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Miller" , Andreas Larsson , linux-snps-arc@lists.infradead.org, linux-hexagon@vger.kernel.org, linux-openrisc@vger.kernel.org, sparclinux@vger.kernel.org, linux-arch@vger.kernel.org, =?UTF-8?q?Michal=20Such=C3=A1nek?= , Jonathan Corbet , linux-doc@vger.kernel.org Subject: [patch 16/18] x86/entry: Get rid of the sys_ni_syscall() indirection References: <20260707181957.433213175@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Invoking sys_ni_syscall() from a code path, which already knows that the syscall number is invalid just to assign -ENOSYS to regs->ax is a pointless exercise. It's even redundant as the low level entry code already has set regs->ax to -ENOSYS on entry. Remove the extra conditionals and the function calls. Signed-off-by: Thomas Gleixner --- arch/x86/entry/syscall_32.c | 2 -- arch/x86/entry/syscall_64.c | 10 +++------- 2 files changed, 3 insertions(+), 9 deletions(-) --- a/arch/x86/entry/syscall_32.c +++ b/arch/x86/entry/syscall_32.c @@ -81,8 +81,6 @@ static __always_inline void do_syscall_3 if (likely(unr < IA32_NR_syscalls)) { unr = array_index_nospec(unr, IA32_NR_syscalls); regs->ax = ia32_sys_call(regs, unr); - } else if (nr != -1) { - regs->ax = __ia32_sys_ni_syscall(regs); } } --- a/arch/x86/entry/syscall_64.c +++ b/arch/x86/entry/syscall_64.c @@ -68,7 +68,7 @@ static __always_inline bool do_syscall_x return false; } -static __always_inline bool do_syscall_x32(struct pt_regs *regs, int nr) +static __always_inline void do_syscall_x32(struct pt_regs *regs, int nr) { /* * Adjust the starting offset of the table, and convert numbers @@ -80,9 +80,7 @@ static __always_inline bool do_syscall_x if (IS_ENABLED(CONFIG_X86_X32_ABI) && likely(xnr < X32_NR_syscalls)) { xnr = array_index_nospec(xnr, X32_NR_syscalls); regs->ax = x32_sys_call(regs, xnr); - return true; } - return false; } /* Returns true to return using SYSRET, or false to use IRET */ @@ -92,10 +90,8 @@ static __always_inline bool do_syscall_x instrumentation_begin(); - if (!do_syscall_x64(regs, nr) && !do_syscall_x32(regs, nr) && nr != -1) { - /* Invalid system call, but still a system call. */ - regs->ax = __x64_sys_ni_syscall(regs); - } + if (!do_syscall_x64(regs, nr)) + do_syscall_x32(regs, nr); instrumentation_end(); syscall_exit_to_user_mode(regs);