FAIL
  #127/p calls: invalid kfunc call: PTR_TO_BTF_ID with negative offset FAIL
  #128/p calls: invalid kfunc call: PTR_TO_BTF_ID with variable offset FAIL
  #129/p calls: invalid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID FAIL
  #130/p calls: valid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID FAIL
  #486/p map_kptr: ref: reference state created and released on xchg FAIL

This is because the kfuncs in the loaded module are far away from
__bpf_call_base:

  ffff800002009440 t bpf_kfunc_call_test_fail1    [bpf_testmod]
  9000000002e128d8 T __bpf_call_base

The offset relative to __bpf_call_base does NOT fit in s32, which breaks
the assumption in BPF core. Enable bpf_jit_supports_far_kfunc_call() lifts
this limit.

Note that to reproduce the above result, tools/testing/selftests/bpf/config
should be applied, and run the test with JIT enabled, unpriv BPF enabled.

With this change, the test_verifier tests now all passed:

  # ./test_verifier
  ...
  Summary: 777 PASSED, 0 SKIPPED, 0 FAILED

Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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