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authorAl Viro <viro@zeniv.linux.org.uk>2020-06-01 19:42:40 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2020-07-27 14:24:50 -0400
commitb4e9c9549f62329d2412f899635fddc5212b9cd4 (patch)
tree2d62ec21ef17f93c1d4b4152b4db978c82adc11e /kernel
parentb3a9e3b9622ae10064826dccb4f7a52bd88c7407 (diff)
introduction of regset ->get() wrappers, switching ELF coredumps to those
Two new helpers: given a process and regset, dump into a buffer. regset_get() takes a buffer and size, regset_get_alloc() takes size and allocates a buffer. Return value in both cases is the amount of data actually dumped in case of success or -E... on error. In both cases the size is capped by regset->n * regset->size, so ->get() is called with offset 0 and size no more than what regset expects. binfmt_elf.c callers of ->get() are switched to using those; the other caller (copy_regset_to_user()) will need some preparations to switch. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/Makefile2
-rw-r--r--kernel/regset.c54
2 files changed, 55 insertions, 1 deletions
diff --git a/kernel/Makefile b/kernel/Makefile
index f3218bc5ec69..e6e03380a0f1 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -10,7 +10,7 @@ obj-y = fork.o exec_domain.o panic.o \
extable.o params.o \
kthread.o sys_ni.o nsproxy.o \
notifier.o ksysfs.o cred.o reboot.o \
- async.o range.o smpboot.o ucount.o
+ async.o range.o smpboot.o ucount.o regset.o
obj-$(CONFIG_MODULES) += kmod.o
obj-$(CONFIG_MULTIUSER) += groups.o
diff --git a/kernel/regset.c b/kernel/regset.c
new file mode 100644
index 000000000000..6b39fa0993ec
--- /dev/null
+++ b/kernel/regset.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/regset.h>
+
+static int __regset_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int size,
+ void **data)
+{
+ void *p = *data, *to_free = NULL;
+ int res;
+
+ if (!regset->get)
+ return -EOPNOTSUPP;
+ if (size > regset->n * regset->size)
+ size = regset->n * regset->size;
+ if (!p) {
+ to_free = p = kzalloc(size, GFP_KERNEL);
+ if (!p)
+ return -ENOMEM;
+ }
+ res = regset->get(target, regset, 0, size, p, NULL);
+ if (unlikely(res < 0)) {
+ kfree(to_free);
+ return res;
+ }
+ *data = p;
+ if (regset->get_size) { // arm64-only kludge, will go away
+ unsigned max_size = regset->get_size(target, regset);
+ if (size > max_size)
+ size = max_size;
+ }
+ return size;
+}
+
+int regset_get(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int size,
+ void *data)
+{
+ return __regset_get(target, regset, size, &data);
+}
+EXPORT_SYMBOL(regset_get);
+
+int regset_get_alloc(struct task_struct *target,
+ const struct user_regset *regset,
+ unsigned int size,
+ void **data)
+{
+ *data = NULL;
+ return __regset_get(target, regset, size, data);
+}
+EXPORT_SYMBOL(regset_get_alloc);