diff options
| author | Helge Deller <deller@gmx.de> | 2021-12-08 11:06:52 +0100 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2022-03-11 19:49:30 +0100 |
| commit | df24e1783e6e0eb3dc0e3ba5a8df3bb0cc537408 (patch) | |
| tree | 73050ce6de41a1fd03e20bffa47c82fb598ef816 /arch/parisc/kernel/signal32.h | |
| parent | 14615ecccb8b0022589b7a7841cdfdf96319724b (diff) | |
parisc: Add vDSO support
Add minimal vDSO support, which provides the signal trampoline helpers,
but none of the userspace syscall helpers like time wrappers.
The big benefit of this vDSO implementation is, that we now don't need
an executeable stack any longer. PA-RISC is one of the last
architectures where an executeable stack was needed in oder to implement
the signal trampolines by putting assembly instructions on the stack
which then gets executed. Instead the kernel will provide the relevant
code in the vDSO page and only put the pointers to the signal
information on the stack.
By dropping the need for executable stacks we avoid running into issues
with applications which want non executable stacks for security reasons.
Additionally, alternative stacks on memory areas without exec
permissions are supported too.
This code is based on an initial implementation by Randolph Chung from 2006:
https://lore.kernel.org/linux-parisc/4544A34A.6080700@tausq.org/
I did the porting and lifted the code to current code base. Dave fixed
the unwind code so that gdb and glibc are able to backtrace through the
code. An additional patch to gdb will be pushed upstream by Dave.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Dave Anglin <dave.anglin@bell.net>
Cc: Randolph Chung <randolph@tausq.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'arch/parisc/kernel/signal32.h')
| -rw-r--r-- | arch/parisc/kernel/signal32.h | 19 |
1 files changed, 5 insertions, 14 deletions
diff --git a/arch/parisc/kernel/signal32.h b/arch/parisc/kernel/signal32.h index f166250f2d06..c03eb1ed4c53 100644 --- a/arch/parisc/kernel/signal32.h +++ b/arch/parisc/kernel/signal32.h @@ -36,21 +36,12 @@ struct compat_regfile { compat_int_t rf_sar; }; -#define COMPAT_SIGRETURN_TRAMP 4 -#define COMPAT_SIGRESTARTBLOCK_TRAMP 5 -#define COMPAT_TRAMP_SIZE (COMPAT_SIGRETURN_TRAMP + \ - COMPAT_SIGRESTARTBLOCK_TRAMP) - struct compat_rt_sigframe { - /* XXX: Must match trampoline size in arch/parisc/kernel/signal.c - Secondary to that it must protect the ERESTART_RESTARTBLOCK - trampoline we left on the stack (we were bad and didn't - change sp so we could run really fast.) */ - compat_uint_t tramp[COMPAT_TRAMP_SIZE]; - compat_siginfo_t info; - struct compat_ucontext uc; - /* Hidden location of truncated registers, *must* be last. */ - struct compat_regfile regs; + unsigned int tramp[2]; /* holds original return address */ + compat_siginfo_t info; + struct compat_ucontext uc; + /* Hidden location of truncated registers, *must* be last. */ + struct compat_regfile regs; }; /* |