Hi Tim Pambor, > -----Original Message----- > From: Tim Pambor <tp@xxxxxxxxxxxxx> > Sent: Wednesday, March 6, 2024 10:11 AM > Subject: Re: [PATCH] arm64: dts: r9a07g044: Add complete CPU cache information > > Hi Biju, > > thanks for the review. > > > Hi Tim Pambor, > > > > Thanks for the patch. > > > > > -----Original Message----- > > > From: Tim Pambor <tp@xxxxxxxxxxxxx> > > > Sent: Tuesday, March 5, 2024 3:14 PM > > > Subject: [PATCH] arm64: dts: r9a07g044: Add complete CPU cache > > > information > > > > > > Based on ARM Cortex-A55 TRM and RZG2/L user's manual, each Cortex- > > > A55 has > > > > RZ/G2L > > > > > - 32 KB of L1 4-way, set-associative instruction cache > > > - 32 KB of L1 4-way, set-associative data cache > > > > > > Each cache has a cache line length of 64B and therefore there are > > > 32768B/(4 * 64B)=128 sets for each cache. > > > > > > RZG2/L are not configured with the optional per-core L2 cache but > > > only have a L3 cache shared among all > > RZ/G2L > > > cores. In this case, the L3 cache appears as a L2 cache to the > > > system. Therefore, specify "cache-level = <2>" for the L3 cache. > > > > I will send a v2 with the commit message corrected. > > > You mean for L3 Cache, cache-level = <2> if there is no L2 Cache on > > the system? Does it need any update on dt-bindings to make this clear? > > I followed the approach chosen for the Rockchip RK356x, which also has a Cortex-A55 with an L3 cache > but no L2 cache [1]. I can add a comment to the device tree explaining that there is no L2 cache and > that therefore the L3 cache appears as a L2 cache to the system. Do you consider that sufficient? I am leaving this to Geert and other DT maintainer's for their view on this topic. Cheers, Biju > > > Currently, having cache-level = <3> also causes a out-of-bounds access in populate_cache_leaves. > > [ 0.066217] ================================================================== > [ 0.066369] BUG: KASAN: slab-out-of-bounds in populate_cache_leaves+0x25c/0x2d0 > [ 0.066495] Write of size 4 at addr ffff0000082370dc by task swapper/0/1 > [ 0.066580] > [ 0.066619] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.8.0-rc2-00016-g30d5a685c65d #6 > [ 0.066719] Hardware name: MYC-YG2LX (DT) > [ 0.066793] Call trace: > [ 0.066836] dump_backtrace+0x98/0x118 > [ 0.066900] show_stack+0x18/0x24 > [ 0.066959] dump_stack_lvl+0x60/0xac > [ 0.067029] print_report+0xf8/0x5d8 > [ 0.067096] kasan_report+0xc0/0x100 > [ 0.067159] __asan_report_store4_noabort+0x20/0x2c > [ 0.067235] populate_cache_leaves+0x25c/0x2d0 > [ 0.067308] detect_cache_attributes+0x34c/0x1998 > [ 0.067384] update_siblings_masks+0x30/0x554 > [ 0.067460] store_cpu_topology+0xe8/0x188 > [ 0.067528] smp_prepare_cpus+0x5c/0x238 > [ 0.067602] kernel_init_freeable+0x258/0xb18 > [ 0.067673] kernel_init+0x30/0x208 > [ 0.067736] ret_from_fork+0x10/0x20 > [ 0.067802] > [ 0.067835] Allocated by task 1: > [ 0.067889] kasan_save_stack+0x3c/0x64 > [ 0.067956] kasan_save_track+0x20/0x3c > [ 0.068020] kasan_save_alloc_info+0x68/0x78 > [ 0.068090] __kasan_kmalloc+0xd4/0xd8 > [ 0.068154] __kmalloc+0x1c0/0x430 > [ 0.068215] allocate_cache_info+0xa8/0x204 > [ 0.068284] fetch_cache_info+0xc4/0x200 > [ 0.068349] init_cpu_topology+0x348/0x45c > [ 0.068423] smp_prepare_cpus+0x1c/0x238 > [ 0.068492] kernel_init_freeable+0x258/0xb18 > [ 0.068561] kernel_init+0x30/0x208 > [ 0.068622] ret_from_fork+0x10/0x20 > [ 0.068685] > [ 0.068719] The buggy address belongs to the object at ffff000008237000 > [ 0.068719] which belongs to the cache kmalloc-256 of size 256 > [ 0.068849] The buggy address is located 4 bytes to the right of > [ 0.068849] allocated 216-byte region [ffff000008237000, ffff0000082370d8) > [ 0.068984] > [ 0.069018] The buggy address belongs to the physical page: > [ 0.069089] page:(____ptrval____) refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 > pfn:0x48236 > [ 0.069201] head:(____ptrval____) order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0 > [ 0.069297] flags: 0x840(slab|head|zone=0) > [ 0.069366] page_type: 0xffffffff() > [ 0.069430] raw: 0000000000000840 ffff000008001b40 dead000000000122 0000000000000000 > [ 0.069526] raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 > [ 0.069616] page dumped because: kasan: bad access detected > [ 0.069684] > [ 0.069717] Memory state around the buggy address: > [ 0.069781] ffff000008236f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > [ 0.069870] ffff000008237000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > [ 0.069958] >ffff000008237080: 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc fc > [ 0.070042] ^ > [ 0.070116] ffff000008237100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > [ 0.070204] ffff000008237180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > [ 0.070290] ================================================================== > > [1] https://lore.kernel.org/linux- > rockchip/2285ee41e165813011220f9469e28697923aa6e0.1709491108.git.dsimic@xxxxxxxxxxx/ > > > > > Cheers, > > Biju > >
