Re: [PATCH 2/2] arch: Reserve map_shadow_stack() syscall number for all architectures
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2023-09-14 12:27:08
Also in:
linux-alpha, linux-arch, linux-m68k, linux-mips, linux-perf-users, linux-s390, linux-sh, linuxppc-dev, lkml, sparclinux
"Edgecombe, Rick P" [off-list ref] writes:
On Mon, 2023-09-11 at 18:02 +0000, Sohil Mehta wrote:quoted
diff --git a/arch/powerpc/kernel/syscalls/syscall.tblb/arch/powerpc/kernel/syscalls/syscall.tbl index 20e50586e8a2..2767b8a42636 100644--- a/arch/powerpc/kernel/syscalls/syscall.tbl +++ b/arch/powerpc/kernel/syscalls/syscall.tbl@@ -539,3 +539,4 @@450 nospu set_mempolicy_home_node sys_set_mempolicy_hom e_node 451 common cachestat sys_cachestat 452 common fchmodat2 sys_fchmodat2 +453 common map_shadow_stack sys_map_shadow_stackI noticed in powerpc, the not implemented syscalls are manually mapped to sys_ni_syscall. It also has some special extra sys_ni_syscall() implementation bits to handle both ARCH_HAS_SYSCALL_WRAPPER and !ARCH_HAS_SYSCALL_WRAPPER. So wondering if it might need special treatment. Did you see those parts?
I don't think it needs any special treatment. It's processed by the same script as other arches (scripts/syscalltbl.sh). So if there's no compat or native entry it will default to sys_ni_syscall. I think it's just habit/historical that we always spell out sys_ni_syscall. cheers