[Devel] [PATCH RHEL7 COMMIT] ms/x86/coredump: use pr_reg size, rather that TIF_IA32 flag

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-327.22.2.vz7.16.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-327.22.2.vz7.16.5
------>
commit 0a3d4066663908d4d47823a2fbc0f6c08f37fbf2
Author: Dmitry Safonov <dsafonov at virtuozzo.com>
Date:   Thu Aug 11 13:28:02 2016 +0400

    ms/x86/coredump: use pr_reg size, rather that TIF_IA32 flag
    
    Patchset description:
    
    Compat C/R patches
    
      Those patches adds possibility to C/R compatible 32-bit application
    with CRIU help. Tested with criu-dev branch with a couple of v3.10
    specific patches (which are also good for v3.11, which CRIU supports),
    I will sent them to criu shortly.
      3/4 first patches are backports of my upstream patches, which *arn't*
    yet in vanilla, but lkml folks found them good [1].
    The fourth patch is made from a scratch, as vDSO part of the kernel
    has been changed from v3.10 quit greatly.
    
    [1]: http://lwn.net/Articles/693012/
    
    Cc: Cyrill Gorcunov <gorcunov at openvz.org>
    Cc: Pavel Emelyanov <xemul at virtuozzo.com>
    Cc: Vladimir Davydov <vdavydov at virtuozzo.com>
    Cc: Konstantin Khorenko <khorenko at virtuozzo.com>
    
    Dmitry Safonov (4):
      x86/coredump: use pr_reg size, rather that TIF_IA32 flag
      x86/ptrace: down with test_thread_flag(TIF_IA32)
      x86/signal: add SA_{X32,IA32}_ABI sa_flags
      x86/arch_prctl/vdso: add ARCH_MAP_VDSO_*
    
    ==================================
    This patch description:
    
    Killed PR_REG_SIZE and PR_REG_PTR macro as we can get regset size
    from regset view.
    I wish I could also kill PRSTATUS_SIZE nicely.
    
    Suggested-by: Oleg Nesterov <oleg at redhat.com>
    Cc: Oleg Nesterov <oleg at redhat.com>
    Cc: Andy Lutomirski <luto at kernel.org>
    Cc: Ingo Molnar <mingo at redhat.com>
    Cc: Cyrill Gorcunov <gorcunov at openvz.org>
    Cc: Pavel Emelyanov <xemul at virtuozzo.com>
    Cc: x86 at kernel.org
    Cc: Alexander Viro <viro at zeniv.linux.org.uk>
    Cc: linux-fsdevel at vger.kernel.org
    Signed-off-by: Dmitry Safonov <dsafonov at virtuozzo.com>
---
 arch/x86/include/asm/compat.h |  8 ++++----
 fs/binfmt_elf.c               | 23 ++++++++---------------
 2 files changed, 12 insertions(+), 19 deletions(-)

diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index 59c6c40..6a07267 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -264,10 +264,10 @@ struct compat_shmid64_ds {
 #ifdef CONFIG_X86_X32_ABI
 typedef struct user_regs_struct compat_elf_gregset_t;
 
-#define PR_REG_SIZE(S) (test_thread_flag(TIF_IA32) ? 68 : 216)
-#define PRSTATUS_SIZE(S) (test_thread_flag(TIF_IA32) ? 144 : 296)
-#define SET_PR_FPVALID(S,V) \
-  do { *(int *) (((void *) &((S)->pr_reg)) + PR_REG_SIZE(0)) = (V); } \
+/* Full regset -- prstatus on x32, otherwise on ia32 */
+#define PRSTATUS_SIZE(S, R) (R != sizeof(S.pr_reg) ? 144 : 296)
+#define SET_PR_FPVALID(S, V, R) \
+  do { *(int *) (((void *) &((S)->pr_reg)) + R) = (V); } \
   while (0)
 
 #define COMPAT_USE_64BIT_TIME \
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index ea61aa7..640092c 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1520,20 +1520,12 @@ static void do_thread_regset_writeback(struct task_struct *task,
 		regset->writeback(task, regset, 1);
 }
 
-#ifndef PR_REG_SIZE
-#define PR_REG_SIZE(S) sizeof(S)
-#endif
-
 #ifndef PRSTATUS_SIZE
-#define PRSTATUS_SIZE(S) sizeof(S)
-#endif
-
-#ifndef PR_REG_PTR
-#define PR_REG_PTR(S) (&((S)->pr_reg))
+#define PRSTATUS_SIZE(S, R) sizeof(S)
 #endif
 
 #ifndef SET_PR_FPVALID
-#define SET_PR_FPVALID(S, V) ((S)->pr_fpvalid = (V))
+#define SET_PR_FPVALID(S, V, R) ((S)->pr_fpvalid = (V))
 #endif
 
 static int fill_thread_core_info(struct elf_thread_core_info *t,
@@ -1541,6 +1533,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 				 long signr, size_t *total)
 {
 	unsigned int i;
+	unsigned int regset_size = view->regsets[0].n * view->regsets[0].size;
 
 	/*
 	 * NT_PRSTATUS is the one special case, because the regset data
@@ -1549,12 +1542,11 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 	 * We assume that regset 0 is NT_PRSTATUS.
 	 */
 	fill_prstatus(&t->prstatus, t->task, signr);
-	(void) view->regsets[0].get(t->task, &view->regsets[0],
-				    0, PR_REG_SIZE(t->prstatus.pr_reg),
-				    PR_REG_PTR(&t->prstatus), NULL);
+	(void) view->regsets[0].get(t->task, &view->regsets[0], 0, regset_size,
+				    &t->prstatus.pr_reg, NULL);
 
 	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
-		  PRSTATUS_SIZE(t->prstatus), &t->prstatus);
+		  PRSTATUS_SIZE(t->prstatus, regset_size), &t->prstatus);
 	*total += notesize(&t->notes[0]);
 
 	do_thread_regset_writeback(t->task, &view->regsets[0]);
@@ -1584,7 +1576,8 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 						  regset->core_note_type,
 						  size, data);
 				else {
-					SET_PR_FPVALID(&t->prstatus, 1);
+					SET_PR_FPVALID(&t->prstatus,
+							1, regset_size);
 					fill_note(&t->notes[i], "CORE",
 						  NT_PRFPREG, size, data);
 				}