From 253f29a4ae9cc6cdc7b94f96517f27a93885a6ce Mon Sep 17 00:00:00 2001 From: Brian Gerst Date: Tue, 10 Feb 2009 09:51:46 -0500 Subject: [PATCH] x86: pass in pt_regs pointer for syscalls that need it Some syscalls need to access the pt_regs structure, either to copy user register state or to modifiy it. This patch adds stubs to load the address of the pt_regs struct into the %eax register, and changes the syscalls to regparm(1) to receive the pt_regs pointer as the first argument. Signed-off-by: Brian Gerst Acked-by: Tejun Heo Signed-off-by: Ingo Molnar --- arch/x86/include/asm/linkage.h | 7 ++++++ arch/x86/include/asm/syscalls.h | 25 ++++++++++++--------- arch/x86/kernel/entry_32.S | 20 +++++++++++++++++ arch/x86/kernel/ioport.c | 4 +--- arch/x86/kernel/process_32.c | 35 ++++++++++++------------------ arch/x86/kernel/signal.c | 35 ++++++------------------------ arch/x86/kernel/syscall_table_32.S | 20 ++++++++--------- arch/x86/kernel/vm86_32.c | 15 ++++++------- 8 files changed, 81 insertions(+), 80 deletions(-) diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h index 5d98d0b68ffc..2fd5926fb97d 100644 --- a/arch/x86/include/asm/linkage.h +++ b/arch/x86/include/asm/linkage.h @@ -17,6 +17,13 @@ */ #define asmregparm __attribute__((regparm(3))) +/* + * For syscalls that need a pointer to the pt_regs struct (ie. fork). + * The regs pointer is passed in %eax as the first argument. The + * remaining function arguments remain on the stack. + */ +#define ptregscall __attribute__((regparm(1))) + /* * Make sure the compiler doesn't do anything stupid with the * arguments on the stack - they are owned by the *caller*, not diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h index c0b0bda754ee..617295255a17 100644 --- a/arch/x86/include/asm/syscalls.h +++ b/arch/x86/include/asm/syscalls.h @@ -29,21 +29,26 @@ asmlinkage int sys_get_thread_area(struct user_desc __user *); /* X86_32 only */ #ifdef CONFIG_X86_32 /* kernel/process_32.c */ -asmlinkage int sys_fork(struct pt_regs); -asmlinkage int sys_clone(struct pt_regs); -asmlinkage int sys_vfork(struct pt_regs); -asmlinkage int sys_execve(struct pt_regs); +ptregscall int sys_fork(struct pt_regs *); +ptregscall int sys_clone(struct pt_regs *, unsigned long, + unsigned long, int __user *, + unsigned long, int __user *); +ptregscall int sys_vfork(struct pt_regs *); +ptregscall int sys_execve(struct pt_regs *, char __user *, + char __user * __user *, + char __user * __user *); /* kernel/signal_32.c */ asmlinkage int sys_sigsuspend(int, int, old_sigset_t); asmlinkage int sys_sigaction(int, const struct old_sigaction __user *, struct old_sigaction __user *); -asmlinkage int sys_sigaltstack(unsigned long); -asmlinkage unsigned long sys_sigreturn(unsigned long); -asmlinkage int sys_rt_sigreturn(unsigned long); +ptregscall int sys_sigaltstack(struct pt_regs *, const stack_t __user *, + stack_t __user *); +ptregscall unsigned long sys_sigreturn(struct pt_regs *); +ptregscall int sys_rt_sigreturn(struct pt_regs *); /* kernel/ioport.c */ -asmlinkage long sys_iopl(unsigned long); +ptregscall long sys_iopl(struct pt_regs *, unsigned int); /* kernel/sys_i386_32.c */ asmlinkage long sys_mmap2(unsigned long, unsigned long, unsigned long, @@ -59,8 +64,8 @@ struct oldold_utsname; asmlinkage