// SPDX-License-Identifier: GPL-2.0
/*
 *  arch/sparc64/kernel/signal.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 1995, 2008 David S. Miller (davem@davemloft.net)
 *  Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
 *  Copyright (C) 1997 Eddie C. Dost   (ecd@skynet.be)
 *  Copyright (C) 1997,1998 Jakub Jelinek   (jj@sunsite.mff.cuni.cz)
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/resume_user_mode.h>
#include <linux/unistd.h>
#include <linux/mm.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/bitops.h>
#include <linux/context_tracking.h>

#include <linux/uaccess.h>
#include <asm/ptrace.h>
#include <asm/fpumacro.h>
#include <asm/uctx.h>
#include <asm/siginfo.h>
#include <asm/visasm.h>
#include <asm/switch_to.h>
#include <asm/cacheflush.h>

#include "sigutil.h"
#include "systbls.h"
#include "kernel.h"
#include "entry.h"

/* {set, get}context() needed for 64-bit SparcLinux userland. */
asmlinkage void sparc64_set_context(struct pt_regs *regs)
{
        struct ucontext __user *ucp = (struct ucontext __user *)
                regs->u_regs[UREG_I0];
        enum ctx_state prev_state = exception_enter();
        mc_gregset_t __user *grp;
        unsigned long pc, npc, tstate;
        unsigned long fp, i7;
        unsigned char fenab;
        int err;

        synchronize_user_stack();
        if (get_thread_wsaved()                                 ||
            (((unsigned long)ucp) & (sizeof(unsigned long)-1))  ||
            (!__access_ok(ucp, sizeof(*ucp))))
                goto do_sigsegv;
        grp  = &ucp->uc_mcontext.mc_gregs;
        err  = __get_user(pc, &((*grp)[MC_PC]));
        err |= __get_user(npc, &((*grp)[MC_NPC]));
        if (err || ((pc | npc) & 3))
                goto do_sigsegv;
        if (regs->u_regs[UREG_I1]) {
                sigset_t set;

                if (_NSIG_WORDS == 1) {
                        if (__get_user(set.sig[0], &ucp->uc_sigmask.sig[0]))
                                goto do_sigsegv;
                } else {
                        if (__copy_from_user(&set, &ucp->uc_sigmask, sizeof(sigset_t)))
                                goto do_sigsegv;
                }
                set_current_blocked(&set);
        }
        if (test_thread_flag(TIF_32BIT)) {
                pc &= 0xffffffff;
                npc &= 0xffffffff;
        }
        regs->tpc = pc;
        regs->tnpc = npc;
        err |= __get_user(regs->y, &((*grp)[MC_Y]));
        err |= __get_user(tstate, &((*grp)[MC_TSTATE]));
        regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
        regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));
        err |= __get_user(regs->u_regs[UREG_G1], (&(*grp)[MC_G1]));
        err |= __get_user(regs->u_regs[UREG_G2], (&(*grp)[MC_G2]));
        err |= __get_user(regs->u_regs[UREG_G3], (&(*grp)[MC_G3]));
        err |= __get_user(regs->u_regs[UREG_G4], (&(*grp)[MC_G4]));
        err |= __get_user(regs->u_regs[UREG_G5], (&(*grp)[MC_G5]));
        err |= __get_user(regs->u_regs[UREG_G6], (&(*grp)[MC_G6]));

        /* Skip %g7 as that's the thread register in userspace.  */

        err |= __get_user(regs->u_regs[UREG_I0], (&(*grp)[MC_O0]));
        err |= __get_user(regs->u_regs[UREG_I1], (&(*grp)[MC_O1]));
        err |= __get_user(regs->u_regs[UREG_I2], (&(*grp)[MC_O2]));
        err |= __get_user(regs->u_regs[UREG_I3], (&(*grp)[MC_O3]));
        err |= __get_user(regs->u_regs[UREG_I4], (&(*grp)[MC_O4]));
        err |= __get_user(regs->u_regs[UREG_I5], (&(*grp)[MC_O5]));
        err |= __get_user(regs->u_regs[UREG_I6], (&(*grp)[MC_O6]));
        err |= __get_user(regs->u_regs[UREG_I7], (&(*grp)[MC_O7]));

