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linux-stable/arch/m68k/kernel/signal.c
Al Viro 0d20abde98 m68k: Leave stack mangling to asm wrapper of sigreturn() 
sigreturn has to deal with an unpleasant problem - exception stack frames
have different sizes, depending upon the exception (and processor model, as
well) and variable-sized part of exception frame may contain information
needed for instruction restart.  So when signal handler terminates and calls
sigreturn to resume the execution at the place where we'd been when we caught
the signal, it has to rearrange the frame at the bottom of kernel stack.
Worse, it might need to open a gap in the kernel stack, shifting pt_regs
towards lower addresses.

Doing that from C is insane - we'd need to shift stack frames (return addresses,
local variables, etc.) of C call chain, right under the nose of compiler and
hope it won't fall apart horribly.  What had been actually done is only slightly
less insane - an inline asm in mangle_kernel_stack() moved the stuff around,
then reset stack pointer and jumped to label in asm glue.

However, we can avoid all that mess if the asm wrapper we have to use anyway
would reserve some space on the stack between switch_stack and the C stack
frame of do_{rt_,}sigreturn().   Then C part can simply memmove() pt_regs +
switch_stack, memcpy() the variable part of exception frame into the opened
gap - all of that without inline asm, buggering C call chain, magical jumps
to asm labels, etc.

Asm wrapper would need to know where the moved switch_stack has ended up -
it might have been shifted into the gap we'd reserved before do_rt_sigreturn()
call.  That's where it needs to set the stack pointer to.  So let the C part
return just that and be done with that.

While we are at it, the call of berr_040cleanup() we need to do when
returning via 68040 bus error exception frame can be moved into C part
as well.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Michael Schmitz <schmitzmic@gmail.com>
Reviewed-by: Michael Schmitz <schmitzmic@gmail.com>
Tested-by: Finn Thain <fthain@linux-m68k.org>
Link: https://lore.kernel.org/r/YP2dTQPm1wGPWFgD@zeniv-ca.linux.org.uk
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2021-09-24 13:35:03 +02:00

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/*
* linux/arch/m68k/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive
* for more details.
*/
/*
* Linux/m68k support by Hamish Macdonald
*
* 68060 fixes by Jesper Skov
*
* 1997-12-01 Modified for POSIX.1b signals by Andreas Schwab
*
* mathemu support by Roman Zippel
* (Note: fpstate in the signal context is completely ignored for the emulator
* and the internal floating point format is put on stack)
*/
/*
* ++roman (07/09/96): implemented signal stacks (specially for tosemu on
* Atari :-) Current limitation: Only one sigstack can be active at one time.
* If a second signal with SA_ONSTACK set arrives while working on a sigstack,
* SA_ONSTACK is ignored. This behaviour avoids lots of trouble with nested
* signal handlers!
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/syscalls.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/highuid.h>
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/binfmts.h>
#include <linux/extable.h>
#include <linux/tracehook.h>
#include <asm/setup.h>
#include <linux/uaccess.h>
#include <asm/traps.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.h>
#ifdef CONFIG_MMU
/*
* Handle the slight differences in classic 68k and ColdFire trap frames.
*/
#ifdef CONFIG_COLDFIRE
#define FORMAT 4
#define FMT4SIZE 0
#else
#define FORMAT 0
#define FMT4SIZE sizeof_field(struct frame, un.fmt4)
#endif
static const int frame_size_change[16] = {
[1] = -1, /* sizeof_field(struct frame, un.fmt1), */
[2] = sizeof_field(struct frame, un.fmt2),
[3] = sizeof_field(struct frame, un.fmt3),
[4] = FMT4SIZE,
[5] = -1, /* sizeof_field(struct frame, un.fmt5), */
[6] = -1, /* sizeof_field(struct frame, un.fmt6), */
[7] = sizeof_field(struct frame, un.fmt7),
[8] = -1, /* sizeof_field(struct frame, un.fmt8), */
[9] = sizeof_field(struct frame, un.fmt9),
[10] = sizeof_field(struct frame, un.fmta),
[11] = sizeof_field(struct frame, un.fmtb),
[12] = -1, /* sizeof_field(struct frame, un.fmtc), */
[13] = -1, /* sizeof_field(struct frame, un.fmtd), */
[14] = -1, /* sizeof_field(struct frame, un.fmte), */
[15] = -1, /* sizeof_field(struct frame, un.fmtf), */
};
static inline int frame_extra_sizes(int f)
{
return frame_size_change[f];
}
int fixup_exception(struct pt_regs *regs)
{
const struct exception_table_entry *fixup;
struct pt_regs *tregs;
/* Are we prepared to handle this kernel fault? */
fixup = search_exception_tables(regs->pc);
if (!fixup)
return 0;
/* Create a new four word stack frame, discarding the old one. */
regs->stkadj = frame_extra_sizes(regs->format);
tregs = (struct pt_regs *)((long)regs + regs->stkadj);
tregs->vector = regs->vector;
tregs->format = FORMAT;
tregs->pc = fixup->fixup;
tregs->sr = regs->sr;
return 1;
}
static inline void push_cache (unsigned long vaddr)
{
/*
* Using the old cache_push_v() was really a big waste.
