[RFC v2 -tip 2/3] x86: signal: use {get|put}_user_try and catch

Hiroshi Shimamoto
2009-01-23T23:50:28Z

From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>

Impact: use new framework

Use {get|put}_user_try, catch, and _ex in arch/x86/kernel/signal.c.

Note: this patch contains "WARNING: line over 80 characters", because when
introducing new block I insert an indent to avoid mistakes by edit.

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
---
arch/x86/kernel/signal.c | 297 ++++++++++++++++++++++++----------------------
1 files changed, 157 insertions(+), 140 deletions(-)

diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 0bc73d6..40e089b 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -51,24 +51,24 @@
#endif

#define COPY(x) { \
- err |= __get_user(regs->x, &sc->x); \
+ get_user_ex(regs->x, &sc->x); \
}

#define COPY_SEG(seg) { \
unsigned short tmp; \
- err |= __get_user(tmp, &sc->seg); \
+ get_user_ex(tmp, &sc->seg); \
regs->seg = tmp; \
}

#define COPY_SEG_CPL3(seg) { \
unsigned short tmp; \
- err |= __get_user(tmp, &sc->seg); \
+ get_user_ex(tmp, &sc->seg); \
regs->seg = tmp | 3; \
}

#define GET_SEG(seg) { \
unsigned short tmp; \
- err |= __get_user(tmp, &sc->seg); \
+ get_user_ex(tmp, &sc->seg); \
loadsegment(seg, tmp); \
}

@@ -83,45 +83,49 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc,
/* Always make any pending restarted system calls return -EINTR */
current_thread_info()->restart_block.fn = do_no_restart_syscall;

+ get_user_try {
+
#ifdef CONFIG_X86_32
- GET_SEG(gs);
- COPY_SEG(fs);
- COPY_SEG(es);
- COPY_SEG(ds);
+ GET_SEG(gs);
+ COPY_SEG(fs);
+ COPY_SEG(es);
+ COPY_SEG(ds);
#endif /* CONFIG_X86_32 */

- COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
- COPY(dx); COPY(cx); COPY(ip);
+ COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
+ COPY(dx); COPY(cx); COPY(ip);

#ifdef CONFIG_X86_64
- COPY(r8);
- COPY(r9);
- COPY(r10);
- COPY(r11);
- COPY(r12);
- COPY(r13);
- COPY(r14);
- COPY(r15);
+ COPY(r8);
+ COPY(r9);
+ COPY(r10);
+ COPY(r11);
+ COPY(r12);
+ COPY(r13);
+ COPY(r14);
+ COPY(r15);
#endif /* CONFIG_X86_64 */

#ifdef CONFIG_X86_32
- COPY_SEG_CPL3(cs);
- COPY_SEG_CPL3(ss);
+ COPY_SEG_CPL3(cs);
+ COPY_SEG_CPL3(ss);
#else /* !CONFIG_X86_32 */
- /* Kernel saves and restores only the CS segment register on signals,
- * which is the bare minimum needed to allow mixed 32/64-bit code.
- * App's signal handler can save/restore other segments if needed. */
- COPY_SEG_CPL3(cs);
+ /* Kernel saves and restores only the CS segment register on signals,
+ * which is the bare minimum needed to allow mixed 32/64-bit code.
+ * App's signal handler can save/restore other segments if needed. */
+ COPY_SEG_CPL3(cs);
#endif /* CONFIG_X86_32 */

- err |= __get_user(tmpflags, &sc->flags);
- regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
- regs->orig_ax = -1; /* disable syscall checks */
+ get_user_ex(tmpflags, &sc->flags);
+ regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);
+ regs->orig_ax = -1; /* disable syscall checks */
+
+ get_user_ex(buf, &sc->fpstate);
+ err |= restore_i387_xstate(buf);

- err |= __get_user(buf, &sc->fpstate);
- err |= restore_i387_xstate(buf);
+ get_user_ex(*pax, &sc->ax);
+ } get_user_catch(err);

- err |= __get_user(*pax, &sc->ax);
return err;
}

@@ -131,57 +135,60 @@ setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,
{
int err = 0;

+ put_user_try {
+
#ifdef CONFIG_X86_32
- {
- unsigned int tmp;
+ {
+ unsigned int tmp;

- savesegment(gs, tmp);
- err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
- }
- err |= __put_user(regs->fs, (unsigned int __user *)&sc->fs);
- err |= __put_user(regs->es, (unsigned int __user *)&sc->es);
- err |= __put_user(regs->ds, (unsigned int __user *)&sc->ds);
+ savesegment(gs, tmp);
+ put_user_ex(tmp, (unsigned int __user *)&sc->gs);
+ }
+ put_user_ex(regs->fs, (unsigned int __user *)&sc->fs);
+ put_user_ex(regs->es, (unsigned int __user *)&sc->es);
+ put_user_ex(regs->ds, (unsigned int __user *)&sc->ds);
#endif /* CONFIG_X86_32 */

