linux.git/arch/s390/include/asm/processor.h, branch v5.19

s390: simplify early program check handler

2022-05-25T09:46:02+00:00

Due to historic reasons the base program check handler calls a
configurable function. Given that there is only the early program
check handler left, simplify the code by directly calling that
function.

The only other user was removed with commit d485235b0054 ("s390:
assume diag308 set always works").

Also rename all functions and the asm file to reflect this.

Reviewed-by: Sven Schnelle 
Signed-off-by: Heiko Carstens

s390/vdso: map vdso above stack

2022-04-25T11:54:14+00:00

In the current code vdso is mapped below the stack. This is
problematic when programs mapped to the top of the address space
are allocating a lot of memory, because the heap will clash with
the vdso. To avoid this map the vdso above the stack and move
STACK_TOP so that it all fits into three level paging.

Signed-off-by: Sven Schnelle 
Reviewed-by: Heiko Carstens 
Signed-off-by: Heiko Carstens

s390/vdso: move vdso mapping to its own function

2022-04-25T11:54:14+00:00

This is a preparation patch for adding vdso randomization to s390.
It adds a function vdso_size(), which will be used later in calculating
the STACK_TOP value. It also moves the vdso mapping into a new function
vdso_map(), to keep the code similar to other architectures.

Signed-off-by: Sven Schnelle 
Reviewed-by: Heiko Carstens 
Signed-off-by: Heiko Carstens

s390: current_stack_pointer shouldn't be a function

2022-04-12T09:56:08+00:00

s390 defines current_stack_pointer as function while all other
architectures use 'register unsigned long asm("").

This make codes like the following from check_stack_object() fail:

	if (IS_ENABLED(CONFIG_STACK_GROWSUP)) {
		if ((void *)current_stack_pointer < obj + len)
			return BAD_STACK;
	} else {
		if (obj < (void *)current_stack_pointer)
			return BAD_STACK;
	}

because this would compare the address of current_stack_pointer() and
not the stackpointer value.

Reported-by: Karsten Graul 
Fixes: 2792d84e6da5 ("usercopy: Check valid lifetime via stack depth")
Cc: Kees Cook 
Cc: Vasily Gorbik 
Cc: Alexander Gordeev 
Signed-off-by: Sven Schnelle 
Reviewed-by: Heiko Carstens 
Signed-off-by: Heiko Carstens

s390/maccess: rework absolute lowcore accessors

2022-03-27T20:18:39+00:00

Macro mem_assign_absolute() is able to access the whole memory, but
is only used and makes sense when updating the absolute lowcore.
Instead, introduce get_abs_lowcore() and put_abs_lowcore() macros
that limit access to absolute lowcore addresses only.

Suggested-by: Heiko Carstens 
Reviewed-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev 
Signed-off-by: Vasily Gorbik

s390: convert ".insn" encoding to instruction names

2022-03-10T14:58:17+00:00

With z10 as minimum supported machine generation many ".insn" encodings
could be now converted to instruction names. There are couple of exceptions
- stfle is used from the als code built for z900 and cannot be converted
- few ".insn" directives encode unsupported instruction formats

The generated code is identical before/after this change.

Acked-by: Ilya Leoshkevich 
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/base: pass pt_regs to early program check handler

2022-03-07T23:33:00+00:00

Pass pt_regs to early program check handler like it is done for every
other interrupt and exception handler.

Also the passed pt_regs can be changed by the called function and the
changes register contents and psw contents will be taken into account
when returning. In addition the return psw will not be copied to the
program check old psw in lowcore, but to the usual return psw
location, like it is also done by the regular program check handler.
This allows also to get rid of the code that disabled lowcore
protection when changing the return address.

Reviewed-by: Alexander Gordeev 
Signed-off-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik

s390/maccess: fix semantics of memcpy_real() and its callers

2022-02-09T21:56:04+00:00

There is a confusion with regard to the source address of
memcpy_real() and calling functions. While the declared
type for a source assumes a virtual address, in fact it
always called with physical address of the source.

This confusion led to bugs in copy_oldmem_kernel() and
copy_oldmem_user() functions, where __pa() macro applied
mistakenly to physical addresses. It does not lead to a
real issue, since virtual and physical addresses are
currently the same.

Fix both the bugs and memcpy_real() prototype by making
type of source address consistent to the function name
and the way it actually used.

Reviewed-by: Heiko Carstens 
Signed-off-by: Alexander Gordeev 
Signed-off-by: Vasily Gorbik

s390: remove unused TASK_SIZE_OF

2021-12-29T09:33:40+00:00

This macro isn't used in Linux sched, now. Delete in
include/linux/sched.h and arch's include/asm.

Signed-off-by: Guo Ren 
Signed-off-by: Guo Ren 
Reviewed-by: Arnd Bergmann 
Link: https://lore.kernel.org/r/20211228064730.2882351-6-guoren@kernel.org
Signed-off-by: Heiko Carstens

sched: Add wrapper for get_wchan() to keep task blocked

2021-10-15T09:25:14+00:00

Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zijlstra 
Signed-off-by: Kees Cook 
Signed-off-by: Peter Zijlstra (Intel) 
Acked-by: Geert Uytterhoeven 
Acked-by: Russell King (Oracle)  [arm]
Tested-by: Mark Rutland  [arm64]
Link: https://lkml.kernel.org/r/20211008111626.332092234@infradead.org