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authorMichal Suchanek <msuchanek@suse.de>2018-04-24 14:15:55 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2018-06-03 20:43:44 +1000
commit2eea7f067f495e33b8b116b35b5988ab2b8aec55 (patch)
treeed00f86636a5220a2ddd369284af72cf1deb79ff /arch/powerpc/lib
parenta6b3964ad71a61bb7c61d80a60bea7d42187b2eb (diff)
powerpc/64s: Add support for ori barrier_nospec patching
Based on the RFI patching. This is required to be able to disable the speculation barrier. Only one barrier type is supported and it does nothing when the firmware does not enable it. Also re-patching modules is not supported So the only meaningful thing that can be done is patching out the speculation barrier at boot when the user says it is not wanted. Signed-off-by: Michal Suchanek <msuchanek@suse.de> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/lib')
-rw-r--r--arch/powerpc/lib/feature-fixups.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index f3e46d4edd72..ae911dad9b16 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -162,6 +162,33 @@ void do_rfi_flush_fixups(enum l1d_flush_type types)
(types & L1D_FLUSH_MTTRIG) ? "mttrig type"
: "unknown");
}
+
+void do_barrier_nospec_fixups(bool enable)
+{
+ unsigned int instr, *dest;
+ long *start, *end;
+ int i;
+
+ start = PTRRELOC(&__start___barrier_nospec_fixup),
+ end = PTRRELOC(&__stop___barrier_nospec_fixup);
+
+ instr = 0x60000000; /* nop */
+
+ if (enable) {
+ pr_info("barrier-nospec: using ORI speculation barrier\n");
+ instr = 0x63ff0000; /* ori 31,31,0 speculation barrier */
+ }
+
+ for (i = 0; start < end; start++, i++) {
+ dest = (void *)start + *start;
+
+ pr_devel("patching dest %lx\n", (unsigned long)dest);
+ patch_instruction(dest, instr);
+ }
+
+ printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
+}
+
#endif /* CONFIG_PPC_BOOK3S_64 */
void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)