On Wed, 10 Feb 2021 14:15:46 +0100 Nicolas Saenz Julienne wrote: > [ Add Robin, Catalin and Florian in case they want to chime in ] > > Hi Juerg, thanks for the report! > > On Wed, 2021-02-10 at 11:48 +0100, Juerg Haefliger wrote: > > Trying to dump the BCM2711 registers kills the kernel: > > > > # cat /sys/kernel/debug/regmap/dummy-avs-monitor\@fd5d2000/range > > 0-efc > > # cat /sys/kernel/debug/regmap/dummy-avs-monitor\@fd5d2000/registers > > > > [ 62.857661] SError Interrupt on CPU1, code 0xbf000002 -- SError > > So ESR's IDS (bit 24) is set, which means it's an 'Implementation Defined > SError,' hence IIUC the rest of the error code is meaningless to anyone outside > of Broadcom/RPi. > > The regmap is created through the following syscon device: > > avs_monitor: avs-monitor@7d5d2000 { > compatible = "brcm,bcm2711-avs-monitor", > "syscon", "simple-mfd"; > reg = <0x7d5d2000 0xf00>; > > thermal: thermal { > compatible = "brcm,bcm2711-thermal"; > #thermal-sensor-cells = <0>; > }; > }; > > I've done some tests with devmem, and the whole <0x7d5d2000 0xf00> range is > full of addresses that trigger this same error. Also note that as per Florian's > comments[1]: "AVS_RO_REGISTERS_0: 0x7d5d2200 - 0x7d5d22e3." But from what I can > tell, at least 0x7d5d22b0 seems to be faulty too. > > Any ideas/comments? My guess is that those addresses are marked somehow as > secure, and only for VC4 to access (VC4 is RPi4's co-processor). Ultimately, > the solution is to narrow the register range exposed by avs-monitor to whatever > bcm2711-thermal needs (which is ATM a single 32bit register). Yeah, that's what I tried but wasn't sure if that's the correct approach or if there was something wrong with the DTB (which I know virtually nothing about). With [1] I get seemingly the correct behavior: # cat /sys/kernel/debug/regmap/dummy-avs-monitor\@fd5d2200/range 0-0 # cat /sys/kernel/debug/regmap/dummy-avs-monitor\@fd5d2200/registers 0: 000106fa # cat /sys/class/thermal/thermal_zone0/temp 39433 On a different note, how did you come up with that address range in the DTB? Is that public information? ...Juerg [1] diff --git a/arch/arm/boot/dts/bcm2711.dtsi b/arch/arm/boot/dts/bcm2711.dtsi index 4847dd305317..a7059967aab1 100644 --- a/arch/arm/boot/dts/bcm2711.dtsi +++ b/arch/arm/boot/dts/bcm2711.dtsi @@ -65,10 +65,10 @@ gicv2: interrupt-controller@40041000 { IRQ_TYPE_LEVEL_HIGH)>; }; - avs_monitor: avs-monitor@7d5d2000 { + avs_monitor: avs-monitor@7d5d2200 { compatible = "brcm,bcm2711-avs-monitor", "syscon", "simple-mfd"; - reg = <0x7d5d2000 0xf00>; + reg = <0x7d5d2200 0x4>; thermal: thermal { compatible = "brcm,bcm2711-thermal"; diff --git a/drivers/thermal/broadcom/bcm2711_thermal.c b/drivers/thermal/broadcom/bcm2711_thermal.c index 67c2a737bc9d..3b5a84402b89 100644 --- a/drivers/thermal/broadcom/bcm2711_thermal.c +++ b/drivers/thermal/broadcom/bcm2711_thermal.c @@ -22,7 +22,7 @@ #include "../thermal_hwmon.h" -#define AVS_RO_TEMP_STATUS 0x200 +#define AVS_RO_TEMP_STATUS 0x0 /* address 0x7d5d2200 */ #define AVS_RO_TEMP_STATUS_VALID_MSK (BIT(16) | BIT(10)) #define AVS_RO_TEMP_STATUS_DATA_MSK GENMASK(9, 0) > Regards, > Nicolas > > [1] https://lore.kernel.org/linux-pm/82125042-684a-b4e2-fbaa-45a393b2ce5e@gmx.net/ > > > [ 62.857671] CPU: 1 PID: 478 Comm: cat Not tainted 5.11.0-rc7 #4 > > [ 62.857674] Hardware name: Raspberry Pi 4 Model B Rev 1.2 (DT) > > [ 62.857676] pstate: 20000085 (nzCv daIf -PAN -UAO -TCO BTYPE=--) > > [ 62.857679] pc : regmap_mmio_read32le+0x1c/0x34 > > [ 62.857681] lr : regmap_mmio_read+0x50/0x80 > > [ 62.857682] sp : ffff8000105c3c00 > > [ 62.857685] x29: ffff8000105c3c00 x28: 0000000000000014 > > [ 62.857694] x27: 0000000000000014 x26: ffffd2ea1c2060b0 > > [ 62.857699] x25: ffff4e34408ecc00 x24: 0000000000000efc > > [ 62.857704] x23: ffff8000105c3e20 x22: ffff8000105c3d3c > > [ 62.857710] x21: ffff8000105c3d3c x20: 0000000000000014 > > [ 62.857715] x19: ffff4e344037a900 x18: 0000000000000020 > > [ 62.857720] x17: 