@@ -61,7 +61,18 @@ struct unw_addr_space
struct cursor
{
struct dwarf_cursor dwarf; /* must be first */
+ enum
+ {
+ ARM_SCF_NONE, /* no signal frame */
+ ARM_SCF_LINUX_SIGFRAME, /* non-RT signal frame, kernel >=2.6.18 */
+ ARM_SCF_LINUX_RT_SIGFRAME, /* RT signal frame, kernel >=2.6.18 */
+ ARM_SCF_LINUX_OLD_SIGFRAME, /* non-RT signal frame, kernel < 2.6.18 */
+ ARM_SCF_LINUX_OLD_RT_SIGFRAME /* RT signal frame, kernel < 2.6.18 */
+ }
+ sigcontext_format;
unw_word_t sigcontext_addr;
+ unw_word_t sigcontext_sp;
+ unw_word_t sigcontext_pc;
};
#define DWARF_GET_LOC(l) ((l).val)
@@ -24,6 +24,7 @@ OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include "unwind_i.h"
+#include "offsets.h"
#ifndef UNW_REMOTE_ONLY
@@ -33,27 +34,62 @@ arm_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
#ifdef __linux__
struct cursor *c = (struct cursor *) cursor;
ucontext_t *uc = c->dwarf.as_arg;
- unsigned long regs[10];
-
- /* Copy the register contents to be restored. */
- regs[0] = uc->uc_mcontext.arm_r4;
- regs[1] = uc->uc_mcontext.arm_r5;
- regs[2] = uc->uc_mcontext.arm_r6;
- regs[3] = uc->uc_mcontext.arm_r7;
- regs[4] = uc->uc_mcontext.arm_r8;
- regs[5] = uc->uc_mcontext.arm_r9;
- regs[6] = uc->uc_mcontext.arm_r10;
- regs[7] = uc->uc_mcontext.arm_fp;
- regs[8] = uc->uc_mcontext.arm_sp;
- regs[9] = uc->uc_mcontext.arm_lr;
-
- /* Restore the registers. */
- asm __volatile__ (
- "ldmia %0, {r4-r12, lr}\n"
- "mov sp, r12\n"
- "bx lr\n"
- : : "r" (regs) :
- );
+
+ if (c->sigcontext_format == ARM_SCF_NONE)
+ {
+ /* Since there are no signals involved here we restore the non scratch
+ registers only. */
+ unsigned long regs[10];
+ regs[0] = uc->uc_mcontext.arm_r4;
+ regs[1] = uc->uc_mcontext.arm_r5;
+ regs[2] = uc->uc_mcontext.arm_r6;
+ regs[3] = uc->uc_mcontext.arm_r7;
+ regs[4] = uc->uc_mcontext.arm_r8;
+ regs[5] = uc->uc_mcontext.arm_r9;
+ regs[6] = uc->uc_mcontext.arm_r10;
+ regs[7] = uc->uc_mcontext.arm_fp;
+ regs[8] = uc->uc_mcontext.arm_sp;
+ regs[9] = uc->uc_mcontext.arm_lr;
+
+ asm __volatile__ (
+ "ldmia %0, {r4-r12, lr}\n"
+ "mov sp, r12\n"
+ "bx lr\n"
+ : : "r" (regs) :
+ );
+ }
+ else
+ {
+ /* In case a signal frame is involved, we're using its trampoline which
+ calls sigreturn. */
+ struct sigcontext *sc = (struct sigcontext *) c->sigcontext_addr;
+ sc->arm_r0 = uc->uc_mcontext.arm_r0;
+ sc->arm_r1 = uc->uc_mcontext.arm_r1;
+ sc->arm_r2 = uc->uc_mcontext.arm_r2;
+ sc->arm_r3 = uc->uc_mcontext.arm_r3;
+ sc->arm_r4 = uc->uc_mcontext.arm_r4;
+ sc->arm_r5 = uc->uc_mcontext.arm_r5;
+ sc->arm_r6 = uc->uc_mcontext.arm_r6;
+ sc->arm_r7 = uc->uc_mcontext.arm_r7;
+ sc->arm_r8 = uc->uc_mcontext.arm_r8;
+ sc->arm_r9 = uc->uc_mcontext.arm_r9;
+ sc->arm_r10 = uc->uc_mcontext.arm_r10;
+ sc->arm_fp = uc->uc_mcontext.arm_fp;
+ sc->arm_ip = uc->uc_mcontext.arm_ip;
+ sc->arm_sp = uc->uc_mcontext.arm_sp;
+ sc->arm_lr = uc->uc_mcontext.arm_lr;
+ sc->arm_pc = uc->uc_mcontext.arm_pc;
+ /* clear the ITSTATE bits. */
+ sc->arm_cpsr &= 0xf9ff03ffUL;
+
+ /* Set the SP and the PC in order to continue execution at the modified
+ trampoline which restores the signal mask and the registers. */
+ asm __volatile__ (
+ "mov sp, %0\n"
+ "bx %1\n"
+ : : "r" (c->sigcontext_sp), "r" (c->sigcontext_pc) :
+ );
+ }
#else
printf ("%s: implement me\n", __FUNCTION__);
#endif
@@ -27,6 +27,8 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include "offsets.h"
#include "ex_tables.h"
+#include <signal.h>
+
#define arm_exidx_step UNW_OBJ(arm_exidx_step)
static inline int
@@ -71,6 +73,95 @@ arm_exidx_step (struct cursor *c)
}
PROTECTED int
+unw_handle_signal_frame (unw_cursor_t *cursor)
+{
+ struct cursor *c = (struct cursor *) cursor;
+ int ret;
+ unw_word_t sc_addr, sp, sp_addr = c->dwarf.cfa;
+ struct dwarf_loc sp_loc = DWARF_LOC (sp_addr, 0);
+
+ if ((ret = dwarf_get (&c->dwarf, sp_loc, &sp)) < 0)
+ return -UNW_EUNSPEC;
+
+ /* Obtain signal frame type (non-RT or RT). */
+ ret = unw_is_signal_frame (cursor);
+
+ /* Save the SP and PC to be able to return execution at this point
+ later in time (unw_resume). */
+ c->sigcontext_sp = c->dwarf.cfa;
+ c->sigcontext_pc = c->dwarf.ip;
+
+ /* Since kernel version 2.6.18 the non-RT signal frame starts with a
+ ucontext while the RT signal frame starts with a siginfo, followed
+ by a sigframe whose first element is an ucontext.
