On 02/18/2010 06:02 PM, David Daney wrote:
Well this patch set does cause gdb to no longer be able to generate
stack traces from signal handlers, but that just means gdb needs to be
fixed. We will work on that next.
Attached is the corresponding gdb patch. I will push it into the
upstream gdb.
David Daney
libgcc can unwind through signal handlers both with and without the patch.
David Daney
On 02/18/2010 04:13 PM, David Daney wrote:
This patch set creates a vdso and moves the signal
trampolines to it from their previous home on the stack.
In the original patch set:
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=49EE3B0F.3040506%40caviumnetworks.com
I stated:
Tested with a 64-bit kernel on a Cavium Octeon cn3860 where I have the
following results from lmbench2:
Before:
n64 - Signal handler overhead: 14.517 microseconds
n32 - Signal handler overhead: 14.497 microseconds
o32 - Signal handler overhead: 16.637 microseconds
After:
n64 - Signal handler overhead: 7.935 microseconds
n32 - Signal handler overhead: 7.334 microseconds
o32 - Signal handler overhead: 8.628 microsecond
All that is still true.
Improvements from the first version:
* Compiles and runs in 32-bit kernels (on qemu at least).
* Updated for linux-queue based 2.6.33-rc8
David Daney (3):
MIPS: Add SYSCALL to uasm.
MIPS: Preliminary vdso.
MIPS: Move signal trampolines off of the stack.
arch/mips/include/asm/abi.h | 6 +-
arch/mips/include/asm/elf.h | 4 +
arch/mips/include/asm/mmu.h | 5 +-
arch/mips/include/asm/mmu_context.h | 2 +-
arch/mips/include/asm/processor.h | 11 +++-
arch/mips/include/asm/uasm.h | 1 +
arch/mips/include/asm/vdso.h | 29 +++++++++
arch/mips/kernel/Makefile | 2 +-
arch/mips/kernel/signal-common.h | 5 --
arch/mips/kernel/signal.c | 86 ++++++---------------------
arch/mips/kernel/signal32.c | 55 ++++-------------
arch/mips/kernel/signal_n32.c | 26 ++------
arch/mips/kernel/syscall.c | 6 ++-
arch/mips/kernel/vdso.c | 112 +++++++++++++++++++++++++++++++++++
arch/mips/mm/uasm.c | 19 +++++-
15 files changed, 226 insertions(+), 143 deletions(-)
create mode 100644 arch/mips/include/asm/vdso.h
create mode 100644 arch/mips/kernel/vdso.c
Index: gdb/mips-linux-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/mips-linux-tdep.c,v
retrieving revision 1.81
diff -u -p -r1.81 mips-linux-tdep.c
--- gdb/mips-linux-tdep.c 1 Jan 2010 07:31:37 -0000 1.81
+++ gdb/mips-linux-tdep.c 19 Feb 2010 21:58:32 -0000
@@ -797,7 +797,7 @@ static const struct tramp_frame mips_lin
struct sigframe {
u32 sf_ass[4]; [argument save space for o32]
- u32 sf_code[2]; [signal trampoline]
+ u32 sf_code[2]; [signal trampoline or fill]
struct sigcontext sf_sc;
sigset_t sf_mask;
};
@@ -827,7 +827,7 @@ static const struct tramp_frame mips_lin
struct rt_sigframe {
u32 rs_ass[4]; [argument save space for o32]
- u32 rs_code[2] [signal trampoline]
+ u32 rs_code[2] [signal trampoline or fill]
struct siginfo rs_info;
struct ucontext rs_uc;
};
@@ -871,7 +871,7 @@ mips_linux_o32_sigframe_init (const stru
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
int ireg, reg_position;
- CORE_ADDR sigcontext_base = func - SIGFRAME_CODE_OFFSET;
+ CORE_ADDR sigcontext_base = get_frame_sp (this_frame);
const struct mips_regnum *regs = mips_regnum (gdbarch);
CORE_ADDR regs_base;
@@ -1038,7 +1038,7 @@ mips_linux_n32n64_sigframe_init (const s
{
struct gdbarch *gdbarch = get_frame_arch (this_frame);
int ireg, reg_position;
- CORE_ADDR sigcontext_base = func - SIGFRAME_CODE_OFFSET;
+ CORE_ADDR sigcontext_base = get_frame_sp (this_frame);
const struct mips_regnum *regs = mips_regnum (gdbarch);
if (self == &mips_linux_n32_rt_sigframe)
