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authorSandra Loosemore <sandra@codesourcery.com>2015-05-08 12:34:52 -0700
committerSandra Loosemore <sandra@codesourcery.com>2015-05-08 12:34:52 -0700
commit35d54293c3a0fb5e8cd3a82a1e2a6e0481b615af (patch)
treefd4f965f63423881acda7101f03bded7153f8b04
parent21e94bd9f0888034c094e02c75d382d75340326c (diff)
downloadbinutils-gdb-35d54293c3a0fb5e8cd3a82a1e2a6e0481b615af.tar.gz
Fix register save offset for nios2 signal handler trampolines.
2015-05-08 Sandra Loosemore <sandra@codesourcery.com> gdb/ * nios2-linux-tdep.c (NIOS2_SIGRETURN_TRAMP_ADDR): Define. (NIOS2_SIGRETURN_REGSAVE_OFFSET): Define. (nios2_linux_rt_sigreturn_init): Adjust base address of register save area.
-rw-r--r--gdb/ChangeLog7
-rw-r--r--gdb/nios2-linux-tdep.c23
2 files changed, 28 insertions, 2 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f895f9ccafb..b7a29e6396d 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
2015-05-08 Sandra Loosemore <sandra@codesourcery.com>
+ * nios2-linux-tdep.c (NIOS2_SIGRETURN_TRAMP_ADDR): Define.
+ (NIOS2_SIGRETURN_REGSAVE_OFFSET): Define.
+ (nios2_linux_rt_sigreturn_init): Adjust base address of
+ register save area.
+
+2015-05-08 Sandra Loosemore <sandra@codesourcery.com>
+
* nios2-tdep.c (nios2_breakpoint_from_pc): Revert to using
"trap 31" as the breakpoint instruction on all targets.
diff --git a/gdb/nios2-linux-tdep.c b/gdb/nios2-linux-tdep.c
index b829569c9c4..0a837b0a093 100644
--- a/gdb/nios2-linux-tdep.c
+++ b/gdb/nios2-linux-tdep.c
@@ -114,7 +114,25 @@ nios2_iterate_over_regset_sections (struct gdbarch *gdbarch,
}
/* Initialize a trad-frame cache corresponding to the tramp-frame.
- FUNC is the address of the instruction TRAMP[0] in memory. */
+ FUNC is the address of the instruction TRAMP[0] in memory.
+
+ This ABI is not documented. It corresponds to rt_setup_ucontext in
+ the kernel arch/nios2/kernel/signal.c file.
+
+ The key points are:
+ - The kernel creates a trampoline at the hard-wired address 0x1044.
+ - The stack pointer points to an object of type struct rt_sigframe.
+ The definition of this structure is not exported from the kernel.
+ The register save area is located at offset 152 bytes (as determined
+ by inspection of the stack contents in the debugger), and the
+ registers are saved as r1-r23, ra, fp, gp, ea, sp.
+
+ This interface was implemented with kernel version 3.19 (the first
+ official mainline kernel). Older unofficial kernel versions used
+ incompatible conventions; we do not support those here. */
+
+#define NIOS2_SIGRETURN_TRAMP_ADDR 0x1044
+#define NIOS2_SIGRETURN_REGSAVE_OFFSET 152
static void
nios2_linux_rt_sigreturn_init (const struct tramp_frame *self,
@@ -122,7 +140,8 @@ nios2_linux_rt_sigreturn_init (const struct tramp_frame *self,
struct trad_frame_cache *this_cache,
CORE_ADDR func)
{
- CORE_ADDR base = func + 41 * 4;
+ CORE_ADDR sp = get_frame_register_unsigned (next_frame, NIOS2_SP_REGNUM);
+ CORE_ADDR base = sp + NIOS2_SIGRETURN_REGSAVE_OFFSET;
int i;
for (i = 0; i < 23; i++)