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-api, linux-arch, linux-m68k, linux-mips, linux-perf-users, linux-s390, linux-sh, lkml, sparclinux
Reply to
Edgecombe, Rick P, 2023-09-11
"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.tbl
b/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_stack
I 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
Thread (8 messages) 8 messages, 3 authors, last reply 2023-09-14
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