diff options
Diffstat (limited to 'arch/parisc/kernel/signal.c')
-rw-r--r-- | arch/parisc/kernel/signal.c | 621 |
1 files changed, 621 insertions, 0 deletions
diff --git a/arch/parisc/kernel/signal.c b/arch/parisc/kernel/signal.c new file mode 100644 index 000000000..79b05eac2 --- /dev/null +++ b/arch/parisc/kernel/signal.c @@ -0,0 +1,621 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/arch/parisc/kernel/signal.c: Architecture-specific signal + * handling support. + * + * Copyright (C) 2000 David Huggins-Daines <dhd@debian.org> + * Copyright (C) 2000 Linuxcare, Inc. + * + * Based on the ia64, i386, and alpha versions. + * + * Like the IA-64, we are a recent enough port (we are *starting* + * with glibc2.2) that we do not need to support the old non-realtime + * Linux signals. Therefore we don't. + */ + +#include <linux/sched.h> +#include <linux/sched/debug.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/kernel.h> +#include <linux/signal.h> +#include <linux/errno.h> +#include <linux/wait.h> +#include <linux/ptrace.h> +#include <linux/tracehook.h> +#include <linux/unistd.h> +#include <linux/stddef.h> +#include <linux/compat.h> +#include <linux/elf.h> +#include <asm/ucontext.h> +#include <asm/rt_sigframe.h> +#include <linux/uaccess.h> +#include <asm/pgalloc.h> +#include <asm/cacheflush.h> +#include <asm/asm-offsets.h> + +#ifdef CONFIG_COMPAT +#include "signal32.h" +#endif + +#define DEBUG_SIG 0 +#define DEBUG_SIG_LEVEL 2 + +#if DEBUG_SIG +#define DBG(LEVEL, ...) \ + ((DEBUG_SIG_LEVEL >= LEVEL) \ + ? printk(__VA_ARGS__) : (void) 0) +#else +#define DBG(LEVEL, ...) +#endif + +/* gcc will complain if a pointer is cast to an integer of different + * size. If you really need to do this (and we do for an ELF32 user + * application in an ELF64 kernel) then you have to do a cast to an + * integer of the same size first. The A() macro accomplishes + * this. */ +#define A(__x) ((unsigned long)(__x)) + +/* + * Do a signal return - restore sigcontext. + */ + +/* Trampoline for calling rt_sigreturn() */ +#define INSN_LDI_R25_0 0x34190000 /* ldi 0,%r25 (in_syscall=0) */ +#define INSN_LDI_R25_1 0x34190002 /* ldi 1,%r25 (in_syscall=1) */ +#define INSN_LDI_R20 0x3414015a /* ldi __NR_rt_sigreturn,%r20 */ +#define INSN_BLE_SR2_R0 0xe4008200 /* be,l 0x100(%sr2,%r0),%sr0,%r31 */ +#define INSN_NOP 0x08000240 /* nop */ +/* For debugging */ +#define INSN_DIE_HORRIBLY 0x68000ccc /* stw %r0,0x666(%sr0,%r0) */ + +static long +restore_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs) +{ + long err = 0; + + err |= __copy_from_user(regs->gr, sc->sc_gr, sizeof(regs->gr)); + err |= __copy_from_user(regs->fr, sc->sc_fr, sizeof(regs->fr)); + err |= __copy_from_user(regs->iaoq, sc->sc_iaoq, sizeof(regs->iaoq)); + err |= __copy_from_user(regs->iasq, sc->sc_iasq, sizeof(regs->iasq)); + err |= __get_user(regs->sar, &sc->sc_sar); + DBG(2,"restore_sigcontext: iaoq is %#lx / %#lx\n", + regs->iaoq[0],regs->iaoq[1]); + DBG(2,"restore_sigcontext: r28 is %ld\n", regs->gr[28]); + return err; +} + +void +sys_rt_sigreturn(struct pt_regs *regs, int in_syscall) +{ + struct rt_sigframe __user *frame; + sigset_t set; + unsigned long usp = (regs->gr[30] & ~(0x01UL)); + unsigned long sigframe_size = PARISC_RT_SIGFRAME_SIZE; +#ifdef CONFIG_64BIT + struct compat_rt_sigframe __user * compat_frame; + + if (is_compat_task()) + sigframe_size = PARISC_RT_SIGFRAME_SIZE32; +#endif + + current->restart_block.fn = do_no_restart_syscall; + + /* Unwind the user stack to get the rt_sigframe structure. */ + frame = (struct rt_sigframe __user *) + (usp - sigframe_size); + DBG(2,"sys_rt_sigreturn: frame is %p\n", frame); + + regs->orig_r28 = 1; /* no restarts for sigreturn */ + +#ifdef CONFIG_64BIT + compat_frame = (struct compat_rt_sigframe __user *)frame; + + if (is_compat_task()) { + DBG(2,"sys_rt_sigreturn: ELF32 process.\n"); + if (get_compat_sigset(&set, &compat_frame->uc.uc_sigmask)) + goto give_sigsegv; + } else +#endif + { + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) + goto give_sigsegv; + } + + set_current_blocked(&set); + + /* Good thing we saved the old gr[30], eh? */ +#ifdef CONFIG_64BIT + if (is_compat_task()) { + DBG(1,"sys_rt_sigreturn: compat_frame->uc.uc_mcontext 0x%p\n", + &compat_frame->uc.uc_mcontext); +// FIXME: Load upper half from register file + if (restore_sigcontext32(&compat_frame->uc.uc_mcontext, + &compat_frame->regs, regs)) + goto give_sigsegv; + DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", + usp, &compat_frame->uc.uc_stack); + if (compat_restore_altstack(&compat_frame->uc.uc_stack)) + goto give_sigsegv; + } else +#endif + { + DBG(1,"sys_rt_sigreturn: frame->uc.uc_mcontext 0x%p\n", + &frame->uc.uc_mcontext); + if (restore_sigcontext(&frame->uc.uc_mcontext, regs)) + goto give_sigsegv; + DBG(1,"sys_rt_sigreturn: usp %#08lx stack 0x%p\n", + usp, &frame->uc.uc_stack); + if (restore_altstack(&frame->uc.uc_stack)) + goto give_sigsegv; + } + + + + /* If we are on the syscall path IAOQ will not be restored, and + * if we are on the interrupt path we must not corrupt gr31. + */ + if (in_syscall) + regs->gr[31] = regs->iaoq[0]; +#if DEBUG_SIG + DBG(1,"sys_rt_sigreturn: returning to %#lx, DUMPING REGS:\n", regs->iaoq[0]); + show_regs(regs); +#endif + return; + +give_sigsegv: + DBG(1,"sys_rt_sigreturn: Sending SIGSEGV\n"); + force_sig(SIGSEGV, current); + return; +} + +/* + * Set up a signal frame. + */ + +static inline void __user * +get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size) +{ + /*FIXME: ELF32 vs. ELF64 has different frame_size, but since we + don't use the parameter it doesn't matter */ + + DBG(1,"get_sigframe: ka = %#lx, sp = %#lx, frame_size = %#lx\n", + (unsigned long)ka, sp, frame_size); + + /* Align alternate stack and reserve 64 bytes for the signal + handler's frame marker. */ + if ((ka->sa.sa_flags & SA_ONSTACK) != 0 && ! sas_ss_flags(sp)) + sp = (current->sas_ss_sp + 0x7f) & ~0x3f; /* Stacks grow up! */ + + DBG(1,"get_sigframe: Returning sp = %#lx\n", (unsigned long)sp); + return (void __user *) sp; /* Stacks grow up. Fun. */ +} + +static long +setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs, int in_syscall) + +{ + unsigned long flags = 0; + long err = 0; + + if (on_sig_stack((unsigned