        err |= __get_user(fp, &(ucp->uc_mcontext.mc_fp));
        err |= __get_user(i7, &(ucp->uc_mcontext.mc_i7));
        err |= __put_user(fp,
              (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
        err |= __put_user(i7,
              (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));

        err |= __get_user(fenab, &(ucp->uc_mcontext.mc_fpregs.mcfpu_enab));
        if (fenab) {
                unsigned long *fpregs = current_thread_info()->fpregs;
                unsigned long fprs;
                
                fprs_write(0);
                err |= __get_user(fprs, &(ucp->uc_mcontext.mc_fpregs.mcfpu_fprs));
                if (fprs & FPRS_DL)
                        err |= copy_from_user(fpregs,
                                              &(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs),
                                              (sizeof(unsigned int) * 32));
                if (fprs & FPRS_DU)
                        err |= copy_from_user(fpregs+16,
                         ((unsigned long __user *)&(ucp->uc_mcontext.mc_fpregs.mcfpu_fregs))+16,
                         (sizeof(unsigned int) * 32));
                err |= __get_user(current_thread_info()->xfsr[0],
                                  &(ucp->uc_mcontext.mc_fpregs.mcfpu_fsr));
                err |= __get_user(current_thread_info()->gsr[0],
                                  &(ucp->uc_mcontext.mc_fpregs.mcfpu_gsr));
                regs->tstate &= ~TSTATE_PEF;
        }
        if (err)
                goto do_sigsegv;
out:
        exception_exit(prev_state);
        return;
do_sigsegv:
        force_sig(SIGSEGV);
        goto out;
}

asmlinkage void sparc64_get_context(struct pt_regs *regs)
{
        struct ucontext __user *ucp = (struct ucontext __user *)
                regs->u_regs[UREG_I0];
        enum ctx_state prev_state = exception_enter();
        mc_gregset_t __user *grp;
        mcontext_t __user *mcp;
        unsigned long fp, i7;
        unsigned char fenab;
        int err;

        synchronize_user_stack();
        if (get_thread_wsaved() || clear_user(ucp, sizeof(*ucp)))
                goto do_sigsegv;

#if 1
        fenab = 0; /* IMO get_context is like any other system call, thus modifies FPU state -jj */
#else
        fenab = (current_thread_info()->fpsaved[0] & FPRS_FEF);
#endif
                
        mcp = &ucp->uc_mcontext;
        grp = &mcp->mc_gregs;

        /* Skip over the trap instruction, first. */
        if (test_thread_flag(TIF_32BIT)) {
                regs->tpc   = (regs->tnpc & 0xffffffff);
                regs->tnpc  = (regs->tnpc + 4) & 0xffffffff;
        } else {
                regs->tpc   = regs->tnpc;
                regs->tnpc += 4;
        }
        err = 0;
        if (_NSIG_WORDS == 1)
                err |= __put_user(current->blocked.sig[0],
                                  (unsigned long __user *)&ucp->uc_sigmask);
        else
                err |= __copy_to_user(&ucp->uc_sigmask, &current->blocked,
                                      sizeof(sigset_t));

