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| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2011-05-23 10:24:23 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2011-05-23 10:24:28 +0200 |
| commit | 043d07084b5347a26eab0a07aa13a4a929ad9e71 (patch) | |
| tree | 13c2a902ccb2ecb779722c8b81ada32d242760c8 /arch/s390/include/asm/lowcore.h | |
| parent | 9bf05098ce34e68a9e15f09ad6cdfea4ed64057a (diff) | |
| download | linux-043d07084b5347a26eab0a07aa13a4a929ad9e71.tar.gz linux-043d07084b5347a26eab0a07aa13a4a929ad9e71.tar.bz2 linux-043d07084b5347a26eab0a07aa13a4a929ad9e71.zip | |
[S390] Remove data execution protection
The noexec support on s390 does not rely on a bit in the page table
entry but utilizes the secondary space mode to distinguish between
memory accesses for instructions vs. data. The noexec code relies
on the assumption that the cpu will always use the secondary space
page table for data accesses while it is running in the secondary
space mode. Up to the z9-109 class machines this has been the case.
Unfortunately this is not true anymore with z10 and later machines.
The load-relative-long instructions lrl, lgrl and lgfrl access the
memory operand using the same addressing-space mode that has been
used to fetch the instruction.
This breaks the noexec mode for all user space binaries compiled
with march=z10 or later. The only option is to remove the current
noexec support.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/lowcore.h')
| -rw-r--r-- | arch/s390/include/asm/lowcore.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/s390/include/asm/lowcore.h b/arch/s390/include/asm/lowcore.h index 65e172f8209d..b8624d53c379 100644 --- a/arch/s390/include/asm/lowcore.h +++ b/arch/s390/include/asm/lowcore.h @@ -124,7 +124,7 @@ struct _lowcore { /* Address space pointer. */ __u32 kernel_asce; /* 0x02ac */ __u32 user_asce; /* 0x02b0 */ - __u32 user_exec_asce; /* 0x02b4 */ + __u8 pad_0x02b4[0x02b8-0x02b4]; /* 0x02b4 */ /* SMP info area */ __u32 cpu_nr; /* 0x02b8 */ @@ -255,7 +255,7 @@ struct _lowcore { /* Address space pointer. */ __u64 kernel_asce; /* 0x0310 */ __u64 user_asce; /* 0x0318 */ - __u64 user_exec_asce; /* 0x0320 */ + __u8 pad_0x0320[0x0328-0x0320]; /* 0x0320 */ /* SMP info area */ __u32 cpu_nr; /* 0x0328 */ |