diff options
| -rw-r--r-- | arch/powerpc/include/asm/processor.h | 10 | ||||
| -rw-r--r-- | arch/powerpc/kernel/dexcr.c | 101 | ||||
| -rw-r--r-- | include/uapi/linux/prctl.h | 16 | ||||
| -rw-r--r-- | kernel/sys.c | 16 |
4 files changed, 143 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index aad85a24134a..e44cac0da346 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -334,6 +334,16 @@ extern int set_endian(struct task_struct *tsk, unsigned int val); extern int get_unalign_ctl(struct task_struct *tsk, unsigned long adr); extern int set_unalign_ctl(struct task_struct *tsk, unsigned int val); +#ifdef CONFIG_PPC_BOOK3S_64 + +#define PPC_GET_DEXCR_ASPECT(tsk, asp) get_dexcr_prctl((tsk), (asp)) +#define PPC_SET_DEXCR_ASPECT(tsk, asp, val) set_dexcr_prctl((tsk), (asp), (val)) + +int get_dexcr_prctl(struct task_struct *tsk, unsigned long asp); +int set_dexcr_prctl(struct task_struct *tsk, unsigned long asp, unsigned long val); + +#endif + extern void load_fp_state(struct thread_fp_state *fp); extern void store_fp_state(struct thread_fp_state *fp); extern void load_vr_state(struct thread_vr_state *vr); diff --git a/arch/powerpc/kernel/dexcr.c b/arch/powerpc/kernel/dexcr.c index d5cd77421088..3a0358e91c60 100644 --- a/arch/powerpc/kernel/dexcr.c +++ b/arch/powerpc/kernel/dexcr.c @@ -21,3 +21,104 @@ static int __init init_task_dexcr(void) return 0; } early_initcall(init_task_dexcr) + +/* Allow thread local configuration of these by default */ +#define DEXCR_PRCTL_EDITABLE ( \ + DEXCR_PR_IBRTPD | \ + DEXCR_PR_SRAPD | \ + DEXCR_PR_NPHIE) + +static int prctl_to_aspect(unsigned long which, unsigned int *aspect) +{ + switch (which) { + case PR_PPC_DEXCR_SBHE: + *aspect = DEXCR_PR_SBHE; + break; + case PR_PPC_DEXCR_IBRTPD: + *aspect = DEXCR_PR_IBRTPD; + break; + case PR_PPC_DEXCR_SRAPD: + *aspect = DEXCR_PR_SRAPD; + break; + case PR_PPC_DEXCR_NPHIE: + *aspect = DEXCR_PR_NPHIE; + break; + default: + return -ENODEV; + } + + return 0; +} + +int get_dexcr_prctl(struct task_struct *task, unsigned long which) +{ + unsigned int aspect; + int ret; + + ret = prctl_to_aspect(which, &aspect); + if (ret) + return ret; + + if (aspect & DEXCR_PRCTL_EDITABLE) + ret |= PR_PPC_DEXCR_CTRL_EDITABLE; + + if (aspect & mfspr(SPRN_DEXCR)) + ret |= PR_PPC_DEXCR_CTRL_SET; + else + ret |= PR_PPC_DEXCR_CTRL_CLEAR; + + if (aspect & task->thread.dexcr_onexec) + ret |= PR_PPC_DEXCR_CTRL_SET_ONEXEC; + else + ret |= PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC; + + return ret; +} + +int set_dexcr_prctl(struct task_struct *task, unsigned long which, unsigned long ctrl) +{ + unsigned long dexcr; + unsigned int aspect; + int err = 0; + + err = prctl_to_aspect(which, &aspect); + if (err) + return err; + + if (!