        err |= __put_user(regs->tstate, &((*grp)[MC_TSTATE]));
        err |= __put_user(regs->tpc, &((*grp)[MC_PC]));
        err |= __put_user(regs->tnpc, &((*grp)[MC_NPC]));
        err |= __put_user(regs->y, &((*grp)[MC_Y]));
        err |= __put_user(regs->u_regs[UREG_G1], &((*grp)[MC_G1]));
        err |= __put_user(regs->u_regs[UREG_G2], &((*grp)[MC_G2]));
        err |= __put_user(regs->u_regs[UREG_G3], &((*grp)[MC_G3]));
        err |= __put_user(regs->u_regs[UREG_G4], &((*grp)[MC_G4]));
        err |= __put_user(regs->u_regs[UREG_G5], &((*grp)[MC_G5]));
        err |= __put_user(regs->u_regs[UREG_G6], &((*grp)[MC_G6]));
        err |= __put_user(regs->u_regs[UREG_G7], &((*grp)[MC_G7]));
        err |= __put_user(regs->u_regs[UREG_I0], &((*grp)[MC_O0]));
        err |= __put_user(regs->u_regs[UREG_I1], &((*grp)[MC_O1]));
        err |= __put_user(regs->u_regs[UREG_I2], &((*grp)[MC_O2]));
        err |= __put_user(regs->u_regs[UREG_I3], &((*grp)[MC_O3]));
        err |= __put_user(regs->u_regs[UREG_I4], &((*grp)[MC_O4]));
        err |= __put_user(regs->u_regs[UREG_I5], &((*grp)[MC_O5]));
        err |= __put_user(regs->u_regs[UREG_I6], &((*grp)[MC_O6]));
        err |= __put_user(regs->u_regs[UREG_I7], &((*grp)[MC_O7]));

        err |= __get_user(fp,
                 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[6])));
        err |= __get_user(i7,
                 (&(((struct reg_window __user *)(STACK_BIAS+regs->u_regs[UREG_I6]))->ins[7])));
        err |= __put_user(fp, &(mcp->mc_fp));
        err |= __put_user(i7, &(mcp->mc_i7));

        err |= __put_user(fenab, &(mcp->mc_fpregs.mcfpu_enab));
        if (fenab) {
                unsigned long *fpregs = current_thread_info()->fpregs;
                unsigned long fprs;
                
                fprs = current_thread_info()->fpsaved[0];
                if (fprs & FPRS_DL)
                        err |= copy_to_user(&(mcp->mc_fpregs.mcfpu_fregs), fpregs,
                                            (sizeof(unsigned int) * 32));
                if (fprs & FPRS_DU)
                        err |= copy_to_user(
                          ((unsigned long __user *)&(mcp->mc_fpregs.mcfpu_fregs))+16, fpregs+16,
                          (sizeof(unsigned int) * 32));
                err |= __put_user(current_thread_info()->xfsr[0], &(mcp->mc_fpregs.mcfpu_fsr));
                err |= __put_user(current_thread_info()->gsr[0], &(mcp->mc_fpregs.mcfpu_gsr));
                err |= __put_user(fprs, &(mcp->mc_fpregs.mcfpu_fprs));
        }
        if (err)
                goto do_sigsegv;
out:
        exception_exit(prev_state);
        return;
do_sigsegv:
        force_sig(SIGSEGV);
        goto out;
}

/* Checks if the fp is valid.  We always build rt signal frames which
 * are 16-byte aligned, therefore we can always enforce that the
 * restore frame has that property as well.
 */
static bool invalid_frame_pointer(void __user *fp)
{
        if (((unsigned long) fp) & 15)
                return true;
        return false;
}

struct rt_signal_frame {
        struct sparc_stackf     ss;
        siginfo_t               info;
        struct pt_regs          regs;
        __siginfo_fpu_t __user  *fpu_save;
        stack_t                 stack;
        sigset_t                mask;
        __siginfo_rwin_t        *rwin_save;
};

void do_rt_sigreturn(struct pt_regs *regs)
{
        unsigned long tpc, tnpc, tstate, ufp;
        struct rt_signal_frame __user *sf;
        __siginfo_fpu_t __user *fpu_save;
        __siginfo_rwin_t __user *rwin_save;
        sigset_t set;
        int err;

        /* Always make any pending restarted system calls return -EINTR */
        current->restart_block.fn = do_no_restart_syscall;

        synchronize_user_stack ();
        sf = (struct rt_signal_frame __user *)
                (regs->u_regs [UREG_FP] + STACK_BIAS);

