diff options
author | Finn Thain <fthain@telegraphics.com.au> | 2020-09-05 09:02:20 +1000 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-10-29 09:07:09 +0100 |
commit | 9fb97ac5b1c9070ec9eaa56c7dcb4a4b2303d598 (patch) | |
tree | cedf6dc1ebcb17d954fbffeec57b5ab2fb0a2396 /arch/powerpc/kernel | |
parent | cbd0b229995bcb691eb5d353a79435fa0331b55d (diff) |
powerpc/tau: Disable TAU between measurements
[ Upstream commit e63d6fb5637e92725cf143559672a34b706bca4f ]
Enabling CONFIG_TAU_INT causes random crashes:
Unrecoverable exception 1700 at c0009414 (msr=1000)
Oops: Unrecoverable exception, sig: 6 [#1]
BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=2 PowerMac
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.7.0-pmac-00043-gd5f545e1a8593 #5
NIP: c0009414 LR: c0009414 CTR: c00116fc
REGS: c0799eb8 TRAP: 1700 Not tainted (5.7.0-pmac-00043-gd5f545e1a8593)
MSR: 00001000 <ME> CR: 22000228 XER: 00000100
GPR00: 00000000 c0799f70 c076e300 00800000 0291c0ac 00e00000 c076e300 00049032
GPR08: 00000001 c00116fc 00000000 dfbd3200 ffffffff 007f80a8 00000000 00000000
GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 c075ce04
GPR24: c075ce04 dfff8880 c07b0000 c075ce04 00080000 00000001 c079ef98 c079ef5c
NIP [c0009414] arch_cpu_idle+0x24/0x6c
LR [c0009414] arch_cpu_idle+0x24/0x6c
Call Trace:
[c0799f70] [00000001] 0x1 (unreliable)
[c0799f80] [c0060990] do_idle+0xd8/0x17c
[c0799fa0] [c0060ba4] cpu_startup_entry+0x20/0x28
[c0799fb0] [c072d220] start_kernel+0x434/0x44c
[c0799ff0] [00003860] 0x3860
Instruction dump:
XXXXXXXX XXXXXXXX XXXXXXXX 3d20c07b XXXXXXXX XXXXXXXX XXXXXXXX 7c0802a6
XXXXXXXX XXXXXXXX XXXXXXXX 4e800421 XXXXXXXX XXXXXXXX XXXXXXXX 7d2000a6
---[ end trace 3a0c9b5cb216db6b ]---
Resolve this problem by disabling each THRMn comparator when handling
the associated THRMn interrupt and by disabling the TAU entirely when
updating THRMn thresholds.
Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2")
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/5a0ba3dc5612c7aac596727331284a3676c08472.1599260540.git.fthain@telegraphics.com.au
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r-- | arch/powerpc/kernel/tau_6xx.c | 65 |
1 files changed, 24 insertions, 41 deletions
diff --git a/arch/powerpc/kernel/tau_6xx.c b/arch/powerpc/kernel/tau_6xx.c index 9e8b709a2aae..2615cd66dad8 100644 --- a/arch/powerpc/kernel/tau_6xx.c +++ b/arch/powerpc/kernel/tau_6xx.c @@ -38,8 +38,6 @@ static struct tau_temp struct timer_list tau_timer; -#undef DEBUG - /* TODO: put these in a /proc interface, with some sanity checks, and maybe * dynamic adjustment to minimize # of interrupts */ /* configurable values for step size and how much to expand the window when @@ -72,42 +70,33 @@ void set_thresholds(unsigned long cpu) void TAUupdate(int cpu) { - unsigned thrm; - -#ifdef DEBUG - printk("TAUupdate "); -#endif + u32 thrm; + u32 bits = THRM1_TIV | THRM1_TIN | THRM1_V; /* if both thresholds are crossed, the step_sizes cancel out * and the window winds up getting expanded twice. */ - if((thrm = mfspr(SPRN_THRM1)) & THRM1_TIV){ /* is valid? */ - if(thrm & THRM1_TIN){ /* crossed low threshold */ - if (tau[cpu].low >= step_size){ - tau[cpu].low -= step_size; - tau[cpu].high -= (step_size - window_expand); - } - tau[cpu].grew = 1; -#ifdef DEBUG - printk("low threshold crossed "); -#endif + thrm = mfspr(SPRN_THRM1); + if ((thrm & bits) == bits) { + mtspr(SPRN_THRM1, 0); + + if (tau[cpu].low >= step_size) { + tau[cpu].low -= step_size; + tau[cpu].high -= (step_size - window_expand); } + tau[cpu].grew = 1; + pr_debug("%s: low threshold crossed\n", __func__); } - if((thrm = mfspr(SPRN_THRM2)) & THRM1_TIV){ /* is valid? */ - if(thrm & THRM1_TIN){ /* crossed high threshold */ - if (tau[cpu].high <= 127-step_size){ - tau[cpu].low += (step_size - window_expand); - tau[cpu].high += step_size; - } - tau[cpu].grew = 1; -#ifdef DEBUG - printk("high threshold crossed "); -#endif + thrm = mfspr(SPRN_THRM2); + if ((thrm & bits) == bits) { + mtspr(SPRN_THRM2, 0); + + if (tau[cpu].high <= 127 - step_size) { + tau[cpu].low += (step_size - window_expand); + tau[cpu].high += step_size; } + tau[cpu].grew = 1; + pr_debug("%s: high threshold crossed\n", __func__); } - -#ifdef DEBUG - printk("grew = %d\n", tau[cpu].grew); -#endif } #ifdef CONFIG_TAU_INT @@ -132,18 +121,18 @@ void TAUException(struct pt_regs * regs) static void tau_timeout(void * info) { int cpu; - unsigned long flags; int size; int shrink; - /* disabling interrupts *should* be okay */ - local_irq_save(flags); cpu = smp_processor_id(); #ifndef CONFIG_TAU_INT TAUupdate(cpu); #endif + /* Stop thermal sensor comparisons and interrupts */ + mtspr(SPRN_THRM3, 0); + size = tau[cpu].high - tau[cpu].low; if (size > min_window && ! tau[cpu].grew) { /* do an exponential shrink of half the amount currently over size */ @@ -165,18 +154,12 @@ static void tau_timeout(void * info) set_thresholds(cpu); - /* - * Do the enable every time, since otherwise a bunch of (relatively) - * complex sleep code needs to be added. One mtspr every time - * tau_timeout is called is probably not a big deal. - * + /* Restart thermal sensor comparisons and interrupts. * The "PowerPC 740 and PowerPC 750 Microprocessor Datasheet" * recommends that "the maximum value be set in THRM3 under all * conditions." */ mtspr(SPRN_THRM3, THRM3_SITV(0x1fff) | THRM3_E); - - local_irq_restore(flags); } static void tau_timeout_smp(unsigned long unused) |