[PATCH stable v4.9 16/35] powerpc/fsl: Add barrier_nospec implementation for NXP PowerPC Book3E

Michael Ellerman
2019-04-11T11:47:02Z

From: Diana Craciun <diana.craciun@nxp.com>

commit ebcd1bfc33c7a90df941df68a6e5d4018c022fba upstream.

Implement the barrier_nospec as a isync;sync instruction sequence.
The implementation uses the infrastructure built for BOOK3S 64.

Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
[mpe: Split out of larger patch]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/include/asm/barrier.h | 8 +++++++-
arch/powerpc/lib/feature-fixups.c | 31 ++++++++++++++++++++++++++++++
3 files changed, 39 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index a238698178fc..fa8f2aa88189 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -167,7 +167,7 @@ config PPC
config PPC_BARRIER_NOSPEC
bool
default y
- depends on PPC_BOOK3S_64
+ depends on PPC_BOOK3S_64 || PPC_FSL_BOOK3E

config GENERIC_CSUM
def_bool CPU_LITTLE_ENDIAN
diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h
index 465a64316897..80024c4f2093 100644
--- a/arch/powerpc/include/asm/barrier.h
+++ b/arch/powerpc/include/asm/barrier.h
@@ -77,12 +77,18 @@ do { \

#define smp_mb__before_spinlock() smp_mb()

+#ifdef CONFIG_PPC_BOOK3S_64
+#define NOSPEC_BARRIER_SLOT nop
+#elif defined(CONFIG_PPC_FSL_BOOK3E)
+#define NOSPEC_BARRIER_SLOT nop; nop
+#endif
+
#ifdef CONFIG_PPC_BARRIER_NOSPEC
/*
* Prevent execution of subsequent instructions until preceding branches have
* been fully resolved and are no longer executing speculatively.
*/
-#define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; nop
+#define barrier_nospec_asm NOSPEC_BARRIER_FIXUP_SECTION; NOSPEC_BARRIER_SLOT

// This also acts as a compiler barrier due to the memory clobber.
#define barrier_nospec() asm (stringify_in_c(barrier_nospec_asm) ::: "memory")
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index 5df57f7bae0a..b3e362437ec4 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -318,6 +318,37 @@ void do_barrier_nospec_fixups(bool enable)
}
#endif /* CONFIG_PPC_BARRIER_NOSPEC */

+#ifdef CONFIG_PPC_FSL_BOOK3E
+void do_barrier_nospec_fixups_range(bool enable, void *fixup_start, void *fixup_end)
+{
+ unsigned int instr[2], *dest;
+ long *start, *end;
+ int i;
+
+ start = fixup_start;
+ end = fixup_end;
+
+ instr[0] = PPC_INST_NOP;
+ instr[1] = PPC_INST_NOP;
+
+ if (enable) {
+ pr_info("barrier-nospec: using isync; sync as speculation barrier\n");
+ instr[0] = PPC_INST_ISYNC;
+ instr[1] = PPC_INST_SYNC;
+ }
+
+ for (i = 0; start < end; start++, i++) {
+ dest = (void *)start + *start;
+
+ pr_devel("patching dest %lx\n", (unsigned long)dest);
+ patch_instruction(dest, instr[0]);
+ patch_instruction(dest + 1, instr[1]);
+ }
+
+ printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
+}
+#endif /* CONFIG_PPC_FSL_BOOK3E */
+
void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
{
long *start, *end;
--
2.20.1