+ Prior 2.6.18 the non-RT signal frame starts with a sigcontext while
+ the RT signal frame starts with two pointers followed by a siginfo
+ and an ucontext. The first pointer points to the start of the siginfo
+ structure and the second one to the ucontext structure. */
+
+ if (ret == 1)
+ {
+ /* Handle non-RT signal frames. Check if the first word on the stack
+ is the magic number. */
+ if (sp == 0x5ac3c35a)
+ {
+ c->sigcontext_format = ARM_SCF_LINUX_SIGFRAME;
+ sc_addr = sp_addr + LINUX_UC_MCONTEXT_OFF;
+ }
+ else
+ {
+ c->sigcontext_format = ARM_SCF_LINUX_OLD_SIGFRAME;
+ sc_addr = sp_addr;
+ }
+ c->sigcontext_addr = sp_addr;
+ }
+ else if (ret == 2)
+ {
+ /* Handle RT signal frames. Check if the first word on the stack is a
+ pointer to the siginfo structure. */
+ if (sp == sp_addr + 8)
+ {
+ c->sigcontext_format = ARM_SCF_LINUX_OLD_RT_SIGFRAME;
+ c->sigcontext_addr = sp_addr + 8 + sizeof (siginfo_t);
+ }
+ else
+ {
+ c->sigcontext_format = ARM_SCF_LINUX_RT_SIGFRAME;
+ c->sigcontext_addr = sp_addr + sizeof (siginfo_t);
+ }
+ sc_addr = c->sigcontext_addr + LINUX_UC_MCONTEXT_OFF;
+ }
+ else
+ return -UNW_EUNSPEC;
+
+ /* Update the dwarf cursor.
+ Set the location of the registers to the corresponding addresses of the
+ uc_mcontext / sigcontext structure contents. */
+ c->dwarf.loc[UNW_ARM_R0] = DWARF_LOC (sc_addr + LINUX_SC_R0_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R1] = DWARF_LOC (sc_addr + LINUX_SC_R1_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R2] = DWARF_LOC (sc_addr + LINUX_SC_R2_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R3] = DWARF_LOC (sc_addr + LINUX_SC_R3_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R4] = DWARF_LOC (sc_addr + LINUX_SC_R4_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R5] = DWARF_LOC (sc_addr + LINUX_SC_R5_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R6] = DWARF_LOC (sc_addr + LINUX_SC_R6_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R7] = DWARF_LOC (sc_addr + LINUX_SC_R7_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R8] = DWARF_LOC (sc_addr + LINUX_SC_R8_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R9] = DWARF_LOC (sc_addr + LINUX_SC_R9_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R10] = DWARF_LOC (sc_addr + LINUX_SC_R10_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R11] = DWARF_LOC (sc_addr + LINUX_SC_FP_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R12] = DWARF_LOC (sc_addr + LINUX_SC_IP_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R13] = DWARF_LOC (sc_addr + LINUX_SC_SP_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R14] = DWARF_LOC (sc_addr + LINUX_SC_LR_OFF, 0);
+ c->dwarf.loc[UNW_ARM_R15] = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0);
+
+ /* Set SP/CFA and PC/IP. */
+ dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R13], &c->dwarf.cfa);
+ dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R15], &c->dwarf.ip);
+
+ return 1;
+}
+
+PROTECTED int
unw_step (unw_cursor_t *cursor)
{
struct cursor *c = (struct cursor *) cursor;
@@ -78,6 +169,10 @@ unw_step (unw_cursor_t *cursor)
Debug (1, "(cursor=%p)\n", c);
+ /* Check if this is a signal frame. */
+ if (unw_is_signal_frame (cursor))
+ return unw_handle_signal_frame (cursor);
+
/* First, try DWARF-based unwinding. */
if (UNW_TRY_METHOD(UNW_ARM_METHOD_DWARF))
{
@@ -58,6 +58,11 @@ common_init (struct cursor *c, unsigned use_prev_instr)
if (ret < 0)
return ret;
+ c->sigcontext_format = ARM_SCF_NONE;
+ c->sigcontext_addr = 0;
+ c->sigcontext_sp = 0;
+ c->sigcontext_pc = 0;
+
/* FIXME: Initialisation for other registers. */
c->dwarf.args_size = 0;
This patch add support for resuming at a certain stack frame even if signal frames are involved. For restoring the registers the trampoline (sigreturn) is used. RT and non-RT signal frames are handled for both >=2.6.18 and <2.6.18 kernels. Signed-off-by: Ken Werner <ken.werner@linaro.org> --- include/tdep-arm/libunwind_i.h | 11 +++++ src/arm/Gresume.c | 74 +++++++++++++++++++++++-------- src/arm/Gstep.c | 95 ++++++++++++++++++++++++++++++++++++++++ src/arm/init.h | 5 ++ 4 files changed, 166 insertions(+), 19 deletions(-)