        /* 1. Make sure we are not getting garbage from the user */
        if (invalid_frame_pointer(sf))
                goto segv;

        if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
                goto segv;

        if ((ufp + STACK_BIAS) & 0x7)
                goto segv;

        err = __get_user(tpc, &sf->regs.tpc);
        err |= __get_user(tnpc, &sf->regs.tnpc);
        if (test_thread_flag(TIF_32BIT)) {
                tpc &= 0xffffffff;
                tnpc &= 0xffffffff;
        }
        err |= ((tpc | tnpc) & 3);

        /* 2. Restore the state */
        err |= __get_user(regs->y, &sf->regs.y);
        err |= __get_user(tstate, &sf->regs.tstate);
        err |= copy_from_user(regs->u_regs, sf->regs.u_regs, sizeof(regs->u_regs));

        /* User can only change condition codes and %asi in %tstate. */
        regs->tstate &= ~(TSTATE_ASI | TSTATE_ICC | TSTATE_XCC);
        regs->tstate |= (tstate & (TSTATE_ASI | TSTATE_ICC | TSTATE_XCC));

        err |= __get_user(fpu_save, &sf->fpu_save);
        if (!err && fpu_save)
                err |= restore_fpu_state(regs, fpu_save);

        err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
        err |= restore_altstack(&sf->stack);
        if (err)
                goto segv;

        err |= __get_user(rwin_save, &sf->rwin_save);
        if (!err && rwin_save) {
                if (restore_rwin_state(rwin_save))
                        goto segv;
        }

        regs->tpc = tpc;
        regs->tnpc = tnpc;

        /* Prevent syscall restart.  */
        pt_regs_clear_syscall(regs);

        set_current_blocked(&set);
        return;
segv:
        force_sig(SIGSEGV);
}

static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
{
        unsigned long sp = regs->u_regs[UREG_FP] + STACK_BIAS;

        /*
         * If we are on the alternate signal stack and would overflow it, don't.
         * Return an always-bogus address instead so we will die with SIGSEGV.
         */
        if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
                return (void __user *) -1L;

        /* This is the X/Open sanctioned signal stack switching.  */
        sp = sigsp(sp, ksig) - framesize;

        /* Always align the stack frame.  This handles two cases.  First,
         * sigaltstack need not be mindful of platform specific stack
         * alignment.  Second, if we took this signal because the stack
         * is not aligned properly, we'd like to take the signal cleanly
         * and report that.
         */
        sp &= ~15UL;

        return (void __user *) sp;
}

static inline int
setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
{
        struct rt_signal_frame __user *sf;
        int wsaved, err, sf_size;
        void __user *tail;

        /* 1. Make sure everything is clean */
        synchronize_user_stack();
        save_and_clear_fpu();
        
        wsaved = get_thread_wsaved();

        sf_size = sizeof(struct rt_signal_frame);
        if (current_thread_info()->fpsaved[0] & FPRS_FEF)
                sf_size += sizeof(__siginfo_fpu_t);
        if (wsaved)
                sf_size += sizeof(__siginfo_rwin_t);
        sf = (struct rt_signal_frame __user *)
                get_sigframe(ksig, regs, sf_size);

        if (invalid_frame_pointer (sf)) {
                if (show_unhandled_signals)
                        pr_info("%s[%d] bad frame in setup_rt_frame: %016lx TPC %016lx O7 %016lx\n",
                                current->comm, current->pid, (unsigned long)sf,
                                regs->tpc, regs->u_regs[UREG_I7]);
                force_sigsegv(ksig->sig);
                return -EINVAL;
        }

        tail = (sf + 1);

        /* 2. Save the current process state */
        err = copy_to_user(&sf->regs, regs, sizeof (*regs));

        if (current_thread_info()->fpsaved[0] & FPRS_FEF) {
                __siginfo_fpu_t __user *fpu_save = tail;
                tail += sizeof(__siginfo_fpu_t);
                err |= save_fpu_state(regs, fpu_save);
                err |= __put_user((u64)fpu_save, &sf->fpu_save);
        } else {
                err |= __put_user(0, &sf->fpu_save);
        }
        if (wsaved) {
                __siginfo_rwin_t __user *rwin_save = tail;
                tail += sizeof(__siginfo_rwin_t);
                err |= save_rwin_state(wsaved, rwin_save);
                err |= __put_user((u64)rwin_save, &sf->rwin_save);
                set_thread_wsaved(0);
        } else {
                err |= __put_user(0, &sf->rwin_save);
        }
        
