[PATCH V9 20/20] riscv: compat: Add COMPAT Kbuild skeletal support

[Guenter Roeck]

On Tue, Mar 22, 2022 at 10:40:03PM +0800, guoren at kernel.org wrote:
> From: Guo Ren <guoren at linux.alibaba.com>
> 
> Adds initial skeletal COMPAT Kbuild (Running 32bit U-mode on
> 64bit S-mode) support.
>  - Setup kconfig & dummy functions for compiling.
>  - Implement compat_start_thread by the way.
> 
> Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren at kernel.org>
> Reviewed-by: Arnd Bergmann <arnd at arndb.de>
> Tested-by: Heiko Stuebner <heiko at sntech.de>
> Cc: Palmer Dabbelt <palmer at dabbelt.com>

With this patch in linux-next, all my riscv64 emulations crash.

[   11.600082] Run /sbin/init as init process
[   11.628561] init[1]: unhandled signal 11 code 0x1 at 0x0000000000000000 in libc.so[ffffff8ad39000+a4000]
[   11.629398] CPU: 0 PID: 1 Comm: init Not tainted 5.18.0-rc7-next-20220520 #1
[   11.629462] Hardware name: riscv-virtio,qemu (DT)
[   11.629546] epc : 00ffffff8ada1100 ra : 00ffffff8ada13c8 sp : 00ffffffc58199f0
[   11.629586]  gp : 00ffffff8ad39000 tp : 00ffffff8ade0998 t0 : ffffffffffffffff
[   11.629598]  t1 : 00ffffffc5819fd0 t2 : 0000000000000000 s0 : 00ffffff8ade0cc0
[   11.629610]  s1 : 00ffffff8ade0cc0 a0 : 0000000000000000 a1 : 00ffffffc5819a00
[   11.629622]  a2 : 0000000000000001 a3 : 000000000000001e a4 : 00ffffffc5819b00
[   11.629634]  a5 : 00ffffffc5819b00 a6 : 0000000000000000 a7 : 0000000000000000
[   11.629645]  s2 : 00ffffff8ade0ac8 s3 : 00ffffff8ade0ec8 s4 : 00ffffff8ade0728
[   11.629656]  s5 : 00ffffff8ade0a90 s6 : 0000000000000000 s7 : 00ffffffc5819e40
[   11.629667]  s8 : 00ffffff8ade0ca0 s9 : 00ffffff8addba50 s10: 0000000000000000
[   11.629678]  s11: 0000000000000000 t3 : 0000000000000002 t4 : 0000000000000001
[   11.629688]  t5 : 0000000000020000 t6 : ffffffffffffffff
[   11.629699] status: 0000000000004020 badaddr: 0000000000000000 cause: 000000000000000d
[   11.633421] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
[   11.633664] CPU: 0 PID: 1 Comm: init Not tainted 5.18.0-rc7-next-20220520 #1
[   11.633784] Hardware name: riscv-virtio,qemu (DT)
[   11.633881] Call Trace:
[   11.633960] [<ffffffff80005e72>] dump_backtrace+0x1c/0x24
[   11.634162] [<ffffffff809aa9ec>] show_stack+0x2c/0x38
[   11.634274] [<ffffffff809b8482>] dump_stack_lvl+0x60/0x8e
[   11.634386] [<ffffffff809b84c4>] dump_stack+0x14/0x1c
[   11.634491] [<ffffffff809aaca0>] panic+0x116/0x2e2
[   11.634596] [<ffffffff80015540>] do_exit+0x7ce/0x7d4
[   11.634707] [<ffffffff80015666>] do_group_exit+0x24/0x7c
[   11.634817] [<ffffffff80022294>] get_signal+0x7ee/0x830
[   11.634924] [<ffffffff800051c0>] do_notify_resume+0x6c/0x41c
[   11.635037] [<ffffffff80003ad4>] ret_from_exception+0x0/0x10

Guenter

---
# bad: [18ecd30af1a8402c162cca1bd58771c0e5be7815] Add linux-next specific files for 20220520
# good: [42226c989789d8da4af1de0c31070c96726d990c] Linux 5.18-rc7
git bisect start 'HEAD' 'v5.18-rc7'
# bad: [f9b63740b666dd9887eb0282d21b5f65bb0cadd0] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
git bisect bad f9b63740b666dd9887eb0282d21b5f65bb0cadd0
# bad: [7db97132097c5973ff77466d0ee681650af653de] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux
git bisect bad 7db97132097c5973ff77466d0ee681650af653de
# good: [2b7d17d4b7c1ff40f58b0d32be40fc0bb6c582fb] soc: document merges
git bisect good 2b7d17d4b7c1ff40f58b0d32be40fc0bb6c582fb
# good: [69c9668f853fdd409bb8abbb37d615785510b29a] Merge branch 'clk-next' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git
git bisect good 69c9668f853fdd409bb8abbb37d615785510b29a
# bad: [1577f290aa0d4c5b29c03c46ef52e4952a21bfbb] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux.git
git bisect bad 1577f290aa0d4c5b29c03c46ef52e4952a21bfbb
# good: [34f0971f8ca73d7e5502b4cf299788a9402120f7] powerpc/powernv/flash: Check OPAL flash calls exist before using
git bisect good 34f0971f8ca73d7e5502b4cf299788a9402120f7
# good: [0349d7dfc70a26b3facd8ca97de34980d4b60954] Merge branch 'mips-next' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux.git
git bisect good 0349d7dfc70a26b3facd8ca97de34980d4b60954
# bad: [20bfb54d3b121699674c17a854c5ebc7a8f97d81] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux.git
git bisect bad 20bfb54d3b121699674c17a854c5ebc7a8f97d81
# bad: [9be8459298eadb39b9fe9974b890239e9c123107] riscv: compat: Add COMPAT Kbuild skeletal support
git bisect bad 9be8459298eadb39b9fe9974b890239e9c123107
# good: [01abdfeac81b5f56062d0a78f2cdc805db937a75] riscv: compat: Support TASK_SIZE for compat mode
git bisect good 01abdfeac81b5f56062d0a78f2cdc805db937a75
# good: [f4b395e6f1a588ed6c9a30474e58cf6b27b65783] riscv: compat: Add hw capability check for elf
git bisect good f4b395e6f1a588ed6c9a30474e58cf6b27b65783
# good: [3092eb45637573c5e435fbf5eaf9516316e5f9c6] riscv: compat: vdso: Add setup additional pages implementation
git bisect good 3092eb45637573c5e435fbf5eaf9516316e5f9c6
# good: [4608c159594fb40a5101357d4f614fdde9ce1fdb] riscv: compat: ptrace: Add compat_arch_ptrace implement
git bisect good 4608c159594fb40a5101357d4f614fdde9ce1fdb
# first bad commit: [9be8459298eadb39b9fe9974b890239e9c123107] riscv: compat: Add COMPAT Kbuild skeletal support