[PATCH 7/7] [elf-fdpic] switch coredump to regsets

From: Al Viro
Date: Tue Jun 30 2020 - 00:41:19 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

similar to how elf coredump is working on architectures that
have regsets, and all architectures with elf-fdpic support *do*
have that.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
fs/binfmt_elf_fdpic.c | 23 ++++++++++++++++++-----
1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index 34c45410d587..1af03c8d3c09 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -35,6 +35,7 @@
#include <linux/elfcore.h>
#include <linux/coredump.h>
#include <linux/dax.h>
+#include <linux/regset.h>

#include <linux/uaccess.h>
#include <asm/param.h>
@@ -1456,8 +1457,7 @@ struct elf_thread_status
struct elf_thread_status *next;
struct elf_prstatus_fdpic prstatus; /* NT_PRSTATUS */
elf_fpregset_t fpu; /* NT_PRFPREG */
- struct task_struct *thread;
- struct memelfnote notes[3];
+ struct memelfnote notes[2];
int num_notes;
};

@@ -1468,22 +1468,35 @@ struct elf_thread_status
*/
static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_struct *p, int *sz)
{
+ const struct user_regset_view *view = task_user_regset_view(p);
struct elf_thread_status *t;
+ int i, ret;

t = kzalloc(sizeof(struct elf_thread_status), GFP_KERNEL);
if (!t)
return t;

fill_prstatus(&t->prstatus, p, signr);
- elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
+ regset_get(p, &view->regsets[0],
+ sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);

fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
&t->prstatus);
t->num_notes++;
*sz += notesize(&t->notes[0]);

- t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, task_pt_regs(p),
- &t->fpu);
+ for (i = 1; i < view->n; ++i) {
+ const struct user_regset *regset = &view->regsets[i];
+ if (regset->core_note_type != NT_PRFPREG)
+ continue;
+ if (regset->active && regset->active(p, regset) <= 0)
+ continue;
+ ret = regset_get(p, regset, sizeof(t->fpu), &t->fpu);
+ if (ret >= 0)
+ t->prstatus.pr_fpvalid = 1;
+ break;
+ }
+
if (t->prstatus.pr_fpvalid) {
fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
&t->fpu);
--
2.11.0