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authorMichael Ellerman <mpe@ellerman.id.au>2016-08-12 21:45:52 +1000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-10-07 15:23:46 +0200
commitbef613a0bef4f45c2b73f3fddbe1f08938e0e08a (patch)
tree9dcac5d8e4a96b4b77db1956b260dbc068c1237a
parent32a57f4ed2f654685f200dc6ab0aed67364af570 (diff)
powerpc/prom: Fix sub-processor option passed to ibm, client-architecture-support
commit 66443efa83dc73775100b7442962ce2cb0d4472e upstream. When booting from an OpenFirmware which supports it, we use the "ibm,client-architecture-support" firmware call to communicate our capabilities to firmware. The format of the structure we pass to firmware is specified in PAPR (Power Architecture Platform Requirements), or the public version LoPAPR (Linux on Power Architecture Platform Reference). Referring to table 244 in LoPAPR v1.1, option vector 5 contains a 4 byte field at bytes 17-20 for the "Platform Facilities Enable". This is followed by a 1 byte field at byte 21 for "Sub-Processor Represenation Level". Comparing to the code, there we have the Platform Facilities options (OV5_PFO_*) at byte 17, but we fail to pad that field out to its full width of 4 bytes. This means the OV5_SUB_PROCESSORS option is incorrectly placed at byte 18. Fix it by adding zero bytes for bytes 18, 19, 20, and comment the bytes to hopefully make it clearer in future. As far as I'm aware nothing actually consumes this value at this time, so the effect of this bug is nil in practice. It does mean we've been incorrectly setting bit 15 of the "Platform Facilities Enable" option for the past ~3 1/2 years, so we should avoid allocating that bit to anything else in future. Fixes: df77c7992029 ("powerpc/pseries: Update ibm,architecture.vec for PAPR 2.7/POWER8") Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/powerpc/kernel/prom_init.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index b7e86e00048f..7b89e7b305e6 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -694,7 +694,7 @@ unsigned char ibm_architecture_vec[] = {
OV4_MIN_ENT_CAP, /* minimum VP entitled capacity */
/* option vector 5: PAPR/OF options */
- VECTOR_LENGTH(18), /* length */
+ VECTOR_LENGTH(21), /* length */
0, /* don't ignore, don't halt */
OV5_FEAT(OV5_LPAR) | OV5_FEAT(OV5_SPLPAR) | OV5_FEAT(OV5_LARGE_PAGES) |
OV5_FEAT(OV5_DRCONF_MEMORY) | OV5_FEAT(OV5_DONATE_DEDICATE_CPU) |
@@ -725,8 +725,11 @@ unsigned char ibm_architecture_vec[] = {
0,
0,
OV5_FEAT(OV5_PFO_HW_RNG) | OV5_FEAT(OV5_PFO_HW_ENCR) |
- OV5_FEAT(OV5_PFO_HW_842),
- OV5_FEAT(OV5_SUB_PROCESSORS),
+ OV5_FEAT(OV5_PFO_HW_842), /* Byte 17 */
+ 0, /* Byte 18 */
+ 0, /* Byte 19 */
+ 0, /* Byte 20 */
+ OV5_FEAT(OV5_SUB_PROCESSORS), /* Byte 21 */
/* option vector 6: IBM PAPR hints */
VECTOR_LENGTH(3), /* length */