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Merge branch 'for-curr' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

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Pull ARC fix from Vineet Gupta:
 "Chrisitian found/fixed issue with SA_SIGINFO based signal handler
  corrupting the user space registers post after signal handling"

* 'for-curr' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
  ARC: Fix signal frame management for SA_SIGINFO
This commit is contained in:
Linus Torvalds 2013-10-03 08:55:50 -07:00
commit afe05d41e2
1 changed files with 13 additions and 12 deletions
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25
arch/arc/kernel/signal.c
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@ -101,7 +101,6 @@ SYSCALL_DEFINE0(rt_sigreturn)
{ {
struct rt_sigframe __user *sf; struct rt_sigframe __user *sf;
unsigned int magic; unsigned int magic;
int err;
struct pt_regs *regs = current_pt_regs(); struct pt_regs *regs = current_pt_regs();
/* Always make any pending restarted system calls return -EINTR */ /* Always make any pending restarted system calls return -EINTR */
@ -119,15 +118,16 @@ SYSCALL_DEFINE0(rt_sigreturn)
if (!access_ok(VERIFY_READ, sf, sizeof(*sf))) if (!access_ok(VERIFY_READ, sf, sizeof(*sf)))
goto badframe; goto badframe;
err = restore_usr_regs(regs, sf); if (__get_user(magic, &sf->sigret_magic))
err |= __get_user(magic, &sf->sigret_magic);
if (err)
goto badframe; goto badframe;
if (unlikely(is_do_ss_needed(magic))) if (unlikely(is_do_ss_needed(magic)))
if (restore_altstack(&sf->uc.uc_stack)) if (restore_altstack(&sf->uc.uc_stack))
goto badframe; goto badframe;
if (restore_usr_regs(regs, sf))
goto badframe;
/* Don't restart from sigreturn */ /* Don't restart from sigreturn */
syscall_wont_restart(regs); syscall_wont_restart(regs);
@ -190,6 +190,15 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info,
if (!sf) if (!sf)
return 1; return 1;
/*
* w/o SA_SIGINFO, struct ucontext is partially populated (only
* uc_mcontext/uc_sigmask) for kernel's normal user state preservation
* during signal handler execution. This works for SA_SIGINFO as well
* although the semantics are now overloaded (the same reg state can be
* inspected by userland: but are they allowed to fiddle with it ?
*/
err |= stash_usr_regs(sf, regs, set);
/* /*
* SA_SIGINFO requires 3 args to signal handler: * SA_SIGINFO requires 3 args to signal handler:
* #1: sig-no (common to any handler) * #1: sig-no (common to any handler)
@ -213,14 +222,6 @@ setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info,
magic = MAGIC_SIGALTSTK; magic = MAGIC_SIGALTSTK;
} }
/*
* w/o SA_SIGINFO, struct ucontext is partially populated (only
* uc_mcontext/uc_sigmask) for kernel's normal user state preservation
* during signal handler execution. This works for SA_SIGINFO as well
* although the semantics are now overloaded (the same reg state can be
* inspected by userland: but are they allowed to fiddle with it ?
*/
err |= stash_usr_regs(sf, regs, set);
err |= __put_user(magic, &sf->sigret_magic); err |= __put_user(magic, &sf->sigret_magic);
if (err) if (err)
return err; return err;