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Subject[REVIEW][PATCH 19/22] signal/um: Use force_sig_fault in relay_signal.
Today user mode linux only works on x86 and x86_64 and this allows
simplifications of relay_signal.

- x86 always set si_errno to 0 in fault handlers.
- x86 does not implement si_trapno.
- Only si_codes between SI_USER and SI_KERNEL have a fault address.

Therefore warn if si_errno is set (it should never be).
Use force_sig_info in the case where we know we have a good fault.

For signals whose content it is not clear how to relay use plain
force_sig and let the signal sending code come up with an
appropriate generic siginfo.

Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: user-mode-linux-devel@lists.sourceforge.net
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---
arch/um/kernel/trap.c | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)

diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index d4d38520c4c6..5f0ff17cd790 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -296,9 +296,6 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,

void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)
{
- struct faultinfo *fi;
- struct siginfo clean_si;
-
if (!UPT_IS_USER(regs)) {
if (sig == SIGBUS)
printk(KERN_ERR "Bus error - the host /dev/shm or /tmp "
@@ -308,29 +305,30 @@ void relay_signal(int sig, struct siginfo *si, struct uml_pt_regs *regs)

arch_examine_signal(sig, regs);

- clear_siginfo(&clean_si);
- clean_si.si_signo = si->si_signo;
- clean_si.si_errno = si->si_errno;
- clean_si.si_code = si->si_code;
+ if (unlikely(si->si_errno)) {
+ printk(KERN_ERR "Attempted to relay signal %d (si_code = %d) with errno %d\n",
+ sig, si->si_code, si->si_errno);
+ }
switch (sig) {
case SIGILL:
case SIGFPE:
case SIGSEGV:
case SIGBUS:
case SIGTRAP:
- fi = UPT_FAULTINFO(regs);
- clean_si.si_addr = (void __user *) FAULT_ADDRESS(*fi);
- current->thread.arch.faultinfo = *fi;
-#ifdef __ARCH_SI_TRAPNO
- clean_si.si_trapno = si->si_trapno;
-#endif
- break;
+ if ((si->si_code > SI_USER) && (si->si_code < SI_KERNEL)) {
+ struct faultinfo *fi = UPT_FAULTINFO(regs);
+ current->thread.arch.faultinfo = *fi;
+ force_sig_fault(sig, si->si_code,
+ (void __user *)FAULT_ADDRESS(*fi),
+ current);
+ break;
+ }
default:
printk(KERN_ERR "Attempted to relay unknown signal %d (si_code = %d)\n",
sig, si->si_code);
}

- force_sig_info(sig, &clean_si, current);
+ force_sig(sig, current);
}

void bus_handler(int sig, struct siginfo *si, struct uml_pt_regs *regs)
--
2.14.1
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