linux-toradex.git/arch/powerpc/kernel/exceptions-64e.S, branch v4.4.89

powerpc/64e: Fix hang when debugging programs with relocated kernel

2017-05-25T12:30:15+00:00

commit fd615f69a18a9d4aa5ef02a1dc83f319f75da8e7 upstream.

Debug interrupts can be taken during interrupt entry, since interrupt
entry does not automatically turn them off.  The kernel will check
whether the faulting instruction is between [interrupt_base_book3e,
__end_interrupts], and if so clear MSR[DE] and return.

However, when the kernel is built with CONFIG_RELOCATABLE, it can't use
LOAD_REG_IMMEDIATE(r14,interrupt_base_book3e) and
LOAD_REG_IMMEDIATE(r15,__end_interrupts), as they ignore relocation.
Thus, if the kernel is actually running at a different address than it
was built at, the address comparison will fail, and the exception entry
code will hang at kernel_dbg_exc.

r2(toc) is also not usable here, as r2 still holds data from the
interrupted context, so LOAD_REG_ADDR() doesn't work either.  So we use
the *name@got* to get the EV of two labels directly.

Test programs test.c shows as follows:
int main(int argc, char *argv[])
{
	if (access("/proc/sys/kernel/perf_event_paranoid", F_OK) == -1)
		printf("Kernel doesn't have perf_event support\n");
}

Steps to reproduce the bug, for example:
 1) ./gdb ./test
 2) (gdb) b access
 3) (gdb) r
 4) (gdb) s

Signed-off-by: Liu Hailong 
Signed-off-by: Jiang Xuexin 
Reviewed-by: Jiang Biao 
Reviewed-by: Liu Song 
Reviewed-by: Huang Jian 
[scottwood: cleaned up commit message, and specified bad behavior
 as a hang rather than an oops to correspond to mainline kernel behavior]
Fixes: 1cb6e0649248 ("powerpc/book3e: support CONFIG_RELOCATABLE")
Signed-off-by: Scott Wood 
Signed-off-by: Greg Kroah-Hartman

powerpc/book3e: support CONFIG_RELOCATABLE

2015-10-27T23:13:27+00:00

book3e is different with book3s since 3s includes the exception
vectors code in head_64.S as it relies on absolute addressing
which is only possible within this compilation unit. So we have
to get that label address with got.

And when boot a relocated kernel, we should reset ipvr properly again
after .relocate.

Signed-off-by: Tiejun Chen 
[scottwood: cleanup and ifdef removal]
Signed-off-by: Scott Wood

powerpc/book3e-64: rename interrupt_end_book3e with __end_interrupts

2015-10-27T23:13:26+00:00

Rename 'interrupt_end_book3e' to '__end_interrupts' so that the symbol
can be used by both book3s and book3e.

Signed-off-by: Tiejun Chen 
[scottwood: edit changelog]
Signed-off-by: Scott Wood

powerpc/fsl: Force coherent memory on e500mc derivatives

2015-08-08T04:00:01+00:00

In CoreNet systems it is not allowed to mix M and non-M mappings to the
same memory, and coherent DMA accesses are considered to be M mappings
for this purpose.  Ignoring this has been observed to cause hard
lockups in non-SMP kernels on e6500.

Furthermore, e6500 implements the LRAT (logical to real address table)
which allows KVM guests to control the WIMGE bits.  This means that
KVM cannot force the M bit on the way it usually does, so the guest had
better set it itself.

Signed-off-by: Scott Wood

powerpc/booke: Revert SPE/AltiVec common defines for interrupt numbers

2014-09-22T08:11:31+00:00

Book3E specification defines shared interrupt numbers for SPE and AltiVec
units. Still SPE is present in e200/e500v2 cores while AltiVec is present in
e6500 core. So we can currently decide at compile-time which unit to support
exclusively. As Alexander Graf suggested, this will improve code readability
especially in KVM.

Use distinct defines to identify SPE/AltiVec interrupt numbers, reverting
c58ce397 and 6b310fc5 patches that added common defines.

Signed-off-by: Mihai Caraman 
Acked-by: Scott Wood 
Signed-off-by: Alexander Graf

powerpc: Remove platforms/wsp and associated pieces

2014-06-11T06:35:38+00:00

__attribute__ ((unused))

WSP is the last user of CONFIG_PPC_A2, so we remove that as well.

Although CONFIG_PPC_ICSWX still exists, it's no longer selectable for
any Book3E platform, so we can remove the code in mmu-book3e.h that
depended on it.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt

powerpc: Remove dot symbol usage in exception macros

2014-04-23T00:05:19+00:00

STD_EXCEPTION_COMMON, STD_EXCEPTION_COMMON_ASYNC and
MASKABLE_EXCEPTION branch to the handler, so we can remove
the explicit dot symbol and binutils will do the right thing.

Signed-off-by: Anton Blanchard

powerpc: Remove some unnecessary uses of _GLOBAL() and _STATIC()

2014-04-23T00:05:18+00:00

There is no need to create a function descriptor for functions
called locally out of assembly.

Signed-off-by: Anton Blanchard

powerpc: No need to use dot symbols when branching to a function

2014-04-23T00:05:16+00:00

binutils is smart enough to know that a branch to a function
descriptor is actually a branch to the functions text address.

Alan tells me that binutils has been doing this for 9 years.

Signed-off-by: Anton Blanchard

powerpc/booke64: Critical and machine check exception support

2014-03-20T00:57:27+00:00

Add special state saving for critical and machine check exceptions.

Most of this code could be used to handle debug exceptions taken from
kernel space, but actually doing so is outside the scope of this patch.

The various critical and machine check exceptions now point to their
real handlers, rather than hanging the kernel.

Signed-off-by: Scott Wood