Commit 4206d3aa authored by Roland McGrath's avatar Roland McGrath Committed by Ingo Molnar

elf core dump: notes user_regset

This modifies the ELF core dump code under #ifdef CORE_DUMP_USE_REGSET.
It changes nothing when this macro is not defined.  When it's #define'd
by some arch header (e.g. asm/elf.h), the arch must support the
user_regset (linux/regset.h) interface for reading thread state.

This provides an alternate version of note segment writing that is based
purely on the user_regset interfaces.  When CORE_DUMP_USE_REGSET is set,
the arch need not define macros such as ELF_CORE_COPY_REGS and ELF_ARCH.
All that information is taken from the user_regset data structures.
The core dumps come out exactly the same if arch's definitions for its
user_regset details are correct.
Signed-off-by: default avatarRoland McGrath <roland@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 3aba481f
......@@ -1528,6 +1528,228 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
}
#ifdef CORE_DUMP_USE_REGSET
#include <linux/regset.h>
struct elf_thread_core_info {
struct elf_thread_core_info *next;
struct task_struct *task;
struct elf_prstatus prstatus;
struct memelfnote notes[0];
};
struct elf_note_info {
struct elf_thread_core_info *thread;
struct memelfnote psinfo;
struct memelfnote auxv;
size_t size;
int thread_notes;
};
static int fill_thread_core_info(struct elf_thread_core_info *t,
const struct user_regset_view *view,
long signr, size_t *total)
{
unsigned int i;
/*
* NT_PRSTATUS is the one special case, because the regset data
* goes into the pr_reg field inside the note contents, rather
* than being the whole note contents. We fill the reset in here.
* 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, sizeof(t->prstatus.pr_reg),
&t->prstatus.pr_reg, NULL);
fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
sizeof(t->prstatus), &t->prstatus);
*total += notesize(&t->notes[0]);
/*
* Each other regset might generate a note too. For each regset
* that has no core_note_type or is inactive, we leave t->notes[i]
* all zero and we'll know to skip writing it later.
*/
for (i = 1; i < view->n; ++i) {
const struct user_regset *regset = &view->regsets[i];
if (regset->core_note_type &&
(!regset->active || regset->active(t->task, regset))) {
int ret;
size_t size = regset->n * regset->size;
void *data = kmalloc(size, GFP_KERNEL);
if (unlikely(!data))
return 0;
ret = regset->get(t->task, regset,
0, size, data, NULL);
if (unlikely(ret))
kfree(data);
else {
if (regset->core_note_type != NT_PRFPREG)
fill_note(&t->notes[i], "LINUX",
regset->core_note_type,
size, data);
else {
t->prstatus.pr_fpvalid = 1;
fill_note(&t->notes[i], "CORE",
NT_PRFPREG, size, data);
}
*total += notesize(&t->notes[i]);
}
}
}
return 1;
}
static int fill_note_info(struct elfhdr *elf, int phdrs,
struct elf_note_info *info,
long signr, struct pt_regs *regs)
{
struct task_struct *dump_task = current;
const struct user_regset_view *view = task_user_regset_view(dump_task);
struct elf_thread_core_info *t;
struct elf_prpsinfo *psinfo;
struct task_struct *g, *p;
unsigned int i;
info->size = 0;
info->thread = NULL;
psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
if (psinfo == NULL)
return 0;
/*
* Figure out how many notes we're going to need for each thread.
*/
info->thread_notes = 0;
for (i = 0; i < view->n; ++i)
if (view->regsets[i].core_note_type != 0)
++info->thread_notes;
/*
* Sanity check. We rely on regset 0 being in NT_PRSTATUS,
* since it is our one special case.
*/
if (unlikely(info->thread_notes == 0) ||
unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
WARN_ON(1);
return 0;
}
/*
* Initialize the ELF file header.
*/
fill_elf_header(elf, phdrs,
view->e_machine, view->e_flags, view->ei_osabi);
/*
* Allocate a structure for each thread.
*/
rcu_read_lock();
do_each_thread(g, p)
if (p->mm == dump_task->mm) {
t = kzalloc(offsetof(struct elf_thread_core_info,
notes[info->thread_notes]),
GFP_ATOMIC);
if (unlikely(!t)) {
rcu_read_unlock();
return 0;
}
t->task = p;
if (p == dump_task || !info->thread) {
t->next = info->thread;
info->thread = t;
} else {
/*
* Make sure to keep the original task at
* the head of the list.
*/
t->next = info->thread->next;
info->thread->next = t;
}
}
while_each_thread(g, p);
rcu_read_unlock();
/*
* Now fill in each thread's information.
*/
for (t = info->thread; t != NULL; t = t->next)
if (!fill_thread_core_info(t, view, signr, &info->size))
return 0;
/*
* Fill in the two process-wide notes.
*/
fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
info->size += notesize(&info->psinfo);
fill_auxv_note(&info->auxv, current->mm);
info->size += notesize(&info->auxv);
return 1;
}
static size_t get_note_info_size(struct elf_note_info *info)
{
return info->size;
}
/*
* Write all the notes for each thread. When writing the first thread, the
* process-wide notes are interleaved after the first thread-specific note.
*/
static int write_note_info(struct elf_note_info *info,
struct file *file, loff_t *foffset)
{
bool first = 1;
struct elf_thread_core_info *t = info->thread;
do {
int i;
if (!writenote(&t->notes[0], file, foffset))
return 0;
if (first && !writenote(&info->psinfo, file, foffset))
return 0;
if (first && !writenote(&info->auxv, file, foffset))
return 0;
for (i = 1; i < info->thread_notes; ++i)
if (t->notes[i].data &&
!writenote(&t->notes[i], file, foffset))
return 0;
first = 0;
t = t->next;
} while (t);
return 1;
}
static void free_note_info(struct elf_note_info *info)
{
struct elf_thread_core_info *threads = info->thread;
while (threads) {
unsigned int i;
struct elf_thread_core_info *t = threads;
threads = t->next;
WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
for (i = 1; i < info->thread_notes; ++i)
kfree(t->notes[i].data);
kfree(t);
}
kfree(info->psinfo.data);
}
#else
/* Here is the structure in which status of each thread is captured. */
struct elf_thread_status
{
......@@ -1748,6 +1970,8 @@ static void free_note_info(struct elf_note_info *info)
#endif
}
#endif
static struct vm_area_struct *first_vma(struct task_struct *tsk,
struct vm_area_struct *gate_vma)
{
......
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