From 111a833dc5cbef3d05b2a796a7e23cb7f6ff2192 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Wed, 3 May 2023 14:12:52 +0100 Subject: [PATCH] firmware: arm_ffa: Set reserved/MBZ fields to zero in the memory descriptors The transmit buffers allocated by the driver can be used to transmit data by any messages/commands needing the buffer. However, it is not guaranteed to have been zero-ed before every new transmission and hence it will just contain residual value from the previous transmission. There are several reserved fields in the memory descriptors that must be zero(MBZ). The receiver can reject the transmission if any such MBZ fields are non-zero. While we can set the whole page to zero, it is not optimal as most of the fields get initialised to the value required for the current transmission. So, just set the reserved/MBZ fields to zero in the memory descriptors explicitly to honour the requirement and keep the receiver happy. Fixes: cc2195fe536c ("firmware: arm_ffa: Add support for MEM_* interfaces") Reported-by: Marc Bonnici Link: https://lore.kernel.org/r/20230503131252.12585-1-sudeep.holla@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_ffa/driver.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/firmware/arm_ffa/driver.c b/drivers/firmware/arm_ffa/driver.c index 4aced2e5b772..e23409138667 100644 --- a/drivers/firmware/arm_ffa/driver.c +++ b/drivers/firmware/arm_ffa/driver.c @@ -421,12 +421,17 @@ ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize, ep_mem_access->receiver = args->attrs[idx].receiver; ep_mem_access->attrs = args->attrs[idx].attrs; ep_mem_access->composite_off = COMPOSITE_OFFSET(args->nattrs); + ep_mem_access->flag = 0; + ep_mem_access->reserved = 0; } + mem_region->reserved_0 = 0; + mem_region->reserved_1 = 0; mem_region->ep_count = args->nattrs; composite = buffer + COMPOSITE_OFFSET(args->nattrs); composite->total_pg_cnt = ffa_get_num_pages_sg(args->sg); composite->addr_range_cnt = num_entries; + composite->reserved = 0; length = COMPOSITE_CONSTITUENTS_OFFSET(args->nattrs, num_entries); frag_len = COMPOSITE_CONSTITUENTS_OFFSET(args->nattrs, 0); @@ -461,6 +466,7 @@ ffa_setup_and_transmit(u32 func_id, void *buffer, u32 max_fragsize, constituents->address = sg_phys(args->sg); constituents->pg_cnt = args->sg->length / FFA_PAGE_SIZE; + constituents->reserved = 0; constituents++; frag_len += sizeof(struct ffa_mem_region_addr_range); } while ((args->sg = sg_next(args->sg)));