long) sc)) + flags |= PARISC_SC_FLAG_ONSTACK; + if (in_syscall) { + flags |= PARISC_SC_FLAG_IN_SYSCALL; + /* regs->iaoq is undefined in the syscall return path */ + err |= __put_user(regs->gr[31], &sc->sc_iaoq[0]); + err |= __put_user(regs->gr[31]+4, &sc->sc_iaoq[1]); + err |= __put_user(regs->sr[3], &sc->sc_iasq[0]); + err |= __put_user(regs->sr[3], &sc->sc_iasq[1]); + DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (in syscall)\n", + regs->gr[31], regs->gr[31]+4); + } else { + err |= __copy_to_user(sc->sc_iaoq, regs->iaoq, sizeof(regs->iaoq)); + err |= __copy_to_user(sc->sc_iasq, regs->iasq, sizeof(regs->iasq)); + DBG(1,"setup_sigcontext: iaoq %#lx / %#lx (not in syscall)\n", + regs->iaoq[0], regs->iaoq[1]); + } + + err |= __put_user(flags, &sc->sc_flags); + err |= __copy_to_user(sc->sc_gr, regs->gr, sizeof(regs->gr)); + err |= __copy_to_user(sc->sc_fr, regs->fr, sizeof(regs->fr)); + err |= __put_user(regs->sar, &sc->sc_sar); + DBG(1,"setup_sigcontext: r28 is %ld\n", regs->gr[28]); + + return err; +} + +static long +setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs, + int in_syscall) +{ + struct rt_sigframe __user *frame; + unsigned long rp, usp; + unsigned long haddr, sigframe_size; + unsigned long start, end; + int err = 0; +#ifdef CONFIG_64BIT + struct compat_rt_sigframe __user * compat_frame; +#endif + + usp = (regs->gr[30] & ~(0x01UL)); +#ifdef CONFIG_64BIT + if (is_compat_task()) { + /* The gcc alloca implementation leaves garbage in the upper 32 bits of sp */ + usp = (compat_uint_t)usp; + } +#endif + /*FIXME: frame_size parameter is unused, remove it. */ + frame = get_sigframe(&ksig->ka, usp, sizeof(*frame)); + + DBG(1,"SETUP_RT_FRAME: START\n"); + DBG(1,"setup_rt_frame: frame %p info %p\n", frame, ksig->info); + + +#ifdef CONFIG_64BIT + + compat_frame = (struct compat_rt_sigframe __user *)frame; + + if (is_compat_task()) { + DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &compat_frame->info); + err |= copy_siginfo_to_user32(&compat_frame->info, &ksig->info); + err |= __compat_save_altstack( &compat_frame->uc.uc_stack, regs->gr[30]); + DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &compat_frame->uc); + DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &compat_frame->uc.uc_mcontext); + err |= setup_sigcontext32(&compat_frame->uc.uc_mcontext, + &compat_frame->regs, regs, in_syscall); + err |= put_compat_sigset(&compat_frame->uc.uc_sigmask, set, + sizeof(compat_sigset_t)); + } else +#endif + { + DBG(1,"setup_rt_frame: frame->info = 0x%p\n", &frame->info); + err |= copy_siginfo_to_user(&frame->info, &ksig->info); + err |= __save_altstack(&frame->uc.uc_stack, regs->gr[30]); + DBG(1,"setup_rt_frame: frame->uc = 0x%p\n", &frame->uc); + DBG(1,"setup_rt_frame: frame->uc.uc_mcontext = 0x%p\n", &frame->uc.uc_mcontext); + err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, in_syscall); + /* FIXME: Should probably be converted as well for the compat case */ + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); + } + + if (err) + return -EFAULT; + + /* Set up to return from userspace. If provided, use a stub + already in userspace. The first words of tramp are used to + save the previous sigrestartblock trampoline that might be + on the stack. We start the sigreturn trampoline at + SIGRESTARTBLOCK_TRAMP+X. */ + err |= __put_user(in_syscall ? INSN_LDI_R25_1 : INSN_LDI_R25_0, + &frame->tramp[SIGRESTARTBLOCK_TRAMP+0]); + err |= __put_user(INSN_LDI_R20, + &frame->tramp[SIGRESTARTBLOCK_TRAMP+1]); + err |= __put_user(INSN_BLE_SR2_R0, + &frame->tramp[SIGRESTARTBLOCK_TRAMP+2]); + err |= __put_user(INSN_NOP, &frame->tramp[SIGRESTARTBLOCK_TRAMP+3]); + +#if DEBUG_SIG + /* Assert that we're flushing in the correct space... */ + { + unsigned long sid; + asm ("mfsp %%sr3,%0" : "=r" (sid)); + DBG(1,"setup_rt_frame: Flushing 64 bytes at space %#x offset %p\n", + sid, frame->tramp); + } +#endif + + start = (unsigned long) &frame->tramp[0]; + end = (unsigned long) &frame->tramp[TRAMP_SIZE]; + flush_user_dcache_range_asm(start, end); + flush_user_icache_range_asm(start, end); + + /* TRAMP Words 0-4, Length 5 = SIGRESTARTBLOCK_TRAMP + * TRAMP Words 5-9, Length 4 = SIGRETURN_TRAMP + * So the SIGRETURN_TRAMP is at the end of SIGRESTARTBLOCK_TRAMP + */ + rp = (unsigned long) &frame->tramp[SIGRESTARTBLOCK_TRAMP]; + + if (err) + return -EFAULT; + + haddr = A(ksig->ka.sa.sa_handler); + /* The sa_handler may be a pointer to a function descriptor */ +#ifdef CONFIG_64BIT + if (is_compat_task()) { +#endif + if (haddr & PA_PLABEL_FDESC) { + Elf32_Fdesc fdesc; + Elf32_Fdesc __user *ufdesc = (Elf32_Fdesc __user *)A(haddr & ~3); + + err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc)); + + if (err) + return -EFAULT; + + haddr = fdesc.addr; + regs->gr[19] = fdesc.gp; + } +#ifdef CONFIG_64BIT + } else { + Elf64_Fdesc fdesc; + Elf64_Fdesc __user *ufdesc = (Elf64_Fdesc __user *)A(haddr & ~3); + + err = __copy_from_user(&fdesc, ufdesc, sizeof(fdesc)); + + if (err) + return -EFAULT; + + haddr = fdesc.addr; + regs->gr[19] = fdesc.gp; + DBG(1,"setup_rt_frame: 64 bit signal, exe=%#lx, r19=%#lx, in_syscall=%d\n", + haddr, regs->gr[19], in_syscall); + } +#endif + + /* The syscall return path will create IAOQ values from r31. + */ + sigframe_size = PARISC_RT_SIGFRAME_SIZE; +#ifdef CONFIG_64BIT + if (is_compat_task()) + sigframe_size = PARISC_RT_SIGFRAME_SIZE32; +#endif + if (in_syscall) { + regs->gr[31] = haddr; +#ifdef CONFIG_64BIT + if (!test_thread_flag(TIF_32BIT)) + sigframe_size |= 1; +#endif + } else { + unsigned long psw = USER_PSW; +#ifdef CONFIG_64BIT + if (!test_thread_flag(TIF_32BIT)) + psw |= PSW_W; +#endif + + /* If we are singlestepping, arrange a trap to be delivered + when we return to userspace. Note the semantics -- we + should trap before the first insn in the handler is + executed. Ref: + http://sources.redhat.com/ml/gdb/2004-11/msg00245.html + */ + if (pa_psw(current)->r) { + pa_psw(current)->r = 0; + psw |= PSW_R; + mtctl(-1, 0); + } + + regs->gr[0] = psw; + regs->iaoq[0] = haddr | 3; + regs->iaoq[1] = regs->iaoq[0] + 4; + } + + regs->gr[2] = rp; /* userland return pointer */ + regs->gr[26] = ksig->sig; /* signal number */ + +#ifdef CONFIG_64BIT + if (is_compat_task()) { + regs->gr[25] = A(&compat_frame->info); /* siginfo pointer */ + regs->gr[24] = A(&compat_frame->uc); /* ucontext pointer */ + } else +#endif + { + regs->gr[25] = A(&frame->info); /* siginfo pointer */ + regs->gr[24] = A(&frame->uc); /* ucontext pointer */ + } + + DBG(1,"setup_rt_frame: making sigreturn frame: %#lx + %#lx = %#lx\n", + regs->gr[30], sigframe_size, + regs->gr[30] + sigframe_size); + /* Raise the user stack pointer to make a proper call frame. */ + regs->gr[30] = (A(frame) + sigframe_size); + + + DBG(1,"setup_rt_frame: sig deliver (%s,%d) frame=0x%p sp=%#lx iaoq=%#lx/%#lx rp=%#lx\n", + current->comm, current->pid, frame, regs->gr[30], + regs->iaoq[0], regs->iaoq[1], rp); + + return 0; +} + +/* + * OK, we're invoking a handler. + */ + +static void +handle_signal(struct ksignal *ksig, struct pt_regs *regs, int in_syscall) +{ + int ret; + sigset_t *oldset = sigmask_to_save(); + + DBG(1,"handle_signal: sig=%ld, ka=%p, info=%p, oldset=%p, regs=%p\n", + ksig->sig, ksig->ka, ksig->info, oldset, regs); + + /* Set up the stack frame */ + ret = setup_rt_frame(ksig, oldset, regs, in_syscall); + + signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP) || + test_thread_flag(TIF_BLOCKSTEP)); + + DBG(1,KERN_DEBUG "do_signal: Exit (success), regs->gr[28] = %ld\n", + regs->gr[28]); +} + +/* + * Check how the syscall number gets loaded into %r20 within + * the delay branch in userspace and adjust as needed. + */ + +static void check_syscallno_in_delay_branch(struct pt_regs *regs) +{ + u32 opcode, source_reg; + u32 __user *uaddr; + int err; + + /* Usually we don't have to restore %r20 (the system call number) + * because it gets loaded in the delay slot of the branch external + * instruction via the ldi instruction. + * In some cases a register-to-register copy instruction might have + * been used instead, in which case we need to copy the syscall + * number into the source register before returning to userspace. + */ + + /* A syscall is just a branch, so all we have to do is fiddle the + * return pointer so that the ble instruction gets executed again. + */ + regs->gr[31] -= 8; /* delayed branching */ + + /* Get assembler opcode of code in delay branch */ + uaddr = (unsigned int *) ((regs->gr[31] & ~3) + 4); + err = get_user(opcode, uaddr); + if (err) + return; + + /* Check if delay branch uses "ldi int,%r20" */ + if ((opcode & 0xffff0000) == 0x34140000) + return; /* everything ok, just return */ + + /* Check if delay branch uses "nop" */ + if (opcode == INSN_NOP) + return; + + /* Check if delay branch uses "copy %rX,%r20" */ + if ((opcode & 0xffe0ffff) == 0x08000254) { + source_reg = (opcode >> 16) & 31; + regs->gr[source_reg] = regs->gr[20]; + return; + } + + pr_warn("syscall restart: %s (pid %d): unexpected opcode 0x%08x\n", + current->comm, task_pid_nr(current), opcode); +} + +static inline void +syscall_restart(struct pt_regs *regs, struct k_sigaction *ka) +{ + if (regs->orig_r28) + return; + regs->orig_r28 = 1; /* no more restarts */ + /* Check the return code */ + switch (regs->gr[28]) { + case -ERESTART_RESTARTBLOCK: + case -ERESTARTNOHAND: + DBG(1,"ERESTARTNOHAND: returning -EINTR\n"); + regs->gr[28] = -EINTR; + break; + + case -ERESTARTSYS: + if (!