*
* What we are trying to do is to flush 8 bytes to ram.
* Flushing 2 cache lines of 16 bytes is much cheaper than
* flushing 1 or 2 pages, as previously done in
* cache_push_v().
* Jes
*/
if (CPU_IS_040) {
unsigned long temp;
__asm__ __volatile__ (".chip 68040\n\t"
"nop\n\t"
"ptestr (%1)\n\t"
"movec %%mmusr,%0\n\t"
".chip 68k"
: "=r" (temp)
: "a" (vaddr));
temp &= PAGE_MASK;
temp |= vaddr & ~PAGE_MASK;
__asm__ __volatile__ (".chip 68040\n\t"
"nop\n\t"
"cpushl %%bc,(%0)\n\t"
".chip 68k"
: : "a" (temp));
}
else if (CPU_IS_060) {
unsigned long temp;
__asm__ __volatile__ (".chip 68060\n\t"
"plpar (%0)\n\t"
".chip 68k"
: "=a" (temp)
: "0" (vaddr));
__asm__ __volatile__ (".chip 68060\n\t"
"cpushl %%bc,(%0)\n\t"
".chip 68k"
: : "a" (temp));
} else if (!CPU_IS_COLDFIRE) {
/*
* 68030/68020 have no writeback cache;
* still need to clear icache.
* Note that vaddr is guaranteed to be long word aligned.
*/
unsigned long temp;
asm volatile ("movec %%cacr,%0" : "=r" (temp));
temp += 4;
asm volatile ("movec %0,%%caar\n\t"
"movec %1,%%cacr"
: : "r" (vaddr), "r" (temp));
asm volatile ("movec %0,%%caar\n\t"
"movec %1,%%cacr"
: : "r" (vaddr + 4), "r" (temp));
} else {
/* CPU_IS_COLDFIRE */
#if defined(CONFIG_CACHE_COPYBACK)
flush_cf_dcache(0, DCACHE_MAX_ADDR);
#endif
/* Invalidate instruction cache for the pushed bytes */
clear_cf_icache(vaddr, vaddr + 8);
}
}
static inline void adjustformat(struct pt_regs *regs)
{
}
static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
{
}
#else /* CONFIG_MMU */
void ret_from_user_signal(void);
void ret_from_user_rt_signal(void);
static inline int frame_extra_sizes(int f)
{
/* No frame size adjustments required on non-MMU CPUs */
return 0;
}
static inline void adjustformat(struct pt_regs *regs)
{
/*
* set format byte to make stack appear modulo 4, which it will
* be when doing the rte
*/
regs->format = 0x4;
}
static inline void save_a5_state(struct sigcontext *sc, struct pt_regs *regs)
{
sc->sc_a5 = ((struct switch_stack *)regs - 1)->a5;
}
static inline void push_cache(unsigned long vaddr)
{
}
#endif /* CONFIG_MMU */
/*
* Do a signal return; undo the signal stack.
*
* Keep the return code on the stack quadword aligned!
* That makes the cache flush below easier.
