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x86/signals: Add missing signal_compat code for x86 features

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The 32-bit siginfo is a different binary format than the 64-bit
one.  So, when running 32-bit binaries on 64-bit kernels, we have
to convert the kernel's 64-bit version to a 32-bit version that
userspace can grok.

We've added a few features to siginfo over the past few years and
neglected to add them to arch/x86/kernel/signal_compat.c:

   1. The si_addr_lsb used in SIGBUS's sent for machine checks
   2. The upper/lower bounds for MPX SIGSEGV faults
   3. The protection key for pkey faults

I caught this with some protection keys unit tests and realized
it affected a few more features.

This was tested only with my protection keys patch that looks
for a proper value in si_pkey.  I didn't actually test the machine
check or MPX code.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave@sr71.net>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac@vger.kernel.org
Link: http://lkml.kernel.org/r/20160608172533.F8F05637@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dave Hansen 2016-06-08 10:25:33 -07:00 committed by Ingo Molnar
parent f0702555b1
commit a4455082dc
2 changed files with 26 additions and 0 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

11
arch/x86/include/asm/compat.h
View file

@ -40,6 +40,7 @@ typedef s32 compat_long_t;
typedef s64 __attribute__((aligned(4))) compat_s64;
typedef u32 compat_uint_t;
typedef u32 compat_ulong_t;
typedef u32 compat_u32;
typedef u64 __attribute__((aligned(4))) compat_u64;
typedef u32 compat_uptr_t;
@ -181,6 +182,16 @@ typedef struct compat_siginfo {
/* SIGILL, SIGFPE, SIGSEGV, SIGBUS */
struct {
unsigned int _addr; /* faulting insn/memory ref. */
short int _addr_lsb; /* Valid LSB of the reported address. */
union {
/* used when si_code=SEGV_BNDERR */
struct {
compat_uptr_t _lower;
compat_uptr_t _upper;
} _addr_bnd;
/* used when si_code=SEGV_PKUERR */
compat_u32 _pkey;
};
} _sigfault;
/* SIGPOLL */

15
arch/x86/kernel/signal_compat.c
View file

@ -32,6 +32,21 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from)
&to->_sifields._pad[0]);
switch (from->si_code >> 16) {
case __SI_FAULT >> 16:
if (from->si_signo == SIGBUS &&
(from->si_code == BUS_MCEERR_AR ||
from->si_code == BUS_MCEERR_AO))
put_user_ex(from->si_addr_lsb, &to->si_addr_lsb);
if (from->si_signo == SIGSEGV) {
if (from->si_code == SEGV_BNDERR) {
compat_uptr_t lower = (unsigned long)&to->si_lower;
compat_uptr_t upper = (unsigned long)&to->si_upper;
put_user_ex(lower, &to->si_lower);
put_user_ex(upper, &to->si_upper);
}
if (from->si_code == SEGV_PKUERR)
put_user_ex(from->si_pkey, &to->si_pkey);
}
break;
case __SI_SYS >> 16:
put_user_ex(from->si_syscall, &to->si_syscall);