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powerpc/signal: Add helper function to fetch quad word aligned pointer
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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>
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Anshuman Khandual authored and Michael Ellerman committed Jul 21, 2015
1 parent 4c57622 commit 2476c09
Showing 1 changed file with 16 additions and 5 deletions.
21 changes: 16 additions & 5 deletions arch/powerpc/kernel/signal_64.c
Original file line number Diff line number Diff line change
Expand Up @@ -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.
*/
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand Down

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