ARCv2 has some configuration dependent registers (r30, r58, r59) which
could be targetted by the compiler. To keep the ABI stable, these were
unconditionally part of the glibc ABI
(sysdeps/unix/sysv/linux/arc/sys/ucontext.h:mcontext_t) however we
missed populating them (by saving/restoring them across signal
handling).
This patch fixes the issue by
- adding arcv2 ABI regs to kernel struct sigcontext
- populating them during signal handling
Change to struct sigcontext might seem like a glibc ABI change (although
it primarily uses ucontext_t:mcontext_t) but the fact is
- it has only been extended (existing fields are not touched)
- the old sigcontext was ABI incomplete to begin with anyways
Fixes: https://github.com/foss-for-synopsys-dwc-arc-processors/linux/issues/53
Cc: <[email protected]>
Reported-by: Vladimir Isaev <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>
---
arch/arc/include/uapi/asm/sigcontext.h | 1 +
arch/arc/kernel/signal.c | 29 ++++++++++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/arch/arc/include/uapi/asm/sigcontext.h b/arch/arc/include/uapi/asm/sigcontext.h
index 95f8a4380e11..7a5449dfcb29 100644
--- a/arch/arc/include/uapi/asm/sigcontext.h
+++ b/arch/arc/include/uapi/asm/sigcontext.h
@@ -18,6 +18,7 @@
*/
struct sigcontext {
struct user_regs_struct regs;
+ struct user_regs_arcv2 v2abi;
};
#endif /* _ASM_ARC_SIGCONTEXT_H */
diff --git a/arch/arc/kernel/signal.c b/arch/arc/kernel/signal.c
index b3ccb9e5ffe4..534b3d9bafc8 100644
--- a/arch/arc/kernel/signal.c
+++ b/arch/arc/kernel/signal.c
@@ -94,6 +94,21 @@ stash_usr_regs(struct rt_sigframe __user *sf, struct pt_regs *regs,
err = __copy_to_user(&(sf->uc.uc_mcontext.regs.scratch), &uregs.scratch,
sizeof(sf->uc.uc_mcontext.regs.scratch));
+
+ if (is_isa_arcv2()) {
+ struct user_regs_arcv2 v2abi;
+
+ v2abi.r30 = regs->r30;
+#ifdef CONFIG_ARC_HAS_ACCL_REGS
+ v2abi.r58 = regs->r58;
+ v2abi.r59 = regs->r59;
+#else
+ v2abi.r58 = v2abi.r59 = 0;
+#endif
+ err |= __copy_to_user(&(sf->uc.uc_mcontext.v2abi), &v2abi,
+ sizeof(sf->uc.uc_mcontext.v2abi));
+ }
+
err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(sigset_t));
return err ? -EFAULT : 0;
@@ -109,6 +124,20 @@ static int restore_usr_regs(struct pt_regs *regs, struct rt_sigframe __user *sf)
err |= __copy_from_user(&uregs.scratch,
&(sf->uc.uc_mcontext.regs.scratch),
sizeof(sf->uc.uc_mcontext.regs.scratch));
+
+ if (is_isa_arcv2()) {
+ struct user_regs_arcv2 v2abi;
+
+ err |= __copy_from_user(&v2abi, &(sf->uc.uc_mcontext.v2abi),
+ sizeof(sf->uc.uc_mcontext.v2abi));
+
+ regs->r30 = v2abi.r30;
+#ifdef CONFIG_ARC_HAS_ACCL_REGS
+ regs->r58 = v2abi.r58;
+ regs->r59 = v2abi.r59;
+#endif
+ }
+
if (err)
return -EFAULT;
--
2.25.1