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| author | Alexander Gordeev <agordeev@linux.ibm.com> | 2023-04-03 09:44:40 +0300 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2023-04-19 18:24:16 +0300 |
| commit | 2d1b21eceaf0765d60b543b2b8e26c2f55517259 (patch) | |
| tree | 1de582fe2a05fc11880b4365c886b1d3be288058 /arch/s390/include | |
| parent | 82caf7aba107dbc0e70c330786bed9961a098ab0 (diff) | |
| download | linux-2d1b21eceaf0765d60b543b2b8e26c2f55517259.tar.xz | |
s390/kdump: remove nodat stack restriction for calling nodat functions
To allow calling of DAT-off code from kernel the stack needs
to be switched to nodat_stack (or other stack mapped as 1:1).
Before call_nodat() macro was introduced that was necessary
to provide the very same memory address for STNSM and STOSM
instructions. If the kernel would stay on a random stack
(e.g. a virtually mapped one) then a virtual address provided
for STNSM instruction could differ from the physical address
needed for the corresponding STOSM instruction.
After call_nodat() macro is introduced the kernel stack does
not need to be mapped 1:1 anymore, since the macro stores the
physical memory address of return PSW in a register before
entering DAT-off mode. This way the return LPSWE instruction
is able to pick the correct memory location and restore the
DAT-on mode. That however might fail in case the 16-byte return
PSW happened to cross page boundary: PSW mask and PSW address
could end up in two separate non-contiguous physical pages.
Align the return PSW on 16-byte boundary so it always fits
into a single physical page. As result any stack (including
the virtually mapped one) could be used for calling DAT-off
code and prior switching to nodat_stack becomes unnecessary.
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390/include')
| -rw-r--r-- | arch/s390/include/asm/stacktrace.h | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/s390/include/asm/stacktrace.h b/arch/s390/include/asm/stacktrace.h index 1966422cf030..78f7b729b65f 100644 --- a/arch/s390/include/asm/stacktrace.h +++ b/arch/s390/include/asm/stacktrace.h @@ -210,7 +210,9 @@ static __always_inline unsigned long get_stack_pointer(struct task_struct *task, #define call_nodat(nr, rettype, fn, ...) \ ({ \ rettype (*__fn)(CALL_PARM_##nr(__VA_ARGS__)) = (fn); \ - psw_t psw_enter, psw_leave; \ + /* aligned since psw_leave must not cross page boundary */ \ + psw_t __aligned(16) psw_leave; \ + psw_t psw_enter; \ CALL_LARGS_##nr(__VA_ARGS__); \ CALL_REGS_##nr; \ \ |