commit 99a3ae51d557d8e38a7aece65678a31f9db215ee upstream.

In the C-code we need to put the physical address of the hpmc handler in
the interrupt vector table (IVA) in order to get HPMCs working.  Since
on parisc64 function pointers are indirect (in fact they are function
descriptors) we instead export the address as variable and not as
function.

This reverts a small part of commit f39cce654f9a ("parisc: Add
cfi_startproc and cfi_endproc to assembly code").

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org>    [4.9+]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 1138b6718ff74d2a934459643e3754423d23b5e2 upstream.

Helge noticed that the address of the os_hpmc handler was not being
correctly calculated in the hpmc macro.  As a result, PDCE_CHECK would
fail to call os_hpmc:

<Cpu2> e800009802e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu2> 37000f7302e00000  8040004000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu2> f600105e02e00000  fffffff0f0c00000  CC_MC_HPMC_MONARCH_SELECTED
<Cpu2> 140003b202e00000  000000000000000b  CC_ERR_HPMC_STATE_ENTRY
<Cpu2> 5600100b02e00000  00000000000001a0  CC_MC_OS_HPMC_LEN_ERR
<Cpu2> 5600106402e00000  fffffff0f0438e70  CC_MC_BR_TO_OS_HPMC_FAILED
<Cpu2> e800009802e00000  0000000000000000  CC_ERR_CHECK_HPMC
<Cpu2> 37000f7302e00000  8040004000000000  CC_ERR_CPU_CHECK_SUMMARY
<Cpu2> 4000109f02e00000  0000000000000000  CC_MC_HPMC_INITIATED
<Cpu2> 4000101902e00000  0000000000000000  CC_MC_MULTIPLE_HPMCS
<Cpu2> 030010d502e00000  0000000000000000  CC_CPU_STOP

The address problem can be seen by dumping the fault vector:

0000000040159000 <fault_vector_20>:
    40159000:   63 6f 77 73     stb r15,-2447(dp)
    40159004:   20 63 61 6e     ldil L%b747000,r3
    40159008:   20 66 6c 79     ldil L%-1c3b3000,r3
        ...
    40159020:   08 00 02 40     nop
    40159024:   20 6e 60 02     ldil L%15d000,r3
    40159028:   34 63 00 00     ldo 0(r3),r3
    4015902c:   e8 60 c0 02     bv,n r0(r3)
    40159030:   08 00 02 40     nop
    40159034:   00 00 00 00     break 0,0
    40159038:   c0 00 70 00     bb,*< r0,sar,40159840 <fault_vector_20+0x840>
    4015903c:   00 00 00 00     break 0,0

Location 40159038 should contain the physical address of os_hpmc:

000000004015d000 <os_hpmc>:
    4015d000:   08 1a 02 43     copy r26,r3
    4015d004:   01 c0 08 a4     mfctl iva,r4
    4015d008:   48 85 00 68     ldw 34(r4),r5

This patch moves the address setup into initialize_ivt to resolve the
above problem.  I tested the change by dumping the HPMC entry after setup:

0000000040209020:  8000240
0000000040209024: 206a2004
0000000040209028: 34630ac0
000000004020902c: e860c002
0000000040209030:  8000240
0000000040209034: 1bdddce6
0000000040209038:   15d000
000000004020903c:      1a0

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

As noticed by Dave Anglin, the last commit introduced a small bug where
the potentially uninitialized r struct is used instead of the regs
pointer as input for unwind_frame_init(). Fix it.

Signed-off-by: Helge Deller <deller@gmx.de>
Reported-by: John David Anglin <dave.anglin@bell.net>

Signed-off-by: Helge Deller <deller@gmx.de>

Commit c8921d72e390 ("parisc: Fix and improve kernel stack unwinding")
broke booting of 64-bit kernels. On 64-bit kernels function pointers are
actually function descriptors which require dereferencing. In this patch
we instead declare functions in assembly code which are referenced from
C-code as external data pointers with the ENTRY() macro and thus can use
a simple external reference to the functions.

Signed-off-by: Helge Deller <deller@gmx.de>
Fixes: c8921d72e390 ("parisc: Fix and improve kernel stack unwinding")

Signed-off-by: Helge Deller <deller@gmx.de>

We do support running 64-bit userspace processes, although there isn't
yet full gcc and glibc support. Anyway, fix the comments to reflect the
reality.

Signed-off-by: Helge Deller <deller@gmx.de>

Fix the strace code path to call 64-bit syscalls in case we are
executing by a 64-bit application.

Signed-off-by: Helge Deller <deller@gmx.de>

Executing 64-bit applications was broken. This patch restores this
support and cleans up some code paths.

Signed-off-by: Helge Deller <deller@gmx.de>

This patchset fixes and improves stack unwinding a lot:
1. Show backward stack traces with up to 30 callsites
2. Add callinfo to ENTRY_CFI() such that every assembler function will get an
   entry in the unwind table
3. Use constants instead of numbers in call_on_stack()
4. Do not depend on CONFIG_KALLSYMS to generate backtraces.
5. Speed up backtrace generation

Make sure you have this patch to GNU as installed:
https://sourceware.org/ml/binutils/2018-07/msg00474.html
Without this patch, unwind info in the kernel is often wrong for various
functions.

Signed-off-by: Helge Deller <deller@gmx.de>