*/
struct sigframe
{
char __user *pretcode;
int sig;
int code;
struct sigcontext __user *psc;
char retcode[8];
unsigned long extramask[_NSIG_WORDS-1];
struct sigcontext sc;
};
struct rt_sigframe
{
char __user *pretcode;
int sig;
struct siginfo __user *pinfo;
void __user *puc;
char retcode[8];
struct siginfo info;
struct ucontext uc;
};
#define FPCONTEXT_SIZE 216
#define uc_fpstate uc_filler[0]
#define uc_formatvec uc_filler[FPCONTEXT_SIZE/4]
#define uc_extra uc_filler[FPCONTEXT_SIZE/4+1]
#ifdef CONFIG_FPU
static unsigned char fpu_version; /* version number of fpu, set by setup_frame */
static inline int restore_fpu_state(struct sigcontext *sc)
{
int err = 1;
if (FPU_IS_EMU) {
/* restore registers */
memcpy(current->thread.fpcntl, sc->sc_fpcntl, 12);
memcpy(current->thread.fp, sc->sc_fpregs, 24);
return 0;
}
if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
/* Verify the frame format. */
if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
(sc->sc_fpstate[0] != fpu_version))
goto out;
if (CPU_IS_020_OR_030) {
if (m68k_fputype & FPU_68881 &&
!(sc->sc_fpstate[1] == 0x18 || sc->sc_fpstate[1] == 0xb4))
goto out;
if (m68k_fputype & FPU_68882 &&
!(sc->sc_fpstate[1] == 0x38 || sc->sc_fpstate[1] == 0xd4))
goto out;
} else if (CPU_IS_040) {
if (!(sc->sc_fpstate[1] == 0x00 ||
sc->sc_fpstate[1] == 0x28 ||
sc->sc_fpstate[1] == 0x60))
goto out;
} else if (CPU_IS_060) {
if (!(sc->sc_fpstate[3] == 0x00 ||
sc->sc_fpstate[3] == 0x60 ||
sc->sc_fpstate[3] == 0xe0))
goto out;
} else if (CPU_IS_COLDFIRE) {
if (!(sc->sc_fpstate[0] == 0x00 ||
sc->sc_fpstate[0] == 0x05 ||
sc->sc_fpstate[0] == 0xe5))
goto out;
} else
goto out;
if (CPU_IS_COLDFIRE) {
__asm__ volatile ("fmovemd %0,%%fp0-%%fp1\n\t"
"fmovel %1,%%fpcr\n\t"
"fmovel %2,%%fpsr\n\t"
"fmovel %3,%%fpiar"
: /* no outputs */
: "m" (sc->sc_fpregs[0]),
"m" (sc->sc_fpcntl[0]),
"m" (sc->sc_fpcntl[1]),
"m" (sc->sc_fpcntl[2]));
} else {
__asm__ volatile (".chip 68k/68881\n\t"
"fmovemx %0,%%fp0-%%fp1\n\t"
"fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
".chip 68k"
: /* no outputs */
: "m" (*sc->sc_fpregs),
"m" (*sc->sc_fpcntl));
}
}
if (CPU_IS_COLDFIRE) {
__asm__ volatile ("frestore %0" : : "m" (*sc->sc_fpstate));
} else {
__asm__ volatile (".chip 68k/68881\n\t"
"frestore %0\n\t"
".chip 68k"
: : "m" (*sc->sc_fpstate));
}
err = 0;
out:
return err;
}
static inline int rt_restore_fpu_state(struct ucontext __user *uc)
{
unsigned char fpstate[FPCONTEXT_SIZE];
int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
fpregset_t fpregs;
int err = 1;
if (FPU_IS_EMU) {
/* restore fpu control register */
if (__copy_from_user(current->thread.fpcntl,
uc->uc_mcontext.fpregs.f_fpcntl, 12))
goto out;
/* restore all other fpu register */
if (__copy_from_user(current->thread.fp,
uc->uc_mcontext.fpregs.f_fpregs, 96))
goto out;
return 0;
}
if (__get_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate))
goto out;
if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
context_size = fpstate[1];
/* Verify the frame format. */
if (!(CPU_IS_060 || CPU_IS_COLDFIRE) &&
(fpstate[0] != fpu_version))
goto out;
if (CPU_IS_020_OR_030) {
if (m68k_fputype & FPU_68881 &&
!(context_size == 0x18 || context_size == 0xb4))
goto out;
if (m68k_fputype & FPU_68882 &&
!(context_size == 0x38 || context_size == 0xd4))
goto out;
} else if (CPU_IS_040) {
if (!(context_size == 0x00 ||
context_size == 0x28 ||
context_size == 0x60))
goto out;
} else if (CPU_IS_060) {
if (!(fpstate[3] == 0x00 ||
fpstate[3] == 0x60 ||
fpstate[3] == 0xe0))
goto out;
} else if (CPU_IS_COLDFIRE) {
if (!(fpstate[3] == 0x00 ||
fpstate[3] == 0x05 ||
fpstate[3] == 0xe5))
goto out;
} else
goto out;
if (__copy_from_user(&fpregs, &uc->uc_mcontext.fpregs,
sizeof(fpregs)))
goto out;
if (CPU_IS_COLDFIRE) {
__asm__ volatile ("fmovemd %0,%%fp0-%%fp7\n\t"
"fmovel %1,%%fpcr\n\t"
"fmovel %2,%%fpsr\n\t"
"fmovel %3,%%fpiar"
: /* no outputs */
: "m" (fpregs.f_fpregs[0]),
"m" (fpregs.f_fpcntl[0]),
"m" (fpregs.f_fpcntl[1]),
"m" (fpregs.f_fpcntl[2]));
} else {
__asm__ volatile (".chip 68k/68881\n\t"
"fmovemx %0,%%fp0-%%fp7\n\t"
"fmoveml %1,%%fpcr/%%fpsr/%%fpiar\n\t"
".chip 68k"
: /* no outputs */
: "m" (*fpregs.f_fpregs),
"m" (*fpregs.f_fpcntl));
}
}
if (context_size &&
__copy_from_user(fpstate + 4, (long __user *)&uc->uc_fpstate + 1,
context_size))
goto out;
if (CPU_IS_COLDFIRE) {
__asm__ volatile ("frestore %0" : : "m" (*fpstate));
} else {
__asm__ volatile (".chip 68k/68881\n\t"
"frestore %0\n\t"
".chip 68k"
: : "m" (*fpstate));
}
err = 0;
out:
return err;
}
/*
* Set up a signal frame.
