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Reject nonzero > ranges whose end overflows the address space while preserving the > zero-size range representation. > > Read decoder base and size registers low then high through a shared > helper used by enumeration and the reset snapshot. > > Read switch target lists and endpoint DPA skip in their respective > branches of init_hdm_decoder(). > > Preserve the decoder ID allocated by cxl_decoder_init() when publishing > the parsed configuration. > > Signed-off-by: Srirangan Madhavan > Assisted-by: LLM > Reviewed-by: Richard Cheng I like this change, LGTM. Just a small nit below. > --- > Reference branch: https://git.kernel.org/pub/scm/linux/kernel/git/djiang/linux.git/commit/?id=7d6ed7faf7d8e14abce8ae23902d5323738868d2 > --- > drivers/cxl/core/core.h | 5 +++ > drivers/cxl/core/hdm.c | 65 ++++++++------------------------ > drivers/cxl/core/hdm_regs.c | 74 +++++++++++++++++++++++++++++++++++++ > 3 files changed, 95 insertions(+), 49 deletions(-) > > diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h > index fb14b222f3ca..ea539f00e55d 100644 > --- a/drivers/cxl/core/core.h > +++ b/drivers/cxl/core/core.h > @@ -147,6 +147,11 @@ void cxl_commit_start_switch(const struct cxl_decoder_config *config, > u64 targets, void __iomem *hdm); > int cxld_await_commit(void __iomem *hdm, int id); > > +int cxl_hdm_unpack_decoder(struct cxl_decoder_config *config, int id, > + u32 ctrl, u64 base, u64 size); > +int cxl_hdm_read_decoder(struct cxl_decoder_config *config, void __iomem *hdm, > + int id, u32 ctrl); > + > int cxl_memdev_init(void); > void cxl_memdev_exit(void); > void cxl_mbox_init(void); > diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c > index 2c373dfbc070..5b5f5f22ea32 100644 > --- a/drivers/cxl/core/hdm.c > +++ b/drivers/cxl/core/hdm.c > @@ -938,11 +938,11 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld, > u64 *dpa_base, struct cxl_endpoint_dvsec_info *info) > { > struct cxl_endpoint_decoder *cxled = NULL; > - u64 size, base, skip, dpa_size, lo, hi; > - bool committed; > + u64 size, skip, dpa_size, lo, hi; > + struct cxl_decoder_config config; > u32 remainder; > - int i, rc; > u32 ctrl; > + int i, rc; > union { > u64 value; > unsigned char target_id[8]; > @@ -953,41 +953,25 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld, > which, info); > > ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(which)); > - lo = readl(hdm + CXL_HDM_DECODER0_BASE_LOW_OFFSET(which)); > - hi = readl(hdm + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(which)); > - base = (hi << 32) + lo; > - lo = readl(hdm + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(which)); > - hi = readl(hdm + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(which)); > - size = (hi << 32) + lo; > - committed = !!(ctrl & CXL_HDM_DECODER0_CTRL_COMMITTED); > + rc = cxl_hdm_read_decoder(&config, hdm, which, ctrl); > + if (rc) { > + dev_warn(&port->dev, > + "decoder%d.%d: Invalid decoder configuration (ctrl: %#x): %d\n", > + port->id, cxld->config.id, ctrl, rc); > + return rc; > + } > + > + config.id = cxld->config.id; > cxld->commit = cxl_decoder_commit; > cxld->reset = cxl_decoder_reset; > - > - if (!committed) > - size = 0; > - if (base == U64_MAX || size == U64_MAX) { > - dev_warn(&port->dev, "decoder%d.%d: Invalid resource range\n", > - port->id, cxld->config.id); > - return -ENXIO; > - } > + cxld->config = config; > + size = range_len(&cxld->config.hpa_range); > > if (info) > cxled = to_cxl_endpoint_decoder(&cxld->dev); > - cxld->config.hpa_range = (struct range) { > - .start = base, > - .end = base + size - 1, > - }; > > /* decoders are enabled if committed */ > - if (committed) { > - cxld->config.flags |= CXL_DECODER_F_ENABLE; > - if (ctrl & CXL_HDM_DECODER0_CTRL_LOCK) > - cxld->config.flags |= CXL_DECODER_F_LOCK; > - if (FIELD_GET(CXL_HDM_DECODER0_CTRL_HOSTONLY, ctrl)) > - cxld->config.target_type = CXL_DECODER_HOSTONLYMEM; > - else > - cxld->config.target_type = CXL_DECODER_DEVMEM; > - > + if (cxld->config.flags & CXL_DECODER_F_ENABLE) { > guard(rwsem_write)(&cxl_rwsem.region); > if (cxld->config.id != cxl_num_decoders_committed(port)) { > dev_warn(&port->dev, > @@ -1021,23 +1005,6 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld, > writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(which)); > } > } > - rc = eiw_to_ways(FIELD_GET(CXL_HDM_DECODER0_CTRL_IW_MASK, ctrl), > - &cxld->config.interleave_ways); > - if (rc) { > - dev_warn(&port->dev, > - "decoder%d.