Added vDSO support; signal trampoline is no longer on the stack so it no longer needs to be executable. Signed-off-by: Richard Kuo Signed-off-by: Linas Vepstas --- arch/hexagon/include/asm/sigcontext.h | 32 +++ arch/hexagon/include/asm/signal.h | 26 ++ arch/hexagon/include/asm/vdso.h | 31 +++ arch/hexagon/kernel/signal.c | 320 ++++++++++++++++++++++++++++++++++ arch/hexagon/kernel/trampoline.S | 35 +++ arch/hexagon/kernel/vdso.c | 101 ++++++++++ 6 files changed, 545 insertions(+) Index: linux-hexagon-kernel/arch/hexagon/include/asm/sigcontext.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-hexagon-kernel/arch/hexagon/include/asm/sigcontext.h 2011-09-08 19:22:01.150239048 -0500 @@ -0,0 +1,32 @@ +/* + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#ifndef _ASM_SIGCONTEXT_H +#define _ASM_SIGCONTEXT_H + +#include + +/* + * Signal context structure - contains all info to do with the state + * before the signal handler was invoked. + */ +struct sigcontext { + struct pt_regs sc_regs; +}; + +#endif Index: linux-hexagon-kernel/arch/hexagon/include/asm/signal.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-hexagon-kernel/arch/hexagon/include/asm/signal.h 2011-09-08 19:22:01.150239048 -0500 @@ -0,0 +1,26 @@ +/* + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#ifndef _ASM_SIGNAL_H +#define _ASM_SIGNAL_H + +extern unsigned long __rt_sigtramp_template[2]; + +#include + +#endif Index: linux-hexagon-kernel/arch/hexagon/kernel/signal.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-hexagon-kernel/arch/hexagon/kernel/signal.c 2011-09-08 19:22:01.150239048 -0500 @@ -0,0 +1,320 @@ +/* + * Signal support for Hexagon processor + * + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +struct sigframe { + unsigned long pad[2]; /* Used to be signal tramp */ + struct sigcontext sc; + sigset_t mask; +}; + +struct rt_sigframe { + unsigned long pad[2]; /* Used to be signal tramp */ + struct siginfo info; + struct ucontext uc; +}; + +static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, + size_t frame_size) +{ + unsigned long sp = regs->r29; + + /* Switch to signal stack if appropriate */ + if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0)) + sp = current->sas_ss_sp + current->sas_ss_size; + + return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1)); +} + +static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) +{ + int err = 0; + + /* + * Need to revisit if we're leaking anything inappropriate to user + * stack. + */ + + err |= copy_to_user(&sc->sc_regs, regs, sizeof(struct pt_regs)); + return err; +} + +static int restore_sigcontext(struct pt_regs *regs, + struct sigcontext __user *sc) +{ + int err = 0; + + /* + * Should only restore vmel in case user stack is corrupted, + * bogus status shouldn't be used in the rte. + */ + + err |= copy_from_user(regs, &sc->sc_regs, + offsetof(struct pt_regs, hvmer.vmel) + + sizeof(unsigned long)); + return err; +} + +/* + * Setup signal stack frame with siginfo structure + */ +static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info, + sigset_t *set, struct pt_regs *regs) +{ + int err = 0; + struct rt_sigframe __user *frame; + struct hexagon_vdso *vdso = current->mm->context.vdso; + + frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe)); + + if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe))) + goto sigsegv; + + if (copy_siginfo_to_user(&frame->info, info)) + goto sigsegv; + + mb(); + err |= setup_sigcontext(regs, &frame->uc.uc_mcontext); + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + if (err) + goto sigsegv; + + /* Load r0/r1 pair with signumber/siginfo pointer... */ + regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32) + | (unsigned long long)signr; + regs->r02 = (unsigned long) &frame->uc; + regs->r31 = (unsigned long) vdso->rt_signal_trampoline; + pt_psp(regs) = (unsigned long) frame; + pt_set_elr(regs, (unsigned long)ka->sa.sa_handler); + + return 0; + +sigsegv: + force_sigsegv(signr, current); + return -EFAULT; +} + +/* + * Setup invocation of signal handler + */ +static int handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka, + sigset_t *oldset, struct pt_regs *regs) +{ + int rc; + + /* + * If we're handling a signal that aborted a system call, + * set up the error return value before adding the signal + * frame to the stack. + */ + + if (regs->syscall_nr >= 0) { + switch (regs->r00) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + regs->r00 = -EINTR; + break; + case -ERESTARTSYS: + if (!