From 2476c09f391eddb546a73fef9f6ab86886a9f2b1 Mon Sep 17 00:00:00 2001
From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Date: Mon, 20 Jul 2015 08:28:43 +0530
Subject: [PATCH] powerpc/signal: Add helper function to fetch quad word
aligned pointer
This patch adds one helper function 'sigcontext_vmx_regs' which computes
quad word aligned pointer for 'vmx_reserve' array element in sigcontext
structure making the code more readable.
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
[mpe: Reword comment and fix build for CONFIG_ALTIVEC=n]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/kernel/signal_64.c | 21 ++++++++++++++++-----
1 file changed, 16 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index c7c24d2e2bdbc..20756dfb9f346 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -73,6 +73,19 @@ static const char fmt32[] = KERN_INFO \
static const char fmt64[] = KERN_INFO \
"%s[%d]: bad frame in %s: %016lx nip %016lx lr %016lx\n";
+/*
+ * This computes a quad word aligned pointer inside the vmx_reserve array
+ * element. For historical reasons sigcontext might not be quad word aligned,
+ * but the location we write the VMX regs to must be. See the comment in
+ * sigcontext for more detail.
+ */
+#ifdef CONFIG_ALTIVEC
+static elf_vrreg_t __user *sigcontext_vmx_regs(struct sigcontext __user *sc)
+{
+ return (elf_vrreg_t __user *) (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
+}
+#endif
+
/*
* Set up the sigcontext for the signal frame.
*/
@@ -90,7 +103,7 @@ static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
* v_regs pointer or not
*/
#ifdef CONFIG_ALTIVEC
- elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
+ elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
#endif
unsigned long msr = regs->msr;
long err = 0;
@@ -181,10 +194,8 @@ static long setup_tm_sigcontexts(struct sigcontext __user *sc,
* v_regs pointer or not.
*/
#ifdef CONFIG_ALTIVEC
- elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)
- (((unsigned long)sc->vmx_reserve + 15) & ~0xful);
- elf_vrreg_t __user *tm_v_regs = (elf_vrreg_t __user *)
- (((unsigned long)tm_sc->vmx_reserve + 15) & ~0xful);
+ elf_vrreg_t __user *v_regs = sigcontext_vmx_regs(sc);
+ elf_vrreg_t __user *tm_v_regs = sigcontext_vmx_regs(tm_sc);
#endif
unsigned long msr = regs->msr;
long err = 0;