*/
static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
{
if (FPU_IS_EMU) {
/* save registers */
memcpy(sc->sc_fpcntl, current->thread.fpcntl, 12);
memcpy(sc->sc_fpregs, current->thread.fp, 24);
return;
}
if (CPU_IS_COLDFIRE) {
__asm__ volatile ("fsave %0"
: : "m" (*sc->sc_fpstate) : "memory");
} else {
__asm__ volatile (".chip 68k/68881\n\t"
"fsave %0\n\t"
".chip 68k"
: : "m" (*sc->sc_fpstate) : "memory");
}
if (CPU_IS_060 ? sc->sc_fpstate[2] : sc->sc_fpstate[0]) {
fpu_version = sc->sc_fpstate[0];
if (CPU_IS_020_OR_030 && !regs->stkadj &&
regs->vector >= (VEC_FPBRUC * 4) &&
regs->vector <= (VEC_FPNAN * 4)) {
/* Clear pending exception in 68882 idle frame */
if (*(unsigned short *) sc->sc_fpstate == 0x1f38)
sc->sc_fpstate[0x38] |= 1 << 3;
}
if (CPU_IS_COLDFIRE) {
__asm__ volatile ("fmovemd %%fp0-%%fp1,%0\n\t"
"fmovel %%fpcr,%1\n\t"
"fmovel %%fpsr,%2\n\t"
"fmovel %%fpiar,%3"
: "=m" (sc->sc_fpregs[0]),
"=m" (sc->sc_fpcntl[0]),
"=m" (sc->sc_fpcntl[1]),
"=m" (sc->sc_fpcntl[2])
: /* no inputs */
: "memory");
} else {
__asm__ volatile (".chip 68k/68881\n\t"
"fmovemx %%fp0-%%fp1,%0\n\t"
"fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
".chip 68k"
: "=m" (*sc->sc_fpregs),
"=m" (*sc->sc_fpcntl)
: /* no inputs */
: "memory");
}
}
}
static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
{
unsigned char fpstate[FPCONTEXT_SIZE];
int context_size = CPU_IS_060 ? 8 : (CPU_IS_COLDFIRE ? 12 : 0);
int err = 0;
if (FPU_IS_EMU) {
/* save fpu control register */
err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpcntl,
current->thread.fpcntl, 12);
/* save all other fpu register */
err |= copy_to_user(uc->uc_mcontext.fpregs.f_fpregs,
current->thread.fp, 96);
return err;
}
if (CPU_IS_COLDFIRE) {
__asm__ volatile ("fsave %0" : : "m" (*fpstate) : "memory");
} else {
__asm__ volatile (".chip 68k/68881\n\t"
"fsave %0\n\t"
".chip 68k"
: : "m" (*fpstate) : "memory");
}
err |= __put_user(*(long *)fpstate, (long __user *)&uc->uc_fpstate);
if (CPU_IS_060 ? fpstate[2] : fpstate[0]) {
fpregset_t fpregs;
if (!(CPU_IS_060 || CPU_IS_COLDFIRE))
context_size = fpstate[1];
fpu_version = fpstate[0];
if (CPU_IS_020_OR_030 && !regs->stkadj &&
regs->vector >= (VEC_FPBRUC * 4) &&
regs->vector <= (VEC_FPNAN * 4)) {
/* Clear pending exception in 68882 idle frame */
if (*(unsigned short *) fpstate == 0x1f38)
fpstate[0x38] |= 1 << 3;
}
if (CPU_IS_COLDFIRE) {
__asm__ volatile ("fmovemd %%fp0-%%fp7,%0\n\t"
"fmovel %%fpcr,%1\n\t"
"fmovel %%fpsr,%2\n\t"
"fmovel %%fpiar,%3"
: "=m" (fpregs.f_fpregs[0]),
"=m" (fpregs.f_fpcntl[0]),
"=m" (fpregs.f_fpcntl[1]),
"=m" (fpregs.f_fpcntl[2])
: /* no inputs */
: "memory");
} else {
__asm__ volatile (".chip 68k/68881\n\t"
"fmovemx %%fp0-%%fp7,%0\n\t"
"fmoveml %%fpcr/%%fpsr/%%fpiar,%1\n\t"
".chip 68k"
: "=m" (*fpregs.f_fpregs),
"=m" (*fpregs.f_fpcntl)
: /* no inputs */
: "memory");
}
err |= copy_to_user(&uc->uc_mcontext.fpregs, &fpregs,
sizeof(fpregs));
}
if (context_size)
err |= copy_to_user((long __user *)&uc->uc_fpstate + 1, fpstate + 4,
context_size);
return err;
}
#else /* CONFIG_FPU */
/*
* For the case with no FPU configured these all do nothing.