(ka->sa.sa_flags & SA_RESTART)) { + regs->r00 = -EINTR; + break; + } + /* Fall through */ + case -ERESTARTNOINTR: + regs->r06 = regs->syscall_nr; + pt_set_elr(regs, pt_elr(regs) - 4); + regs->r00 = regs->restart_r0; + break; + default: + break; + } + } + + /* + * Set up the stack frame; not doing the SA_SIGINFO thing. We + * only set up the rt_frame flavor. + */ + rc = setup_rt_frame(sig, ka, info, oldset, regs); + + /* If there was an error on setup, no signal was delivered. */ + if (rc) + return rc; + + spin_lock_irq(¤t->sighand->siglock); + sigorsets(¤t->blocked, ¤t->blocked, &ka->sa.sa_mask); + if (!(ka->sa.sa_flags & SA_NODEFER)) + sigaddset(¤t->blocked, sig); + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + return 0; +} + +/* + * Called from return-from-event code. + */ +static void do_signal(struct pt_regs *regs) +{ + struct k_sigaction sigact; + siginfo_t info; + int signo; + + if (!user_mode(regs)) + return; + + if (try_to_freeze()) + goto no_signal; + + signo = get_signal_to_deliver(&info, &sigact, regs, NULL); + + if (signo > 0) { + sigset_t *oldset; + + if (test_thread_flag(TIF_RESTORE_SIGMASK)) + oldset = ¤t->saved_sigmask; + else + oldset = ¤t->blocked; + + if (handle_signal(signo, &info, &sigact, oldset, regs) == 0) { + /* + * Successful delivery case. The saved sigmask is + * stored in the signal frame, and will be restored + * by sigreturn. We can clear the TIF flag. + */ + clear_thread_flag(TIF_RESTORE_SIGMASK); + } + return; + } + +no_signal: + /* + * If we came from a system call, handle the restart. + */ + if (regs->syscall_nr >= 0) { + switch (regs->r00) { + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + regs->r06 = regs->syscall_nr; + break; + case -ERESTART_RESTARTBLOCK: + regs->r06 = __NR_restart_syscall; + break; + default: + goto no_restart; + } + pt_set_elr(regs, pt_elr(regs) - 4); + regs->r00 = regs->restart_r0; + } + +no_restart: + /* If there's no signal to deliver, put the saved sigmask back */ + if (test_thread_flag(TIF_RESTORE_SIGMASK)) { + clear_thread_flag(TIF_RESTORE_SIGMASK); + sigprocmask(SIG_SETMASK, ¤t->saved_sigmask, NULL); + } +} + +void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) +{ + if (thread_info_flags & _TIF_SIGPENDING) + do_signal(regs); + + if (thread_info_flags & _TIF_NOTIFY_RESUME) { + clear_thread_flag(TIF_NOTIFY_RESUME); + if (current->replacement_session_keyring) + key_replace_session_keyring(); + } +} + +/* + * Architecture-specific wrappers for signal-related system calls + */ +asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss) +{ + struct pt_regs *regs = current_thread_info()->regs; + + return do_sigaltstack(uss, uoss, regs->r29); +} + +asmlinkage int sys_rt_sigreturn(void) +{ + struct pt_regs *regs = current_thread_info()->regs; + struct rt_sigframe __user *frame; + sigset_t blocked; + + frame = (struct rt_sigframe __user *)pt_psp(regs); + if (!access_ok(VERIFY_READ, frame, sizeof(*frame))) + goto badframe; + if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked))) + goto badframe; + + sigdelsetmask(&blocked, ~_BLOCKABLE); + spin_lock_irq(¤t->sighand->siglock); + current->blocked = blocked; + recalc_sigpending(); + spin_unlock_irq(¤t->sighand->siglock); + + if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + goto badframe; + + /* Restore the user's stack as well */ + pt_psp(regs) = regs->r29; + + /* + * Leave a trace in the stack frame that this was a sigreturn. + * If the system call is to replay, we've already restored the + * number in the GPR slot and it will be regenerated on the + * new system call trap entry. Note that if restore_sigcontext() + * did something other than a bulk copy