[PATCH 4.9 01/16] ARM: 8789/1: signal: copy registers using __copy_to_user()

David Long
2019-02-14T14:51:43Z

From: Julien Thierry <julien.thierry@arm.com>

Commit 5ca451cf6ed04443774bbb7ee45332dafa42e99f upstream.

When saving the ARM integer registers, use __copy_to_user() to
copy them into user signal frame, rather than __put_user_error().
This has the benefit of disabling/enabling PAN once for the whole copy
intead of once per write.

Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: David A. Long <dave.long@linaro.org>
---
arch/arm/kernel/signal.c | 49 ++++++++++++++++++++++------------------
1 file changed, 27 insertions(+), 22 deletions(-)

diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index 6bee5c9b1133..fbb325ff8acc 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -256,30 +256,35 @@ static int
setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
{
struct aux_sigframe __user *aux;
+ struct sigcontext context;
int err = 0;

- __put_user_error(regs->ARM_r0, &sf->uc.uc_mcontext.arm_r0, err);
- __put_user_error(regs->ARM_r1, &sf->uc.uc_mcontext.arm_r1, err);
- __put_user_error(regs->ARM_r2, &sf->uc.uc_mcontext.arm_r2, err);
- __put_user_error(regs->ARM_r3, &sf->uc.uc_mcontext.arm_r3, err);
- __put_user_error(regs->ARM_r4, &sf->uc.uc_mcontext.arm_r4, err);
- __put_user_error(regs->ARM_r5, &sf->uc.uc_mcontext.arm_r5, err);
- __put_user_error(regs->ARM_r6, &sf->uc.uc_mcontext.arm_r6, err);
- __put_user_error(regs->ARM_r7, &sf->uc.uc_mcontext.arm_r7, err);
- __put_user_error(regs->ARM_r8, &sf->uc.uc_mcontext.arm_r8, err);
- __put_user_error(regs->ARM_r9, &sf->uc.uc_mcontext.arm_r9, err);
- __put_user_error(regs->ARM_r10, &sf->uc.uc_mcontext.arm_r10, err);
- __put_user_error(regs->ARM_fp, &sf->uc.uc_mcontext.arm_fp, err);
- __put_user_error(regs->ARM_ip, &sf->uc.uc_mcontext.arm_ip, err);
- __put_user_error(regs->ARM_sp, &sf->uc.uc_mcontext.arm_sp, err);
- __put_user_error(regs->ARM_lr, &sf->uc.uc_mcontext.arm_lr, err);
- __put_user_error(regs->ARM_pc, &sf->uc.uc_mcontext.arm_pc, err);
- __put_user_error(regs->ARM_cpsr, &sf->uc.uc_mcontext.arm_cpsr, err);
-
- __put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no, err);
- __put_user_error(current->thread.error_code, &sf->uc.uc_mcontext.error_code, err);
- __put_user_error(current->thread.address, &sf->uc.uc_mcontext.fault_address, err);
- __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);
+ context = (struct sigcontext) {
+ .arm_r0 = regs->ARM_r0,
+ .arm_r1 = regs->ARM_r1,
+ .arm_r2 = regs->ARM_r2,
+ .arm_r3 = regs->ARM_r3,
+ .arm_r4 = regs->ARM_r4,
+ .arm_r5 = regs->ARM_r5,
+ .arm_r6 = regs->ARM_r6,
+ .arm_r7 = regs->ARM_r7,
+ .arm_r8 = regs->ARM_r8,
+ .arm_r9 = regs->ARM_r9,
+ .arm_r10 = regs->ARM_r10,
+ .arm_fp = regs->ARM_fp,
+ .arm_ip = regs->ARM_ip,
+ .arm_sp = regs->ARM_sp,
+ .arm_lr = regs->ARM_lr,
+ .arm_pc = regs->ARM_pc,
+ .arm_cpsr = regs->ARM_cpsr,
+
+ .trap_no = current->thread.trap_no,
+ .error_code = current->thread.error_code,
+ .fault_address = current->thread.address,
+ .oldmask = set->sig[0],
+ };
+
+ err |= __copy_to_user(&sf->uc.uc_mcontext, &context, sizeof(context));

err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));

--
2.17.1