diff options
| author | Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> | 2006-03-31 02:30:21 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-31 12:18:52 -0800 |
| commit | 972410b0232e97609fcefc8e408fe3037fcd607b (patch) | |
| tree | 2de18ed5d823dc7e24c0171f720f6354a9cd57e4 /arch/um/include | |
| parent | fbdf2161552a2065047e5df2dbf9ebf69d66a0e9 (diff) | |
[PATCH] uml: clean arch_switch usage
Call arch_switch also in switch_to_skas, even if it's, for now, a no-op for
that case (and mark this in the comment); this will change soon.
Also, arch_switch for TT mode is actually useless when the PT proxy (a
complicate debugging instrumentation for TT mode) is not enabled. In fact, it
only calls update_debugregs, which checks debugregs_seq against seq (to check
if the registers are up-to-date - seq here means a "version number" of the
registers).
If the ptrace proxy is not enabled, debugregs_seq always stays 0 and
update_debugregs will be a no-op. So, optimize this out (the compiler can't
do it).
Also, I've been disappointed by the fact that it would make a lot of sense if,
after calling a successful
update_debugregs(current->thread.arch.debugregs_seq),
current->thread.arch.debugregs_seq were updated with the new debugregs_seq.
But this is not done. Is this a bug or a feature? For all purposes, it seems
a bug (otherwise the whole mechanism does not make sense, which is also a
possibility to check), which causes some performance only problems (not
correctness), since we write_debugregs when not needed.
Also, as suggested by Jeff, remove a redundant enabling of SIGVTALRM,
comprised in the subsequent local_irq_enable(). I'm just a bit dubious if
ordering matters there...
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/um/include')
| -rw-r--r-- | arch/um/include/kern_util.h | 6 | ||||
| -rw-r--r-- | arch/um/include/sysdep-i386/ptrace.h | 5 |
2 files changed, 10 insertions, 1 deletions
diff --git a/arch/um/include/kern_util.h b/arch/um/include/kern_util.h index 07176d92e1c9..42557130a408 100644 --- a/arch/um/include/kern_util.h +++ b/arch/um/include/kern_util.h @@ -116,7 +116,11 @@ extern void *get_current(void); extern struct task_struct *get_task(int pid, int require); extern void machine_halt(void); extern int is_syscall(unsigned long addr); -extern void arch_switch(void); + +extern void arch_switch_to_tt(struct task_struct *from, struct task_struct *to); + +extern void arch_switch_to_skas(struct task_struct *from, struct task_struct *to); + extern void free_irq(unsigned int, void *); extern int cpu(void); diff --git a/arch/um/include/sysdep-i386/ptrace.h b/arch/um/include/sysdep-i386/ptrace.h index c8ee9559f3ab..6670cc992ecb 100644 --- a/arch/um/include/sysdep-i386/ptrace.h +++ b/arch/um/include/sysdep-i386/ptrace.h @@ -14,7 +14,12 @@ #define MAX_REG_NR (UM_FRAME_SIZE / sizeof(unsigned long)) #define MAX_REG_OFFSET (UM_FRAME_SIZE) +#ifdef UML_CONFIG_PT_PROXY extern void update_debugregs(int seq); +#else +static inline void update_debugregs(int seq) {} +#endif + /* syscall emulation path in ptrace */ |