Re: [PATCH 17/23] powerpc: Enable compile-time check for syscall handlers
From: "Nicholas Piggin" <npiggin@gmail.com>
Date: 2022-09-20 01:31:11
On Fri Sep 16, 2022 at 3:32 PM AEST, Rohan McLure wrote:
The table of syscall handlers and registered compatibility syscall handlers has in past been produced using assembly, with function references resolved at link time. This moves link-time errors to compile-time, by rewriting systbl.S in C, and including the linux/syscalls.h, linux/compat.h and asm/syscalls.h headers for prototypes. Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Rohan McLure <redacted> Reported-by: Nicholas Piggin <npiggin@gmail.com> --- V1 -> V2: New patch. V4 -> V5: For this patch only, represent handler function pointers as unsigned long. Remove reference to syscall wrappers. Use asm/syscalls.h which implies asm/syscall.h
Thanks, I think this is the right way to split the patches. I'm not sure if I reported this issue, but I really like the patch. Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
quoted hunk ↗ jump to hunk
--- arch/powerpc/kernel/{systbl.S => systbl.c} | 28 ++++++++------------ 1 file changed, 11 insertions(+), 17 deletions(-)diff --git a/arch/powerpc/kernel/systbl.S b/arch/powerpc/kernel/systbl.c similarity index 61% rename from arch/powerpc/kernel/systbl.S rename to arch/powerpc/kernel/systbl.c index 6c1db3b6de2d..ce52bd2ec292 100644 --- a/arch/powerpc/kernel/systbl.S +++ b/arch/powerpc/kernel/systbl.c@@ -10,32 +10,26 @@ * PPC64 updates by Dave Engebretsen (engebret@us.ibm.com) */ -#include <asm/ppc_asm.h> +#include <linux/syscalls.h> +#include <linux/compat.h> +#include <asm/unistd.h> +#include <asm/syscalls.h> -.section .rodata,"a" +#define __SYSCALL_WITH_COMPAT(nr, entry, compat) __SYSCALL(nr, entry) +#define __SYSCALL(nr, entry) [nr] = (unsigned long) &entry, -#ifdef CONFIG_PPC64 - .p2align 3 -#define __SYSCALL(nr, entry) .8byte entry -#else - .p2align 2 -#define __SYSCALL(nr, entry) .long entry -#endif - -#define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native) -.globl sys_call_table -sys_call_table: +const unsigned long sys_call_table[] = { #ifdef CONFIG_PPC64 #include <asm/syscall_table_64.h> #else #include <asm/syscall_table_32.h> #endif +}; #ifdef CONFIG_COMPAT #undef __SYSCALL_WITH_COMPAT #define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, compat) -.globl compat_sys_call_table -compat_sys_call_table: -#define compat_sys_sigsuspend sys_sigsuspend +const unsigned long compat_sys_call_table[] = { #include <asm/syscall_table_32.h> -#endif +}; +#endif /* CONFIG_COMPAT */-- 2.34.1