of the pt_regs struct, + * we could avoid this assignment by simply not overwriting + * regs->syscall_nr. + */ + regs->syscall_nr = __NR_rt_sigreturn; + + /* + * If we were meticulous, we'd only call this if we knew that + * we were actually going to use an alternate stack, and we'd + * consider any error to be fatal. What we do here, in common + * with many other architectures, is call it blindly and only + * consider the -EFAULT return case to be proof of a problem. + */ + if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT) + goto badframe; + + return 0; + +badframe: + force_sig(SIGSEGV, current); + return 0; +} Index: linux-hexagon-kernel/arch/hexagon/kernel/trampoline.S =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-hexagon-kernel/arch/hexagon/kernel/trampoline.S 2011-09-08 19:22:01.150239048 -0500 @@ -0,0 +1,35 @@ +/* + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +/* + * Trampoline sequences to be copied onto user stack. + * This consumes a little more space than hand-assembling + * immediate constants for use in C, but is more portable + * to future tweaks to the Hexagon instruction set. + */ + +#include + +/* Sig trampolines - call sys_sigreturn or sys_rt_sigreturn as appropriate */ + +/* plain sigreturn is gone. */ + + .globl __rt_sigtramp_template +__rt_sigtramp_template: + r6 = #__NR_rt_sigreturn; + trap0(#1); Index: linux-hexagon-kernel/arch/hexagon/include/asm/vdso.h =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-hexagon-kernel/arch/hexagon/include/asm/vdso.h 2011-09-08 19:36:15.052799920 -0500 @@ -0,0 +1,31 @@ +/* + * vDSO implementation for Hexagon + * + * Copyright (c) 2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#ifndef __ASM_VDSO_H +#define __ASM_VDSO_H + +#include + +struct hexagon_vdso { + u32 rt_signal_trampoline[2]; +}; + +#endif /* __ASM_VDSO_H */ + Index: linux-hexagon-kernel/arch/hexagon/kernel/vdso.c =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-hexagon-kernel/arch/hexagon/kernel/vdso.c 2011-09-08 19:22:01.150239048 -0500 @@ -0,0 +1,101 @@ +/* + * vDSO implementation for Hexagon + * + * Copyright (c) 2011, Code Aurora Forum. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 and + * only version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +#include +#include +#include + +#include + +static struct page *vdso_page; + +/* Create a vDSO page holding the signal trampoline. + * We want this for a non-executable stack. + */ +static int __init vdso_init(void) +{ + struct hexagon_vdso *vdso; + + vdso_page = alloc_page(GFP_KERNEL); + if (!vdso_page) + panic("Cannot allocate vdso"); + + vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL); + if (!vdso) + panic("Cannot map vdso"); + clear_page(vdso); + + /* Install the signal trampoline; currently looks like this: + * r6 = #__NR_rt_sigreturn; + * trap0(#1); + */ + vdso->rt_signal_trampoline[0] = __rt_sigtramp_template[0]; + vdso->rt_signal_trampoline[1] = __rt_sigtramp_template[1]; + + vunmap(vdso); + + return 0; +} +arch_initcall(vdso_init); + +/* + * Called from binfmt_elf. Create a VMA for the vDSO page. + */ +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) +{ + int ret; + unsigned long vdso_base; + struct mm_struct *mm = current->mm; + + down_write(&mm->mmap_sem); + + /* Try to get it loaded right near ld.so/glibc. */ + vdso_base = STACK_TOP; + + vdso_base = get_unmapped_area(NULL, vdso_base, PAGE_SIZE, 0, 0); + if (IS_ERR_VALUE(vdso_base)) { + ret = vdso_base; + goto up_fail; + } + + /* MAYWRITE to allow gdb to COW and set breakpoints. */ + ret = install_special_mapping(mm, vdso_base, PAGE_SIZE, + VM_READ|VM_EXEC| + VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC| + VM_ALWAYSDUMP, + &vdso_page); + + if (ret) + goto up_fail; + + mm->context.vdso = (void *)vdso_base; + +up_fail: + up_write(&mm->mmap_sem); + return ret; +} + +const char *arch_vma_name(struct vm_area_struct *vma) +{ + if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) + return "[vdso]"; + return NULL; +} + -- Sent by an employee of the Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/