*/
static inline int restore_fpu_state(struct sigcontext *sc)
{
return 0;
}
static inline int rt_restore_fpu_state(struct ucontext __user *uc)
{
return 0;
}
static inline void save_fpu_state(struct sigcontext *sc, struct pt_regs *regs)
{
}
static inline int rt_save_fpu_state(struct ucontext __user *uc, struct pt_regs *regs)
{
return 0;
}
#endif /* CONFIG_FPU */
static inline void siginfo_build_tests(void)
{
/*
* This needs to be tested on m68k as it has a lesser
* alignment requirement than x86 and that can cause surprises.
*/
/* This is part of the ABI and can never change in size: */
BUILD_BUG_ON(sizeof(siginfo_t) != 128);
/* Ensure the known fields never change in location */
BUILD_BUG_ON(offsetof(siginfo_t, si_signo) != 0);
BUILD_BUG_ON(offsetof(siginfo_t, si_errno) != 4);
BUILD_BUG_ON(offsetof(siginfo_t, si_code) != 8);
/* _kill */
BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x0c);
BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x10);
/* _timer */
BUILD_BUG_ON(offsetof(siginfo_t, si_tid) != 0x0c);
BUILD_BUG_ON(offsetof(siginfo_t, si_overrun) != 0x10);
BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x14);
/* _rt */
BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x0c);
BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x10);
BUILD_BUG_ON(offsetof(siginfo_t, si_value) != 0x14);
/* _sigchld */
BUILD_BUG_ON(offsetof(siginfo_t, si_pid) != 0x0c);
BUILD_BUG_ON(offsetof(siginfo_t, si_uid) != 0x10);
BUILD_BUG_ON(offsetof(siginfo_t, si_status) != 0x14);
BUILD_BUG_ON(offsetof(siginfo_t, si_utime) != 0x18);
BUILD_BUG_ON(offsetof(siginfo_t, si_stime) != 0x1c);
/* _sigfault */
BUILD_BUG_ON(offsetof(siginfo_t, si_addr) != 0x0c);
/* _sigfault._mcerr */
BUILD_BUG_ON(offsetof(siginfo_t, si_addr_lsb) != 0x10);
/* _sigfault._addr_bnd */
BUILD_BUG_ON(offsetof(siginfo_t, si_lower) != 0x12);
BUILD_BUG_ON(offsetof(siginfo_t, si_upper) != 0x16);
/* _sigfault._addr_pkey */
BUILD_BUG_ON(offsetof(siginfo_t, si_pkey) != 0x12);
/* _sigfault._perf */
BUILD_BUG_ON(offsetof(siginfo_t, si_perf_data) != 0x10);
BUILD_BUG_ON(offsetof(siginfo_t, si_perf_type) != 0x14);
/* _sigpoll */
BUILD_BUG_ON(offsetof(siginfo_t, si_band) != 0x0c);
BUILD_BUG_ON(offsetof(siginfo_t, si_fd) != 0x10);
/* _sigsys */
BUILD_BUG_ON(offsetof(siginfo_t, si_call_addr) != 0x0c);
BUILD_BUG_ON(offsetof(siginfo_t, si_syscall) != 0x10);
BUILD_BUG_ON(offsetof(siginfo_t, si_arch) != 0x14);
/* any new si_fields should be added here */
}
static int mangle_kernel_stack(struct pt_regs *regs, int formatvec,
void __user *fp)
{
int extra = frame_extra_sizes(formatvec >> 12);
char buf[sizeof_field(struct frame, un)];
if (extra < 0) {
/*
* user process trying to return with weird frame format
*/
pr_debug("user process returning with weird frame format\n");
return -1;
}
if (extra && copy_from_user(buf, fp, extra))
return -1;
regs->format = formatvec >> 12;
regs->vector = formatvec & 0xfff;
if (extra) {
void *p = (struct switch_stack *)regs - 1;
struct frame *new = (void *)regs - extra;
int size = sizeof(struct pt_regs)+sizeof(struct switch_stack);
memmove(p - extra, p, size);
memcpy(p - extra + size, buf, extra);
current->thread.esp0 = (unsigned long)&new->ptregs;
#ifdef CONFIG_M68040
/* on 68040 complete pending writebacks if any */
if (new->ptregs.format == 7) // bus error frame
berr_040cleanup(new);
#endif
}
return extra;
}
