diff options
| -rw-r--r-- | arch/s390/include/asm/uaccess.h | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/ftrace.c | 12 | ||||
| -rw-r--r-- | arch/s390/kernel/jump_label.c | 2 | ||||
| -rw-r--r-- | arch/s390/kernel/kprobes.c | 2 | ||||
| -rw-r--r-- | arch/s390/mm/maccess.c | 29 |
5 files changed, 28 insertions, 18 deletions
diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h index cd4c68e0398d..d64a7a62164f 100644 --- a/arch/s390/include/asm/uaccess.h +++ b/arch/s390/include/asm/uaccess.h @@ -372,5 +372,6 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo } int copy_to_user_real(void __user *dest, void *src, unsigned long count); +void s390_kernel_write(void *dst, const void *src, size_t size); #endif /* __S390_UACCESS_H */ diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index 6c79f1b44fe7..e0eaf11134b4 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -130,8 +130,7 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, /* Verify that the to be replaced code matches what we expect. */ if (memcmp(&orig, &old, sizeof(old))) return -EINVAL; - if (probe_kernel_write((void *) rec->ip, &new, sizeof(new))) - return -EPERM; + s390_kernel_write((void *) rec->ip, &new, sizeof(new)); return 0; } @@ -159,8 +158,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr) /* Verify that the to be replaced code matches what we expect. */ if (memcmp(&orig, &old, sizeof(old))) return -EINVAL; - if (probe_kernel_write((void *) rec->ip, &new, sizeof(new))) - return -EPERM; + s390_kernel_write((void *) rec->ip, &new, sizeof(new)); return 0; } @@ -231,14 +229,16 @@ int ftrace_enable_ftrace_graph_caller(void) { u8 op = 0x04; /* set mask field to zero */ - return probe_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op)); + s390_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op)); + return 0; } int ftrace_disable_ftrace_graph_caller(void) { u8 op = 0xf4; /* set mask field to all ones */ - return probe_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op)); + s390_kernel_write(__va(ftrace_graph_caller)+1, &op, sizeof(op)); + return 0; } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/s390/kernel/jump_label.c b/arch/s390/kernel/jump_label.c index 830066f936c8..a90299600483 100644 --- a/arch/s390/kernel/jump_label.c +++ b/arch/s390/kernel/jump_label.c @@ -78,7 +78,7 @@ static void __jump_label_transform(struct jump_entry *entry, if (memcmp((void *)entry->code, &old, sizeof(old))) jump_label_bug(entry, &old, &new); } - probe_kernel_write((void *)entry->code, &new, sizeof(new)); + s390_kernel_write((void *)entry->code, &new, sizeof(new)); } static int __sm_arch_jump_label_transform(void *data) diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c index f516edc1fbe3..389db56a2208 100644 --- a/arch/s390/kernel/kprobes.c +++ b/arch/s390/kernel/kprobes.c @@ -178,7 +178,7 @@ static int swap_instruction(void *data) } skip_ftrace: kcb->kprobe_status = KPROBE_SWAP_INST; - probe_kernel_write(p->addr, &new_insn, len); + s390_kernel_write(p->addr, &new_insn, len); kcb->kprobe_status = status; return 0; } diff --git a/arch/s390/mm/maccess.c b/arch/s390/mm/maccess.c index 2eb34bdfc613..fb737e9e0683 100644 --- a/arch/s390/mm/maccess.c +++ b/arch/s390/mm/maccess.c @@ -16,13 +16,7 @@ #include <asm/ctl_reg.h> #include <asm/io.h> -/* - * This function writes to kernel memory bypassing DAT and possible - * write protection. It copies one to four bytes from src to dst - * using the stura instruction. - * Returns the number of bytes copied or -EFAULT. - */ -static long probe_kernel_write_odd(void *dst, const void *src, size_t size) +static notrace long s390_kernel_write_odd(void *dst, const void *src, size_t size) { unsigned long count, aligned; int offset, mask; @@ -48,19 +42,34 @@ static long probe_kernel_write_odd(void *dst, const void *src, size_t size) return rc ? rc : count; } -long probe_kernel_write(void *dst, const void *src, size_t size) +/* + * s390_kernel_write - write to kernel memory bypassing DAT + * @dst: destination address + * @src: source address + * @size: number of bytes to copy + * + * This function writes to kernel memory bypassing DAT and possible page table + * write protection. It writes to the destination using the sturg instruction. + * Therefore we have a read-modify-write sequence: the function reads four + * bytes from destination at a four byte boundary, modifies the bytes + * requested and writes the result back in a loop. + * + * Note: this means that this function may not be called concurrently on + * several cpus with overlapping words, since this may potentially + * cause data corruption. + */ +void notrace s390_kernel_write(void *dst, const void *src, size_t size) { long copied = 0; while (size) { - copied = probe_kernel_write_odd(dst, src, size); + copied = s390_kernel_write_odd(dst, src, size); if (copied < 0) break; dst += copied; src += copied; size -= copied; } - return copied < 0 ? -EFAULT : 0; } static int __memcpy_real(void *dest, void *src, size_t count) |