diff options
| author | Michael Neuling <mikey@neuling.org> | 2017-09-15 15:25:48 +1000 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2017-09-27 08:23:22 +1000 |
| commit | 5080332c2c893118dbc18755f35c8b0131cf0fc4 (patch) | |
| tree | 8c045081ddd230fc9c2e2477b29f0a27687cc4a9 /arch/powerpc/kernel/exceptions-64s.S | |
| parent | b9fde58db7e5738cacb740b0ec547933fe314fbe (diff) | |
powerpc/64s: Add workaround for P9 vector CI load issue
POWER9 DD2.1 and earlier has an issue where some cache inhibited
vector load will return bad data. The workaround is two part, one
firmware/microcode part triggers HMI interrupts when hitting such
loads, the other part is this patch which then emulates the
instructions in Linux.
The affected instructions are limited to lxvd2x, lxvw4x, lxvb16x and
lxvh8x.
When an instruction triggers the HMI, all threads in the core will be
sent to the HMI handler, not just the one running the vector load.
In general, these spurious HMIs are detected by the emulation code and
we just return back to the running process. Unfortunately, if a
spurious interrupt occurs on a vector load that's to normal memory we
have no way to detect that it's spurious (unless we walk the page
tables, which is very expensive). In this case we emulate the load but
we need do so using a vector load itself to ensure 128bit atomicity is
preserved.
Some additional debugfs emulated instruction counters are added also.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Switch CONFIG_PPC_BOOK3S_64 to CONFIG_VSX to unbreak the build]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/exceptions-64s.S')
| -rw-r--r-- | arch/powerpc/kernel/exceptions-64s.S | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S index 48da0f5d2f7f..8c32dd4cac20 100644 --- a/arch/powerpc/kernel/exceptions-64s.S +++ b/arch/powerpc/kernel/exceptions-64s.S @@ -1010,6 +1010,8 @@ TRAMP_REAL_BEGIN(hmi_exception_early) EXCEPTION_PROLOG_COMMON_3(0xe60) addi r3,r1,STACK_FRAME_OVERHEAD BRANCH_LINK_TO_FAR(hmi_exception_realmode) /* Function call ABI */ + cmpdi cr0,r3,0 + /* Windup the stack. */ /* Move original HSRR0 and HSRR1 into the respective regs */ ld r9,_MSR(r1) @@ -1026,10 +1028,15 @@ TRAMP_REAL_BEGIN(hmi_exception_early) REST_8GPRS(2, r1) REST_GPR(10, r1) ld r11,_CCR(r1) + REST_2GPRS(12, r1) + bne 1f mtcr r11 REST_GPR(11, r1) - REST_2GPRS(12, r1) - /* restore original r1. */ + ld r1,GPR1(r1) + hrfid + +1: mtcr r11 + REST_GPR(11, r1) ld r1,GPR1(r1) /* @@ -1042,8 +1049,9 @@ hmi_exception_after_realmode: EXCEPTION_PROLOG_0(PACA_EXGEN) b tramp_real_hmi_exception -EXC_COMMON_ASYNC(hmi_exception_common, 0xe60, handle_hmi_exception) - +EXC_COMMON_BEGIN(hmi_exception_common) +EXCEPTION_COMMON(PACA_EXGEN, 0xe60, hmi_exception_common, handle_hmi_exception, + ret_from_except, FINISH_NAP;ADD_NVGPRS;ADD_RECONCILE;RUNLATCH_ON) EXC_REAL_OOL_MASKABLE_HV(h_doorbell, 0xe80, 0x20) EXC_VIRT_OOL_MASKABLE_HV(h_doorbell, 0x4e80, 0x20, 0xe80) |