static inline int
restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *usc, void __user *fp)
{
int formatvec;
struct sigcontext context;
siginfo_build_tests();
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
/* get previous context */
if (copy_from_user(&context, usc, sizeof(context)))
return -1;
/* restore passed registers */
regs->d0 = context.sc_d0;
regs->d1 = context.sc_d1;
regs->a0 = context.sc_a0;
regs->a1 = context.sc_a1;
regs->sr = (regs->sr & 0xff00) | (context.sc_sr & 0xff);
regs->pc = context.sc_pc;
regs->orig_d0 = -1; /* disable syscall checks */
wrusp(context.sc_usp);
formatvec = context.sc_formatvec;
if (restore_fpu_state(&context))
return -1;
return mangle_kernel_stack(regs, formatvec, fp);
}
static inline int
rt_restore_ucontext(struct pt_regs *regs, struct switch_stack *sw,
struct ucontext __user *uc)
{
int temp;
greg_t __user *gregs = uc->uc_mcontext.gregs;
unsigned long usp;
int err;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
err = __get_user(temp, &uc->uc_mcontext.version);
if (temp != MCONTEXT_VERSION)
return -1;
/* restore passed registers */
err |= __get_user(regs->d0, &gregs[0]);
err |= __get_user(regs->d1, &gregs[1]);
err |= __get_user(regs->d2, &gregs[2]);
err |= __get_user(regs->d3, &gregs[3]);
err |= __get_user(regs->d4, &gregs[4]);
err |= __get_user(regs->d5, &gregs[5]);
err |= __get_user(sw->d6, &gregs[6]);
err |= __get_user(sw->d7, &gregs[7]);
err |= __get_user(regs->a0, &gregs[8]);
err |= __get_user(regs->a1, &gregs[9]);
err |= __get_user(regs->a2, &gregs[10]);
err |= __get_user(sw->a3, &gregs[11]);
err |= __get_user(sw->a4, &gregs[12]);
err |= __get_user(sw->a5, &gregs[13]);
err |= __get_user(sw->a6, &gregs[14]);
err |= __get_user(usp, &gregs[15]);
wrusp(usp);
err |= __get_user(regs->pc, &gregs[16]);
err |= __get_user(temp, &gregs[17]);
regs->sr = (regs->sr & 0xff00) | (temp & 0xff);
regs->orig_d0 = -1; /* disable syscall checks */
err |= __get_user(temp, &uc->uc_formatvec);
err |= rt_restore_fpu_state(uc);
err |= restore_altstack(&uc->uc_stack);
if (err)
return -1;
return mangle_kernel_stack(regs, temp, &uc->uc_extra);
}
asmlinkage void *do_sigreturn(struct pt_regs *regs, struct switch_stack *sw)
{
unsigned long usp = rdusp();
struct sigframe __user *frame = (struct sigframe __user *)(usp - 4);
sigset_t set;
int size;
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__get_user(set.sig[0], &frame->sc.sc_mask) ||
(_NSIG_WORDS > 1 &&
__copy_from_user(&set.sig[1], &frame->extramask,
sizeof(frame->extramask))))
goto badframe;
set_current_blocked(&set);
size = restore_sigcontext(regs, &frame->sc, frame + 1);
if (size < 0)
goto badframe;
return (void *)sw - size;
badframe:
force_sig(SIGSEGV);
return sw;
}
asmlinkage void *do_rt_sigreturn(struct pt_regs *regs, struct switch_stack *sw)
{
unsigned long usp = rdusp();
struct rt_sigframe __user *frame = (struct rt_sigframe __user *)(usp - 4);
sigset_t set;
int size;
if (!access_ok(frame, sizeof(*frame)))
goto badframe;
if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
goto badframe;
set_current_blocked(&set);
size = rt_restore_ucontext(regs, sw, &frame->uc);
if (size < 0)
goto badframe;
return (void *)sw - size;
badframe:
force_sig(SIGSEGV);
return sw;
}
static inline struct pt_regs *rte_regs(struct pt_regs *regs)
{
return (void *)regs + regs->stkadj;
}
static void setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
