From: Arnd Bergmann arnd@arndb.de
[ Upstream commit c29dfd661fe2f8d1b48c7f00590929c04b25bf40 ]
gcc-14 produces a bogus warning in some configurations:
drivers/edac/ie31200_edac.c: In function 'ie31200_probe1.isra': drivers/edac/ie31200_edac.c:412:26: error: 'dimm_info' is used uninitialized [-Werror=uninitialized] 412 | struct dimm_data dimm_info[IE31200_CHANNELS][IE31200_DIMMS_PER_CHANNEL]; | ^~~~~~~~~ drivers/edac/ie31200_edac.c:412:26: note: 'dimm_info' declared here 412 | struct dimm_data dimm_info[IE31200_CHANNELS][IE31200_DIMMS_PER_CHANNEL]; | ^~~~~~~~~
I don't see any way the unintialized access could really happen here, but I can see why the compiler gets confused by the two loops.
Instead, rework the two nested loops to only read the addr_decode registers and then keep only one instance of the dimm info structure.
[Tony: Qiuxu pointed out that the "populate DIMM info" comment was left behind in the refactor and suggested moving it. I deleted the comment as unnecessry in front os a call to populate_dimm_info(). That seems pretty self-describing.]
Signed-off-by: Arnd Bergmann arnd@arndb.de Acked-by: Jason Baron jbaron@akamai.com Signed-off-by: Tony Luck tony.luck@intel.com Link: https://lore.kernel.org/all/20250122065031.1321015-1-arnd@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/edac/ie31200_edac.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/drivers/edac/ie31200_edac.c b/drivers/edac/ie31200_edac.c index d3d9916b1ba3f..f865528728d75 100644 --- a/drivers/edac/ie31200_edac.c +++ b/drivers/edac/ie31200_edac.c @@ -398,10 +398,9 @@ static int ie31200_probe1(struct pci_dev *pdev, int dev_idx) int i, j, ret; struct mem_ctl_info *mci = NULL; struct edac_mc_layer layers[2]; - struct dimm_data dimm_info[IE31200_CHANNELS][IE31200_DIMMS_PER_CHANNEL]; void __iomem *window; struct ie31200_priv *priv; - u32 addr_decode, mad_offset; + u32 addr_decode[IE31200_CHANNELS], mad_offset;
/* * Kaby Lake, Coffee Lake seem to work like Skylake. Please re-visit @@ -459,19 +458,10 @@ static int ie31200_probe1(struct pci_dev *pdev, int dev_idx) mad_offset = IE31200_MAD_DIMM_0_OFFSET; }
- /* populate DIMM info */ for (i = 0; i < IE31200_CHANNELS; i++) { - addr_decode = readl(window + mad_offset + + addr_decode[i] = readl(window + mad_offset + (i * 4)); - edac_dbg(0, "addr_decode: 0x%x\n", addr_decode); - for (j = 0; j < IE31200_DIMMS_PER_CHANNEL; j++) { - populate_dimm_info(&dimm_info[i][j], addr_decode, j, - skl); - edac_dbg(0, "size: 0x%x, rank: %d, width: %d\n", - dimm_info[i][j].size, - dimm_info[i][j].dual_rank, - dimm_info[i][j].x16_width); - } + edac_dbg(0, "addr_decode: 0x%x\n", addr_decode[i]); }
/* @@ -482,14 +472,22 @@ static int ie31200_probe1(struct pci_dev *pdev, int dev_idx) */ for (i = 0; i < IE31200_DIMMS_PER_CHANNEL; i++) { for (j = 0; j < IE31200_CHANNELS; j++) { + struct dimm_data dimm_info; struct dimm_info *dimm; unsigned long nr_pages;
- nr_pages = IE31200_PAGES(dimm_info[j][i].size, skl); + populate_dimm_info(&dimm_info, addr_decode[j], i, + skl); + edac_dbg(0, "size: 0x%x, rank: %d, width: %d\n", + dimm_info.size, + dimm_info.dual_rank, + dimm_info.x16_width); + + nr_pages = IE31200_PAGES(dimm_info.size, skl); if (nr_pages == 0) continue;
- if (dimm_info[j][i].dual_rank) { + if (dimm_info.dual_rank) { nr_pages = nr_pages / 2; dimm = EDAC_DIMM_PTR(mci->layers, mci->dimms, mci->n_layers, (i * 2) + 1,