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| author | Nicholas Piggin <npiggin@gmail.com> | 2017-04-19 16:05:47 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-04-23 13:31:46 +0300 |
| commit | 1945bc4549e5cb1f9aa873ec29191aa54dc851d2 (patch) | |
| tree | 38b03e90b086496355f21d0da028aa9cb6411c19 /arch/powerpc/kernel/idle_book3s.S | |
| parent | 10101aa9aa9d2e6b403610de196945ecbf93cf06 (diff) | |
| download | linux-1945bc4549e5cb1f9aa873ec29191aa54dc851d2.tar.xz | |
powerpc/64s: Fix POWER9 machine check handler from stop state
The ISA specifies power save wakeup due to a machine check exception can
cause a machine check interrupt (rather than the usual system reset
interrupt).
The machine check handler copes with this by doing low level machine
check recovery without restoring full state from idle, then queues up a
machine check event for logging, then directly executes the same idle
instruction it woke from. This minimises the work done before recovery
is performed.
The problem is that it requires machine specific instructions and
knowledge of the book3s idle code. Currently it only has code to handle
POWER8 idle, so POWER9 crashes when trying to execute the P8 idle
instructions which don't exist in ISAv3.0B.
cpu 0x0: Vector: e40 (Emulation Assist) at [c0000000008f3810]
pc: c000000000008380: machine_check_handle_early+0x130/0x2f0
lr: c00000000053a098: stop_loop+0x68/0xd0
sp: c0000000008f3a90
msr: 9000000000081001
current = 0xc0000000008a1080
paca = 0xc00000000ffd0000 softe: 0 irq_happened: 0x01
pid = 0, comm = swapper/0
Instead of going to sleep after recovery, do the usual idle wakeup and
state restoration by calling into the normal idle wakeup path. This
reuses the normal idle wakeup paths.
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Reviewed-by: Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/idle_book3s.S')
| -rw-r--r-- | arch/powerpc/kernel/idle_book3s.S | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/idle_book3s.S b/arch/powerpc/kernel/idle_book3s.S index dd8ca7fdf55a..4e5a4fed86c5 100644 --- a/arch/powerpc/kernel/idle_book3s.S +++ b/arch/powerpc/kernel/idle_book3s.S @@ -416,6 +416,31 @@ power9_dd1_recover_paca: blr /* + * Called from machine check handler for powersave wakeups. + * Low level machine check processing has already been done. Now just + * go through the wake up path to get everything in order. + * + * r3 - The original SRR1 value. + * Original SRR[01] have been clobbered. + * MSR_RI is clear. + */ +.global pnv_powersave_wakeup_mce +pnv_powersave_wakeup_mce: + /* Set cr3 for pnv_powersave_wakeup */ + rlwinm r11,r3,47-31,30,31 + cmpwi cr3,r11,2 + + /* + * Now put the original SRR1 with SRR1_WAKEMCE_RESVD as the wake + * reason into SRR1, which allows reuse of the system reset wakeup + * code without being mistaken for another type of wakeup. + */ + oris r3,r3,SRR1_WAKEMCE_RESVD@h + mtspr SPRN_SRR1,r3 + + b pnv_powersave_wakeup + +/* * Called from reset vector for powersave wakeups. * cr3 - set to gt if waking up with partial/complete hypervisor state loss */ |