(ka->sa.sa_flags & SA_RESTART)) { + DBG(1,"ERESTARTSYS: putting -EINTR\n"); + regs->gr[28] = -EINTR; + break; + } + /* fallthrough */ + case -ERESTARTNOINTR: + check_syscallno_in_delay_branch(regs); + break; + } +} + +static inline void +insert_restart_trampoline(struct pt_regs *regs) +{ + if (regs->orig_r28) + return; + regs->orig_r28 = 1; /* no more restarts */ + switch(regs->gr[28]) { + case -ERESTART_RESTARTBLOCK: { + /* Restart the system call - no handlers present */ + unsigned int *usp = (unsigned int *)regs->gr[30]; + unsigned long start = (unsigned long) &usp[2]; + unsigned long end = (unsigned long) &usp[5]; + long err = 0; + + /* Setup a trampoline to restart the syscall + * with __NR_restart_syscall + * + * 0: <return address (orig r31)> + * 4: <2nd half for 64-bit> + * 8: ldw 0(%sp), %r31 + * 12: be 0x100(%sr2, %r0) + * 16: ldi __NR_restart_syscall, %r20 + */ +#ifdef CONFIG_64BIT + err |= put_user(regs->gr[31] >> 32, &usp[0]); + err |= put_user(regs->gr[31] & 0xffffffff, &usp[1]); + err |= put_user(0x0fc010df, &usp[2]); +#else + err |= put_user(regs->gr[31], &usp[0]); + err |= put_user(0x0fc0109f, &usp[2]); +#endif + err |= put_user(0xe0008200, &usp[3]); + err |= put_user(0x34140000, &usp[4]); + + WARN_ON(err); + + /* flush data/instruction cache for new insns */ + flush_user_dcache_range_asm(start, end); + flush_user_icache_range_asm(start, end); + + regs->gr[31] = regs->gr[30] + 8; + return; + } + case -ERESTARTNOHAND: + case -ERESTARTSYS: + case -ERESTARTNOINTR: + check_syscallno_in_delay_branch(regs); + return; + default: + break; + } +} + +/* + * Note that 'init' is a special process: it doesn't get signals it doesn't + * want to handle. Thus you cannot kill init even with a SIGKILL even by + * mistake. + * + * We need to be able to restore the syscall arguments (r21-r26) to + * restart syscalls. Thus, the syscall path should save them in the + * pt_regs structure (it's okay to do so since they are caller-save + * registers). As noted below, the syscall number gets restored for + * us due to the magic of delayed branching. + */ +asmlinkage void +do_signal(struct pt_regs *regs, long in_syscall) +{ + struct ksignal ksig; + + DBG(1,"\ndo_signal: regs=0x%p, sr7 %#lx, in_syscall=%d\n", + regs, regs->sr[7], in_syscall); + + if (get_signal(&ksig)) { + DBG(3,"do_signal: signr = %d, regs->gr[28] = %ld\n", signr, regs->gr[28]); + /* Restart a system call if necessary. */ + if (in_syscall) + syscall_restart(regs, &ksig.ka); + + handle_signal(&ksig, regs, in_syscall); + return; + } + + /* Did we come from a system call? */ + if (in_syscall) + insert_restart_trampoline(regs); + + DBG(1,"do_signal: Exit (not delivered), regs->gr[28] = %ld\n", + regs->gr[28]); + + restore_saved_sigmask(); +} + +void do_notify_resume(struct pt_regs *regs, long in_syscall) +{ + if (test_thread_flag(TIF_SIGPENDING)) + do_signal(regs, in_syscall); + + if (test_thread_flag(TIF_NOTIFY_RESUME)) { + clear_thread_flag(TIF_NOTIFY_RESUME); + tracehook_notify_resume(regs); + } +} |