        /* Setup sigaltstack */
        err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]);

        err |= copy_to_user(&sf->mask, sigmask_to_save(), sizeof(sigset_t));

        if (!wsaved) {
                err |= raw_copy_in_user((u64 __user *)sf,
                                        (u64 __user *)(regs->u_regs[UREG_FP] +
                                           STACK_BIAS),
                                        sizeof(struct reg_window));
        } else {
                struct reg_window *rp;

                rp = &current_thread_info()->reg_window[wsaved - 1];
                err |= copy_to_user(sf, rp, sizeof(struct reg_window));
        }
        if (ksig->ka.sa.sa_flags & SA_SIGINFO)
                err |= copy_siginfo_to_user(&sf->info, &ksig->info);
        else {
                err |= __put_user(ksig->sig, &sf->info.si_signo);
                err |= __put_user(SI_NOINFO, &sf->info.si_code);
        }
        if (err)
                return err;
        
        /* 3. signal handler back-trampoline and parameters */
        regs->u_regs[UREG_FP] = ((unsigned long) sf) - STACK_BIAS;
        regs->u_regs[UREG_I0] = ksig->sig;
        regs->u_regs[UREG_I1] = (unsigned long) &sf->info;

        /* The sigcontext is passed in this way because of how it
         * is defined in GLIBC's /usr/include/bits/sigcontext.h
         * for sparc64.  It includes the 128 bytes of siginfo_t.
         */
        regs->u_regs[UREG_I2] = (unsigned long) &sf->info;

        /* 5. signal handler */
        regs->tpc = (unsigned long) ksig->ka.sa.sa_handler;
        regs->tnpc = (regs->tpc + 4);
        if (test_thread_flag(TIF_32BIT)) {
                regs->tpc &= 0xffffffff;
                regs->tnpc &= 0xffffffff;
        }
        /* 4. return to kernel instructions */
        regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
        return 0;
}

static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
                                   struct sigaction *sa)
{
        switch (regs->u_regs[UREG_I0]) {
        case ERESTART_RESTARTBLOCK:
        case ERESTARTNOHAND:
        no_system_call_restart:
                regs->u_regs[UREG_I0] = EINTR;
                regs->tstate |= (TSTATE_ICARRY|TSTATE_XCARRY);
                break;
        case ERESTARTSYS:
                if (!(sa->sa_flags & SA_RESTART))
                        goto no_system_call_restart;
                fallthrough;
        case ERESTARTNOINTR:
                regs->u_regs[UREG_I0] = orig_i0;
                regs->tpc -= 4;
                regs->tnpc -= 4;
        }
}

/* 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.
 */
static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
{
        struct ksignal ksig;
        int restart_syscall;
        bool has_handler;
        
        /* It's a lot of work and synchronization to add a new ptrace
         * register for GDB to save and restore in order to get
         * orig_i0 correct for syscall restarts when debugging.
         *
         * Although it should be the case that most of the global
         * registers are volatile across a system call, glibc already
         * depends upon that fact that we preserve them.  So we can't
         * just use any global register to save away the orig_i0 value.
         *
         * In particular %g2, %g3, %g4, and %g5 are all assumed to be
         * preserved across a system call trap by various pieces of
         * code in glibc.
         *
         * %g7 is used as the "thread register".   %g6 is not used in
         * any fixed manner.  %g6 is used as a scratch register and
         * a compiler temporary, but its value is never used across
         * a system call.  Therefore %g6 is usable for orig_i0 storage.
         */
        if (pt_regs_is_syscall(regs) &&
            (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY)))
                regs->u_regs[UREG_G6] = orig_i0;