- err |= __put_user(regs->di, &sc->di);
- err |= __put_user(regs->si, &sc->si);
- err |= __put_user(regs->bp, &sc->bp);
- err |= __put_user(regs->sp, &sc->sp);
- err |= __put_user(regs->bx, &sc->bx);
- err |= __put_user(regs->dx, &sc->dx);
- err |= __put_user(regs->cx, &sc->cx);
- err |= __put_user(regs->ax, &sc->ax);
+ put_user_ex(regs->di, &sc->di);
+ put_user_ex(regs->si, &sc->si);
+ put_user_ex(regs->bp, &sc->bp);
+ put_user_ex(regs->sp, &sc->sp);
+ put_user_ex(regs->bx, &sc->bx);
+ put_user_ex(regs->dx, &sc->dx);
+ put_user_ex(regs->cx, &sc->cx);
+ put_user_ex(regs->ax, &sc->ax);
#ifdef CONFIG_X86_64
- err |= __put_user(regs->r8, &sc->r8);
- err |= __put_user(regs->r9, &sc->r9);
- err |= __put_user(regs->r10, &sc->r10);
- err |= __put_user(regs->r11, &sc->r11);
- err |= __put_user(regs->r12, &sc->r12);
- err |= __put_user(regs->r13, &sc->r13);
- err |= __put_user(regs->r14, &sc->r14);
- err |= __put_user(regs->r15, &sc->r15);
+ put_user_ex(regs->r8, &sc->r8);
+ put_user_ex(regs->r9, &sc->r9);
+ put_user_ex(regs->r10, &sc->r10);
+ put_user_ex(regs->r11, &sc->r11);
+ put_user_ex(regs->r12, &sc->r12);
+ put_user_ex(regs->r13, &sc->r13);
+ put_user_ex(regs->r14, &sc->r14);
+ put_user_ex(regs->r15, &sc->r15);
#endif /* CONFIG_X86_64 */

- err |= __put_user(current->thread.trap_no, &sc->trapno);
- err |= __put_user(current->thread.error_code, &sc->err);
- err |= __put_user(regs->ip, &sc->ip);
+ put_user_ex(current->thread.trap_no, &sc->trapno);
+ put_user_ex(current->thread.error_code, &sc->err);
+ put_user_ex(regs->ip, &sc->ip);
#ifdef CONFIG_X86_32
- err |= __put_user(regs->cs, (unsigned int __user *)&sc->cs);
- err |= __put_user(regs->flags, &sc->flags);
- err |= __put_user(regs->sp, &sc->sp_at_signal);
- err |= __put_user(regs->ss, (unsigned int __user *)&sc->ss);
+ put_user_ex(regs->cs, (unsigned int __user *)&sc->cs);
+ put_user_ex(regs->flags, &sc->flags);
+ put_user_ex(regs->sp, &sc->sp_at_signal);
+ put_user_ex(regs->ss, (unsigned int __user *)&sc->ss);
#else /* !CONFIG_X86_32 */
- err |= __put_user(regs->flags, &sc->flags);
- err |= __put_user(regs->cs, &sc->cs);
- err |= __put_user(0, &sc->gs);
- err |= __put_user(0, &sc->fs);
+ put_user_ex(regs->flags, &sc->flags);
+ put_user_ex(regs->cs, &sc->cs);
+ put_user_ex(0, &sc->gs);
+ put_user_ex(0, &sc->fs);
#endif /* CONFIG_X86_32 */

- err |= __put_user(fpstate, &sc->fpstate);
+ put_user_ex(fpstate, &sc->fpstate);

- /* non-iBCS2 extensions.. */
- err |= __put_user(mask, &sc->oldmask);
- err |= __put_user(current->thread.cr2, &sc->cr2);
+ /* non-iBCS2 extensions.. */
+ put_user_ex(mask, &sc->oldmask);
+ put_user_ex(current->thread.cr2, &sc->cr2);
+ } put_user_catch(err);

return err;
}
@@ -336,43 +343,41 @@ static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return -EFAULT;

- 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, info);
- if (err)
- return -EFAULT;
-
- /* Create the ucontext. */
- if (cpu_has_xsave)
- err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
- else
- err |= __put_user(0, &frame->uc.uc_flags);
- err |= __put_user(0, &frame->uc.uc_link);
- err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
- err |= __put_user(sas_ss_flags(regs->sp),
- &frame->uc.uc_stack.ss_flags);
- err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
- err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
- regs, set->sig[0]);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
- if (err)
- return -EFAULT;
+ put_user_try {
+ put_user_ex(sig, &frame->sig);
+ put_user_ex(&frame->info, &frame->pinfo);
+ put_user_ex(&frame->uc, &frame->puc);
+ err |= copy_siginfo_to_user(&frame->info, info);