%d: Invalid interleave ways (ctrl: %#x)\n", > - port->id, cxld->config.id, ctrl); > - return rc; > - } > - rc = eig_to_granularity(FIELD_GET(CXL_HDM_DECODER0_CTRL_IG_MASK, ctrl), > - &cxld->config.interleave_granularity); > - if (rc) { > - dev_warn(&port->dev, > - "decoder%d.%d: Invalid interleave granularity (ctrl: %#x)\n", > - port->id, cxld->config.id, ctrl); > - return rc; > - } > - > dev_dbg(&port->dev, "decoder%d.%d: range: %#llx-%#llx iw: %d ig: %d\n", > port->id, cxld->config.id, cxld->config.hpa_range.start, cxld->config.hpa_range.end, > cxld->config.interleave_ways, cxld->config.interleave_granularity); > @@ -1052,7 +1019,7 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld, > return 0; > } > > - if (!committed) > + if (!(cxld->config.flags & CXL_DECODER_F_ENABLE)) > return 0; > > dpa_size = div_u64_rem(size, cxld->config.interleave_ways, &remainder); > diff --git a/drivers/cxl/core/hdm_regs.c b/drivers/cxl/core/hdm_regs.c > index 53d2f236e49c..684a17e9a601 100644 > --- a/drivers/cxl/core/hdm_regs.c > +++ b/drivers/cxl/core/hdm_regs.c > @@ -116,3 +116,77 @@ void cxl_commit_start_switch(const struct cxl_decoder_config *config, > writel(ctrl, hdm + CXL_HDM_DECODER0_CTRL_OFFSET(id)); > } > EXPORT_SYMBOL_FOR_MODULES(cxl_commit_start_switch, "cxl_core"); > + > +int cxl_hdm_unpack_decoder(struct cxl_decoder_config *config, int id, > + u32 ctrl, u64 base, u64 size) > +{ > + bool committed = FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl); > + enum cxl_decoder_type target_type = 0; > + int interleave_granularity; > + unsigned long flags = 0; > + struct range hpa_range; > + int interleave_ways; > + u64 end; > + int rc; > + > + if (!committed) > + size = 0; > + if (base == U64_MAX || size == U64_MAX) > + return -ENXIO; > + if (size && check_add_overflow(base, size - 1, &end)) > + return -ENXIO; > + if (!size) > + end = base - 1; > + What about making "end = base - 1" the default value of "end" and then call "check_add_overflow()", this would preserve the same behavior while elimate one branch. Just I think we can add some comments describing it's for the case of zero-size HDM. Best regards, Richard Cheng. > + hpa_range = (struct range) { > + .start = base, > + .end = end, > + }; > + > + if (committed) { > + flags |= CXL_DECODER_F_ENABLE; > + if (ctrl & CXL_HDM_DECODER0_CTRL_LOCK) > + flags |= CXL_DECODER_F_LOCK; > + if (FIELD_GET(CXL_HDM_DECODER0_CTRL_HOSTONLY, ctrl)) > + target_type = CXL_DECODER_HOSTONLYMEM; > + else > + target_type = CXL_DECODER_DEVMEM; > + } > + > + rc = eiw_to_ways(FIELD_GET(CXL_HDM_DECODER0_CTRL_IW_MASK, ctrl), > + &interleave_ways); > + if (rc) > + return rc; > + rc = eig_to_granularity(FIELD_GET(CXL_HDM_DECODER0_CTRL_IG_MASK, ctrl), > + &interleave_granularity); > + if (rc) > + return rc; > + > + *config = (struct cxl_decoder_config) { > + .id = id, > + .hpa_range = hpa_range, > + .interleave_ways = interleave_ways, > + .interleave_granularity = interleave_granularity, > + .target_type = target_type, > + .flags = flags, > + }; > + > + return 0; > +} > +EXPORT_SYMBOL_FOR_MODULES(cxl_hdm_unpack_decoder, "cxl_core"); > + > +int cxl_hdm_read_decoder(struct cxl_decoder_config *config, void __iomem *hdm, > + int id, u32 ctrl) > +{ > + u64 lo, hi, base, size; > + > + lo = readl(hdm + CXL_HDM_DECODER0_BASE_LOW_OFFSET(id)); > + hi = readl(hdm + CXL_HDM_DECODER0_BASE_HIGH_OFFSET(id)); > + base = (hi << 32) | lo; > + lo = readl(hdm + CXL_HDM_DECODER0_SIZE_LOW_OFFSET(id)); > + hi = readl(hdm + CXL_HDM_DECODER0_SIZE_HIGH_OFFSET(id)); > + size = (hi << 32) | lo; > + > + return cxl_hdm_unpack_decoder(config, id, ctrl, base, size); > +} > +EXPORT_SYMBOL_FOR_MODULES(cxl_hdm_read_decoder, "cxl_core"); > -- > 2.43.0 >