0000000000000000 x16: 0000000000000000 > > [ 62.857725] x15: ffff4e3447ac40f0 x14: 0000000000000003 > > [ 62.857730] x13: ffff4e34422c0000 x12: ffff4e34422a0046 > > [ 62.857735] x11: ffffd2ea1c8765e0 x10: 0000000000000000 > > [ 62.857741] x9 : ffffd2ea1b9495a0 x8 : ffff4e34429ef980 > > [ 62.857746] x7 : 000000000000000f x6 : ffff4e34422a004b > > [ 62.857751] x5 : 00000000fffffff9 x4 : 0000000000000000 > > [ 62.857757] x3 : ffffd2ea1b949550 x2 : ffffd2ea1b949330 > > [ 62.857761] x1 : 0000000000000014 x0 : 0000000000000000 > > [ 62.857767] Kernel panic - not syncing: Asynchronous SError Interrupt > > [ 62.857770] CPU: 1 PID: 478 Comm: cat Not tainted 5.11.0-rc7 #4 > > [ 62.857773] Hardware name: Raspberry Pi 4 Model B Rev 1.2 (DT) > > [ 62.857775] Call trace: > > [ 62.857777] dump_backtrace+0x0/0x1e0 > > [ 62.857778] show_stack+0x24/0x70 > > [ 62.857780] dump_stack+0xd0/0x12c > > [ 62.857782] panic+0x168/0x370 > > [ 62.857783] nmi_panic+0x98/0xa0 > > [ 62.857786] arm64_serror_panic+0x8c/0x98 > > [ 62.857787] do_serror+0x3c/0x6c > > [ 62.857789] el1_error+0x78/0xf0 > > [ 62.857791] regmap_mmio_read32le+0x1c/0x34 > > [ 62.857793] _regmap_bus_reg_read+0x24/0x30 > > [ 62.857795] _regmap_read+0x6c/0x17c > > [ 62.857797] regmap_read+0x58/0x84 > > [ 62.857799] regmap_read_debugfs+0x138/0x3f4 > > [ 62.857801] regmap_map_read_file+0x34/0x40 > > [ 62.857803] full_proxy_read+0x6c/0xc0 > > [ 62.857805] vfs_read+0xb8/0x1e4 > > [ 62.857807] ksys_read+0x78/0x10c > > [ 62.857809] __arm64_sys_read+0x28/0x34 > > [ 62.857811] el0_svc_common.constprop.0+0x7c/0x194 > > [ 62.857813] do_el0_svc+0x30/0x9c > > [ 62.857814] el0_svc+0x20/0x30 > > [ 62.857816] el0_sync_handler+0x1a4/0x1b0 > > [ 62.857818] el0_sync+0x174/0x180 > > [ 62.857842] SMP: stopping secondary CPUs > > [ 62.857845] Kernel Offset: 0x52ea0b080000 from 0xffff800010000000 > > [ 62.857847] PHYS_OFFSET: 0xffffb1cc00000000 > > [ 62.857849] CPU features: 0x00240022,61806000 > > [ 62.857851] Memory Limit: none > > > > Sprinkling printks around regmap_read [1] shows that reading from 0x14 (20) > > seems to cause the issue: > > > > > > [ 40.456230] map=ffff020a069c9c00, from=0, to=3836, count=131072 > > [ 40.462520] map=ffff020a069c9c00, i=0 > > [ 40.466319] ret=0, val=0 > > [ 40.468922] map=ffff020a069c9c00, i=4 > > [ 40.472684] ret=0, val=0 > > [ 40.475292] map=ffff020a069c9c00, i=8 > > [ 40.479048] ret=0, val=0 > > [ 40.481649] map=ffff020a069c9c00, i=12 > > [ 40.485492] ret=0, val=0 > > [ 40.488080] map=ffff020a069c9c00, i=16 > > [ 40.491922] ret=0, val=0 > > [ 40.494523] map=ffff020a069c9c00, i=20 > > [ 40.498497] SError Interrupt on CPU0, code 0xbf000002 -- SError > > [ 40.498499] CPU: 0 PID: 486 Comm: cat Not tainted 5.11.0-rc7+ #8 > > [ 40.498501] Hardware name: Raspberry Pi 4 Model B Rev 1.2 (DT) > > > > > > ...Juerg > > > > [1] > > diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c > > index ff2ee87987c7..9465f5a2f3b8 100644 > > --- a/drivers/base/regmap/regmap-debugfs.c > > +++ b/drivers/base/regmap/regmap-debugfs.c > > @@ -229,6 +229,7 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from, > >         if (count > (PAGE_SIZE << (MAX_ORDER - 1))) > >                 count = PAGE_SIZE << (MAX_ORDER - 1); > >   > > > > + printk("map=%px, from=%d, to=%d, count=%ld\n", map, from, to, count); > >         buf = kmalloc(count, GFP_KERNEL); > >         if (!buf) > >                 return -ENOMEM; > > @@ -253,7 +254,9 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from, > >                         buf_pos += map->debugfs_reg_len + 2; > >   > > > >                         /* Format the value, write all X if we can't read */ > > + printk("map=%px, i=%d\n", map, i); > >                         ret = regmap_read(map, i, &val); > > + printk("ret=%ld, val=%x\n", ret, val); > >                         if (ret == 0) > >                                 snprintf(buf + buf_pos, count - buf_pos, > >                                          "%.*x", map->debugfs_val_len, val); > > > > >