diff options
Diffstat (limited to 'kernel/rseq.c')
| -rw-r--r-- | kernel/rseq.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/kernel/rseq.c b/kernel/rseq.c index 415d75b6df2c..09848bb14ec2 100644 --- a/kernel/rseq.c +++ b/kernel/rseq.c @@ -71,6 +71,7 @@ #define RSEQ_BUILD_SLOW_PATH #include <linux/debugfs.h> +#include <linux/prctl.h> #include <linux/ratelimit.h> #include <linux/rseq_entry.h> #include <linux/sched.h> @@ -501,6 +502,57 @@ efault: #ifdef CONFIG_RSEQ_SLICE_EXTENSION DEFINE_STATIC_KEY_TRUE(rseq_slice_extension_key); +int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3) +{ + switch (arg2) { + case PR_RSEQ_SLICE_EXTENSION_GET: + if (arg3) + return -EINVAL; + return current->rseq.slice.state.enabled ? PR_RSEQ_SLICE_EXT_ENABLE : 0; + + case PR_RSEQ_SLICE_EXTENSION_SET: { + u32 rflags, valid = RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE; + bool enable = !!(arg3 & PR_RSEQ_SLICE_EXT_ENABLE); + + if (arg3 & ~PR_RSEQ_SLICE_EXT_ENABLE) + return -EINVAL; + if (!rseq_slice_extension_enabled()) + return -ENOTSUPP; + if (!current->rseq.usrptr) + return -ENXIO; + + /* No change? */ + if (enable == !!current->rseq.slice.state.enabled) + return 0; + + if (get_user(rflags, ¤t->rseq.usrptr->flags)) + goto die; + + if (current->rseq.slice.state.enabled) + valid |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED; + + if ((rflags & valid) != valid) + goto die; + + rflags &= ~RSEQ_CS_FLAG_SLICE_EXT_ENABLED; + rflags |= RSEQ_CS_FLAG_SLICE_EXT_AVAILABLE; + if (enable) + rflags |= RSEQ_CS_FLAG_SLICE_EXT_ENABLED; + + if (put_user(rflags, ¤t->rseq.usrptr->flags)) + goto die; + + current->rseq.slice.state.enabled = enable; + return 0; + } + default: + return -EINVAL; + } +die: + force_sig(SIGSEGV); + return -EFAULT; +} + static int __init rseq_slice_cmdline(char *str) { bool on; |