diff options
| author | Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> | 2006-03-31 14:30:21 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-04-01 00:18:52 +0400 |
| commit | 972410b0232e97609fcefc8e408fe3037fcd607b (patch) | |
| tree | 2de18ed5d823dc7e24c0171f720f6354a9cd57e4 /arch/um/sys-i386/ptrace_user.c | |
| parent | fbdf2161552a2065047e5df2dbf9ebf69d66a0e9 (diff) | |
| download | linux-972410b0232e97609fcefc8e408fe3037fcd607b.tar.xz | |
[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/sys-i386/ptrace_user.c')
| -rw-r--r-- | arch/um/sys-i386/ptrace_user.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/arch/um/sys-i386/ptrace_user.c b/arch/um/sys-i386/ptrace_user.c index 7c376c95de50..9f3bd8ed78f5 100644 --- a/arch/um/sys-i386/ptrace_user.c +++ b/arch/um/sys-i386/ptrace_user.c @@ -14,6 +14,7 @@ #include "sysdep/thread.h" #include "user.h" #include "os.h" +#include "uml-config.h" int ptrace_getregs(long pid, unsigned long *regs_out) { @@ -43,6 +44,7 @@ int ptrace_setfpregs(long pid, unsigned long *regs) return 0; } +/* All the below stuff is of interest for TT mode only */ static void write_debugregs(int pid, unsigned long *regs) { struct user *dummy; @@ -75,7 +77,6 @@ static void read_debugregs(int pid, unsigned long *regs) /* Accessed only by the tracing thread */ static unsigned long kernel_debugregs[8] = { [ 0 ... 7 ] = 0 }; -static int debugregs_seq = 0; void arch_enter_kernel(void *task, int pid) { @@ -89,6 +90,11 @@ void arch_leave_kernel(void *task, int pid) write_debugregs(pid, TASK_DEBUGREGS(task)); } +#ifdef UML_CONFIG_PT_PROXY +/* Accessed only by the tracing thread */ +static int debugregs_seq; + +/* Only called by the ptrace proxy */ void ptrace_pokeuser(unsigned long addr, unsigned long data) { if((addr < offsetof(struct user, u_debugreg[0])) || @@ -109,6 +115,7 @@ static void update_debugregs_cb(void *arg) write_debugregs(pid, kernel_debugregs); } +/* Optimized out in its header when not defined */ void update_debugregs(int seq) { int me; @@ -118,6 +125,7 @@ void update_debugregs(int seq) me = os_getpid(); initial_thread_cb(update_debugregs_cb, &me); } +#endif /* * Overrides for Emacs so that we follow Linus's tabbing style. |