- /* Set up to return from userspace. */
- restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
- if (ka->sa.sa_flags & SA_RESTORER)
- restorer = ka->sa.sa_restorer;
- err |= __put_user(restorer, &frame->pretcode);
+ /* Create the ucontext. */
+ if (cpu_has_xsave)
+ put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
+ else
+ put_user_ex(0, &frame->uc.uc_flags);
+ put_user_ex(0, &frame->uc.uc_link);
+ put_user_ex(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
+ put_user_ex(sas_ss_flags(regs->sp),
+ &frame->uc.uc_stack.ss_flags);
+ put_user_ex(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+ err |= setup_sigcontext(&frame->uc.uc_mcontext, fpstate,
+ regs, set->sig[0]);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ /* Set up to return from userspace. */
+ restorer = VDSO32_SYMBOL(current->mm->context.vdso, rt_sigreturn);
+ if (ka->sa.sa_flags & SA_RESTORER)
+ restorer = ka->sa.sa_restorer;
+ put_user_ex(restorer, &frame->pretcode);

- /*
- * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
- *
- * WE DO NOT USE IT ANY MORE! It's only left here for historical
- * reasons and because gdb uses it as a signature to notice
- * signal handler stack frames.
- */
- err |= __put_user(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
+ /*
+ * This is movl $__NR_rt_sigreturn, %ax ; int $0x80
+ *
+ * WE DO NOT USE IT ANY MORE! It's only left here for historical
+ * reasons and because gdb uses it as a signature to notice
+ * signal handler stack frames.
+ */
+ put_user_ex(*((u64 *)&rt_retcode), (u64 *)frame->retcode);
+ } put_user_catch(err);

if (err)
return -EFAULT;
@@ -436,28 +441,30 @@ static int __setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
return -EFAULT;
}

- /* Create the ucontext. */
- if (cpu_has_xsave)
- err |= __put_user(UC_FP_XSTATE, &frame->uc.uc_flags);
- else
- err |= __put_user(0, &frame->uc.uc_flags);
- err |= __put_user(0, &frame->uc.uc_link);
- err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
- err |= __put_user(sas_ss_flags(regs->sp),
- &frame->uc.uc_stack.ss_flags);
- err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
- err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
- err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
-
- /* Set up to return from userspace. If provided, use a stub
- already in userspace. */
- /* x86-64 should always use SA_RESTORER. */
- if (ka->sa.sa_flags & SA_RESTORER) {
- err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
- } else {
- /* could use a vstub here */
- return -EFAULT;
- }
+ put_user_try {
+ /* Create the ucontext. */
+ if (cpu_has_xsave)
+ put_user_ex(UC_FP_XSTATE, &frame->uc.uc_flags);
+ else
+ put_user_ex(0, &frame->uc.uc_flags);
+ put_user_ex(0, &frame->uc.uc_link);
+ put_user_ex(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
+ put_user_ex(sas_ss_flags(regs->sp),
+ &frame->uc.uc_stack.ss_flags);
+ put_user_ex(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
+ err |= setup_sigcontext(&frame->uc.uc_mcontext, fp, regs, set->sig[0]);
+ err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+ /* Set up to return from userspace. If provided, use a stub
+ already in userspace. */
+ /* x86-64 should always use SA_RESTORER. */
+ if (ka->sa.sa_flags & SA_RESTORER) {
+ put_user_ex(ka->sa.sa_restorer, &frame->pretcode);
+ } else {
+ /* could use a vstub here */
+ err |= -EFAULT;
+ }
+ } put_user_catch(err);

if (err)
return -EFAULT;
@@ -509,31 +516,41 @@ sys_sigaction(int sig, const struct old_sigaction __user *act,
struct old_sigaction __user *oact)
{
struct k_sigaction new_ka, old_ka;
- int ret;
+ int ret = 0;

if (act) {
old_sigset_t mask;

- if (!access_ok(VERIFY_READ, act, sizeof(*act)) ||
- __get_user(new_ka.sa.sa_handler, &act->sa_handler) ||
- __get_user(new_ka.sa.sa_restorer, &act->sa_restorer))
+ if (!access_ok(VERIFY_READ, act, sizeof(*act)))
return -EFAULT;

- __get_user(new_ka.sa.sa_flags, &act->sa_flags);
- __get_user(mask, &act->sa_mask);
+ get_user_try {
+ get_user_ex(new_ka.sa.sa_handler, &act->sa_handler);
+ get_user_ex(new_ka.sa.sa_flags, &act->sa_flags);
+ get_user_ex(mask, &act->sa_mask);
+ get_user_ex(new_ka.sa.sa_restorer, &act->sa_restorer);
+ } get_user_catch(ret);
+
+ if (ret)
+ return -EFAULT;
siginitset(&new_ka.sa.sa_mask, mask);
}

ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);

if (!ret && oact) {
- if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)) ||
- __put_user(old_ka.sa.sa_handler, &oact->sa_handler) ||
- __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer))
+ if (!access_ok(VERIFY_WRITE, oact, sizeof(*oact)))
return -EFAULT;

- __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
- __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
+ put_user_try {
+ put_user_ex(old_ka.sa.sa_handler, &oact->sa_handler);
+ put_user_ex(old_ka.sa.sa_flags, &oact->sa_flags);
+ put_user_ex(old_ka.sa.sa_mask.sig[0], &oact->sa_mask);
+ put_user_ex(old_ka.sa.sa_restorer, &oact->sa_restorer);
+ } put_user_catch(ret);
+
+ if (ret)
+ return -EFAULT;
}

return ret;
--
1.6.0.4