[RFC 2/3] x86/coredump: use core regs, rather that TIF_IA32 flag

From: Dmitry Safonov
Date: Mon Apr 25 2016 - 12:14:40 EST


As we have here core registers, use them to determine application's
mode and sizes of register set and elf_prstatus.

Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-fsdevel@xxxxxxxxxxxxxxx
Signed-off-by: Dmitry Safonov <dsafonov@xxxxxxxxxxxxx>
---
arch/x86/include/asm/compat.h | 8 ++++----
fs/binfmt_elf.c | 18 ++++++++++--------
2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index 5a3b2c119ed0..d0b517fc77ff 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); } \
+#define PR_REG_SIZE(S, R) (!user_64bit_mode(R) ? 68 : 216)
+#define PRSTATUS_SIZE(S, R) (!user_64bit_mode(R) ? 144 : 296)
+#define SET_PR_FPVALID(S, V, R) \
+ do { *(int *) (((void *) &((S)->pr_reg)) + PR_REG_SIZE(0, R)) = (V); } \
while (0)

#define COMPAT_USE_64BIT_TIME \
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 81381cc0dd17..6be281ef34f9 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1621,11 +1621,11 @@ static void do_thread_regset_writeback(struct task_struct *task,
}

#ifndef PR_REG_SIZE
-#define PR_REG_SIZE(S) sizeof(S)
+#define PR_REG_SIZE(S, R) sizeof(S)
#endif

#ifndef PRSTATUS_SIZE
-#define PRSTATUS_SIZE(S) sizeof(S)
+#define PRSTATUS_SIZE(S, R) sizeof(S)
#endif

#ifndef PR_REG_PTR
@@ -1633,12 +1633,13 @@ static void do_thread_regset_writeback(struct task_struct *task,
#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,
const struct user_regset_view *view,
- long signr, size_t *total)
+ long signr, size_t *total,
+ struct pt_regs *regs __maybe_unused)
{
unsigned int i;

@@ -1650,11 +1651,11 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
*/
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),
+ 0, PR_REG_SIZE(t->prstatus.pr_reg, regs),
PR_REG_PTR(&t->prstatus), NULL);

fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
- PRSTATUS_SIZE(t->prstatus), &t->prstatus);
+ PRSTATUS_SIZE(t->prstatus, regs), &t->prstatus);
*total += notesize(&t->notes[0]);

do_thread_regset_writeback(t->task, &view->regsets[0]);
@@ -1684,7 +1685,7 @@ 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, regs);
fill_note(&t->notes[i], "CORE",
NT_PRFPREG, size, data);
}
@@ -1770,7 +1771,8 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
* Now fill in each thread's information.
*/
for (t = info->thread; t != NULL; t = t->next)
- if (!fill_thread_core_info(t, view, siginfo->si_signo, &info->size))
+ if (!fill_thread_core_info(t, view, siginfo->si_signo,
+ &info->size, regs))
return 0;

/*
--
2.8.0