[PATCH 3.16 055/305] MIPS: Adjust set_pte() SMP fix to handle R10000_LLSC_WAR

Ben Hutchings
2016-08-14T11:51:28Z

From: Joshua Kinard <kumba@gentoo.org>

commit 128639395b2ceacc6a56a0141d0261012bfe04d3 upstream.

Update the recent changes to set_pte() that were added in 46011e6ea392
to handle R10000_LLSC_WAR, and format the assembly to match other areas
of the MIPS tree using the same WAR.

This also incorporates a patch recently sent in my Markos Chandras,
"Remove local LL/SC preprocessor variants", so that patch doesn't need
to be applied if this one is accepted.

Signed-off-by: Joshua Kinard <kumba@gentoo.org>
Fixes: 46011e6ea392 ("MIPS: Make set_pte() SMP safe.)
Cc: David Daney <david.daney@cavium.com>
Cc: Linux/MIPS <linux-mips@linux-mips.org>
Patchwork: https://patchwork.linux-mips.org/patch/11103/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
[bwh: Backported to 3.2:
- Use {LL,SC}_INSN not __{LL,SC}
- Use literal arch=r4000 instead of MIPS_ISA_ARCH_LEVEL since R6 is not
supported]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
arch/mips/include/asm/pgtable.h | 45 +++++++++++++++++++++++++++++------------
1 file changed, 32 insertions(+), 13 deletions(-)

--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -167,20 +167,39 @@ static inline void set_pte(pte_t *ptep,
unsigned long page_global = _PAGE_GLOBAL;
unsigned long tmp;

- __asm__ __volatile__ (
- " .set push\n"
- " .set noreorder\n"
- "1: " LL_INSN " %[tmp], %[buddy]\n"
- " bnez %[tmp], 2f\n"
- " or %[tmp], %[tmp], %[global]\n"
- " " SC_INSN " %[tmp], %[buddy]\n"
- " beqz %[tmp], 1b\n"
- " nop\n"
- "2:\n"
- " .set pop"
- : [buddy] "+m" (buddy->pte),
- [tmp] "=&r" (tmp)
+ if (kernel_uses_llsc && R10000_LLSC_WAR) {
+ __asm__ __volatile__ (
+ " .set arch=r4000 \n"
+ " .set push \n"
+ " .set noreorder \n"
+ "1:" LL_INSN " %[tmp], %[buddy] \n"
+ " bnez %[tmp], 2f \n"
+ " or %[tmp], %[tmp], %[global] \n"
+ SC_INSN " %[tmp], %[buddy] \n"
+ " beqzl %[tmp], 1b \n"
+ " nop \n"
+ "2: \n"
+ " .set pop \n"
+ " .set mips0 \n"
+ : [buddy] "+m" (buddy->pte), [tmp] "=&r" (tmp)
: [global] "r" (page_global));
+ } else if (kernel_uses_llsc) {
+ __asm__ __volatile__ (
+ " .set arch=r4000 \n"
+ " .set push \n"
+ " .set noreorder \n"
+ "1:" LL_INSN " %[tmp], %[buddy] \n"
+ " bnez %[tmp], 2f \n"
+ " or %[tmp], %[tmp], %[global] \n"
+ SC_INSN " %[tmp], %[buddy] \n"
+ " beqz %[tmp], 1b \n"
+ " nop \n"
+ "2: \n"
+ " .set pop \n"
+ " .set mips0 \n"
+ : [buddy] "+m" (buddy->pte), [tmp] "=&r" (tmp)
+ : [global] "r" (page_global));
+ }
#else /* !CONFIG_SMP */
if (pte_none(*buddy))
pte_val(*buddy) = pte_val(*buddy) | _PAGE_GLOBAL;