int sys_olduname(struct oldold_utsname __user *); /* kernel/vm86_32.c */ -asmlinkage int sys_vm86old(struct pt_regs); -asmlinkage int sys_vm86(struct pt_regs); +ptregscall int sys_vm86old(struct pt_regs *, struct vm86_struct __user *); +ptregscall int sys_vm86(struct pt_regs *, unsigned long, unsigned long); #else /* CONFIG_X86_32 */ diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 5f5bd22adcd4..3de7b5710dc8 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -697,6 +697,26 @@ syscall_badsys: END(syscall_badsys) CFI_ENDPROC +/* + * System calls that need a pt_regs pointer. + */ +#define PTREGSCALL(name) \ + ALIGN; \ +ptregs_##name: \ + leal 4(%esp),%eax; \ + jmp sys_##name; + +PTREGSCALL(iopl) +PTREGSCALL(fork) +PTREGSCALL(clone) +PTREGSCALL(vfork) +PTREGSCALL(execve) +PTREGSCALL(sigaltstack) +PTREGSCALL(sigreturn) +PTREGSCALL(rt_sigreturn) +PTREGSCALL(vm86) +PTREGSCALL(vm86old) + .macro FIXUP_ESPFIX_STACK /* since we are on a wrong stack, we cant make it a C code :( */ PER_CPU(gdt_page, %ebx) diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index b12208f4dfee..7ec148646312 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -131,10 +131,8 @@ static int do_iopl(unsigned int level, struct pt_regs *regs) } #ifdef CONFIG_X86_32 -asmlinkage long sys_iopl(unsigned long regsp) +ptregscall long sys_iopl(struct pt_regs *regs, unsigned int level) { - struct pt_regs *regs = (struct pt_regs *)®sp; - unsigned int level = regs->bx; struct thread_struct *t = ¤t->thread; int rc; diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index b50604bb1e41..5a9dcfb01f71 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -603,24 +603,18 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) return prev_p; } -asmlinkage int sys_fork(struct pt_regs regs) +ptregscall int sys_fork(struct pt_regs *regs) { - return do_fork(SIGCHLD, regs.sp, ®s, 0, NULL, NULL); + return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL); } -asmlinkage int sys_clone(struct pt_regs regs) +ptregscall int sys_clone(struct pt_regs *regs, unsigned long clone_flags, + unsigned long newsp, int __user *parent_tidptr, + unsigned long unused, int __user *child_tidptr) { - unsigned long clone_flags; - unsigned long newsp; - int __user *parent_tidptr, *child_tidptr; - - clone_flags = regs.bx; - newsp = regs.cx; - parent_tidptr = (int __user *)regs.dx; - child_tidptr = (int __user *)regs.di; if (!newsp) - newsp = regs.sp; - return do_fork(clone_flags, newsp, ®s, 0, parent_tidptr, child_tidptr); + newsp = regs->sp; + return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr); } /* @@ -633,27 +627,26 @@ asmlinkage int sys_clone(struct pt_regs regs) * do not have enough call-clobbered registers to hold all * the information you need. */ -asmlinkage int sys_vfork(struct pt_regs regs) +ptregscall int sys_vfork(struct pt_regs *regs) { - return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.sp, ®s, 0, NULL, NULL); + return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0, NULL, NULL); } /* * sys_execve() executes a new program. */ -asmlinkage int sys_execve(struct pt_regs regs) +ptregscall int sys_execve(struct pt_regs *regs, char __user *u_filename, + char __user * __user *argv, + char __user * __user *envp) { int error; char *filename; - filename = getname((char __user *) regs.bx); + filename = getname(u_filename); error = PTR_ERR(filename); if (IS_ERR(filename)) goto out; - error = do_execve(filename, - (char __user * __user *) regs.cx, - (char __user * __user *) regs.dx, - ®s); + error = do_execve(filename, argv, envp, regs); if (error == 0) { /* Make sure we don't return using sysenter.. */ set_thread_flag(TIF_IRET); diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 8562387c75a7..d7a158367e38 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -549,39 +549,28 @@ sys_sigaction(int sig, const struct old_sigaction __user *act, #endif /* CONFIG_X86_32 */ #ifdef CONFIG_X86_32 -asmlinkage int sys_sigaltstack(unsigned long bx) -{ - /* - * This is needed to make gcc realize it doesn't own the - * "struct pt_regs" - */ - struct pt_regs *regs = (struct pt_regs *)&bx; - const stack_t __user *uss = (const stack_t __user *)bx; - stack_t __user *uoss = (stack_t __user *)regs->cx; - - return do_sigaltstack(uss, uoss, regs->sp); -} +ptregscall int +sys_sigaltstack(struct pt_regs *regs, const stack_t __user *uss, + stack_t __user *uoss) #else /* !CONFIG_X86_32 */ asmlinkage long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, struct pt_regs *regs) +#endif /* CONFIG_X86_32 */ { return do_sigaltstack(uss, uoss, regs->sp); } -#endif /* CONFIG_X86_32 */ /* * Do a signal return; undo the signal stack. */ #ifdef CONFIG_X86_32 -asmlinkage unsigned long sys_sigreturn(unsigned long __unused) +ptregscall unsigned long sys_sigreturn(struct pt_regs *regs) { struct sigframe __user *frame; - struct pt_regs *regs; unsigned long ax; sigset_t set; - regs = (struct pt_regs *) &__unused; frame = (struct sigframe __user *)(regs->sp - 8); if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) @@ -640,23 +629,13 @@ badframe: } #ifdef CONFIG_X86_32 -/* - * Note: do not pass in pt_regs directly as with tail-call optimization - * GCC will incorrectly stomp on the caller's frame and corrupt user-space - * register state: - */ -asmlinkage int sys_rt_sigreturn(unsigned long __unused) -{ - struct pt_regs *regs = (struct pt_regs *)&__unused; - - return do_rt_sigreturn(regs); -} +ptregscall int sys_rt_sigreturn(struct pt_regs *regs) #else /* !CONFIG_X86_32 */ asmlinkage long sys_rt_sigreturn(struct pt_regs *regs) +#endif /* CONFIG_X86_32 */ { return do_rt_sigreturn(regs); } -#endif /* CONFIG_X86_32 */ /* * OK, we're invoking a handler: diff --git a/arch/x86/kernel/syscall_table_32.S b/arch/x86/kernel/syscall_table_32.S index e2e86a08f31d..3bdb64829b82 100644 --- a/arch/x86/kernel/syscall_table_32.S +++ b/arch/x86/kernel/syscall_table_32.S @@ -1,7 +1,7 @@ ENTRY(sys_call_table) .long sys_restart_syscall /* 0 - old "setup()" system call, used for restarting */ .long sys_exit - .long sys_fork + .long ptregs_fork .long sys_read .long sys_write .long sys_open /* 5 */ @@ -10,7 +10,7 @@ ENTRY(sys_call_table) .long sys_creat .long sys_link .long sys_unlink /* 10 */ - .long sys_execve + .long ptregs_execve .long sys_chdir .long sys_time .long sys_mknod @@ -109,17 +109,17 @@ ENTRY(sys_call_table) .long sys_newlstat .long sys_newfstat .long sys_uname - .long sys_iopl /* 110 */ + .long ptregs_iopl /* 110 */ .long sys_vhangup .long sys_ni_syscall /* old "idle" system