[PATCH 2/3] signal: Implement SIL_FAULT_TRAPNO

From: Eric W. Biederman
Date: Fri Apr 30 2021 - 18:54:25 EST



Now that si_trapno is part of the union in _si_fault and available on
all architectures, add SIL_FAULT_TRAPNO and update siginfo_layout to
return SIL_FAULT_TRAPNO when si_trapno is actually used.

Update the code that uses siginfo_layout to deal with SIL_FAULT_TRAPNO
and have the same code ignore si_trapno in in all other cases.

Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
fs/signalfd.c | 7 ++-----
include/linux/signal.h | 1 +
kernel/signal.c | 36 ++++++++++++++----------------------
3 files changed, 17 insertions(+), 27 deletions(-)

diff --git a/fs/signalfd.c b/fs/signalfd.c
index 040a1142915f..126c681a30e7 100644
--- a/fs/signalfd.c
+++ b/fs/signalfd.c
@@ -123,15 +123,12 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
*/
case SIL_FAULT:
new.ssi_addr = (long) kinfo->si_addr;
-#ifdef __ARCH_SI_TRAPNO
+ case SIL_FAULT_TRAPNO:
+ new.ssi_addr = (long) kinfo->si_addr;
new.ssi_trapno = kinfo->si_trapno;
-#endif
break;
case SIL_FAULT_MCEERR:
new.ssi_addr = (long) kinfo->si_addr;
-#ifdef __ARCH_SI_TRAPNO
- new.ssi_trapno = kinfo->si_trapno;
-#endif
new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;
break;
case SIL_PERF_EVENT:
diff --git a/include/linux/signal.h b/include/linux/signal.h
index 1e98548d7cf6..5160fd45e5ca 100644
--- a/include/linux/signal.h
+++ b/include/linux/signal.h
@@ -40,6 +40,7 @@ enum siginfo_layout {
SIL_TIMER,
SIL_POLL,
SIL_FAULT,
+ SIL_FAULT_TRAPNO,
SIL_FAULT_MCEERR,
SIL_FAULT_BNDERR,
SIL_FAULT_PKUERR,
diff --git a/kernel/signal.c b/kernel/signal.c
index c3017aa8024a..7b2d61cb7411 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1194,6 +1194,7 @@ static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
case SIL_TIMER:
case SIL_POLL:
case SIL_FAULT:
+ case SIL_FAULT_TRAPNO:
case SIL_FAULT_MCEERR:
case SIL_FAULT_BNDERR:
case SIL_FAULT_PKUERR:
@@ -2527,6 +2528,7 @@ static void hide_si_addr_tag_bits(struct ksignal *ksig)
{
switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
case SIL_FAULT:
+ case SIL_FAULT_TRAPNO:
case SIL_FAULT_MCEERR:
case SIL_FAULT_BNDERR:
case SIL_FAULT_PKUERR:
@@ -3206,6 +3208,12 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
if ((sig == SIGBUS) &&
(si_code >= BUS_MCEERR_AR) && (si_code <= BUS_MCEERR_AO))
layout = SIL_FAULT_MCEERR;
+ else if (IS_ENABLED(ALPHA) &&
+ ((sig == SIGFPE) ||
+ ((sig == SIGTRAP) && (si_code == TRAP_UNK))))
+ layout = SIL_FAULT_TRAPNO;
+ else if (IS_ENABLED(SPARC) && (sig == SIGILL) && (si_code == ILL_ILLTRP))
+ layout = SIL_FAULT_TRAPNO;
else if ((sig == SIGSEGV) && (si_code == SEGV_BNDERR))
layout = SIL_FAULT_BNDERR;
#ifdef SEGV_PKUERR
@@ -3317,30 +3325,22 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
break;
case SIL_FAULT:
to->si_addr = ptr_to_compat(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
+ break;
+ case SIL_FAULT_TRAPNO:
+ to->si_addr = ptr_to_compat(from->si_addr);
to->si_trapno = from->si_trapno;
-#endif
break;
case SIL_FAULT_MCEERR:
to->si_addr = ptr_to_compat(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
- to->si_trapno = from->si_trapno;
-#endif
to->si_addr_lsb = from->si_addr_lsb;
break;
case SIL_FAULT_BNDERR:
to->si_addr = ptr_to_compat(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
- to->si_trapno = from->si_trapno;
-#endif
to->si_lower = ptr_to_compat(from->si_lower);
to->si_upper = ptr_to_compat(from->si_upper);
break;
case SIL_FAULT_PKUERR:
to->si_addr = ptr_to_compat(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
- to->si_trapno = from->si_trapno;
-#endif
to->si_pkey = from->si_pkey;
break;
case SIL_PERF_EVENT:
@@ -3401,30 +3401,22 @@ static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
break;
case SIL_FAULT:
to->si_addr = compat_ptr(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
+ break;
+ case SIL_FAULT_TRAPNO:
+ to->si_addr = compat_ptr(from->si_addr);
to->si_trapno = from->si_trapno;
-#endif
break;
case SIL_FAULT_MCEERR:
to->si_addr = compat_ptr(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
- to->si_trapno = from->si_trapno;
-#endif
to->si_addr_lsb = from->si_addr_lsb;
break;
case SIL_FAULT_BNDERR:
to->si_addr = compat_ptr(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
- to->si_trapno = from->si_trapno;
-#endif
to->si_lower = compat_ptr(from->si_lower);
to->si_upper = compat_ptr(from->si_upper);
break;
case SIL_FAULT_PKUERR:
to->si_addr = compat_ptr(from->si_addr);
-#ifdef __ARCH_SI_TRAPNO
- to->si_trapno = from->si_trapno;
-#endif
to->si_pkey = from->si_pkey;
break;
case SIL_PERF_EVENT:
--
2.30.1