In some cases, we weren't even setting errno, just returning -1. Then on
error, we'd get crap from perror() like:
pread: Success
Now get meaningful errstrs and at least have errno set.
E.g.
(On a machine without IA32_PERF_CTL)
/ $ rdmsr 0x199
pread: Bad address, read_msr() faulted on MSR 0x199
/ $ wrmsr 0x198 88888
pwrite: Operation not permitted, MSR 0x198 not in write whitelist
Most of the other errors would be triggered by a rdmsr or wrmsr bugging
out.
Signed-off-by: Barret Rhoden <[email protected]>
---
kern/arch/x86/devarch.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/kern/arch/x86/devarch.c b/kern/arch/x86/devarch.c
index c9e96d3bbb96..9d878f3d7451 100644
--- a/kern/arch/x86/devarch.c
+++ b/kern/arch/x86/devarch.c
@@ -544,7 +544,7 @@ static long archread(struct chan *c, void *a, long n,
int64_t offset)
case Qmsr:
if (!address_range_find(msr_rd_wlist,
ARRAY_SIZE(msr_rd_wlist),
(uintptr_t) offset))
- error(EPERM, ERROR_FIXME);
+ error(EPERM, "MSR 0x%x not in read whitelist",
offset);
core_set_init(&cset);
core_set_fill_available(&cset);
msr_set_address(&msra, (uint32_t) offset);
@@ -564,10 +564,16 @@ static long archread(struct chan *c, void *a, long n,
int64_t offset)
n = -1;
} else {
kfree(values);
- error(ERANGE, ERROR_FIXME);
+ error(ERANGE, "Not enough space for MSR
read");
}
} else {
- n = -1;
+ switch (-err) {
+ case (EFAULT):
+ error(-err, "read_msr() faulted on MSR
0x%x", offset);
+ case (ERANGE):
+ error(-err, "Not enough space for MSR
read");
+ };
+ error(-err, "MSR read failed");
}
kfree(values);
return n;
@@ -665,9 +671,9 @@ static long archwrite(struct chan *c, void *a, long n,
int64_t offset)
case Qmsr:
if (!address_range_find(msr_wr_wlist,
ARRAY_SIZE(msr_wr_wlist),
(uintptr_t) offset))
- error(EPERM, ERROR_FIXME);
+ error(EPERM, "MSR 0x%x not in write whitelist",
offset);
if (n != sizeof(uint64_t))
- error(EINVAL, ERROR_FIXME);
+ error(EINVAL, "Tried to write more than a u64
(%p)", n);
if (memcpy_from_user_errno(current, &value, a,
sizeof(value)))
return -1;
@@ -677,8 +683,15 @@ static long archwrite(struct chan *c, void *a, long n,
int64_t offset)
msr_set_value(&msrv, value);
err = msr_cores_write(&cset, &msra, &msrv);
- if (unlikely(err))
- error(-err, ERROR_FIXME);
+ if (unlikely(err)) {
+ switch (-err) {
+ case (EFAULT):
+ error(-err, "write_msr() faulted on MSR
0x%x", offset);
+ case (ERANGE):
+ error(-err, "Not enough space for MSR
write");
+ };
+ error(-err, "MSR write failed");
+ }
return sizeof(uint64_t);
case Qperf: {
struct perf_context *pc = (struct perf_context *)
c->aux;
--
2.7.0.rc3.207.g0ac5344
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