Messages in this thread | | | From | Zhangjin Wu <> | Subject | Re: [PATCH v1 6/7] DCE/DSE: riscv: add HAVE_TRIM_UNUSED_SYSCALLS support | Date | Sat, 7 Oct 2023 21:29:35 +0800 |
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Hi, Arnd
> On Tue, Sep 26, 2023, at 00:42, Zhangjin Wu wrote: > > For HAVE_TRIM_UNUSED_SYSCALLS, the syscall tables are hacked with the > > inputing unused_syscalls. > > > > Firstly, the intermediate preprocessed .i files are generated from the > > original C version of syscall tables respectively, and named with a > > 'used' suffix: syscall_table_used.i, compat_syscall_table_used.i. > > > > Secondly, all of the unused syscalls are commented. > > > > At last, two new objective files sufixed with 'used' are generated from > > the hacked .i files and they are linked into the eventual kernel image. > > > > Signed-off-by: Zhangjin Wu <falcon@tinylab.org> > > As mentioned in my comment on the mips patch, hacking the preprocessed > file here is too much strain on the old infrastructure, the > asm-generic/unistd.h file is already too hard to understand for > anyone and in need of an overhaul, so let's work together on fixing > it up first. >
Ok, I was thinking about using asm/syscall_table.h instead of asm/unistd.h like mips.
void * const sys_call_table[NR_syscalls] = { [0 ... NR_syscalls - 1] = __riscv_sys_ni_syscall, #include <asm/syscall_table.h> };
Therefore, we can generate syscall_table.h from asm/unist.h with a tool like scripts/syscallused.sh
Another solution may be firstly generate a list of `#define __USED_NR_##call 1` for the used syscalls from Kconfig symbol, and then change __SYSCALL() macro to:
#define __SYSCALL(nr, call) [nr] = __is_defined(__USED_NR_##call) ? __riscv_##call : __riscv_sys_ni_syscall,
`include/linux/kconfig.h` defined the '__is_defined'.
This method may work for the archs with .tbl files too.
Thanks, Zhangjin
> Arnd
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