call */ - .long sys_vm86old + .long ptregs_vm86old .long sys_wait4 .long sys_swapoff /* 115 */ .long sys_sysinfo .long sys_ipc .long sys_fsync - .long sys_sigreturn - .long sys_clone /* 120 */ + .long ptregs_sigreturn + .long ptregs_clone /* 120 */ .long sys_setdomainname .long sys_newuname .long sys_modify_ldt @@ -165,14 +165,14 @@ ENTRY(sys_call_table) .long sys_mremap .long sys_setresuid16 .long sys_getresuid16 /* 165 */ - .long sys_vm86 + .long ptregs_vm86 .long sys_ni_syscall /* Old sys_query_module */ .long sys_poll .long sys_nfsservctl .long sys_setresgid16 /* 170 */ .long sys_getresgid16 .long sys_prctl - .long sys_rt_sigreturn + .long ptregs_rt_sigreturn .long sys_rt_sigaction .long sys_rt_sigprocmask /* 175 */ .long sys_rt_sigpending @@ -185,11 +185,11 @@ ENTRY(sys_call_table) .long sys_getcwd .long sys_capget .long sys_capset /* 185 */ - .long sys_sigaltstack + .long ptregs_sigaltstack .long sys_sendfile .long sys_ni_syscall /* reserved for streams1 */ .long sys_ni_syscall /* reserved for streams2 */ - .long sys_vfork /* 190 */ + .long ptregs_vfork /* 190 */ .long sys_getrlimit .long sys_mmap2 .long sys_truncate64 diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c index 55ea30d2a3d6..8fa6ba7c9233 100644 --- a/arch/x86/kernel/vm86_32.c +++ b/arch/x86/kernel/vm86_32.c @@ -197,9 +197,8 @@ out: static int do_vm86_irq_handling(int subfunction, int irqnumber); static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk); -asmlinkage int sys_vm86old(struct pt_regs regs) +ptregscall int sys_vm86old(struct pt_regs *regs, struct vm86_struct __user *v86) { - struct vm86_struct __user *v86 = (struct vm86_struct __user *)regs.bx; struct kernel_vm86_struct info; /* declare this _on top_, * this avoids wasting of stack space. * This remains on the stack until we @@ -218,7 +217,7 @@ asmlinkage int sys_vm86old(struct pt_regs regs) if (tmp) goto out; memset(&info.vm86plus, 0, (int)&info.regs32 - (int)&info.vm86plus); - info.regs32 = ®s; + info.regs32 = regs; tsk->thread.vm86_info = v86; do_sys_vm86(&info, tsk); ret = 0; /* we never return here */ @@ -227,7 +226,7 @@ out: } -asmlinkage int sys_vm86(struct pt_regs regs) +ptregscall int sys_vm86(struct pt_regs *regs, unsigned long cmd, unsigned long arg) { struct kernel_vm86_struct info; /* declare this _on top_, * this avoids wasting of stack space. @@ -239,12 +238,12 @@ asmlinkage int sys_vm86(struct pt_regs regs) struct vm86plus_struct __user *v86; tsk = current; - switch (regs.bx) { + switch (cmd) { case VM86_REQUEST_IRQ: case VM86_FREE_IRQ: case VM86_GET_IRQ_BITS: case VM86_GET_AND_RESET_IRQ: - ret = do_vm86_irq_handling(regs.bx, (int)regs.cx); + ret = do_vm86_irq_handling(cmd, (int)arg); goto out; case VM86_PLUS_INSTALL_CHECK: /* @@ -261,14 +260,14 @@ asmlinkage int sys_vm86(struct pt_regs regs) ret = -EPERM; if (tsk->thread.saved_sp0) goto out; - v86 = (struct vm86plus_struct __user *)regs.cx; + v86 = (struct vm86plus_struct __user *)arg; tmp = copy_vm86_regs_from_user(&info.regs, &v86->regs, offsetof(struct kernel_vm86_struct, regs32) - sizeof(info.regs)); ret = -EFAULT; if (tmp) goto out; - info.regs32 = ®s; + info.regs32 = regs; info.vm86plus.is_vm86pus = 1; tsk->thread.vm86_info = (struct vm86_struct __user *)v86; do_sys_vm86(&info, tsk); -- 2.20.1