unsigned long mask)
{
struct pt_regs *tregs = rte_regs(regs);
sc->sc_mask = mask;
sc->sc_usp = rdusp();
sc->sc_d0 = regs->d0;
sc->sc_d1 = regs->d1;
sc->sc_a0 = regs->a0;
sc->sc_a1 = regs->a1;
sc->sc_sr = tregs->sr;
sc->sc_pc = tregs->pc;
sc->sc_formatvec = tregs->format << 12 | tregs->vector;
save_a5_state(sc, regs);
save_fpu_state(sc, regs);
}
static inline int rt_setup_ucontext(struct ucontext __user *uc, struct pt_regs *regs)
{
struct switch_stack *sw = (struct switch_stack *)regs - 1;
struct pt_regs *tregs = rte_regs(regs);
greg_t __user *gregs = uc->uc_mcontext.gregs;
int err = 0;
err |= __put_user(MCONTEXT_VERSION, &uc->uc_mcontext.version);
err |= __put_user(regs->d0, &gregs[0]);
err |= __put_user(regs->d1, &gregs[1]);
err |= __put_user(regs->d2, &gregs[2]);
err |= __put_user(regs->d3, &gregs[3]);
err |= __put_user(regs->d4, &gregs[4]);
err |= __put_user(regs->d5, &gregs[5]);
err |= __put_user(sw->d6, &gregs[6]);
err |= __put_user(sw->d7, &gregs[7]);
err |= __put_user(regs->a0, &gregs[8]);
err |= __put_user(regs->a1, &gregs[9]);
err |= __put_user(regs->a2, &gregs[10]);
err |= __put_user(sw->a3, &gregs[11]);
err |= __put_user(sw->a4, &gregs[12]);
err |= __put_user(sw->a5, &gregs[13]);
err |= __put_user(sw->a6, &gregs[14]);
err |= __put_user(rdusp(), &gregs[15]);
err |= __put_user(tregs->pc, &gregs[16]);
err |= __put_user(tregs->sr, &gregs[17]);
err |= __put_user((tregs->format << 12) | tregs->vector, &uc->uc_formatvec);
err |= rt_save_fpu_state(uc, regs);
return err;
}
static inline void __user *
get_sigframe(struct ksignal *ksig, size_t frame_size)
{
unsigned long usp = sigsp(rdusp(), ksig);
return (void __user *)((usp - frame_size) & -8UL);
}
static int setup_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct sigframe __user *frame;
struct pt_regs *tregs = rte_regs(regs);
int fsize = frame_extra_sizes(tregs->format);
struct sigcontext context;
int err = 0, sig = ksig->sig;
if (fsize < 0) {
pr_debug("setup_frame: Unknown frame format %#x\n",
tregs->format);
return -EFAULT;
}
frame = get_sigframe(ksig, sizeof(*frame) + fsize);
if (fsize)
err |= copy_to_user (frame + 1, regs + 1, fsize);
err |= __put_user(sig, &frame->sig);
err |= __put_user(tregs->vector, &frame->code);
err |= __put_user(&frame->sc, &frame->psc);
if (_NSIG_WORDS > 1)
err |= copy_to_user(frame->extramask, &set->sig[1],
sizeof(frame->extramask));
setup_sigcontext(&context, regs, set->sig[0]);
err |= copy_to_user (&frame->sc, &context, sizeof(context));
/* Set up to return from userspace. */
#ifdef CONFIG_MMU
err |= __put_user(frame->retcode, &frame->pretcode);
/* moveq #,d0; trap #0 */
err |= __put_user(0x70004e40 + (__NR_sigreturn << 16),
(long __user *)(frame->retcode));
#else
err |= __put_user((long) ret_from_user_signal,
(long __user *) &frame->pretcode);
#endif
if (err)
return -EFAULT;
push_cache ((unsigned long) &frame->retcode);
/*
* This is subtle; if we build more than one sigframe, all but the
* first one will see frame format 0 and have fsize == 0, so we won't
* screw stkadj.
*/
if (fsize) {
regs->stkadj = fsize;
tregs = rte_regs(regs);
pr_debug("Performing stackadjust=%04lx\n", regs->stkadj);
tregs->vector = 0;
tregs->format = 0;
tregs->sr = regs->sr;
}
/*
* Set up registers for signal handler. All the state we are about
* to destroy is successfully copied to sigframe.
