diff options
Diffstat (limited to 'gdb/sparc64obsd-tdep.c')
| -rw-r--r-- | gdb/sparc64obsd-tdep.c | 32 |
1 files changed, 20 insertions, 12 deletions
diff --git a/gdb/sparc64obsd-tdep.c b/gdb/sparc64obsd-tdep.c index 2d6a617..eae599c 100644 --- a/gdb/sparc64obsd-tdep.c +++ b/gdb/sparc64obsd-tdep.c @@ -68,19 +68,27 @@ sparc64obsd_supply_gregset (const struct regset *regset, /* Signal trampolines. */ -/* The OpenBSD kernel maps the signal trampoline at some random - location in user space, which means that the traditional BSD way of - detecting it won't work. - - The signal trampoline will be mapped at an address that is page - aligned. We recognize the signal trampoline by the looking for the - sigreturn system call. The offset where we can find the code that - makes this system call varies from release to release. For OpenBSD - 3.6 and later releases we can find the code at offset 0xec. For - OpenBSD 3.5 and earlier releases, we find it at offset 0xe8. */ - +/* Since OpenBSD 3.2, the sigtramp routine is mapped at a random page + in virtual memory. The randomness makes it somewhat tricky to + detect it, but fortunately we can rely on the fact that the start + of the sigtramp routine is page-aligned. We recognize the + trampoline by looking for the code that invokes the sigreturn + system call. The offset where we can find that code varies from + release to release. + + By the way, the mapping mentioned above is read-only, so you cannot + place a breakpoint in the signal trampoline. */ + +/* Default page size. */ static const int sparc64obsd_page_size = 8192; -static const int sparc64obsd_sigreturn_offset[] = { 0xec, 0xe8, -1 }; + +/* Offset for sigreturn(2). */ +static const int sparc64obsd_sigreturn_offset[] = { + 0xf0, /* OpenBSD 3.8 */ + 0xec, /* OpenBSD 3.6 */ + 0xe8, /* OpenBSD 3.2 */ + -1 +}; static int sparc64obsd_pc_in_sigtramp (CORE_ADDR pc, char *name) |