[PATCH RFC rebase 6/9] powerpc/64: Patch barrier_nospec in modules

[Michal Suchanek]

Note that unlike RFI which is patched only in kernel the nospec state
reflects settings at the time the module was loaded.

Iterating all modules and re-patching every time the settings change is
not implemented.

Based on lwsync patching.

Signed-off-by: Michal Suchanek <msucha...@suse.de>
---
 arch/powerpc/include/asm/setup.h  |  5 ++++-
 arch/powerpc/kernel/module.c      |  6 ++++++
 arch/powerpc/kernel/setup_64.c    |  4 ++--
 arch/powerpc/lib/feature-fixups.c | 17 ++++++++++++++---
 4 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/include/asm/setup.h b/arch/powerpc/include/asm/setup.h
index c7e9e66c2a38..92520d2483b8 100644
--- a/arch/powerpc/include/asm/setup.h
+++ b/arch/powerpc/include/asm/setup.h
@@ -58,7 +58,10 @@ enum spec_barrier_type {
 void setup_rfi_flush(enum l1d_flush_type, bool enable);
 void do_rfi_flush_fixups(enum l1d_flush_type types);
 void setup_barrier_nospec(enum spec_barrier_type, bool enable);
-void do_barrier_nospec_fixups(enum spec_barrier_type type);
+void do_barrier_nospec_fixups_kernel(enum spec_barrier_type type);
+void do_barrier_nospec_fixups(enum spec_barrier_type type,
+                             void *start, void *end);
+extern enum spec_barrier_type powerpc_barrier_nospec;
 
 #endif /* !__ASSEMBLY__ */
 
diff --git a/arch/powerpc/kernel/module.c b/arch/powerpc/kernel/module.c
index 3f7ba0f5bf29..7b6d0ec06a21 100644
--- a/arch/powerpc/kernel/module.c
+++ b/arch/powerpc/kernel/module.c
@@ -72,6 +72,12 @@ int module_finalize(const Elf_Ehdr *hdr,
                do_feature_fixups(powerpc_firmware_features,
                                  (void *)sect->sh_addr,
                                  (void *)sect->sh_addr + sect->sh_size);
+
+       sect = find_section(hdr, sechdrs, "__spec_barrier_fixup");
+       if (sect != NULL)
+               do_barrier_nospec_fixups(powerpc_barrier_nospec,
+                                 (void *)sect->sh_addr,
+                                 (void *)sect->sh_addr + sect->sh_size);
 #endif
 
        sect = find_section(hdr, sechdrs, "__lwsync_fixup");
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index 767240074cad..f60e0e3b5ad2 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -910,11 +910,11 @@ void barrier_nospec_enable(bool enable)
 
        if (enable) {
                powerpc_barrier_nospec = barrier_nospec_type;
-               do_barrier_nospec_fixups(powerpc_barrier_nospec);
+               do_barrier_nospec_fixups_kernel(powerpc_barrier_nospec);
                on_each_cpu(do_nothing, NULL, 1);
        } else {
                powerpc_barrier_nospec = SPEC_BARRIER_NONE;
-               do_barrier_nospec_fixups(powerpc_barrier_nospec);
+               do_barrier_nospec_fixups_kernel(powerpc_barrier_nospec);
        }
 }
 
diff --git a/arch/powerpc/lib/feature-fixups.c 
b/arch/powerpc/lib/feature-fixups.c
index dfeb7feeccef..a529ac6b2a5d 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -160,14 +160,15 @@ void do_rfi_flush_fixups(enum l1d_flush_type types)
                                                : "unknown");
 }
 
-void do_barrier_nospec_fixups(enum spec_barrier_type type)
+void do_barrier_nospec_fixups(enum spec_barrier_type type,
+                             void *fixup_start, void *fixup_end)
 {
        unsigned int instr, *dest;
        long *start, *end;
        int i;
 
-       start = PTRRELOC(&__start___spec_barrier_fixup),
-       end = PTRRELOC(&__stop___spec_barrier_fixup);
+       start = fixup_start;
+       end = fixup_end;
 
        instr = 0x60000000; /* nop */
 
@@ -186,6 +187,16 @@ void do_barrier_nospec_fixups(enum spec_barrier_type type)
        printk(KERN_DEBUG "barrier-nospec: patched %d locations\n", i);
 }
 
+void do_barrier_nospec_fixups_kernel(enum spec_barrier_type type)
+{
+       void *start, *end;
+
+       start = PTRRELOC(&__start___spec_barrier_fixup),
+       end = PTRRELOC(&__stop___spec_barrier_fixup);
+
+       do_barrier_nospec_fixups(type, start, end);
+}
+
 #endif /* CONFIG_PPC_BOOK3S_64 */
 
 void do_lwsync_fixups(unsigned long value, void *fixup_start, void *fixup_end)
-- 
2.13.6