*/
wrusp ((unsigned long) frame);
tregs->pc = (unsigned long) ksig->ka.sa.sa_handler;
adjustformat(regs);
return 0;
}
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
struct pt_regs *tregs = rte_regs(regs);
int fsize = frame_extra_sizes(tregs->format);
int err = 0, sig = ksig->sig;
if (fsize < 0) {
pr_debug("setup_frame: Unknown frame format %#x\n",
regs->format);
return -EFAULT;
}
frame = get_sigframe(ksig, sizeof(*frame));
if (fsize)
err |= copy_to_user (&frame->uc.uc_extra, regs + 1, fsize);
err |= __put_user(sig, &frame->sig);
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(NULL, &frame->uc.uc_link);
err |= __save_altstack(&frame->uc.uc_stack, rdusp());
err |= rt_setup_ucontext(&frame->uc, regs);
err |= copy_to_user (&frame->uc.uc_sigmask, set, sizeof(*set));
/* Set up to return from userspace. */
#ifdef CONFIG_MMU
err |= __put_user(frame->retcode, &frame->pretcode);
#ifdef __mcoldfire__
/* movel #__NR_rt_sigreturn,d0; trap #0 */
err |= __put_user(0x203c0000, (long __user *)(frame->retcode + 0));
err |= __put_user(0x00004e40 + (__NR_rt_sigreturn << 16),
(long __user *)(frame->retcode + 4));
#else
/* moveq #,d0; notb d0; trap #0 */
err |= __put_user(0x70004600 + ((__NR_rt_sigreturn ^ 0xff) << 16),
(long __user *)(frame->retcode + 0));
err |= __put_user(0x4e40, (short __user *)(frame->retcode + 4));
#endif
#else
err |= __put_user((long) ret_from_user_rt_signal,
(long __user *) &frame->pretcode);
#endif /* CONFIG_MMU */
if (err)
return -EFAULT;
push_cache ((unsigned long) &frame->retcode);
/*
* This is subtle; if we build more than one sigframe, all but the
* first one will see frame format 0 and have fsize == 0, so we won't
* screw stkadj.
*/
if (fsize) {
regs->stkadj = fsize;
tregs = rte_regs(regs);
pr_debug("Performing stackadjust=%04lx\n", regs->stkadj);
tregs->vector = 0;
tregs->format = 0;
tregs->sr = regs->sr;
}
/*
* Set up registers for signal handler. All the state we are about
* to destroy is successfully copied to sigframe.
*/
wrusp ((unsigned long) frame);
tregs->pc = (unsigned long) ksig->ka.sa.sa_handler;
adjustformat(regs);
return 0;
}
static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
switch (regs->d0) {
case -ERESTARTNOHAND:
if (!has_handler)
goto do_restart;
regs->d0 = -EINTR;
break;
case -ERESTART_RESTARTBLOCK:
if (!has_handler) {
regs->d0 = __NR_restart_syscall;
regs->pc -= 2;
break;
}
regs->d0 = -EINTR;
break;
case -ERESTARTSYS:
if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
regs->d0 = -EINTR;
break;
}
fallthrough;
case -ERESTARTNOINTR:
do_restart:
regs->d0 = regs->orig_d0;
regs->pc -= 2;
break;
}
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int err;
/* are we from a system call? */
if (regs->orig_d0 >= 0)
/* If so, check system call restarting.. */
handle_restart(regs, &ksig->ka, 1);
/* set up the stack frame */
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
err = setup_rt_frame(ksig, oldset, regs);
else
err = setup_frame(ksig, oldset, regs);
signal_setup_done(err, ksig, 0);
if (test_thread_flag(TIF_DELAYED_TRACE)) {
regs->sr &= ~0x8000;
send_sig(SIGTRAP, current, 1);
}
}
/*
* 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)
{
struct ksignal ksig;
current->thread.esp0 = (unsigned long) regs;
if (get_signal(&ksig)) {
/* Whee! Actually deliver the signal. */
handle_signal(&ksig, regs);
return;
}
/* Did we come from a system call? */
if (regs->orig_d0 >= 0)
/* Restart the system call - no handlers present */
handle_restart(regs, NULL, 0);
/* If there's no signal to deliver, we just restore the saved mask. */
restore_saved_sigmask();
}
void do_notify_resume(struct pt_regs *regs)
{
if (test_thread_flag(TIF_NOTIFY_SIGNAL) ||
test_thread_flag(TIF_SIGPENDING))
do_signal(regs);
if (test_thread_flag(TIF_NOTIFY_RESUME))
tracehook_notify_resume(regs);
}
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