| Message ID | 20191010202418.25098-17-rrichter@marvell.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | EDAC: Rework edac_mc and ghes drivers | expand |
Em Thu, 10 Oct 2019 20:25:37 +0000 Robert Richter <rrichter@marvell.com> escreveu: > The current code to convert a physical address mask to a grain > (defined as granularity in bytes) is: > > e->grain = ~(mem_err->physical_addr_mask & ~PAGE_MASK); > > This is broken in several ways: > > 1) It calculates to wrong grain values. E.g., a physical address mask > of ~0xfff should give a grain of 0x1000. Without considering > PAGE_MASK, there is an off-by-one. Things are worse when also > filtering it with ~PAGE_MASK. This will calculate to a grain with the > upper bits set. In the example it even calculates to ~0. > > 2) The grain does not depend on and is unrelated to the kernel's > page-size. The page-size only matters when unmapping memory in > memory_failure(). Smaller grains are wrongly rounded up to the > page-size, on architectures with a configurable page-size (e.g. arm64) > this could round up to the even bigger page-size of the hypervisor. > > Fix this with: > > e->grain = ~mem_err->physical_addr_mask + 1; > > The grain_bits are defined as: > > grain = 1 << grain_bits; > > Change also the grain_bits calculation accordingly, it is the same > formula as in edac_mc.c now and the code can be unified. > > The value in ->physical_addr_mask coming from firmware is assumed to > be contiguous, but this is not sanity-checked. However, in case the > mask is non-contiguous, a conversion to grain_bits effectively > converts the grain bit mask to a power of 2 by rounding up. > > Suggested-by: James Morse <james.morse@arm.com> > Signed-off-by: Robert Richter <rrichter@marvell.com> Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> > --- > drivers/edac/ghes_edac.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c > index 851aad92e42d..97242cf18a88 100644 > --- a/drivers/edac/ghes_edac.c > +++ b/drivers/edac/ghes_edac.c > @@ -220,6 +220,7 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err) > /* Cleans the error report buffer */ > memset(e, 0, sizeof (*e)); > e->error_count = 1; > + e->grain = 1; > strcpy(e->label, "unknown label"); > e->msg = pvt->msg; > e->other_detail = pvt->other_detail; > @@ -315,7 +316,7 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err) > > /* Error grain */ > if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK) > - e->grain = ~(mem_err->physical_addr_mask & ~PAGE_MASK); > + e->grain = ~mem_err->physical_addr_mask + 1; > > /* Memory error location, mapped on e->location */ > p = e->location; > @@ -428,8 +429,13 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err) > if (p > pvt->other_detail) > *(p - 1) = '\0'; > > + /* Sanity-check driver-supplied grain value. */ > + if (WARN_ON_ONCE(!e->grain)) > + e->grain = 1; > + > + grain_bits = fls_long(e->grain - 1); > + > /* Generate the trace event */ > - grain_bits = fls_long(e->grain); > snprintf(pvt->detail_location, sizeof(pvt->detail_location), > "APEI location: %s %s", e->location, e->other_detail); > trace_mc_event(e->type, e->msg, e->label, e->error_count, Thanks, Mauro
diff --git a/drivers/edac/ghes_edac.c b/drivers/edac/ghes_edac.c index 851aad92e42d..97242cf18a88 100644 --- a/drivers/edac/ghes_edac.c +++ b/drivers/edac/ghes_edac.c @@ -220,6 +220,7 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err) /* Cleans the error report buffer */ memset(e, 0, sizeof (*e)); e->error_count = 1; + e->grain = 1; strcpy(e->label, "unknown label"); e->msg = pvt->msg; e->other_detail = pvt->other_detail; @@ -315,7 +316,7 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err) /* Error grain */ if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK) - e->grain = ~(mem_err->physical_addr_mask & ~PAGE_MASK); + e->grain = ~mem_err->physical_addr_mask + 1; /* Memory error location, mapped on e->location */ p = e->location; @@ -428,8 +429,13 @@ void ghes_edac_report_mem_error(int sev, struct cper_sec_mem_err *mem_err) if (p > pvt->other_detail) *(p - 1) = '\0'; + /* Sanity-check driver-supplied grain value. */ + if (WARN_ON_ONCE(!e->grain)) + e->grain = 1; + + grain_bits = fls_long(e->grain - 1); + /* Generate the trace event */ - grain_bits = fls_long(e->grain); snprintf(pvt->detail_location, sizeof(pvt->detail_location), "APEI location: %s %s", e->location, e->other_detail); trace_mc_event(e->type, e->msg, e->label, e->error_count,
The current code to convert a physical address mask to a grain (defined as granularity in bytes) is: e->grain = ~(mem_err->physical_addr_mask & ~PAGE_MASK); This is broken in several ways: 1) It calculates to wrong grain values. E.g., a physical address mask of ~0xfff should give a grain of 0x1000. Without considering PAGE_MASK, there is an off-by-one. Things are worse when also filtering it with ~PAGE_MASK. This will calculate to a grain with the upper bits set. In the example it even calculates to ~0. 2) The grain does not depend on and is unrelated to the kernel's page-size. The page-size only matters when unmapping memory in memory_failure(). Smaller grains are wrongly rounded up to the page-size, on architectures with a configurable page-size (e.g. arm64) this could round up to the even bigger page-size of the hypervisor. Fix this with: e->grain = ~mem_err->physical_addr_mask + 1; The grain_bits are defined as: grain = 1 << grain_bits; Change also the grain_bits calculation accordingly, it is the same formula as in edac_mc.c now and the code can be unified. The value in ->physical_addr_mask coming from firmware is assumed to be contiguous, but this is not sanity-checked. However, in case the mask is non-contiguous, a conversion to grain_bits effectively converts the grain bit mask to a power of 2 by rounding up. Suggested-by: James Morse <james.morse@arm.com> Signed-off-by: Robert Richter <rrichter@marvell.com> --- drivers/edac/ghes_edac.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)