(aspect & DEXCR_PRCTL_EDITABLE)) + return -EPERM; + + if (ctrl & ~PR_PPC_DEXCR_CTRL_MASK) + return -EINVAL; + + if (ctrl & PR_PPC_DEXCR_CTRL_SET && ctrl & PR_PPC_DEXCR_CTRL_CLEAR) + return -EINVAL; + + if (ctrl & PR_PPC_DEXCR_CTRL_SET_ONEXEC && ctrl & PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC) + return -EINVAL; + + /* + * We do not want an unprivileged process being able to disable + * a setuid process's hash check instructions + */ + if (aspect == DEXCR_PR_NPHIE && + ctrl & PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC && + !capable(CAP_SYS_ADMIN)) + return -EPERM; + + dexcr = mfspr(SPRN_DEXCR); + + if (ctrl & PR_PPC_DEXCR_CTRL_SET) + dexcr |= aspect; + else if (ctrl & PR_PPC_DEXCR_CTRL_CLEAR) + dexcr &= ~aspect; + + if (ctrl & PR_PPC_DEXCR_CTRL_SET_ONEXEC) + task->thread.dexcr_onexec |= aspect; + else if (ctrl & PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC) + task->thread.dexcr_onexec &= ~aspect; + + mtspr(SPRN_DEXCR, dexcr); + + return 0; +} diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h index 370ed14b1ae0..713d28788df7 100644 --- a/include/uapi/linux/prctl.h +++ b/include/uapi/linux/prctl.h @@ -306,4 +306,20 @@ struct prctl_mm_map { # define PR_RISCV_V_VSTATE_CTRL_NEXT_MASK 0xc # define PR_RISCV_V_VSTATE_CTRL_MASK 0x1f +/* PowerPC Dynamic Execution Control Register (DEXCR) controls */ +#define PR_PPC_GET_DEXCR 72 +#define PR_PPC_SET_DEXCR 73 +/* DEXCR aspect to act on */ +# define PR_PPC_DEXCR_SBHE 0 /* Speculative branch hint enable */ +# define PR_PPC_DEXCR_IBRTPD 1 /* Indirect branch recurrent target prediction disable */ +# define PR_PPC_DEXCR_SRAPD 2 /* Subroutine return address prediction disable */ +# define PR_PPC_DEXCR_NPHIE 3 /* Non-privileged hash instruction enable */ +/* Action to apply / return */ +# define PR_PPC_DEXCR_CTRL_EDITABLE 0x1 /* Aspect can be modified with PR_PPC_SET_DEXCR */ +# define PR_PPC_DEXCR_CTRL_SET 0x2 /* Set the aspect for this process */ +# define PR_PPC_DEXCR_CTRL_CLEAR 0x4 /* Clear the aspect for this process */ +# define PR_PPC_DEXCR_CTRL_SET_ONEXEC 0x8 /* Set the aspect on exec */ +# define PR_PPC_DEXCR_CTRL_CLEAR_ONEXEC 0x10 /* Clear the aspect on exec */ +# define PR_PPC_DEXCR_CTRL_MASK 0x1f + #endif /* _LINUX_PRCTL_H */ diff --git a/kernel/sys.c b/kernel/sys.c index 8bb106a56b3a..f9c95410278c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -146,6 +146,12 @@ #ifndef RISCV_V_GET_CONTROL # define RISCV_V_GET_CONTROL() (-EINVAL) #endif +#ifndef PPC_GET_DEXCR_ASPECT +# define PPC_GET_DEXCR_ASPECT(a, b) (-EINVAL) +#endif +#ifndef PPC_SET_DEXCR_ASPECT +# define PPC_SET_DEXCR_ASPECT(a, b, c) (-EINVAL) +#endif /* * this is where the system-wide overflow UID and GID are defined, for @@ -2726,6 +2732,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_GET_MDWE: error = prctl_get_mdwe(arg2, arg3, arg4, arg5); break; + case PR_PPC_GET_DEXCR: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = PPC_GET_DEXCR_ASPECT(me, arg2); + break; + case PR_PPC_SET_DEXCR: + if (arg4 || arg5) + return -EINVAL; + error = PPC_SET_DEXCR_ASPECT(me, arg2, arg3); + break; case PR_SET_VMA: error = prctl_set_vma(arg2, arg3, arg4, arg5); break; |