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[104.188.17.28]) by smtp.gmail.com with ESMTPSA id b30sm59882598pfr.117.2019.07.22.16.27.20 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Mon, 22 Jul 2019 16:27:21 -0700 (PDT) Date: Mon, 22 Jul 2019 16:27:19 -0700 From: Bjorn Andersson To: Stephen Boyd Cc: Andy Gross , linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, Ian Jackson , Julien Grall , Avaneesh Kumar Dwivedi Subject: Re: [PATCH 2/3] firmware: qcom_scm: Cleanup code in qcom_scm_assign_mem() Message-ID: <20190722232719.GT30636@minitux> References: <23774.56553.445601.436491@mariner.uk.xensource.com> <20190517210923.202131-3-swboyd@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190517210923.202131-3-swboyd@chromium.org> User-Agent: Mutt/1.12.0 (2019-05-25) Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Fri 17 May 14:09 PDT 2019, Stephen Boyd wrote: > There are some questionable coding styles in this function. It looks > quite odd to deref a pointer with array indexing that only uses the > first element. Also, destroying an input/output variable halfway through > the function and then overwriting it on success is not clear. It's > better to use a local variable and the kernel macros to step through > each bit set in a bitmask and clearly show where outputs are set. > > Cc: Ian Jackson > Cc: Julien Grall > Cc: Bjorn Andersson > Cc: Avaneesh Kumar Dwivedi > Signed-off-by: Stephen Boyd > --- > drivers/firmware/qcom_scm.c | 34 ++++++++++++++++------------------ > include/linux/qcom_scm.h | 9 +++++---- > 2 files changed, 21 insertions(+), 22 deletions(-) > > diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c > index 0c63495cf269..153f13f72bac 100644 > --- a/drivers/firmware/qcom_scm.c > +++ b/drivers/firmware/qcom_scm.c > @@ -443,7 +443,8 @@ EXPORT_SYMBOL(qcom_scm_set_remote_state); > */ > int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz, > unsigned int *srcvm, > - struct qcom_scm_vmperm *newvm, int dest_cnt) > + const struct qcom_scm_vmperm *newvm, > + unsigned int dest_cnt) > { > struct qcom_scm_current_perm_info *destvm; > struct qcom_scm_mem_map_info *mem_to_map; > @@ -458,11 +459,10 @@ int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz, > int next_vm; > __le32 *src; > void *ptr; > - int ret; > - int len; > - int i; > + int ret, i, b; > + unsigned long srcvm_bits = *srcvm; > > - src_sz = hweight_long(*srcvm) * sizeof(*src); > + src_sz = hweight_long(srcvm_bits) * sizeof(*src); > mem_to_map_sz = sizeof(*mem_to_map); > dest_sz = dest_cnt * sizeof(*destvm); > ptr_sz = ALIGN(src_sz, SZ_64) + ALIGN(mem_to_map_sz, SZ_64) + > @@ -475,28 +475,26 @@ int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz, > > /* Fill source vmid detail */ > src = ptr; > - len = hweight_long(*srcvm); > - for (i = 0; i < len; i++) { > - src[i] = cpu_to_le32(ffs(*srcvm) - 1); > - *srcvm ^= 1 << (ffs(*srcvm) - 1); > - } > + i = 0; > + for_each_set_bit(b, &srcvm_bits, sizeof(srcvm_bits)) The modem is sad that you only pass 8 here. Changed it to BITS_PER_LONG to include the modem's permission bit and applied all three patches. Thanks, Bjorn > + src[i++] = cpu_to_le32(b); > > /* Fill details of mem buff to map */ > mem_to_map = ptr + ALIGN(src_sz, SZ_64); > mem_to_map_phys = ptr_phys + ALIGN(src_sz, SZ_64); > - mem_to_map[0].mem_addr = cpu_to_le64(mem_addr); > - mem_to_map[0].mem_size = cpu_to_le64(mem_sz); > + mem_to_map->mem_addr = cpu_to_le64(mem_addr); > + mem_to_map->mem_size = cpu_to_le64(mem_sz); > > next_vm = 0; > /* Fill details of next vmid detail */ > destvm = ptr + ALIGN(mem_to_map_sz, SZ_64) + ALIGN(src_sz, SZ_64); > dest_phys = ptr_phys + ALIGN(mem_to_map_sz, SZ_64) + ALIGN(src_sz, SZ_64); > - for (i = 0; i < dest_cnt; i++) { > - destvm[i].vmid = cpu_to_le32(newvm[i].vmid); > - destvm[i].perm = cpu_to_le32(newvm[i].perm); > - destvm[i].ctx = 0; > - destvm[i].ctx_size = 0; > - next_vm |= BIT(newvm[i].vmid); > + for (i = 0; i < dest_cnt; i++, destvm++, newvm++) { > + destvm->vmid = cpu_to_le32(newvm->vmid); > + destvm->perm = cpu_to_le32(newvm->perm); > + destvm->ctx = 0; > + destvm->ctx_size = 0; > + next_vm |= BIT(newvm->vmid); > } > > ret = __qcom_scm_assign_mem(__scm->dev, mem_to_map_phys, mem_to_map_sz, > diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h > index d0aecc04c54b..1d406403c843 100644 > --- a/include/linux/qcom_scm.h > +++ b/include/linux/qcom_scm.h > @@ -57,8 +57,9 @@ extern int qcom_scm_pas_mem_setup(u32 peripheral, phys_addr_t addr, > extern int qcom_scm_pas_auth_and_reset(u32 peripheral); > extern int qcom_scm_pas_shutdown(u32 peripheral); > extern int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz, > - unsigned int *src, struct qcom_scm_vmperm *newvm, > - int dest_cnt); > + unsigned int *src, > + const struct qcom_scm_vmperm *newvm, > + unsigned int dest_cnt); > extern void qcom_scm_cpu_power_down(u32 flags); > extern u32 qcom_scm_get_version(void); > extern int qcom_scm_set_remote_state(u32 state, u32 id); > @@ -95,8 +96,8 @@ qcom_scm_pas_auth_and_reset(u32 peripheral) { return -ENODEV; } > static inline int qcom_scm_pas_shutdown(u32 peripheral) { return -ENODEV; } > static inline int qcom_scm_assign_mem(phys_addr_t mem_addr, size_t mem_sz, > unsigned int *src, > - struct qcom_scm_vmperm *newvm, > - int dest_cnt) { return -ENODEV; } > + const struct qcom_scm_vmperm *newvm, > + unsigned int dest_cnt) { return -ENODEV; } > static inline void qcom_scm_cpu_power_down(u32 flags) {} > static inline u32 qcom_scm_get_version(void) { return 0; } > static inline u32 > -- > Sent by a computer through tubes >