mirror of
https://github.com/tobast/libunwind-eh_elf.git
synced 2024-06-28 12:11:45 +02:00
Add support for handling signal frames on ARM Linux.
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>
This commit is contained in:
Ken Werner
parent
9533ea1a6a
commit
36511d3d1f
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@ -61,7 +61,18 @@ struct unw_addr_space
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struct cursor
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{
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struct dwarf_cursor dwarf; /* must be first */
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enum
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{
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ARM_SCF_NONE, /* no signal frame */
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ARM_SCF_LINUX_SIGFRAME, /* non-RT signal frame, kernel >=2.6.18 */
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ARM_SCF_LINUX_RT_SIGFRAME, /* RT signal frame, kernel >=2.6.18 */
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ARM_SCF_LINUX_OLD_SIGFRAME, /* non-RT signal frame, kernel < 2.6.18 */
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ARM_SCF_LINUX_OLD_RT_SIGFRAME /* RT signal frame, kernel < 2.6.18 */
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}
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sigcontext_format;
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unw_word_t sigcontext_addr;
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unw_word_t sigcontext_sp;
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unw_word_t sigcontext_pc;
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};
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#define DWARF_GET_LOC(l) ((l).val)
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@ -24,6 +24,7 @@ OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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#include "unwind_i.h"
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#include "offsets.h"
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#ifndef UNW_REMOTE_ONLY
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@ -33,27 +34,62 @@ arm_local_resume (unw_addr_space_t as, unw_cursor_t *cursor, void *arg)
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#ifdef __linux__
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struct cursor *c = (struct cursor *) cursor;
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ucontext_t *uc = c->dwarf.as_arg;
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unsigned long regs[10];
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/* Copy the register contents to be restored. */
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regs[0] = uc->uc_mcontext.arm_r4;
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regs[1] = uc->uc_mcontext.arm_r5;
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regs[2] = uc->uc_mcontext.arm_r6;
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regs[3] = uc->uc_mcontext.arm_r7;
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regs[4] = uc->uc_mcontext.arm_r8;
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regs[5] = uc->uc_mcontext.arm_r9;
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regs[6] = uc->uc_mcontext.arm_r10;
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regs[7] = uc->uc_mcontext.arm_fp;
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regs[8] = uc->uc_mcontext.arm_sp;
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regs[9] = uc->uc_mcontext.arm_lr;
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if (c->sigcontext_format == ARM_SCF_NONE)
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{
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/* Since there are no signals involved here we restore the non scratch
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registers only. */
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unsigned long regs[10];
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regs[0] = uc->uc_mcontext.arm_r4;
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regs[1] = uc->uc_mcontext.arm_r5;
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regs[2] = uc->uc_mcontext.arm_r6;
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regs[3] = uc->uc_mcontext.arm_r7;
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regs[4] = uc->uc_mcontext.arm_r8;
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regs[5] = uc->uc_mcontext.arm_r9;
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regs[6] = uc->uc_mcontext.arm_r10;
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regs[7] = uc->uc_mcontext.arm_fp;
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regs[8] = uc->uc_mcontext.arm_sp;
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regs[9] = uc->uc_mcontext.arm_lr;
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/* Restore the registers. */
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asm __volatile__ (
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"ldmia %0, {r4-r12, lr}\n"
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"mov sp, r12\n"
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"bx lr\n"
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: : "r" (regs) :
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);
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asm __volatile__ (
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"ldmia %0, {r4-r12, lr}\n"
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"mov sp, r12\n"
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"bx lr\n"
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: : "r" (regs) :
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);
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}
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else
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{
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/* In case a signal frame is involved, we're using its trampoline which
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calls sigreturn. */
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struct sigcontext *sc = (struct sigcontext *) c->sigcontext_addr;
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sc->arm_r0 = uc->uc_mcontext.arm_r0;
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sc->arm_r1 = uc->uc_mcontext.arm_r1;
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sc->arm_r2 = uc->uc_mcontext.arm_r2;
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sc->arm_r3 = uc->uc_mcontext.arm_r3;
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sc->arm_r4 = uc->uc_mcontext.arm_r4;
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sc->arm_r5 = uc->uc_mcontext.arm_r5;
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sc->arm_r6 = uc->uc_mcontext.arm_r6;
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sc->arm_r7 = uc->uc_mcontext.arm_r7;
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sc->arm_r8 = uc->uc_mcontext.arm_r8;
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sc->arm_r9 = uc->uc_mcontext.arm_r9;
