From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Kees Cook Subject: [PATCH v3 3/7] um: Cleanup syscall_handler_t definition/cast, fix warning Date: Sun, 27 Feb 2022 10:45:13 -0800 Message-Id: <20220227184517.504931-4-keescook@chromium.org> In-Reply-To: <20220227184517.504931-1-keescook@chromium.org> References: <20220227184517.504931-1-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Kees Cook Cc: David Gow , "Gustavo A. R. Silva" , Nathan Chancellor , Nick Desaulniers , Rasmus Villemoes , Vitor Massaru Iha , Daniel Latypov , Anton Ivanov , Jeff Dike , Richard Weinberger , Masahiro Yamada , Arnd Bergmann , linux-kernel@vger.kernel.org, linux-um@lists.infradead.org, linux-kbuild@vger.kernel.org, kunit-dev@googlegroups.com, llvm@lists.linux.dev, x86@kernel.org, linux-hardening@vger.kernel.org List-ID: From: David Gow The syscall_handler_t type for x86_64 was defined as 'long (*)(void)', but always cast to 'long (*)(long, long, long, long, long, long)' before use. This now triggers a warning (see below). Define syscall_handler_t as the latter instead, and remove the cast. This simplifies the code, and fixes the warning. Warning: In file included from ../arch/um/include/asm/processor-generic.h:13 from ../arch/x86/um/asm/processor.h:41 from ../include/linux/rcupdate.h:30 from ../include/linux/rculist.h:11 from ../include/linux/pid.h:5 from ../include/linux/sched.h:14 from ../include/linux/ptrace.h:6 from ../arch/um/kernel/skas/syscall.c:7: ../arch/um/kernel/skas/syscall.c: In function ‘handle_syscall’: ../arch/x86/um/shared/sysdep/syscalls_64.h:18:11: warning: cast between incompatible function types from ‘long int (*)(void)’ to ‘long int (*)(long int, long int, long int, long int, long int, long int)’ [ -Wcast-function-type] 18 | (((long (*)(long, long, long, long, long, long)) \ | ^ ../arch/x86/um/asm/ptrace.h:36:62: note: in definition of macro ‘PT_REGS_SET_SYSCALL_RETURN’ 36 | #define PT_REGS_SET_SYSCALL_RETURN(r, res) (PT_REGS_AX(r) = (res)) | ^~~ ../arch/um/kernel/skas/syscall.c:46:33: note: in expansion of macro ‘EXECUTE_SYSCALL’ 46 | EXECUTE_SYSCALL(syscall, regs)); | ^~~~~~~~~~~~~~~ Signed-off-by: David Gow Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20220210034353.1065703-1-davidgow@google.com --- This is just a re-send of the above linked patch, collecting it into this series. --- arch/x86/um/shared/sysdep/syscalls_64.h | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/um/shared/sysdep/syscalls_64.h b/arch/x86/um/shared/sysdep/syscalls_64.h index 48d6cd12f8a5..b6b997225841 100644 --- a/arch/x86/um/shared/sysdep/syscalls_64.h +++ b/arch/x86/um/shared/sysdep/syscalls_64.h @@ -10,13 +10,12 @@ #include #include -typedef long syscall_handler_t(void); +typedef long syscall_handler_t(long, long, long, long, long, long); extern syscall_handler_t *sys_call_table[]; #define EXECUTE_SYSCALL(syscall, regs) \ - (((long (*)(long, long, long, long, long, long)) \ - (*sys_call_table[syscall]))(UPT_SYSCALL_ARG1(®s->regs), \ + (((*sys_call_table[syscall]))(UPT_SYSCALL_ARG1(®s->regs), \ UPT_SYSCALL_ARG2(®s->regs), \ UPT_SYSCALL_ARG3(®s->regs), \ UPT_SYSCALL_ARG4(®s->regs), \ -- 2.32.0