diff options
| -rw-r--r-- | include/linux/rseq.h | 9 | ||||
| -rw-r--r-- | include/uapi/linux/prctl.h | 10 | ||||
| -rw-r--r-- | kernel/rseq.c | 52 | ||||
| -rw-r--r-- | kernel/sys.c | 6 |
4 files changed, 77 insertions, 0 deletions
diff --git a/include/linux/rseq.h b/include/linux/rseq.h index 2266f4dc77b6..3c194a02ad0a 100644 --- a/include/linux/rseq.h +++ b/include/linux/rseq.h @@ -163,4 +163,13 @@ void rseq_syscall(struct pt_regs *regs); static inline void rseq_syscall(struct pt_regs *regs) { } #endif /* !CONFIG_DEBUG_RSEQ */ +#ifdef CONFIG_RSEQ_SLICE_EXTENSION +int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3); +#else /* CONFIG_RSEQ_SLICE_EXTENSION */ +static inline int rseq_slice_extension_prctl(unsigned long arg2, unsigned long arg3) +{ + return -ENOTSUPP; +} +#endif /* !CONFIG_RSEQ_SLICE_EXTENSION */ + #endif /* _LINUX_RSEQ_H */ diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 51c4e8c82b1e..79944b7ae50a 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -386,4 +386,14 @@ struct prctl_mm_map { # define PR_FUTEX_HASH_SET_SLOTS 1 # define PR_FUTEX_HASH_GET_SLOTS 2 +/* RSEQ time slice extensions */ +#define PR_RSEQ_SLICE_EXTENSION 79 +# define PR_RSEQ_SLICE_EXTENSION_GET 1 +# define PR_RSEQ_SLICE_EXTENSION_SET 2 +/* + * Bits for RSEQ_SLICE_EXTENSION_GET/SET + * PR_RSEQ_SLICE_EXT_ENABLE: Enable + */ +# define PR_RSEQ_SLICE_EXT_ENABLE 0x01 + #endif /* _LINUX_PRCTL_H */ 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; diff --git a/kernel/sys.c b/kernel/sys.c index 8b58eece4e58..af71987df81c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -53,6 +53,7 @@ #include <linux/time_namespace.h> #include <linux/binfmts.h> #include <linux/futex.h> +#include <linux/rseq.h> #include <linux/sched.h> #include <linux/sched/autogroup.h> @@ -2868,6 +2869,11 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_FUTEX_HASH: error = futex_hash_prctl(arg2, arg3, arg4); break; + case PR_RSEQ_SLICE_EXTENSION: + if (arg4 || arg5) + return -EINVAL; + error = rseq_slice_extension_prctl(arg2, arg3); + break; default: trace_task_prctl_unknown(option, arg2, arg3, arg4, arg5); error = -EINVAL; |