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sc->arm_r10 = uc->uc_mcontext.arm_r10;
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sc->arm_fp = uc->uc_mcontext.arm_fp;
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sc->arm_ip = uc->uc_mcontext.arm_ip;
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sc->arm_sp = uc->uc_mcontext.arm_sp;
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sc->arm_lr = uc->uc_mcontext.arm_lr;
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sc->arm_pc = uc->uc_mcontext.arm_pc;
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/* clear the ITSTATE bits. */
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sc->arm_cpsr &= 0xf9ff03ffUL;
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/* Set the SP and the PC in order to continue execution at the modified
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trampoline which restores the signal mask and the registers. */
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asm __volatile__ (
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"mov sp, %0\n"
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"bx %1\n"
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: : "r" (c->sigcontext_sp), "r" (c->sigcontext_pc) :
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);
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}
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#else
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printf ("%s: implement me\n", __FUNCTION__);
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#endif
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@ -27,6 +27,8 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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#include "offsets.h"
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#include "ex_tables.h"
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#include <signal.h>
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#define arm_exidx_step UNW_OBJ(arm_exidx_step)
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static inline int
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@ -70,6 +72,95 @@ arm_exidx_step (struct cursor *c)
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return (c->dwarf.ip == 0) ? 0 : 1;
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}
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PROTECTED int
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unw_handle_signal_frame (unw_cursor_t *cursor)
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{
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struct cursor *c = (struct cursor *) cursor;
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int ret;
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unw_word_t sc_addr, sp, sp_addr = c->dwarf.cfa;
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struct dwarf_loc sp_loc = DWARF_LOC (sp_addr, 0);
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if ((ret = dwarf_get (&c->dwarf, sp_loc, &sp)) < 0)
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return -UNW_EUNSPEC;
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/* Obtain signal frame type (non-RT or RT). */
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ret = unw_is_signal_frame (cursor);
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/* Save the SP and PC to be able to return execution at this point
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later in time (unw_resume). */
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c->sigcontext_sp = c->dwarf.cfa;
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c->sigcontext_pc = c->dwarf.ip;
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/* Since kernel version 2.6.18 the non-RT signal frame starts with a
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ucontext while the RT signal frame starts with a siginfo, followed
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by a sigframe whose first element is an ucontext.
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Prior 2.6.18 the non-RT signal frame starts with a sigcontext while
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the RT signal frame starts with two pointers followed by a siginfo
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and an ucontext. The first pointer points to the start of the siginfo
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structure and the second one to the ucontext structure. */
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if (ret == 1)
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{
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/* Handle non-RT signal frames. Check if the first word on the stack
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is the magic number. */
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if (sp == 0x5ac3c35a)
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{
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c->sigcontext_format = ARM_SCF_LINUX_SIGFRAME;
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sc_addr = sp_addr + LINUX_UC_MCONTEXT_OFF;
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}
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else
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{
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c->sigcontext_format = ARM_SCF_LINUX_OLD_SIGFRAME;
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sc_addr = sp_addr;
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}
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c->sigcontext_addr = sp_addr;
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}
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else if (ret == 2)
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{
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/* Handle RT signal frames. Check if the first word on the stack is a
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pointer to the siginfo structure. */
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if (sp == sp_addr + 8)
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{
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c->sigcontext_format = ARM_SCF_LINUX_OLD_RT_SIGFRAME;
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c->sigcontext_addr = sp_addr + 8 + sizeof (siginfo_t);
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}
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else
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{
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c->sigcontext_format = ARM_SCF_LINUX_RT_SIGFRAME;
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c->sigcontext_addr = sp_addr + sizeof (siginfo_t);
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}
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sc_addr = c->sigcontext_addr + LINUX_UC_MCONTEXT_OFF;
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}
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else
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return -UNW_EUNSPEC;
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/* Update the dwarf cursor.
