Re: [PATCH 4/5] x86/syscall/x32: Move x32 syscall table

Sohil Mehta
2025-03-13T23:48:24Z

On 3/13/2025 11:22 AM, Brian Gerst wrote:
> Since commit:
>
> 2e958a8a510d ("x86/entry/x32: Rename __x32_compat_sys_* to
> __x64_compat_sys_*"),
>
> the ABI prefix for x32 syscalls is the same as native 64-bit
> syscalls. Move the x32 syscall table to syscall_64.c
>
> No functional changes.
>
> Signed-off-by: Brian Gerst <brgerst@gmail.com>
> ---
> arch/x86/entry/Makefile | 1 -
> arch/x86/entry/syscall_64.c | 13 +++++++++++++
> arch/x86/entry/syscall_x32.c | 25 -------------------------
> 3 files changed, 13 insertions(+), 26 deletions(-)
> delete mode 100644 arch/x86/entry/syscall_x32.c
>
> diff --git a/arch/x86/entry/Makefile b/arch/x86/entry/Makefile
> index 5fd28abfd5a0..e870f8aa936c 100644
> --- a/arch/x86/entry/Makefile
> +++ b/arch/x86/entry/Makefile
> @@ -27,4 +27,3 @@ CFLAGS_REMOVE_entry_fred.o += -pg $(CC_FLAGS_FTRACE)
> obj-$(CONFIG_X86_FRED) += entry_64_fred.o entry_fred.o
>
> obj-$(CONFIG_IA32_EMULATION) += entry_64_compat.o syscall_32.o
> -obj-$(CONFIG_X86_X32_ABI) += syscall_x32.o
> diff --git a/arch/x86/entry/syscall_64.c b/arch/x86/entry/syscall_64.c
> index 9e0ba339013c..b96f5621a2aa 100644
> --- a/arch/x86/entry/syscall_64.c
> +++ b/arch/x86/entry/syscall_64.c
> @@ -19,6 +19,9 @@
> #define __SYSCALL(nr, sym) extern long __x64_##sym(const struct pt_regs *);
> #define __SYSCALL_NORETURN(nr, sym) extern long __noreturn __x64_##sym(const struct pt_regs *);
> #include <asm/syscalls_64.h>
> +#ifdef CONFIG_X86_X32_ABI
> +#include <asm/syscalls_x32.h>
> +#endif
> #undef __SYSCALL
>
> #undef __SYSCALL_NORETURN
> @@ -44,6 +47,16 @@ long x64_sys_call(const struct pt_regs *regs, unsigned int nr)
> }
> };
>
> +#ifdef CONFIG_X86_X32_ABI
> +long x32_sys_call(const struct pt_regs *regs, unsigned int nr)
> +{
> + switch (nr) {
> + #include <asm/syscalls_x32.h>
> + default: return __x64_sys_ni_syscall(regs);
> + }
> +};

There seems to be a stray semicolon here. The original code also has it
but it doesn't seem necessary.

> +#endif
> +
> static __always_inline bool do_syscall_x64(struct pt_regs *regs, int nr)
> {
> /*
> diff --git a/arch/x86/entry/syscall_x32.c b/arch/x86/entry/syscall_x32.c
> deleted file mode 100644
> index fb77908f44f3..000000000000
> --- a/arch/x86/entry/syscall_x32.c
> +++ /dev/null
> @@ -1,25 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -/* System call table for x32 ABI. */
> -
> -#include <linux/linkage.h>
> -#include <linux/sys.h>
> -#include <linux/cache.h>
> -#include <linux/syscalls.h>
> -#include <asm/syscall.h>
> -
> -#define __SYSCALL(nr, sym) extern long __x64_##sym(const struct pt_regs *);
> -#define __SYSCALL_NORETURN(nr, sym) extern long __noreturn __x64_##sym(const struct pt_regs *);
> -#include <asm/syscalls_x32.h>
> -#undef __SYSCALL
> -
> -#undef __SYSCALL_NORETURN
> -#define __SYSCALL_NORETURN __SYSCALL
> -
> -#define __SYSCALL(nr, sym) case nr: return __x64_##sym(regs);
> -long x32_sys_call(const struct pt_regs *regs, unsigned int nr)
> -{
> - switch (nr) {
> - #include <asm/syscalls_x32.h>
> - default: return __x64_sys_ni_syscall(regs);
> - }
> -};