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authorPeter Maydell <peter.maydell@linaro.org>2010-11-24 15:20:06 +0000
committerRiku Voipio <riku.voipio@nokia.com>2010-12-03 15:09:39 +0200
commit5f9099d9cee0e9ed377aee705ca9f4db75e8948d (patch)
tree34f75c239d5dc6a7c4150fb6f0e737f209c13c2b
parent0d871bdbaac428601c84d29233a49f7cf6ecb6fc (diff)
downloadqemu-arm-5f9099d9cee0e9ed377aee705ca9f4db75e8948d.tar.gz
ARM: linux-user: Restore VFP state from ucontext on sigreturn
Restore the VFP registers from the ucontext on return from a signal handler in linux-user mode. This means that signal handlers cannot accidentally corrupt the interrupted code's VFP state, and allows them to deliberately modify the state via the ucontext structure. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Riku Voipio <riku.voipio@nokia.com>
-rw-r--r--linux-user/signal.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/linux-user/signal.c b/linux-user/signal.c
index af1e0ebda1..63d893b876 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -1535,10 +1535,41 @@ badframe:
return 0;
}
+static abi_ulong *restore_sigframe_v2_vfp(CPUState *env, abi_ulong *regspace)
+{
+ int i;
+ abi_ulong magic, sz;
+ uint32_t fpscr, fpexc;
+ struct target_vfp_sigframe *vfpframe;
+ vfpframe = (struct target_vfp_sigframe *)regspace;
+
+ __get_user(magic, &vfpframe->magic);
+ __get_user(sz, &vfpframe->size);
+ if (magic != TARGET_VFP_MAGIC || sz != sizeof(*vfpframe)) {
+ return 0;
+ }
+ for (i = 0; i < 32; i++) {
+ __get_user(env->vfp.regs[i], &vfpframe->ufp.fpregs[i]);
+ }
+ __get_user(fpscr, &vfpframe->ufp.fpscr);
+ vfp_set_fpscr(env, fpscr);
+ __get_user(fpexc, &vfpframe->ufp_exc.fpexc);
+ /* Sanitise FPEXC: ensure VFP is enabled, FPINST2 is invalid
+ * and the exception flag is cleared
+ */
+ fpexc |= (1 << 30);
+ fpexc &= ~((1 << 31) | (1 << 28));
+ env->vfp.xregs[ARM_VFP_FPEXC] = fpexc;
+ __get_user(env->vfp.xregs[ARM_VFP_FPINST], &vfpframe->ufp_exc.fpinst);
+ __get_user(env->vfp.xregs[ARM_VFP_FPINST2], &vfpframe->ufp_exc.fpinst2);
+ return (abi_ulong*)(vfpframe + 1);
+}
+
static int do_sigframe_return_v2(CPUState *env, target_ulong frame_addr,
struct target_ucontext_v2 *uc)
{
sigset_t host_set;
+ abi_ulong *regspace;
target_to_host_sigset(&host_set, &uc->tuc_sigmask);
sigprocmask(SIG_SETMASK, &host_set, NULL);
@@ -1546,6 +1577,15 @@ static int do_sigframe_return_v2(CPUState *env, target_ulong frame_addr,
if (restore_sigcontext(env, &uc->tuc_mcontext))
return 1;
+ /* Restore coprocessor signal frame */
+ regspace = uc->tuc_regspace;
+ if (arm_feature(env, ARM_FEATURE_VFP)) {
+ regspace = restore_sigframe_v2_vfp(env, regspace);
+ if (!regspace) {
+ return 1;
+ }
+ }
+
if (do_sigaltstack(frame_addr + offsetof(struct target_ucontext_v2, tuc_stack), 0, get_sp_from_cpustate(env)) == -EFAULT)
return 1;