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Set the location of the registers to the corresponding addresses of the
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uc_mcontext / sigcontext structure contents. */
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c->dwarf.loc[UNW_ARM_R0] = DWARF_LOC (sc_addr + LINUX_SC_R0_OFF, 0);
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c->dwarf.loc[UNW_ARM_R1] = DWARF_LOC (sc_addr + LINUX_SC_R1_OFF, 0);
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c->dwarf.loc[UNW_ARM_R2] = DWARF_LOC (sc_addr + LINUX_SC_R2_OFF, 0);
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c->dwarf.loc[UNW_ARM_R3] = DWARF_LOC (sc_addr + LINUX_SC_R3_OFF, 0);
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c->dwarf.loc[UNW_ARM_R4] = DWARF_LOC (sc_addr + LINUX_SC_R4_OFF, 0);
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c->dwarf.loc[UNW_ARM_R5] = DWARF_LOC (sc_addr + LINUX_SC_R5_OFF, 0);
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c->dwarf.loc[UNW_ARM_R6] = DWARF_LOC (sc_addr + LINUX_SC_R6_OFF, 0);
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c->dwarf.loc[UNW_ARM_R7] = DWARF_LOC (sc_addr + LINUX_SC_R7_OFF, 0);
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c->dwarf.loc[UNW_ARM_R8] = DWARF_LOC (sc_addr + LINUX_SC_R8_OFF, 0);
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c->dwarf.loc[UNW_ARM_R9] = DWARF_LOC (sc_addr + LINUX_SC_R9_OFF, 0);
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c->dwarf.loc[UNW_ARM_R10] = DWARF_LOC (sc_addr + LINUX_SC_R10_OFF, 0);
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c->dwarf.loc[UNW_ARM_R11] = DWARF_LOC (sc_addr + LINUX_SC_FP_OFF, 0);
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c->dwarf.loc[UNW_ARM_R12] = DWARF_LOC (sc_addr + LINUX_SC_IP_OFF, 0);
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c->dwarf.loc[UNW_ARM_R13] = DWARF_LOC (sc_addr + LINUX_SC_SP_OFF, 0);
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c->dwarf.loc[UNW_ARM_R14] = DWARF_LOC (sc_addr + LINUX_SC_LR_OFF, 0);
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c->dwarf.loc[UNW_ARM_R15] = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0);
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/* Set SP/CFA and PC/IP. */
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dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R13], &c->dwarf.cfa);
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dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R15], &c->dwarf.ip);
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return 1;
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}
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PROTECTED int
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unw_step (unw_cursor_t *cursor)
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{
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@ -78,6 +169,10 @@ unw_step (unw_cursor_t *cursor)
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Debug (1, "(cursor=%p)\n", c);
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/* Check if this is a signal frame. */
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if (unw_is_signal_frame (cursor))
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return unw_handle_signal_frame (cursor);
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/* First, try DWARF-based unwinding. */
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if (UNW_TRY_METHOD(UNW_ARM_METHOD_DWARF))
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{
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@ -58,6 +58,11 @@ common_init (struct cursor *c, unsigned use_prev_instr)
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if (ret < 0)
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return ret;
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c->sigcontext_format = ARM_SCF_NONE;
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c->sigcontext_addr = 0;
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c->sigcontext_sp = 0;
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c->sigcontext_pc = 0;
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/* FIXME: Initialisation for other registers. */
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c->dwarf.args_size = 0;
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