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authorHeiko Carstens <heiko.carstens@de.ibm.com>2015-03-13 12:55:56 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2015-03-25 11:49:43 +0100
commit8a5d8473dd7e2b0bc2864e34bd6836b520589fa1 (patch)
tree36997ac10fc75d5a0ed5fe5632e58684f90edf24 /arch/s390/kernel
parentb2527d2009903a06b0076bb89166c72a0f17823b (diff)
s390/maccess: remove potentially broken probe_kernel_write()
Remove the s390 architecture implementation of probe_kernel_write() and instead use a new function s390_kernel_write() to modify kernel text and data everywhere. The s390 implementation of probe_kernel_write() was potentially broken since it modified memory in a read-modify-write fashion, which read four bytes, modified the requested bytes within those four bytes and wrote the result back. If two cpus would modify the same four byte area at different locations within that area, this could lead to corruption. Right now the only places which called probe_kernel_write() did run within stop_machine_run. Therefore the scenario can't happen right now, however that might change at any time. To fix this rename probe_kernel_write() to s390_kernel_write() which can have special semantics, like only call it while running within stop_machine(). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/kernel')
-rw-r--r--arch/s390/kernel/ftrace.c12
-rw-r--r--arch/s390/kernel/jump_label.c2
-rw-r--r--arch/s390/kernel/kprobes.c2
3 files changed, 8 insertions, 8 deletions
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;
}