#ifdef CONFIG_COMPAT
        if (test_thread_flag(TIF_32BIT)) {
                do_signal32(regs);
                return;
        }
#endif  

        has_handler = get_signal(&ksig);

        restart_syscall = 0;
        if (pt_regs_is_syscall(regs) &&
            (regs->tstate & (TSTATE_XCARRY | TSTATE_ICARRY))) {
                restart_syscall = 1;
                orig_i0 = regs->u_regs[UREG_G6];
        }

        if (has_handler) {
                if (restart_syscall)
                        syscall_restart(orig_i0, regs, &ksig.ka.sa);
                signal_setup_done(setup_rt_frame(&ksig, regs), &ksig, 0);
        } else {
                if (restart_syscall) {
                        switch (regs->u_regs[UREG_I0]) {
                        case ERESTARTNOHAND:
                        case ERESTARTSYS:
                        case ERESTARTNOINTR:
                                /* replay the system call when we are done */
                                regs->u_regs[UREG_I0] = orig_i0;
                                regs->tpc -= 4;
                                regs->tnpc -= 4;
                                pt_regs_clear_syscall(regs);
                                fallthrough;
                        case ERESTART_RESTARTBLOCK:
                                regs->u_regs[UREG_G1] = __NR_restart_syscall;
                                regs->tpc -= 4;
                                regs->tnpc -= 4;
                                pt_regs_clear_syscall(regs);
                        }
                }
                restore_saved_sigmask();
        }
}

void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0, unsigned long thread_info_flags)
{
        user_exit();
        if (thread_info_flags & _TIF_UPROBE)
                uprobe_notify_resume(regs);
        if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
                do_signal(regs, orig_i0);
        if (thread_info_flags & _TIF_NOTIFY_RESUME)
                resume_user_mode_work(regs);
        user_enter();
}

/*
 * Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
 * changes likely come with new fields that should be added below.
 */
static_assert(NSIGILL   == 11);
static_assert(NSIGFPE   == 15);
static_assert(NSIGSEGV  == 10);
static_assert(NSIGBUS   == 5);
static_assert(NSIGTRAP  == 6);
static_assert(NSIGCHLD  == 6);
static_assert(NSIGSYS   == 2);
static_assert(sizeof(siginfo_t) == 128);
static_assert(__alignof__(siginfo_t) == 8);
static_assert(offsetof(siginfo_t, si_signo)     == 0x00);
static_assert(offsetof(siginfo_t, si_errno)     == 0x04);
static_assert(offsetof(siginfo_t, si_code)      == 0x08);
static_assert(offsetof(siginfo_t, si_pid)       == 0x10);
static_assert(offsetof(siginfo_t, si_uid)       == 0x14);
static_assert(offsetof(siginfo_t, si_tid)       == 0x10);
static_assert(offsetof(siginfo_t, si_overrun)   == 0x14);
static_assert(offsetof(siginfo_t, si_status)    == 0x18);
static_assert(offsetof(siginfo_t, si_utime)     == 0x20);
static_assert(offsetof(siginfo_t, si_stime)     == 0x28);
static_assert(offsetof(siginfo_t, si_value)     == 0x18);
static_assert(offsetof(siginfo_t, si_int)       == 0x18);
static_assert(offsetof(siginfo_t, si_ptr)       == 0x18);
static_assert(offsetof(siginfo_t, si_addr)      == 0x10);
static_assert(offsetof(siginfo_t, si_trapno)    == 0x18);
static_assert(offsetof(siginfo_t, si_addr_lsb)  == 0x18);
static_assert(offsetof(siginfo_t, si_lower)     == 0x20);
static_assert(offsetof(siginfo_t, si_upper)     == 0x28);
static_assert(offsetof(siginfo_t, si_pkey)      == 0x20);
static_assert(offsetof(siginfo_t, si_perf_data) == 0x18);
static_assert(offsetof(siginfo_t, si_perf_type) == 0x20);
static_assert(offsetof(siginfo_t, si_perf_flags) == 0x24);
static_assert(offsetof(siginfo_t, si_band)      == 0x10);
static_assert(offsetof(siginfo_t, si_fd)        == 0x14);