diff options
| author | Robert Richter <rrichter@marvell.com> | 2019-06-24 15:08:55 +0000 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2019-08-03 12:05:51 +0200 |
| commit | 3724ace582d9f675134985727fd5e9811f23c059 (patch) | |
| tree | 784cb7a16e46b0d37ddefca44fc96534b57ed267 | |
| parent | 3123c5c4ca157edc518102ee5385f60cb90f93f5 (diff) | |
EDAC/mc: Fix grain_bits calculation
The grain in EDAC is defined as "minimum granularity for an error
report, in bytes". The following calculation of the grain_bits in
edac_mc is wrong:
grain_bits = fls_long(e->grain) + 1;
Where grain_bits is defined as:
grain = 1 << grain_bits
Example:
grain = 8 # 64 bit (8 bytes)
grain_bits = fls_long(8) + 1
grain_bits = 4 + 1 = 5
grain = 1 << grain_bits
grain = 1 << 5 = 32
Replace it with the correct calculation:
grain_bits = fls_long(e->grain - 1);
The example gives now:
grain_bits = fls_long(8 - 1)
grain_bits = fls_long(7)
grain_bits = 3
grain = 1 << 3 = 8
Also, check if the hardware reports a reasonable grain != 0 and fallback
with a warning to 1 byte granularity otherwise.
[ bp: massage a bit. ]
Signed-off-by: Robert Richter <rrichter@marvell.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>
Link: https://lkml.kernel.org/r/20190624150758.6695-2-rrichter@marvell.com
| -rw-r--r-- | drivers/edac/edac_mc.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c index 64922c8fa7e3..d899d86897d0 100644 --- a/drivers/edac/edac_mc.c +++ b/drivers/edac/edac_mc.c @@ -1235,9 +1235,13 @@ void edac_mc_handle_error(const enum hw_event_mc_err_type type, if (p > e->location) *(p - 1) = '\0'; - /* Report the error via the trace interface */ - grain_bits = fls_long(e->grain) + 1; + /* Sanity-check driver-supplied grain value. */ + if (WARN_ON_ONCE(!e->grain)) + e->grain = 1; + + grain_bits = fls_long(e->grain - 1); + /* Report the error via the trace interface */ if (IS_ENABLED(CONFIG_RAS)) trace_mc_event(type, e->msg, e->label, e->error_count, mci->mc_idx, e->top_layer, e->mid_layer, |